Adansonia digitata L.) is a multipurpose, drought resistant, wild fruit tree, endemic to arid and semi-arid lands of Sub-Saharan Africa. Baobab populations have been showing a lack of regeneration, and therefore causes concern for the species survival. This study investigated the state, distribution and use of baobabs in an under-researched population in Kenya, to identify the potential for further use and development of baobab resources. A baobab population was chosen in Taita–Taveta County, covering a sample area of 2015 km2. A systematic stratified transect survey was done to map baobab distribution using 49 transects (0.5 × 3 km each). The diameter at breast height and other indicators were measured on all baobabs in the transects to assess population status and health. A household survey (n = 46) and focus group discussions (n = 12) were done following the transect survey to gain an idea on the uses and distribution of baobab. In total, 432 baobab trees were measured and recorded in the research area of 2015 km2. The baobabs grew in two clusters . Both clusters showed rejuvenating populations. The main factors identified by the respondents, positively and negatively influencing baobab distribution were environmental factors, wildlife, human impact and commercial value. The study area shows a great potential for baobab to become an important part of the diet, due to its current use as an emergency food during food scarce times, and the relatively healthy and stable rejuvenating populations.Baobab ( Adansonia digitata L.) is a multipurpose, drought resistant, wild fruit tree, that is often found in arid and semi-arid lands (such as savannahs) of Sub-Saharan Africa (SSA) (Sidibe and Williams Baobab (The high concentration of nutrients in the fruit pulp (mainly vitamin C and other micronutrients as well as antioxidants) has been recognized on an international level, triggering export from mainly western and southern Africa to the European Union (EU) and United States of America (USA). Baobab fruit pulp is marketed as a ‘superfood’  production, with two remaining working sisal estates, the plantations Taita and Voi  with a total size of 1125 km2 and included the area where the local population lived and practiced their income generating activities such as farming, representing the hypothesized medium level of disturbance. It also included savannah or wooded areas, accessed by the local population. The third stratum was Sisal plantations  (size 101 km2), which consisted of intensive, highly mechanized farming, and was assumed to be a highly disturbed baobab habitat. The urban areas of Voi, Wundanyi, Mwatate and Taveta were excluded from the strata formation and from the entire survey, due to a lack of trees within these locations , measuring tree height (m), noting the level of debarking based on the scale by Mpofu et al. , denotinDebarking is dangerous for baobab trees as it exposes the inner soft wood to the environment. The three biggest ‘debarkers’ in the research area were found to be elephants (who gauge open the bark to chew on the soft wood for water during drought)  were conducted separately in low-baobab density areas (four FGD locations) and high baobab density areas (four FDG locations). The villages where the FGDs were conducted, were selected randomly per density area (low-density area and high-density area) Fig. . A totalThe baobab distribution was first analyzed using the predefined land use types. Subsequently, due to their distribution patterns, the baobabs were divided into high-density areas and low-density areas, to allow for a better analysis. The high-density areas contained transects having a baobab density ≥ 0.08 baobabs/ha, and low-density areas with a density of <0.08 baobabs/ha, which was the overall mean baobab density found in the research area.From the CBH data collected from each of the baobab trees in the surveyed transects, the DBH was calculated. This was used to classify the baobabs into different size classes, and to estimate the count of baobab trees for each size class in the different land use areas  large baobabs, having a DBH ≥ 1 m and (2) small baobabs with a DBH < 1 m (Venter and Witkowski Size-class distribution (SCD) curves were calculated using the DBH, and used to analyse the age distribution. By plotting SCDs, the reproductive behaviour and age of the population stands can be compared. The SCDs were calculated after the methods of Condit et al.  and LykkIn order to understand the underlying reasons for the quantitatively measured baobab distribution, FGDs were conducted. The FGDs were first transcribed, then post-coded and combined with the household survey results. The post-coding used split respondent comments into separate categories such as, positive and negative views on baobab tree presence. The qualitative analysis was then split between the FGDs done in the low-density areas and high-density areas, as the context of different baobab population densities was bound to affect the answers given in the FGDs and the individual survey. A phenological calendar with regard to leaf emergence and fall, flower occurrence and fruit development and maturity seasons was produced as a result of the responses of the questionnaires. FGDs were then conducted to understand when the different phenological stages occur in comparison to rainy seasons and agricultural activities such as fruit harvesting. In addition, the events leading to baobab population change were analyzed after performing the occurrence game, by counting the bottle caps per field, and evaluating the importance and frequency of each event by the information given by the respondents. The types of use of baobab parts and the baobabs’ importance for local farmers were also evaluated and compared between the low-density areas and the high-density areas.The discussion will be structured using the data of both the quantitative and the qualitative methods to discuss the distribution and regenerative behaviour of the baobabs. Since the two data sets complement each other, they will not be separately labelled, but used together in the discussion.2. Of these 432 trees, only 2 were found in the land use system Sisal, 34 in the NP and 396 in the AAA  than large baobabs (n = 165). Regarding the three land use systems, a higher number of small than large baobabs were documented in the NP  and the AAA , while the Sisal only had two large baobabs, but no small ones  constituted normal seedlings or baobab juveniles, 21% were ‘stunted’ baobabs. These were characterized by a very broad base, wrinkled bark and strange, slightly sprawling thick branch-like outgrowths Fig. . In compThe mean density for all baobabs documented in the study was 0.06 baobabs/ha, however, with marked differences among the three studied land use systems and within transects of one land use system. The highest mean baobab density per land use system was 0.11 baobabs/ha in the AAA and the lowest 0.002 baobabs/ha in the Sisal , one being in Taita northwest of the town Voi (Taita cluster) and one in Taveta, just northeast and southeast of Taveta town (Taveta cluster) Fig. . These bWhile as many as 418 baobabs were found in the two high-density area clusters, only 14 baobabs were found in the whole low-density areas, which had an area twice as large as the high-density area Table . Betweenp = 0.13).The SCD of the two clusters in the high-density areas showed similar curves with a relatively high number of small baobabs and decreasing numbers of larger baobabs Fig. . A compaCommiphora species). It was not possible to see damage on the larger baobab trees as the ‘Noongala’ beetle reportedly attacks branches on the tops of trees, these being too far off the ground for observation. While the ‘Noongala’ beetle was mentioned during FGDs and signs found during the baobab inventory only in the high-density area, respondents in the low-density areas reported a serious pest problem regarding termites. Termites were described as a highly destructive force, which attack all trees in their vicinity.Out of the 432 trees documented in the 49 transects, 75 trees (17%) showed signs of debarking by humans, elephants, insects and unknown entities Fig. . Most ofThe most severe debarking was caused by elephants. However, the frequency of elephant damage (13 affected trees of the damaged 75 trees) was low and concentrated only in the NP and the directly surrounding areas.Not included in the above mentioned documented debarking damages was the hollowing out of the baobab stems by humans for storage facilities, which was mentioned during the FGDs and during the household survey. However, this activity is no longer practised and no baobab with such a stem damage was found during the survey. On the other hand, stakes were often found hammered into the tree’s trunk for makeshift ladders, which, according to the respondents, are used for easy fruit harvesting and as escape routes against attacking wildlife.Zea mays)) due to shading, nutrient uptake and high water use.In the high-density areas, 16 of the interviewed 22 farmers  reported to have baobab trees on their farm. Each farm had a mean of 2 ± 1 baobabs according to the respondents. The baobabs were most commonly located in the farm boundary or the homestead area and were almost unanimously owned by the household head. No baobab tree had actively been planted by the surveyed households, although unintentional ‘sowing’ by fruit consumption and disposal of seeds was not excluded. Respondents mentioned that there is no need to plant baobabs as they grow wild in large numbers. All respondents knew how young baobab seedlings look like, and 11 out of 22 reported to have young baobabs growing on their farm. Most of the respondents (58%) would accept young baobabs growing on their farmland, while 42% of the respondents stated they would remove such seedlings. No respondent had ever cut down a baobab tree, and all referred to a law or taboo as a reason, or to the fact that cutting down a baobab would bring no benefits (such as firewood) and is labour and cost intensive. The baobab was most often perceived by the respondents as having a negative effect on crops  claimed that they use the baobab trees that were not growing on their farms.According to the FGD in the two clusters of high-density areas, baobab flowers and leaves appeared at the same time, in September in Taita and in October in Taveta, which is around the end of the dry season and the beginning of the short rainy season  Fig. . FlowersFor the local communities, baobab does play an important role as an emergency coping mechanism in the area. The season when baobab fruits are consumed coincides with the hunger gap mentioned by the respondents of the household survey. The main baobab consumption period, which is similar to its harvest period, spans from May and goes up to September/October according to the respondents. The ‘hunger gap’ or time when the interviewed household has less food available, spans from May/June to November/December Fig. .In total 27 different uses of baobab were recorded during the 46 individual household surveys and the 12 FGDs. The respondents mentioned the use of six different tree parts including the baobab fruit pulp, leaves, bark, roots, shell of the fruit and wood. In both the individual