Seasonal variations in environmental exposures at birth or during gestation are associated with numerous adult traits and health outcomes later in life. Whether DNA methylation (DNAm) plays a role in the molecular mechanisms underlying the associations between birth season and lifelong phenotypes remains unclear.N = 9358) and in children aged 1–11 years . We conducted meta-analyses to assess the impact of latitude on birth season-specific associations at both time points.We carried out epigenome-wide meta-analyses within the Pregnancy And Childhood Epigenetic Consortium to identify associations of DNAm with birth season, both at differentially methylated probes (DMPs) and regions (DMRs). Associations were examined at two time points: at birth  at two CpGs at birth (winter-born) and four in the childhood (summer-born) analyses when compared to children born in autumn. Furthermore, we identified twenty-six differentially methylated regions (DMR) at birth  and thirty-two in childhood  meta-analyses with few overlapping DMRs between the birth seasons or the two time points. The DMRs were associated with genes of known functions in tumorigenesis, psychiatric/neurological disorders, inflammation, or immunity, amongst others. Latitude-stratified meta-analyses  revealed differences in associations between birth season and DNAm by birth latitude. DMR analysis implicated genes with previously reported links to schizophrenia (LAX1), skin disorders , and airway inflammation including asthma (LTB4R), present only at birth in the higher latitudes (≥ 50°N).We identified associations between birth season and DNAm  associations between DNAm and season of birth that are unique for the seasons of the year  and (ii) latitude-dependent variations in the seasonal associations . DNAm could play a role in the molecular mechanisms underlying the effect of birth season on adult health outcomes.The online version contains supplementary material available at 10.1186/s13148-023-01542-5. Plants and animals adapt to altered seasonal cues such as temperature and light by regulating their transcriptional programmes. It has been well established in humans that many traits, including physiological (e.g. blood pressure and cholesterol), behavioural traits , and life span, display distinct seasonal patterns –5. The iEpigenetic modifications, including alterations in DNA methylation (DNAm), play a key role in the gene regulation of a variety of cellular processes. Such modifications may also act as molecular mediators between season-linked environmental factors and health outcomes. In plants and animals, the role of DNAm in the regulation of several seasonally associated genes is well documented –20. In hN = 175) but was validated in a small independent cohort.Early life environmental exposures result in specific changes in DNAm that may persist throughout the life course. For example, maternal smoking in pregnancy results in a specific DNA methylation signature in offspring  that perN = 12927 participants) from the Pregnancy And Childhood Epigenetics  from 27 independent cohorts  contributed to the at-birth and 12 cohorts (N = 3610) to the childhood meta-analyses. Most cohorts contributed data either for at-birth or childhood analysis (21/27), while six cohorts (~ 18% of the at-birth data and ~ 45% of the childhood data) contributed to both time points. Less than 20% of the study population had data at two time points from the same child. Data for 60 individuals  were excluded from the at-birth analysis due to insufficient numbers (as per the PACE recommendations of ≥ 15/group) of births in the spring season (n (spring) = 4, Additional file Cohorts participating in the PACE consortium with data on season of birth and DNAm at birth and/or later in childhood were invited to participate in a meta-analysis of associations between season of birth and DNA methylation. Twenty-one independent cohorts N = 948 contribThe outcome was DNAm at birth and childhood. For new-born samples, all but two cohorts used cord blood, while CBC and CHS used dried blood spots collected post-delivery  and “higher latitude subgroup” (≥ 50°N with N = 5580). The choice of 50° as the cut off was arbitrary, although it provided ~ 8 h of sunlight/day at the winter equinox. We focussed on comparing (i) the impact of latitudes on the pattern of association between season of birth and methylation signals at-birth and (ii) the pattern of season of birth specific associations across the two time points (at birth and in childhood) in each latitude. However, due to the small sample size contributing to childhood DNAm analysis in the lower latitude (N = 936), the DNAm results of the child cohorts in the higher latitude subgroup alone were used for comparison with the at-birth DNAm associations.Associations of season of birth and DNAm