interviews and the FGDs more uses were mentioned in the high-density areas than in the low-density areas. The knowledge of uses, especially when considering the low-density areas, seemed to be shared more often amongst women than men. However, out of the 27 different uses mentioned, food use was the only use of baobab still actively practiced by the respondents in the research area.The main reason given for consuming baobab fruit pulp during the household interviews differed. For some respondents it was its sweet taste (54% of the 46 respondents mentioning this) and the second most frequent reason was health (18%). Health benefits from baobab were described with comments such as: ‘It makes me feel like I have more blood’. Some respondents (13%) mentioned culture and tradition as reason for eating (‘because the grandparents ate it’) and 10% just the availability of trees in the vicinity. The mode of consumption differed between the surveyed areas. In high-density areas, most respondents reported to eat the raw pulp directly from the fruit, while in low-density areas, most respondents stated that they eat mabuyu sweets . During the household survey as well as the FGDs in the high-density areas, baobab was mentioned as being important as food during the dry season.Respondents claimed that baobab is a ‘poor man’s food’ and ‘food for children’. The main consumers of baobab were finally named as children, herders and pregnant women.In the high-density areas, participants of the FGDs stated that the baobab population is either increasing due to large numbers of small baobabs growing or at least staying the same due to the extremely slow growth of such young baobabs, while some large baobabs may die at the same time. In these areas of high baobab densities, both small and large baobabs were observed  and decreasing factor (browsing of young baobabs). Factors given by the participants that could negatively affect the baobab population in the high-density areas included construction and infrastructure—particularly related to the new Voi–Taveta highway that was being built in the area during the survey. Farming, agricultural expansion and population increase were also mentioned as decreasing factors as were climate change  and drought.During the six FGDs performed in the low-density areas, participants stated that the baobab populations in their area were either staying the same due to a lack of seedlings or decreasing as a result of the missing seedlings and the death of old trees. It was also mentioned that baobabs in the low-density areas often did not bear fruit and that the few fruits were of low quality . The FGD participants in the low-density areas agreed that only few seeds may germinate and that the seedlings do not survive the dry season.In the low-density areas, participants of the FGDs could not give any potential factor causing increasing baobab populations, but they described several factors that could be responsible for a decrease in baobab populations. Bush fires and browsing of small baobabs by livestock and wildlife were mentioned as the main decreasing factors, as well as human impact, mainly referring to the stakes hammered into the baobab trunks for easy climbing that may cause rotting and death of large baobabs according to the FGD participants. Similarly to the high-density areas, FGD participants in the low-density areas listed religion and beliefs in ‘djinnis’ as well as the law on protecting large trees as factors for decreasing baobab populations. The participants mentioned that farmers may remove any young baobab they find on their land before it can grow into a larger tree.FGD participants of both high-density areas and low-density areas described religion/traditional beliefs and law as both increasing and decreasing factors in the baobab population. The traditional beliefs state that there is a djinni or other form of spirit living inside the baobab trees. The presence of the djinni on the one hand preserves the baobab since—according to the participants—terrible things are said to happen if the baobab is cut down. On the other hand, the presence of the djinni is not wanted, therefore, increasing the incentive to remove young baobabs before they reach a certain size. The law was described by the FGD participants as protecting trees after they have reached a certain height, after which removal is forbidden, thus enforcing the removal of baobab seedlings from farmland.The fact that few baobabs were found in the land use type ‘Sisal’ holds true to the initial hypothesis that due to mechanization and intensive mono-cropping in the ‘Sisal’ MEMR , baobabsIn contrast to the NP, the AAA had more baobabs than expected in the present study, despite its high levels of anthropogenic disturbance. The AAA also showed a high variance in its baobab densities as it contains both high-density areas and low-density areas. More baobabs in the AAA could be attributed to a higher number of seed dispersers, such as humans, who consume baobab. Duvall  stated tThe baobabs in the surveyed area formed two distinct clusters at either end of the sample area. The tendency of baobabs to form clusters, or to be present in high and low densities within a confined area, was also reported from other countries such as Malawi and Mali . Respondents mentioned that the baobabs in the area continuously produced few to no fruits, therefore also severely reducing the number of seeds for dispersal. In addition, respondents mentioned that the fruits produced in the low-density areas had a bad taste, and were bitter and hard, therefore reducing their consumption. Due to the low consumption and fruit production, the seeds were never dispersed very far from the tree where they originated, leading to a very local seed dispersal, explaining the cluster formation. Seed viability in the soil seedbank would also decrease with time and predation Venter . Why fruHeterogeneity of landscapes has been observed as conserving many different plant species and species richness in general . It is not clear if the stunted growth of small baobabs in Taveta has a negative effect on the population health of baobabs in this area. The reason for the stunting of baobabs is not clear. The local Maasai respondents attributed the stunting to damage caused by a rose beetle-like insect called ‘Noongala’. Possible candidates that could be harming the baobab trees are the longhorn beetle species ms. Fig. , both knms. Fig. . Similarms. Fig. , b. HoweThe stunting of baobabs could also be attributed to the high numbers of livestock reared by the local Maasai people in the area. A similar damage of baobabs was described by Dhillion and Gustad  and VentActivities such as leaf harvest, bark harvest and intensive fruit harvest can also result in negative effects on baobab populations , some fruits remain on the tree (Jäckering et al. Baobab was an important food source for the most vulnerable members of studied rural communities, but was at the same time perceived as ‘poor man’s food’. Due to their naturally dry fruit pulp, undamaged baobab fruits can be stored for several months and can therefore be used whenever needed for home consumption or sale in emergency situations. The seasonal phenological patterns documented in the FGDs in Taita–Taveta differ slightly from those produced by Maundu  in KibweThe leaves also have the potential to be a highly nutritious and healthy food for humans, due to their high micronutrient content (Chadare et al. Many areas of SSA have reported ageing baobab populations with a lack of rejuvenation. These findings coupled with the possibilities of a growing export market for baobab fruit pulp have generated concern over the long-term stability of baobab populations in SSA. In Taita–Taveta County, we documented rejuvenating baobab populations in two areas with high baobab densities, but also large areas in between with low densities and no regeneration. The patterns in baobab distribution were attributed to environmental factors, wildlife interactions and human impact. Almost all small baobabs in one of the high-density areas were stunted, seemingly due to high livestock pressure and damage by a tree girdling longhorn beetle. This could have consequences for the long-term stability of the population. In the research area, baobab serves as an important emergency food during the ‘hunger gap’ period. However, baobab food products were mainly perceived as poor man’s food and as food for children. Use levels of baobab were therefore rather low and local communities mainly used raw or slightly processed fruit pulp while many of the traditional further uses were forgotten.The generally healthy status of the baobab populations with high numbers of small baobabs and good recruitment rates in parts of the research area together with the detected rather low level of use of baobab products lead to the conclusion that this resource could be used in a more intensive way. Such a sustainable intensification of baobab resource use could also be a measure to conserve plant genetic resources. In low-baobab density areas, planting and actively managing baobabs should be supported if communities want to benefit from the nutrient-rich products and to participate in the baobab business. In the areas with high densities, baobab has already shown a certain potential for improving local livelihoods in Taita–Taveta County. It is ripe during the food scarce time and could provide the local community with nutritious foods and additional income. However, awareness of communities should be raised on additional nutritious food products of baobab such as leaves. If economically viable and marketable in the larger region, forgotten traditional and innovative new processed food products such as baobab juice, soda, yoghurt or ice cream could also be promoted.Intensification of baobab utilization in Taita–Taveta, has to be done with care. Baobab pulp is currently being used within the local community, particularly by children and may contribute substantially to their nutrition, particularly during the lean season. Therefore, it would be prudent to focus most attention on creating a local demand and encouraging the use of baobab on a local scale prior to entering larger or even export markets. It would also be advisable to integrate the traditional resource management techniques and traditional values into future programmes on increased production and marketing of baobab products. In the long run, only domestication and cultivation of improved baobab cultivars may be able to deliver the required qualities and quantities for both domestic and export baobab fruit pulp markets.Supplementary Material


Initial genetic alterations in the development of childhood leukemia occur in utero or before conception; both genetic and environmental factors are suspected to play a role. We aimed to investigate the associations between childhood leukemia and perinatal characteristics including birth order, birth interval to older siblings, parental age, birth weight, and multiple birth.We identified cases diagnosed between 1981 and 2015 and born in Switzerland between 1969 and 2015 from the Swiss Childhood Cancer Registry and randomly sampled five controls per case from national birth records matched on date of birth, sex, and municipality of residence at birth. We used conditional logistic regression to investigate associations between perinatal characteristics and leukemia at ages 0–15 and 0–4 years, and the subtypes acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML).The study included 1,403 cases of leukemia. We observed increased risks associated with high birth weight  and multiple birth . These associations were similar for ALL and stronger for leukemia at ages 0–4 years. For AML, we observed an increased risk for higher birth order . We found no associations with other perinatal characteristics.This register-based case–control study adds to the existing evidence of a positive association between high birth weight and risk of childhood leukemia. Furthermore, it suggests children from multiple births are at an increased risk of leukemia.The online version contains supplementary material available at 10.1007/s10552-021-01423-3. Both genetic and environmental factors are suspected to play a role in the etiology of childhood leukemia , 2. EstaIn view of a possible early origin of childhood leukemia, many studies have investigated associations between perinatal characteristics and later development of disease. A number of studies found decreased risks of acute lymphoblastic leukemia (ALL) for children with older siblings, supporting the hypothesis that increased exposure to infections may be protective –19. HoweWe aimed to investigate the associations between childhood leukemia and perinatal characteristics in a nationwide register-based case–control study in Switzerland. We hypothesized that leukemia risk would be positively associated with higher maternal and paternal age, and negatively associated with higher birth order and a shorter birth interval to the next older sibling. In contrast to an earlier Swiss study of birth characteristics and childhood leukemia, which was based on partially overlapping data , this stWe identified all primary diagnoses of leukemia registered in the Swiss Childhood Cancer Registry (SCCR) between 1981 and 2015 in children who were aged 0–15 years at diagnosis and had been born in Switzerland between 1969 and 2015. The SCCR is a nation-wide population-based cancer registry recording cancers in children and adolescents since 1976. It includes an estimated 91% of all diagnoses since the late 1980s, and an estimated 95% since the mid-1990s . We usedWe randomly sampled five controls (birth records not linked to a cancer case) per case without replacement, matched on date of birth (± 6 months), sex, and municipality of residence of the mother at birth. We matched on municipality to reduce potential confounding by spatially varying risk factors. In some small municipalities, the number of eligible controls was smaller than five, in which case we selected controls from adjacent municipalities (first-order neighbors). This occurred for 3.0% of all controls.We separately investigated the following outcomes based on the International Classification of Childhood Cancers, Third Edition (ICCC-3) : leukemiWe investigated associations with the following perinatal characteristics: birth order in the sequence of live births by the same mother , birth interval to the next older sibling , age of the mother and of the father at date of birth , birth weight , multiple birth (singleton or multiple birth), and nationality of the mother (Swiss or other). We calculated pairwise Spearman’s rank correlations between the included birth characteristics.We extracted all data on perinatal characteristics for both cases and controls from their birth records. In Swiss birth records, birth order and date of birth of the last previous birth are recorded only for births by married mothers, which accounted for 90.7% of total births between 1969 and 2015. Parental age and birth interval to the next older sibling were calculated as completed life years at the index child’s date of birth. Paternal age and the date of birth of the last previous birth were recorded only since 1979, and between 1979 and 1986 only year of birth instead of date of birth was recorded for mothers and fathers. For these years, we randomly attributed a specific date of the year of birth to calculate parental age. For multiple births, birth order was recorded in the order of actual births, i.e., in twins the later born is one rank higher than the earlier born. The birth interval to the next older sibling though was set to be the same for every child of a multiple birth and calculated as for a singleton birth, i.e., the number of years since the last previous birth if a woman had already given birth before and 0 otherwise.We used conditional logistic regression to investigate associations between leukemia, ALL, and AML and perinatal characteristics conditioning on the matched case–control sets. We fitted univariable models for every perinatal characteristic separately and multivariable models including all characteristics simultaneously to obtain crude and adjusted odds-ratios (OR) and 95% confidence intervals (CI). Likelihood ratio tests were performed to compare models with and without a given perinatal characteristic.For leukemia and ALL we tested for possible interactions between pairs of perinatal characteristics that have recently been reported in the literature using likelihood ratio tests. Specifically, we tested for interactions between birth order (dichotomized first-born vs. later-born) and age of the father as well as between birth order and birth weight . We alsoIn sensitivity analyses, we (i) included only one (randomly sampled) twin from every twin pair of children with concordant leukemia; and (ii) excluded case–control sets of cases with trisomy 21.All statistical analyses were performed using the R language for statistical computing version 3.6.0  and STATWe identified 1,623 children diagnosed with leukemia at age 0–15 years during 1981–2015 and born in Switzerland between 1969 and 2015. Of these, 225 (14%) could not be linked with a birth record, leaving 1,403 cases for analysis. Among the included cases, 1,144 (82%) were diagnosed with ALL and 179 (13%) with AML , the estimated risk was lowest for the youngest age category   (Table Results for ALL at 0–15 years Table  and leukp LR test = 0.04 in the adjusted model)  (Table p LR test = 0.049) and leukemia under 5 years of age (p LR test = 0.073) but not for leukemia overall (p LR test = 0.20) (Tables S3–S5). Estimated interaction terms indicted that, among children with high or low birth weight, those born second or later had lower risks compared to first-borns (Tables S3–S5). By contrast, we found no evidence of an interaction between birth order and age of the father for any of the three outcomes .Testing for interactions between perinatal characteristics, we found weak evidence of an interaction between birth order (dichotomized first-born vs. later-born) and birth weight in the adjusted models for ALL diagnosed at 0–15 years  reduced the estimated OR of leukemia for mothers of the age group ≥ 40 years  but left other estimates unchanged (Table S7). Following the suggestion of a reviewer, we repeated the main analyses excluding case–control sets of cases from multiple births. Results from these analyses were very similar to the main analysis (Tables S8–S11).In sensitivity analyses, we included only one twin from each of the four twin pairs with concordant diagnoses of leukemia we identified in the SCCR. In this analysis, the odds ratio for being part of a multiple birth was slightly reduced compared to the main analysis  but the other results remained similar (Table S6). Excluding cases with trisomy 21  and children from multiple births. These associations were similar for ALL and stronger for children diagnosed under the age of 5 years. For AML, there was little evidence for associations with birth weight and multiple births, although including birth weight as a 7-level categorical variable (septiles) was suggestive of a non-linear association, which by visual inspection is compatible with a U-shape Fig. . HoweverOur findings are compatible with the results of our previous study  using paOur current findings on birth weight concur with the literature that has established high birth weight as a risk factor for several childhood cancers including leukemia. Several pooled and meta-analyses have observed a linear trend between birth weight and childhood leukemia or ALL, or both –32, 41. Regarding the association between parental age and ALL, our findings are compatible with the results of a meta-analysis of 77 studies  and a reHigher birth order was found to be associated with reduced risk of ALL in a number of studies –18, 24. This is the first study to report evidence of an increased risk of childhood leukemia and ALL in children from multiple births. While a number of studies of perinatal characteristics have included multiple birth as a covariate in multivariate models, no large cohort or case–control study has reported evidence of any association with childhood leukemia , 25, 48.Because we identified cases from a population-based cancer registry of high coverage and sampled controls from national birth records, the risk of selection bias in our study is limited. Information on birth characteristics was obtained from the same source, namely the birth records, for cases and controls at the time of birth, suggesting that our study is free of recall bias or differential misclassification. We were able to include leukemia cases diagnosed during a period of over three decades, allowing us to achieve a sample size that is comparable with the most recent European case–control or cohort studies. Matching by date of birth and municipality of residence of the mother at time of birth should have reduced the potential risk of confounding by spatial or temporal variation in environmental risk factors, such as traffic-related air-pollution , 49, bacProbabilistic record linkage of cases with their birth records may have resulted in some misclassifications of the outcomes. However, this risk appears small as the outcomes considered are rare and the linkage led to non-ambiguous matches in the overwhelming majority of cases. A considerable proportion of children had missing data for birth order (10%), birth interval to the next older sibling (13%), and age of the father (11%) and excluding these children may have introduced some selection bias if data were not missing at random . This riIt is unclear what might explain the observed association between multiple birth and childhood leukemia in our study. Newborns from multiple births typically have lower birth weight. Early studies reporting a reduced risk were often small and did not (consistently) control for birth weight (reviewed in ). AnotheRegarding other perinatal characteristics our investigation was either compatible  with or provided further support (birth weight) for expected associations , 33. MorOur results add to the existing evidence that high birth weight is associated with an increased risk of childhood leukemia. Furthermore, our study is the first to report evidence suggesting that children from multiple births are at increased risk for developing leukemia overall and ALL specifically.Supplementary file1 (PDF 282 kb)Below is the link to the electronic supplementary material.