at-birth were also investigated in samples stratified by the cohort latitude to explore its influence on DNAm signals. Cohorts were dichotomized into a “lower latitude subgroup” (32.7–50°N with β) using the formula M and U are methylated and unmethylated signal intensities, respectively. Normalised beta values were used in preference to M values Details of cohort-specific methylation assays, data handling, quality control and normalisation are given in Additional file All cohort-specific models, at birth or childhood, included the following covariates: maternal smoking status during pregnancy, maternal socio-economic status (SES), maternal age and gestational age at delivery, new-born’s sex, and estimated cell type proportions. These covariates have been reported to be associated with either season of birth or DNA methylation making them potential confounders of the association between season of birth and DNA methylation or both , 28–30. Each cohort performed independent EWAS analysis following a pre-specified analysis plan and an R script  and DNAm (outcome) at a CpG site of the at-birth or childhood blood DNAm data using analysis of covariance via robust regression applying Huber’s weighting, implemented in the R function rlm. Birth seasons were defined as winter (December–February), spring (March–May), summer (June–August) and autumn (September–November). Briefly, cohorts generated a regression model comparing children born in spring, summer, and winter against autumn as the reference for each of the two time points (at-birth or childhood for which they had methylation data). Models were adjusted for cohort-specific covariates as described above and in Additional file p value threshold of 1.06 × 10−7.Meta-analyses were carried out using fixed effect inverse variance weighted option of METAL . Meta-anp value of 0.05 in all DMR analyses.Differentially methylated region (DMR) analyses were carried out using comb-p in R  on the mp values for association in meta-analyses < 1.0 × 10−5) from the primary and latitude analyses was carried out using EWAS Atlas .I2 < 50) for the FDR-significant CpGs. One of the four CpGs, cg19416462 (mapped to CD83), also passed the Bonferroni-corrected threshold p value. The remaining CpGs, after excluding the cross-reactive probe of the four childhood CpGs, two showed decreased methylation levels in children born in the summer compared to those born in the autumn in 92–100% of the cohorts, while cg15437053 was more methylated than the same CpG in autumn born children in 57% of the cohorts. The corresponding three CpGs in the at-birth samples of summer-born infants lacked even nominal significance but showed an overall tendency towards hypomethylation compared to the autumn-born infants (57–61% of the contributing cohorts). The mean differences in methylation  were small in absolute terms .In the analysis of childhood samples aged 1–11 years), differential DNAm was observed at four CpG sites  in the summer-born children  and to AZU1  and the lower latitude [37.2–50°N ].We performed additional at-birth and childhood meta-analyses in subgroups stratified by latitude to check if the observed temporal associations varied with latitude. Cohorts, all from the northern hemisphere, were divided into two latitude groups—higher latitude  also passed the Bonferroni p value threshold (1.06 × 10−7). There were seven significant  at-birth CpGs, six in the spring-born and one in the winter-born infants in the lower latitude subgroup analyses. One of these seven CpGs, cg23369114, was a cross-reactive probe [In the at-birth analyses, we identified a single CpG, cg06251958, from the spring-born babies of the higher latitude subgroup  CpGs in the winter-born children and none in the spring- and summer-born. Furthermore, there was no overlap in CpG methylation signals between the at-birth and childhood samples. We did not perform childhood DNAm analysis for the lower latitude subgroup due to its small sample size (n = 7) in the spring-born infants of the higher latitude cohorts. Most of the at-birth DMRs identified in the new-borns were unique to the season of birth  except for DMRs which mapped to ELFN1, SEMA5B and LOC154449 (identified in winter- and summer-born children) and AZU1 (in spring- and summer-born). Interrogation of at-birth DMRs of the higher latitude subgroup (≥ 50°N) identified 18 DMRs mapped to 20 unique genes in the winter-born and 25 DMRs (23 mapped genes) in the summer-born infants Table . In contExamination of the biological functions of the genes mapped to the at-birth higher latitude DMRs revealed that most of the genes have roles, amongst others, in the functions of the central nervous system (CNS) including psychological disorders, cancer or inflammation and immunity  identified 47 DMRs which were mapped to 54 genes . These