Electrophorus electricus and many other weakly electric species. These fish possess specialised electric organs that are able to release electric discharges into the water, for electrolocation and communication, and sometimes for predation and defence. All Gymnotiform species possess a myogenic electric organ (mEO) derived from the muscle tissue, and members of the Apteronotidae family uniquely possess a neurogenic electric organ (nEOs) derived from the nervous tissue. A mEO may consist of ‘Type A’ electrocytes that develop within the tail muscle , or ‘Type B’ electrocytes that develop below the tail muscle . In this review, we discuss the diversity in the anatomy, electric discharge and development of electric organs found in different Gymnotiform species, as well as the ecological and environmental factors that have likely contributed to this diversity. We then describe various hypotheses regarding the evolution of electric organs, and discuss the potential evolutionary origin of the nEO: a pair of nerve cords that are located on either side of the aorta in B. gauderio, and which may have expanded and developed into a nEO in the Apteronotidae family during its evolution from a common ancestral species. Finally, we compare potential Gymnotiform phylogenies and their supporting evidence.The Gymnotiformes, also known as the South American or Neotropical knifefishes, include the strongly electric  Electric fish are unique models for studying the evolution of both electric and sensory organs. Numerous different linages have evolved these organs independently; the taxonomic diversity of electric fish is so profound, in fact, that Darwin specifically named them as an important example of convergent evolution . AmongstElectrophorus electricus—a member of the Gymnotidae group) or weakly electric (the vast majority of species) [Like other electric fish, the Gymnotiformes can be categorised as either strongly electric  . Weakly species) , 8, 44. species) .As with all electric fish, the Gymnotiformes are able to generate electric discharges through the use of a specialised electric organ . Most spIn this review, we set out what is known about both the mEO and the nEO in the Gymnotiformes, in terms of anatomy, electric discharge and development. We then consider the ecological factors that have shaped their evolution, examine a wide range of theories regarding how they have evolved, and finally, discuss potential Gymnotiform phylogenies and their supporting evidence.It is worth noting some additional concepts that come into play . In addition to producing electric discharges, electric fish must be able to sense them, which they do through electroreceptors that are distributed over their skin , 37. EacThe majority of electric fish possess a mEO derived from the muscle tissue , 31. SinBrachyhypopomus gauderio [E. electricus [E. electricus is unique in that adults possess three electric organs instead of one: a main organ, a Sach’s organ, and a Hunter’s organ [In the Gymnotiformes, the mEO is a long structure running throughout the tail, spanning the majority of the length of the body . It is cgauderio , and othectricus ; these f’s organ , 57. The’s organ . The mai’s organ .Eigenmannia virescens, Sternopygus macrurus and the Tbrown ghost knifefish, Apteronotus leptorhynchus. ‘Type B’ electrocytes originate from a distinct germinative zone located below the tail muscle [E. electricus, B. gauderio, Brachyhypopomus pinnicaudatus, and various Gymnotus and Rhamphichthys species [B. gauderio, which are extraordinarily large compared with other cells such as myocytes [S. macrurus and E. virescens, cuboidal in Bracyhypopomus and Gymnotus species, and flattened in E. electricus [Two types of myogenic electrocyte have been identified in the Gymnotiformes. ‘Type A’ electrocytes originate from within the tail muscle, between muscle fibres . These hl muscle . These h species , 31, 45.myocytes , 45, altectricus .Since myogenic electrocytes are specialised for membrane excitability rather than contraction (which is explained further below), they have increased levels of proteins involved in the former and are deficient in proteins involved in the latter, when compared to the muscle fibres from which they are derived . HoweverE. electricus is able to produce both a strong discharge thanks to the main organ and a weak discharge thanks to the Hunter’s and Sach’s organs [E. electricus, Gymnotus cylindricus, various Eigenmannia species and a small Brachyhypopomus species) still possess monophasic discharges as adults [Brachyhypopomus species, Gymnotus species and members of the Rhamphichthyidae family have a biphasic adult discharge [The Gymnotiformes are generally weakly electric, although s organs , 38. Thes adults , 38, 46.ischarge , 38, 46.E. electricus [The electric discharge from the mEO represents the summated activity of many electrocytes, synchronously transforming action potentials into external signals . This prectricus . The eleectricus . This biectricus . The movectricus , 36, 58.ectricus , 19, 26.ectricus . This cuectricus .Though the process described above is largely conserved among electric fish species possessing a mEO, it can vary slightly to produce different discharge shapes , 44. ForA. leptorhynchus and E. virescens are unique in that they initially develop a larval organ, which produces an electric discharge for a short period before degenerating and being replaced by a second electric organ in a separate location at the adult stage. In E. virescens, this adult electric organ is another mEO, but in A. leptorhynchus it is a nEO. On the contrary, S. macrurus produces only a single mEO during development. In E. virescens and S. macrurus, the adult mEO continues to grow longitudinally along the tail until it reaches its full extension [In Gymnotiformes possessing Type A electrocytes, the mEO develops within the tail muscle : A. leptxtension .E. electricus is unique in that this germinative region continues to give rise to new rows of electrocytes for a relatively long time, presumably in order to produce all three of the electric organs [B. gauderio [E. electricus, in which it was termed the ‘electromatrix’ [B. gauderio primordium, and results in a similar layered pattern in the newly formed mEO, suggests that a mEO primordium is conserved among B. gauderio, E. electricus and other Gymnotiformes that possess Type B electrocytes [In Gymnotiformes possessing Type B electrocytes, the mEO develops beneath the tail muscle . Developc organs . The earc organs . We recegauderio . We foungauderio . This deomatrix’ . The factrocytes .Fig. 1A S. macrurus, mature muscle fibres fuse with one another before transdifferentiating into electrocytes (in part by disassembling their myofibrils) [S. macrurus [An area of mEO development that is vital to consider is the origin of the electrocytes, and there are multiple contrasting hypotheses concerning how they arise. This has been studied in the Gymnotiformes through the process of regeneration—observations following adult tail amputation have described the regeneration of numerous tissue types, including the mEO , 53, 55.fibrils) , 61. Furfibrils) , 55. Thifibrils) , 45. Thomacrurus , 61, it leptorhynchus.Instead of a mEO derived from the muscle tissue, members of the Gymnotiform family Apteronotidae possess a nEO derived from the nervous tissue , 51, 54.Like the mEO in other Gymnotiformes, the nEO in members of the Apteronotidae family is located in the tail region, and spans the majority of the length of the body . It consThe electrocytes of the nEO are the modified axons of spinal motor neurons, and comprise the entire organ with the exception of associated connective tissue and blood vessels . While tE. electricus, are weakly electric [Members of the Apteronotidae family, like all Gymnotiformes except electric . While telectric .As is the case for the mEO, the electric discharge from the nEO represents the summated activity of many electrocytes, which synchronously transform action potentials into external signals. Physiological data indicate that within the electrocytes described above, current propagates along the anteriorly running regions to generate an initial head-positive phase, and the posteriorly running regions to generate a second head-negative phase. Within these regions, it is likely that the typical nodes of Ranvier are active and generate spikes of current, whereas the unusual nodes are inactive and instead act as capacitors (which they are able to do thanks to an extraordinarily large membrane surface area) . HoweverA. leptorhynchus. The development of the electric organ in this species is complicated, with regard to both anatomy and physiology [Most developmental data concerning the nEO relate to ysiology . As mentysiology . By the ysiology . Interesysiology , 51, 54.After examining what is known about the anatomy, electric discharge and development of the mEO and the nEO within the Gymnotiformes, it is important to consider the ecological factors that are likely to have influenced them, and how they may have evolved.As seen in a variety of animal species, the ecological factors in the living environments of Gymnotiform species would have exerted selection pressures, which led to the evolution of electric organs with traits that enhanced their main functions: electrolocation, electrocommunication, prey incapacitation and predation avoidance , 44. EviE. electricus can readily detect low-frequency discharge components from weakly electric fish [There is considerable evidence to support the role of predation pressure in shaping electric organ evolution. It has been shown that electroreceptive predators such as ric fish , making ric fish . By exteric fish –48.E. electricus and catfish species [The presence and characteristics of an electric organ often reflects the lifestyle of the fish possessing it. For example, the nocturnal lifestyle of some species is likely to have led to the preferred use of an electric organ over eyes for navigating the environment and communicating with other individuals. Evidence for this can be seen in all Gymnotiform species: in the eye, both the retina and the lens are smaller than they are in most other fish, which is consistent with its reliance on electrolocation and electrocommunication . General species , 48, 56.B. gauderio, as the night-time enhancement in discharge duration, amplitude and frequency is increased in the presence of other, competing males, and decreased after a few days of social isolation [Electric organs are hypothesised to play a vital role in reproductive fitness, and evidence for this can be seen in the sexual dimorphism and short-term plasticity of discharge characteristics in the Gymnotiformes , 35, 44.solation . Similarsolation .All animals are subject to the selection pressures exerted by the physical environment that makes up their habitat. For example, waters that are well-oxygenated and fast-flowing  are dominated by the Gymnotiform species with the highest baseline discharge frequencies , 11. It B. gauderio is a good strategy for reducing energy expenditure when foraging and reproduction-related activities are not required [E. virescens and A. leptorhychus exhibit a decreased in discharge amplitude , demonstrating the use of discharge plasticity for the reallocation of energy from producing the discharge to meeting metabolic demands [Since the action potentials generated by the electrocytes are considerably large relative to those generated by typical neurons, it is reasonable to assume that the production of an electric discharge would be energetically costly . The dayrequired . A limitrequired . This parequired , 21, 42,required . When ex demands .It has been identified that the first essential step in the process of electric organ evolution must have been the possession of electroreceptors able to sense electric stimuli , 33. IndScn4aa [Scn4a paralogs that are expressed in the muscle: Scn4aa and Scn4ab [Scn4aa was convergently lost from the muscle but retained in the mEO, before directly contributing to the constructive evolution of the mEO [Scn4aa expression was altered during the origin of the mEO; (b) Scn4aa was subjected to extensive positive selection during or immediately after this origin, and (c) this positive selection did not apply to Scn4ab, the paralog that remains expressed in muscle [Studies have investigated the genomic basis of convergent electric organ evolution—specifically that of the mEO in the Gymnotiformes, the Mormyridae and the Malapteruridae . DespiteScn4aa , 16. DueScn4aa , non-eled Scn4ab . These cd Scn4ab . Studies the mEO . The latn muscle .A. leptorhynchus (and presumably other members of the Apteronotidae family), a mEO containing Type A electrocytes seems to have been replaced during evolution by a nEO in a more medial part of the body [It has been theorised that, in terms of the mEO in the gymnotiformes, Type A electrocytes represent the plesiomorphic condition, which largely stems from the fact that their shape very much resembles that of muscle fibres, which is not the case for Type B electrocytes . This imthe body .A. leptorhynchus—specifically, the same frequency [It has been known that the nEOs in the Apteronotidae species are branched out from the spinal cord motor neurons therefore it has been thought that expansion of such neuron has formed the nEO in these species , 51, 54.requency .B. gauderio: in addition to a mEO, we found a pair of pear-shaped nerve cords (PSNCs) located on either side of the dorsal aorta, with a very similar shape and position to that of the nEO in larval A. leptorhynchus [B. gauderio [B. gauderio, which may preserve the form of an early Gymnotiform, and in both species, the PSNCs could encompass the motor neurons that regulate the mEO, and during the subsequent evolution of the Apteronotidae lineage, they may have developed and grown large enough to produce a discharge themselves and become a functional nEO, replacing the mEO. During this process, the PSNC-like tissue would have likely undergone a massive expansion as a result of genetic changes, involving both hypertrophy (an increase in cell size) and hyperplasia (an increase in cell number). Were this to be true, the ancestral form of the PSNCs observed in B. gauderio could be considered the evolutionary origin of the nEO in the Apteronotidae family.We have recently obtained further supportive evidence from rhynchus  18). Th8. ThB. gB. gauderio that possesses mEO and PSNC. In one branch containing the majority of other Gymnotiformes, these PSNCs could have then remained or diminished to leave only a mEO. In another branch containing only the Apteronotidae family, the PSNCs could have instead differentiated to become a fully functional nEO, replacing the mEO which diminished.This hypothesis provides an evolutionary perspective of the Gymnotiformes: the diversification of the mEO and the nEO may have stemmed from an evolutionary branching point in an ancestral species. This species could be an ancestor of B. gauderio should be further investigated, in order to determine their connection to both the spine and the mEO, and subsequently the extent to which they regulate the mEO. Other species—both other Gymnotiformes and more distantly related species (electric and non-electric)—should also be looked at to determine whether or not they, too, possess PSNCs.To determine the validity of the theory proposed here, a number of steps need to be taken. The PSNCs in There are various hypotheses addressing the phylogenetic relationships between different Gymnotiformes , 51. As E. electricus, a member of the Gymnotidae group, and B. gauderio, a member of the Rhamphichthyoidea group [B. gauderio represent the evolutionary origin of the nEO in the Apteronotidae family [As can be seen in Fig. ea group , 45. Cone family  favours Gymnotus carapo possesses primarily Type B electrocytes, a small number with partial similarities to Type A electrocytes can be found within the tail muscle [E. virescens at the larval stage, at a later stage the mEO develops below the tail muscle, in a position similar to that of a typical mEO consisting of Type B electrocytes [Many theories concerning Gymnotiform evolution are based solely or primarily on morphological traits. Such evidence can be misleading, as morphological traits are often more complex than the categorisation they are given, and similarities can arise through convergent evolution. For example, although Type A and Type B myogenic electrocytes tend to be morphologically and developmentally distinct, more complicated cases are seen in some species , as illul muscle . Additiotrocytes . To avoiIn this review, we have discussed what is currently known about the myogenic and neurogenic electric organs of the Gymnotiformes, using numerous example species to demonstrate the diversity present. This diversity is likely due to the combined adaptive responses of Gymnotiform fish to ecological factors such as predation pressure, lifestyle requirements, reproductive competition, habitat characteristics and energetic demands. Numerous theories concerning when and how electric organs evolved have already been proposed, and we make a suggestion that the nEO evolved from a pair of nerve cords that originally functioned to regulate the mEO. Further investigations using conventional methods of studying anatomy and physiology, combined with recent advancements in whole genome research and ‘omics’ technologies, would allow us to further clarify the evolutionary history of electric organs in Gymnotiformes, and other lineages of electric fish.


The vallecular cyst is a rare cause of stridor, respiratory distress, and failure to thrive in infants. Large vallecular cysts may present with serious complications such as life-threatening airway obstruction. This report is of an infant who presented with stridor and failure to thrive. The patient’s condition was diagnosed as the presence of a vallecular cyst using flexible laryngoscopy. The vallecular cyst was successfully managed using endoscopic marsupialization. After the procedure, the patient was asymptomatic and dramatically gained weight within a few months. This case report serves as a reminder for clinicians to consider vallecular cysts as a differential diagnosis of stridor and failure to thrive in infants. It also emphasizes that early diagnosis and management lead to favorable clinical outcomes. Vallecular cysts are rare, representing 10.5-20.1% of all congenital laryngeal cysts . ClinicaHerein, we present a case of vallecular cyst in an infant who presented with stridor and failure to thrive; the patient’s condition markedly improved, and no complications occurred owing to the appropriate diagnostic procedure and treatment approach. We emphasize the importance of considering a vallecular cyst as a differential diagnosis for stridor and failure to thrive in infants and highlight that prompt diagnosis and proper management of vallecular cysts lead to favorable clinical outcomes.A three-month-old male infant presented with stridor and failure to thrive. He was delivered vaginally at full-term (birth weight 3.5 kg) and had an uncomplicated neonatal course. His parents reported that he had noisy and difficult breathing a few days after birth, which worsened over time and was associated with episodes of cyanosis and poor bottle feeding. A general pediatrician saw him at one month of age for stridor and poor weight gain, assumed a diagnosis of laryngomalacia, and advised the parents to increase the frequency of his feed. After that, his parents sought medical advice several times, including emergency department visits for significant respiratory distress, increasing stridor, and failure to thrive. He was then referred to our neurology clinic to assess hypotonia. No workup was performed, and he was not hospitalized before the referral. Physical examination revealed inspiratory stridor, suprasternal and subcostal retractions, tachypnea, and bilaterally reduced air entry. His oxygen saturation, which was 93% in room air, and improved slightly after oxygen supplementation. His weight at presentation was 4.2 kg, falling below the 3rd percentile of the WHO growth chart. No dysmorphic features were present.Chest X-ray and regular laboratory test findings were normal, including serum electrolytes, complete blood counts, renal and liver functions, thyroid hormone levels, and blood gas analysis. The patient was taken to the operating room for an airway assessment based on the above findings. The patient underwent flexible laryngoscopy, which revealed a cystic mass measuring approximately 2 x 3 cm in size, arising from the lingual surface of the epiglottis and significantly occluding the laryngeal inlet Figure .Direct laryngoscopy and bronchoscopy under general anesthesia were promptly performed to evaluate the extent of the cystic lesion. The vocal cords, subglottic area, and trachea were observed to be normal. A thyroglossal cyst and retention cyst were initially considered as the differential diagnoses. However, based on clinical, endoscopic, and later histological findings, a vallecular cyst was established as the final diagnosis.Microlaryngoscopic marsupialization was performed by the ENT surgeon to remove the cyst, which drained serous fluid. A biopsy of the cyst wall revealed the presence of connective tissue covered with non-keratinizing squamous epithelium with vascular congestion and chronic inflammation, suggestive of a vallecular cyst.Postoperatively, the patient was feeding well and showed a complete resolution of his symptoms. He remained asymptomatic at the follow-up visits at four and seven months. He quickly gained weight within a few months, reaching 5.5 kg at four months and 8.4 kg at seven months of age, indicating that the child’s weight had increased from below the 3rd percentile to the 50th percentile.The vallecular cyst is a rare cystic lesion but a well-recognized cause of stridor, respiratory distress, and failure to thrive in infants due to obstruction at the laryngeal inlet -3. ValleVallecular cysts contain serous fluid and are usually less than 1 cm; however, further expansion may occur with mucus production . InfantsThe most serious complication is respiratory failure or death due to an upper airway obstruction, which is more likely to occur when the cyst is large and close to the laryngeal inlet -6.Anomalies that may complicate the clinical course of vallecular cysts include laryngomalacia and gastroesophageal reflux disease (GERD), which have been reported in 17% and 67% of cases, respectively ,10. HoweDiagnosis of vallecular cysts demands a high level of clinical suspicion. When a vallecular cyst is suspected in infancy, a lateral radiograph of the neck may show an alteration of the airway contour. However, Suzuki et al., in their series of VC cases, found that lateral neck X-ray did not contribute to the diagnosis in 15 of the 39 VC cases . These fThe definitive diagnosis is made by directly visualizing the vallecular cyst using fiberoptic nasal endoscopy, as was performed in our case, or with rigid laryngoscopy/bronchoscopy -11. Comp2 laser, cauterization, or coblation [Treatment options include complete endoscopic excision, marsupialization, or aspiration. Marsupialization is the preferred treatment modality and may be performed using micro-laryngeal instruments, a COoblation . Coblatioblation . The recoblation ; Suzuki oblation . Cyst asoblation . Our patSmall vallecular cysts of less than 1 cm may cause mild symptoms while larger ones may cause life-threatening airway obstruction. Physicians should consider a vallecular cyst as a differential diagnosis of stridor and failure to thrive in infants. Early identification and removal of a vallecular cyst result in its definitive cure and may prevent its associated serious consequences.


Background: In 2017, there were 295,000 maternal deaths worldwide from preventable causes related to birth. The leading cause of maternal mortality is obstetric hemorrhage. In Saudi Arabia, a paucity of evidence about incidences of atonic Postpartum Hemorrhage (PPH) and related risk factors exists. Therefore, aims were to (a) identify incidences of atonic PPH from 2015 to 2018 (b) determine risk factors of atonic PPH in vaginal birth. Methods: Retrospective chart review with purposive sampling conducted revealed 386 charts, 220 (57%) vaginal birth and 166 (43%) caesarian section (CS). Logistic regression analysis was used. Results: Incidences of atonic PPH were 2.5% from 2015 to 2017, with the rate increasing by 12% from 2017 to 2018. In vaginal birth, significant associations between the severity of blood loss with epidural , episiotomy , induction of labor (IOL) , and Interaction between IOL, AUG, and epidural  found. Discussion: Increasing rate of atonic PPH confirmed. Epidural, episiotomy, induction of labor, and induction with augmentation are factors associated with severe atonic PPH in vaginal birth. An estimated 295,000 maternal deaths occurred worldwide in 2017, with 211 maternal deaths per 100,000 live births. The lifetime risk of maternal mortality is estimated at one in 190 births, the deaths in low-resource countries being 40 times higher than developed countries [The leading cause of MM is obstetric hemorrhage . ObstetrPPH is traditionally defined as blood loss greater than 500 mL in vaginal birth and greater than 1000 mL in caesarian section (CS) birth ,8. PrimaThe associated risk factors of the primary atonic PPH are the following: multiple pregnancy, obesity (BMI > 30), advanced maternal age, first birth (nulliparity), history of PPH, and anemia. Risk factors related to pregnancy and the birthing process include gestational age, instrumental delivery, induction and augmentation of labor, prolonged labor (12 to <24 h), uterotonic use, macrosomia (large newborns), laceration, delivery by CS, and vaginal birth after CS ,13.WHO reports feature general statistics about trends in obstetric hemorrhage without concise information about incidences of PPH, causes, and the risk factors in each country. This offers a vital opportunity for researchers to investigate the incidences and causes of PPH in their populations. In Saudi Arabia, there is a paucity of evidence regarding incidences of the primary atonic PPH and its related risk factors. Therefore, the aim of this study is to (a) identify incidences of atonic PPH from 2012 to 2018 at a tertiary hospital in Jeddah, Saudi Arabia, and (b) determine the association of the severity of blood loss in atonic PPH women with the following risk factors: maternal age, history of CS, gestational age, birth weight (newborn weight), maternal body mass index (BMI), parity (number of pregnancies), episiotomy, induction of labor (IOL), and augmentation of labor (AUG).We conducted a retrospective chart review study for women who delivered between January 2015 and December 2018 in a tertiary hospital in Jeddah, Saudi Arabia, with selected cases of atonic PPH. We defined cases as women with diagnoses of atonic PPH  chosen from hospital discharge records. Due to the inadequate adoption of ICD coding in the hospital, we also included the charts of women with documented estimated blood loss > 500 mL in SVD and >1000 mL in CS, excluding placental complications, coagulation dysfunction, uterine rupture in the labor and deliver registry book to ensure full access to the primary atonic PPH cases.Information about the maternal characteristics, obstetric history, pregnancy, labor, and delivery was extracted from the medical records. Expert medical record abstractors used data collection sheets for each case, and inter-rater reliability was applied before data entry to SPSS software. The response variable was amount of blood loss in ml, while the continuous independent variables were age in years, BMI values, parity, gestational age, hemoglobin level at the time of birth, and birth weight. The categorical variables were having an epidural, episiotomy, IOL, and AUG.Institutional review Board (IRB) approval was obtained . The study took into consideration ethical principles for conducting research, which includes beneficence, respect for human dignity, and justice. Because the study is a retrospective chart review study that used preexisting data, not all aspects of human subject protection may apply.For analysis, we used descriptive statistics of number and percentage for reporting incidences of atonic PPH and for identifying the categorical study variables along with mean, median, and standard deviation to describe the continuous variables.Regarding statistical inference, we categorized the amount of the blood loss in women who had atonic PPH during vaginal delivery into mild (500–1000 mL) and severe (>1000 mL) for the purpose of the study. Chi-square is used to determine the relationship between the severity amount of the blood loss and associated variables while the ordinal logistic regression model used to determine the risk factors associated with severity of blood loss in vaginal delivery. The null hypothesis measured the severity of blood loss with associated pairwise comparison, and the alternative hypothesis was blood loss with pairwise independent collection.We used SPSS software  to execute an ordinal logistic regression model. Blood loss (mild and severe) was used as outcome variable, and all others were independent variables. The regression model used the following equation: Blood Loss in Vaginal Birth = Age + Parity + Gestational Age + BMI + Epidural + Episiotomy + Iron Deficiency + IOL + AUG + Hemoglobin Level + Birth Weight.Of the 15,483 deliveries documented in the hospital data base, a total of 386 (2.5%) were atonic PPH. The total increasing rate from 2015 to 2018 was 1.87%. The increasing rate from 2016 to 2017 was 12.7%, and 2017 to 2018 was 14% p = 0.013), episiotomy (p = 0.038), IOL * epidural (p = 0.004), interaction of IOL * AUG * Epidural (p = 0.008) with insignificant association > 0.05 with age, parity, gestational age, BMI, hemoglobin level, Iron Deficiency anemia, and birth weight.p = 0.013), episiotomy , and IOL . The interaction between IOL, AUG, and an epidural on blood loss was significantly associated with the severity of atonic PPH . Age, parity, gestational age, BMI, iron deficiency, hemoglobin level, and birth weight had p-values that exceeded 0.05, which reflected insignificant association with the amount of blood loss during vaginal birth The findings showed significant association between blood loss and the epidural  showed a significant association of severe PPH and AUG, , and SheRegarding epidurals’ effect on the severity of atonic PPH, our findings did show significant association between epidural alone and the severity of atonic PPH, which align with a previous study that stated that epidural is one of the risk factors of atonic PPH . The assRegarding parity and BMI, our study findings did not find significant association between the severity of atonic PPH and age and parity (number of pregnancies) in our sample; however, the majority of women who had atonic PPH were nulliparity (first pregnancy). In addition, the mean BMI was 29, which constitutes being overweight, according the international BMI index. These observations align with previous studies’ findings ,29,30.Regarding hemoglobin level, even though our analysis did not determine significant association of low hemoglobin level with severity of atonic PPH, the average hemoglobin level in our sample was 9.5, considered an abnormally low level. This observation is comparable with previous studies that have suggested that women with anemia at the time of birth were more likely to experience significant blood loss .Our study has several strengths as well as limitations, the important strength being answering the international call reflected in the SDG target 3.1, to reduce global MMR to less than 70 in 100,000 by 2030 and to reduce the baseline rate of 2010 to 70% by 2030, which could not happen without a detailed investigation of the leading cause of obstetric hemorrhage, PPH. Another strength is being the first study to investigate the incidences and risk factors of atonic PPH in Saudi Arabia that addresses the findings of MMR in Saudi Arabia based on the WHO report in 2017. To ensure access to every case of atonic PPH and minimize the risk of under-reporting cases, we used two methods to access atonic PPH cases charts by using ICD codes, and manually by reviewing the labor and delivery registry books for 4 years back. The limitation of our study is that of any retrospective chart review that relies on previous documentations that might be inaccurate, incomplete and shown variation of healthcare providers documentation. Data about history of previous placental complications, medical history of the patients  and pregnancy-related complications such as preeclampsia, eclampsia or gestational diabetes were not collected, which may have added more information regarding atonic PPH cases in Saudi Arabia and added more risk factors. Moreover, the documentation of the duration of second and third stage of labor was not clear in the patient file and no clear answer was taken from the nurses in the labor room, so we remove the labor duration variable which added another limitation to the study. In addition, using atonic PPH data from one setting in Saudi Arabia limits the generalization of our findings regarding atonic PPH incidences and risk factors to the Saudi population in which we need to uncover the trends of atonic PPH.In conclusion, the incidence of atonic PPH in the total sample was 2.5%, with the rate increasing by 12% between 2017 and 2018 in a tertiary hospital in Saudi Arabia. Risk factors that increase the severity of atonic PPH are epidural, episiotomy, induction of labor, and induction supplemented with augmentation of labor. Women who had an episiotomy, induction of labor, or augmentation are predicted to have a larger amount of blood loss (>1000 mL) during vaginal delivery compared to patients who did not receive those procedures. The clinical implications of the study would be the reevaluation of the postpartum hemorrhage risk assessment tool and considering epidural, induction of labor, augmentation of labor, and episiotomy as factors that might increases the risk scores. This will help for the early detection of risky women for severe atonic PPH, which minimizes the adverse effects of the disease and facilitates the early management of it. Future studies are needed regarding the national trends of atonic PPH in Saudi Arabia, with a larger sample size in different settings across the country. This could be national study to ensure a good representation of the Saudi population.


There is no validated evidence base on predictive ability and absolute risk of preterm birth by gestational age of the previous pregnancy.N = 517,558 mothers). For each week of final gestational age of the first birth, we calculated relative and absolute risks of subsequent preterm birth.We conducted a retrospective cohort study of mothers who gave birth to their first two children in New South Wales, 1994–2016  were all less than 14%. For all gestational ages of the first child the median gestational ages of the second child were all at least 38 weeks. Sensitivity and positive predictive values were all below 30%.Previous gestational age alone is a poor predictor of subsequent risk of preterm birth. Preterm birth, most commonly defined as birth before 37 weeks of completed gestation, has a global prevalence of approximately 11% of viable fetuses . The natThis was a retrospective cohort study of births 1994–2016 in New South Wales (NSW), Australia.N = 1,001,596 births) was attributable to restriction to the first two births (parity 0 and 1). After exclusions there were 517,558 mothers each with a parity 0 birth and parity 1 birth .Participants were mothers with two consecutive pregnancies at parity 0 and parity 1. From a starting population of 2,109,871 births, we sequentially excluded 62,511 multiple births; 602 births with missing final gestational age; 612 births with missing parity; 6382 births with erroneously recorded parity; and 3052 births with gestational ages < 22 weeks or > 44 weeks. The largest exclusion  and “relative risks” to evaluate gestational age as a risk factor.< 31 0/7), 31–32 weeks (31 0/7 to 32 6/7), 42–44 weeks (42 0/7 to 44 6/7) [< 28 0/7), < 32 weeks (< 32 0/7), < 34 weeks (< 34 0/7) and < 37 weeks (< 37 0/7) compared to mothers whose first child been born at 40 weeks (40 0/7 to 40 6/7) gestation; (ii) absolute risk of birth of the second child at < 28 weeks (< 28 0/7), < 32 weeks (< 32 0/7), < 34 weeks (< 34 0/7) and < 37 weeks (< 37 0/7); and (iii) centiles  of gestational age for the second child. Relative risk was calculated with log-binomial regression and 95% confidence intervals based on profile likelihoods for relative risks and Wilson score intervals for absolute risks [Gestational ages of the first child that were at the endpoints of the gestational age continuum were aggregated into categories: ≤ 30 weeks ( 44 6/7) . At eachte risks , 13. Relte risks .At first birth, 8.7% of mothers were of age < 20 years, 7.4% at age 35–39 years, and 0.5% at age ≥ 40 years Table . The matFor mothers whose first birth had a gestational age of 22 to 30 weeks the relative risk of second birth before 28, 32, and 34 weeks’ gestation was between 14 and 21 times higher; and the relative risk of second birth before 37 weeks was less than 12 times higher than those whose first birth was at 40 weeks’ gestation. Absolute risk of the second child birth before 28 weeks’ and 30 weeks’ gestation corresponding to all first child gestational ages were less than 5 and 10%, respectively . The other preterm birth classifications had a stable trend.The absolute risks, sensitivity and positive predictive values observed for this cohort imply that preterm birth of a woman’s first child, overall and when categorised were poor predictors for preterm birth of the next, pregnancy with the next child. Our findings validate conclusions for the study from Western Australia . The medOur results were derived from a large Australian cohort (NSW) of singleton births for which the prevalence of preterm birth in first pregnancy was 5.9%. Point and interval estimates were largely consistent with the results from our previous study . The sliScreening whole populations based on attributes of the previous pregnancy such as gestational age –19 wouldWe posit that the first step towards both elucidating the aetiology of recurrence as well as the development of individualised prediction models is the production of a reference for preterm birth or gestational age, based on previous gestational age. Notable regions for replication include Japan, for which national recurrence risk estimates were recently reported by Seyama et al. ; regionsOur results confirm that gestational age is strongly associated with subsequent preterm birth, but is a poor predictor of subsequent preterm birth, and provides an evidence-base for communicating the absolute risks during post-partum counselling. This evidence-base might be used to either identify higher-risk mothers for counselling regarding modifying other risk factors, but also serves to minimise unintentional misinformation which overstates risk among mothers who have experienced a preterm birth and want to know their risk of experiencing a subsequent preterm birth.


Objective: To investigate the incidence of hyponatremia in preterm infants. The secondary aim was to determine the risk factors of late-onset of hyponatremia (LOH) and their influence on neonatal outcomes.Study design: The present study is a retrospective cohort study of 71 preterm infants born before 32 weeks of gestation at King Abdulaziz University Hospital and admitted to the neonatal intensive care unit, level 3, from January to December 2019. Hyponatremia was defined as a sodium level ≤ 132 mEq/L. Retrieved maternal characteristics included age, parity, booking status, medical problems, antenatal steroids, and method of delivery. Retrieved infant characteristics included birth weight, gestational age, Apgar scores, total parenteral nutrition (TPN), breast milk or formula feeding, and body weight. as well as data on early onset of sepsis, chronic lung disease (CLD), patent ductus arteriosus, retinopathy of prematurity, severe intraventricular hemorrhage, and prescribed antibiotics and diuretics.Results: Out of 72 preterm infants, 27% were diagnosed with hyponatremia. Early-onset hyponatremia (EOH) affected 7% (n=5) of the infants while 22.5% (n=16) of preterm neonates developed LOH (two infants developed both EOH and LOH). None of the investigated maternal characteristics were significantly associated with hyponatremia. Some infant characteristics were significantly associated with LOH: lower birth weight, lower gestational age, exclusive breastfeeding, longer duration TPN, and use of diuretics and antibiotics. Infants with LOH had longer hospital stays (p < 0.001) and higher risks of extra-uterine growth retardation (p = 0.007), CLD (p < 0.001), and sepsis (p = 0.001).Conclusion: Twenty-seven percent of preterm infants in King Abdul Aziz University Hospital are born with or develop hyponatremia. Risk factors significantly associated with LOH included lower gestational age, lower birth weight, exclusive breastfeeding, long-term TPN, and prescribed diuretics and antibiotics. Possible outcomes of hyponatremia were long-term hospital stays, growth retardation, sepsis, and CLD. Fluid and electrolyte imbalances are common in neonates, especially preterm infants. In the first weeks of life, the capacity of the newborn kidney to excrete excess water and sodium is limited, which could lead to respiratory distress syndrome, sepsis, and necrotizing enterocolitis. Since sodium is the primary electrolyte in extracellular fluid, studies on hyponatremia have used varying levels of sodium. Among them, Kim et al. defined hyponatremia as an electrolyte imbalance disorder in infants that occurs when the plasma sodium level is below 132 mmol/L )  . Yet, the risk factors that were significantly associated with LOH included lower gestational age, lower birth weight, exclusive breastfeeding, long-term TPN, and the use of diuretics and antibiotics. Our study also found that long-term hospital stays, growth retardation, sepsis, and CLD were possible outcomes of hyponatremia.


The aim of this paper was to provide evidence for the impact of prenatal sex steroid exposure on prenatal and postnatal body size parameters, and muscle strength in children.t-statistics and Cohen’s Δ were used in statistical analysis.The following anthropometric data were studied in a group of 1148 children (536 boys and 612 girls) aged 6–13 years: the 2D:4D digit ratio, birth weight and length, and birth head and chest circumference. Postnatal parameters (6–13 years) included body weight and height, BMI, waist and hip circumference, WHR, as well as grip strength in both hands. All parameters that required it were adjusted for sex and gestational or chronological age. A general linear model, Pearson’s correlation, Among birth size parameters, only birth weight was significantly negatively correlated with the 2D:4D digit ratio in children. Higher (feminized) digit ratios were significantly correlated with postnatal parameters such as body weight, BMI, and waist and hip circumference (positively), as well as hand grip strength–a proxy for muscular strength (negatively).Problems with maintaining adequate body size parameters and muscle strength may be programmed in fetal life and predicted on the basis of the 2D:4D digit ratio. Body weight at birth and in early ontogenesis are additive correlates of the 2D:4D ratio. The present findings suggest that the 2D:4D digit ratio is related to postnatal phenotypes such as birth weight, overweight, and obesity as well as muscle strength in 6–13-year-old children of both sexes. The prenatal period is crucial for child development and any interfering conditions may disturb all subsequent ontogenesis. Sex steroid exposure during fetal life seems to be a significant factor shaping later stages of development , 2. EvalEvidence shows that the digit ratio remains stable throughout ontogenesis, being established in the second trimester of pregnancy. Males typically have lower ratios (with longer fourth fingers) than females (with shorter fourth fingers). A 2011 study by Zheng and Cohn  confirmeTo date few studies have analyzed the 2D:4D digit ratio and body parameters or proportions in adults, with the findings remaining inconclusive –12. HoweThe main objective of this investigation was to establish whether sex steroid proportions during pregnancy have a long-lasting effect and are involved in determining birth size as well as body parameters and muscle strength in mostly prepubertal children.Analysis involved a database containing 1148 records for children aged 6–13 years: 536 boys and 612 girls from central Poland. Participation in the study was conditional on written consent by the parents, who also completed the questionnaires. The study was approved by the Ethical Committee of the University of Lodz (no. 19/KBBN-UŁ/II/2016). Data were collected between 2016 and 2018.Children were recruited at primary schools in Lodz, a city with 677,000 inhabitants located in the center of Poland. Information about birth parameters, i.e., birth weight and length, head and chest circumference, and gestational age (week of pregnancy) were noted by physicians immediately after birth and taken from children’s medical records. Further data were collected by anthropometric measurements according to Martin’s standard procedures . Postnatr), with its significance assessed by t-statistics (Statistica PL.13.0 software). Cohen’s effect sizes (Cohen’s Δ) were calculated using Effect Size Calculator for T-Test (https://www.socscistatistics.com/effectsize/default3.aspx).A general linear model (GLM) was used to assess the significance of the main effects and interactions between factors to explain the variability of individual dependent variables (Statistica PL.13.0 software). The relationship between 2D:4D indicators in girls and boys is illustrated in graphs with individual dependent variables. This relationship was evaluated using Pearson’s linear correlation coefficient . Thus, the measurements of digit lengths were highly accurate and repeatable. p = 0.41), the direction of this correlation applied both to girls and boys  was significantly negatively correlated with right (but not left) 2D:4D, which means that feminized 2D:4D R ratios were associated with lower birth weight than that expected for sex and gestational age. As the interaction of 2D:4D R with sex was not significant  and p < 0.01), and children’s sex did not affect this correlation for 2D:4D R (p = 0.17). In both groups feminized 2D:4D R values were associated with lower right hand grip strength in relation to those expected for the child’s sex and age (p = 0.03) , but not in girls  (Right hand grip strength was negatively correlated with the digit ratio of both hands ( and age . In cont = 0.03)  Fig 2)..p < 0.01 = 0.61) .p = 0.04), but children’s sex did not affect this correlation (p = 0.70). While 2D:4D L and the grip strength of the same hand did not exhibit covariation for the entire study group (p = 0.11), the association between these variables was found to be sex-dependent (p = 0.03) , but not in girls .2D:4D R was significantly associated with left hand grip strength as a main effect ( = 0.03) . A negatPositive correlation between birth weight and postnatal body weight was found in the whole group regardless of sex . Higher birth weight  was associated with higher body mass  regardless the sex . Thus, tRelationship between 2D:4D R, birth weight , and body weight during postnatal ontogenesis  was analyzed. The objective was to establish whether children with feminized 2D:4D R and lower birth weight  tended to reach specific body weight values during postnatal development. The results of individual analyses  and right hand grip strength in children during early ontogenesis . The goal was to determine whether prepubertal children with feminized 2D:4D (R & L) and lower birth weight  tended to exhibit lower hand grip strength . The results were not statistically significant either for boys or girls separately, or for the entire group taken together .All interactions between variables are presented in Intrauterine programming plays a significant role in early ontogenesis. During critical windows. the fetus is more sensitive and any suboptimal conditions can have a range of impacts on further development stages –25. For N = 1148). Few studies to date have reported significant correlations between 2D:4D and birth weight [N = 139) [N = 320) [N = 118). Another study reported results similar to ours, but for both hands in a male group (N = 215), with 2D:4D (R & L) being negatively correlated with birth weight [One of the first potential effects of prenatal development disturbances is abnormal birth weight. There are many well-known prenatal factors that affect birth weight. e.g. parental age and health, the use of stimulants during pregnancy, exposure to tobacco smoke, as well as the prenatal hormonal environment –32. In th weight , 39. witN = 139) , 6. The N = 320) . While iN = 922 boys. 835 girls) [The current findings suggest that prenatal sex steroid exposure (reflected in 2D:4D) affects not only birth weight, with statistically significant positive correlations revealed between 2D:4D R and the majority of examined parameters  measured in children aged 6–13. These results indicate that prenatal estrogen exposure (higher 2D:4D) leads to increased weight-related parameters already in prepubertal children. Until now, some authors have rejected any relationship between those parameters in children and adolescents –18, but 5 girls) . In anot5 girls) . ManningN = 1217) of male children, adolescents, and adults aged 13–40, reported that feminized 2D:4D ratios were significantly correlated with higher BMI values [The present study revealed positive correlations between 2D:4D and most postnatal body size parameters in both sexes. All of those correlations were found for the right hand, which is taken to be a better indicator of prenatal exposure to sex steroids . BagepalI values . The lonI values . Bazaes This study identified a relationship between 2D:4D and hand grip strength, which is important in predicting the physical strength of children. While 2D:4D R was negatively correlated with right hand grip strength in boys and girls, in the case of 2D:4D L a similar relationship was found only in boys for both left and right hand grip strength. The previously cited study by Ranson et al., which analyzed the relationship between 2D:4D R and hand grip strength, also reported a negative correlation only in boys . SimilarAdditionally, the 2D:4D digit ratio in children can be considered an indicator of muscle strength in later life. Halil et al. reported that the higher the digit ratio, the lower the muscle strength among adults, regardless of sex. That relationship was found to continue in the elderly, directly influencing their quality of life . The preIt is necessary to develop additional indicators that would be helpful in identifying the lifelong consequences of impaired intrauterine development. Prenatal sex steroid exposure estimated by the 2D:4D digit ratio may be one of them as it is established in utero and remains invariant throughout ontogenesis. The present study suggests that sex steroid proportions seem to play a significant role in prenatal life, affecting the muscle strength. weight and proportions of the human body. New insights could be provided by investigating individual pathways of developing body parameters from the prenatal stage (2D:4D ratio) through childhood, adolescence, and adulthood.S1 Data(XLSX)Click here for additional data file.


Optimal mode of birth for twins, in particular monochorionic twins, has been the subject of much debate. This retrospective study compared maternal and newborn outcomes after vaginal birth in monochorionic and dichorionic twins, utilizing a large institutional database.Retrospective analysis focusing on 98 monochorionic-diamniotic (MC-DA) and 540 dichorionic-diamniotic (DC-DA) twin births extracted from the perinatal database of a large German hospital. Pregnancies ≥36 weeks of gestation with two viable foetuses born between 2004 and 2014 divided into planned vaginal and planned caesarean delivery were included. Descriptive analysis was performed for maternal characteristics. Odds ratios (OR) with 95% confidences intervals (CI) tested the predictive effect of vaginal birth on neonatal and maternal outcomes.51.0% MC-DA and 46.7% DC-DA twin pregnancies were planned vaginal births and 44.0% MC-DA mothers and 43.7% DC-DA mothers actually gave birth vaginally. The overall rate of caesarean section (CS) during the years under observation was 79.6% for MC-DA and 77.0% for DC-DA pregnancies. There were no significant differences in neonatal outcome between the subsamples, although acidosis was observed more often in the second DC-DA twin and Apgar scores < 7 were observed more often in MC-DA twins.Vaginal birth may be recommended as an option to women with monochorionic twins as no significant differences in outcomes were found between MC-DA and DC-DA twins. However, over half of planned vaginal twin births resulted in CS. The incidence of multiple births has risen over the last years. In Germany, the proportion of multiple births has more than doubled over the last 40 years and in 2019, 1.84% of newborns were multiples. This trend can also be seen in other European countries such as England, Wales and France . ReasonsThis retrospective cohort study covers a period of 11 years (2004–2014) and includes twin births at the Department of Women’s Health, University Hospital of Tuebingen (UFK), Germany. The UFK is a level one perinatal centre with over 3500 births per year and a large percentage of multiple births. Data was extracted from an extensive birth registry . In the 11 years under observation, 1120 twin births were recorded. All twin births ≥36 weeks’ gestation with two viable foetuses were included in the analysis. Of the 638 twin births meeting these criteria, subsets for comparison were created between MC-DA and DC-DA twin pregnancies with planned vaginal birth, according to an intention-to-treat analysis. Successful planned vaginal birth was defined as including instrumental births and a combination of vaginal and instrumental birth. Crosschecking for plausibility was performed prior to analysis. Neonatal outcomes included 5-min Apgar scores, pH-values, need for breathing support (intubation and CPAP), birthweight and mortality, all separated for the first and second twin. Admission to neonatal intensive care unit (NICU) was defined as need for breathing support. Saling’s classification for pH-values was applied, pH-values < 7.20 were assigned to acidosis and pH-values between 7.20 and 7.24 to preacidosis . AdverseThe study was approved by the local ethics committee .P-values for hypothesis tests were two-sided and a p-value < 0.05 was considered statistically significant.SPSS , Microsoft Office Excel (Version 2016) and LaTex were used to analyse the data and to create figures, tables and graphs. Evaluation of normal distribution of variables was performed using Kolmogorov-Smirnov- and Shapiro-Wilk-tests. Medians and ranges were estimated based on non-normally distributed data. Cross tables and percentages for categorial data were performed and Chi-square-test or Fisher’s-exact-test were used to compare categorial data. The decision was made to forego multivariant testing for the subsamples as none of the variables was found to be significant. The Mann-Whitney-U-test was applied for non-normal distribution. Odds Ratio and 95% confidence intervals were calculated for adverse neonatal outcomes comparing vaginally born monochorionic versus dichorionic twins. Between 2004 and 2014 there were 1120 twin births at UFK, 98 of which were MC-DA and 540 DC-DA and fitted the inclusion criteria. One monochorionic-monoamniotic twin pregnancy ≥36 weeks of gestation was excluded, as monochorionic-monoamniotic twins are always elective CS according to hospital protocol. In total, 302 (47.3%) were planned vaginal births and 336 (52.7%) were planned CS births. Vaginal birth was achieved for 132 pregnancies (43.7%), whereas 155 births (51.3%) ended in CS. Additionally, 15 twin pairs (5.0%) were born with a combination of vaginal and caesarean delivery. The mode of birth for the entire cohort was 77.0% CS, 20.7% vaginal and 2.3% combination vaginal and CS.Of the 51.0% of MC-DA pregnancies with planned vaginal births, 44.0% achieved this goal. 77.3% had a normal vaginal birth, 13.6% a vaginal instrumental birth and 9.1% were delivered by a combination of vaginal and instrumental birth  than in DC-DA twins (0.9 and 1.8%), but this was not statistically significant Table . MC-DA aMaternal outcome regarding postpartum blood loss was not statistically significant between the comparison groups Table . Blood lThe optimal mode of birth for twin pregnancies remains a controversial topic and much research has been carried out, mainly regarding neonatal outcome. At the same time, rates of caesarean birth remain high. The CS rates in Germany have increased over the last 30 years and in 2019, 29.6% of all hospital births were caesareans . The aimOf the 638 twin pregnancies found in the database between 2004 and 2014 which met the inclusion criteria, 47.3% were planned vaginal births and 52.7% caesarean, comparable the findings of Dathan-Stumpf et al. . SimilarDemographic differences between the subsamples in our study were found to be statistically non-significant, which is consistent with similar studies , 20, 23.Gestational age at birth did not differ significantly between MC-DA and DC-DA twins in our analysis. Other studies have reported slightly lower gestational ages at birth for both monochorionic and dichorionic twins but these studies included pregnancies ≥24 or rather ≥28 weeks of gestation , 20.Regarding neonatal ouctomes, our analysis showed the median Apgar at 5 min postpartum to be nine for MC-DA and DC-DA twins but Apgar scores < 7 were 5-times as likely for first and 2.5-times as likely for second MC-DA twins than for DC-DA twins after vaginal birth. The risk of an Apgar score < 7 in any of the twins was 1.7-times higher for monochorionic twins. These findings are in accordance with other studies which reported similar percentages of Apgar scores < 7 for mono- and dichorionic twin pregnancies , 23. SauThere was no significant difference in median pH-values between vaginally born MC-DA and DC-DA twins and values were always in ther normal range according to the classification by Saling . Only seMaternal outcome regarding postpartum blood loss showed no significant differences between the comparison groups which is supported by the results of Garabedian et al. .In summary, the findings of our study were consistent with those of other researchers, who also found no significant differences in neonatal outcomes after vaginal birth when comparing MC-DA and DC-DA twins.Both Garabedian et al. and Schmitz et al. showed that the outcomes for monochorionic and dichorionic twins are similar and vaginal birth can be offered to women regardless of chorionicty , 20. SauThis retrospective study in a university hospital setting has the advantage of a large sample size of twin pregnancies and covers a period of 11 years. However, the relatively small number of MC-DA twins is a reason why the differences we have found are not statistically significant. The analysed data are from 2004 to 2014 and are accordingly not entirely current, but they are very consitent and show good comparability with similar studies. The retrospective study design also has to be considered when comparing our results with other findings, as well as the fact that a level one perinatal hospital and fertility centre serves a high-risk population which can also affect results.We found no significant differences in neonatal or maternal outcomes after vaginal birth when comparing MC-DA and DC-DA twin pregnancies. DC-DA twins more often had acidosis whereas MC-DA twins were more often affected by Apgar scores < seven. Vaginal birth can be an option for twin pregnancies regardless of chorionicity. It must be kept in mind, however, that more than half of planned vaginal births resulted in CS, raising the risk of adverese maternal outcomes. The optimal mode of birth for twins has to be decided individually for every twin.