imprinted genes were specific for the summer-born babies and were not identified in the new-borns of spring or winter  was present in both at-birth and in early childhood from the higher latitude subgroup  and lower (< 50°N) latitudes were compared. While the higher latitude new-borns alone had traits enriched in exposure to pollutants  and folic acid supplement, the lower latitude offspring had unique enriched traits associated with response to different treatments, mixed connective tissue disease, asthma, puberty, and household socio-economic status. Parental arsenic exposure and autistic spectrum disorder were common in the new-borns and young children of higher latitude, although weakly enriched in the childhood analysis.p value < 0.05 in meta-analyses for enrichment of metastable epialleles (loci whose epigenetic modifications are established during early embryonic development [We tested CpGs with unadjusted elopment ). Our anThis study investigated the association of season of birth and DNAm at two time points (at-birth and in childhood), and in latitude subgroups, in multiple cohorts recruited from regions across the northern hemisphere. Season of birth can be a proxy for seasonal variations in the length of the day, temperature, availability of sunlight, exposure to UV light, pollen, nutrition, seasonal infectious agents, air pollution, C-section and many more. Here, we show evidence for the existence of season of birth specific associations with DNAm at-birth as well as in childhood. The differential methylation patterns in at-birth samples followed a season-dependent annual periodicity . In addition, we found suggestive evidence for latitude-specific fluctuations in DMRs . To the best of our knowledge, our study is a first to demonstrate such season of birth effects on DNAm as well as the latitude specificity in these effects in a large study population with participants from diverse geographical locations.Our primary analyses found epigenome-wide significant season of birth associations at two and four CpGs in the at-birth and childhood blood samples, respectively. One of the four CpGs in the childhood samples was found to be a cross-reactive probe  and shouLatitude-stratified analyses (higher latitude: ≥ 50°N and lower latitude: < 50°N) were carried out to explore the impact of latitude on seasonal differences in at-birth and childhood DNAm. One of the significant CpGs of the at-birth lower latitude analysis, cg23369114 , was present in the spring-born children of the primary childhood analysis, but not in any of the at-birth analyses that were based mostly on cord blood data. Yet another factor could be the absence of paired comparisons in our study. The at-birth and childhood comparisons were done with > 80% of unpaired data as most cohorts contributed to either at-birth or childhood data. This meant that DNAm measurements at the two time points did not come from the same child. This might have made the true persistent signals, if there were any, undetectable. An analysis with paired data from the six cohorts (data available from the same child at both the time points) would have had limited power to detect methylation signals of small DMR sizes as such data were available for < 20% of the study population. The heterogeneity of the age group in the childhood analysis may also have contributed to the non-persistence of the at-birth DNAm signals. Age effects may be strong, and the age range was wide (1–11 years). It is likely that there may be some remaining effect despite controlling for child’s age in the models.The absence of sustained signals from birth to childhood in this study does not necessarily imply absence of persistence in general. There could be several reasons for this. The smaller sample size of the childhood analysis compared to that of the at-birth analysis might be one of the reasons. Choice of cord blood for the at-birth studies could have masked the birth to childhood persistence of DNAm signals in this study. For example, Paquette and Marsit highlighted the importance of placenta samples for studies on the influence of intrauterine outcomes . The curIt may be noted that persistence of DNAm signals from birth to childhood is not necessarily needed for differential methylation to have an effect. Differential methylation at birth, which affects developmental programmes at a critical period, may have long-lasting effects, even if the differential methylation does not persist into early childhood.The season-related DNAm signals (CpGs and DMRs) identified in the primary and latitude analyses were non-overlapping. The primary analysis investigated the seasonal variations disregarding the information on the latitude of birth of the children. The results make use of the distribution of methylation signals across the seasons only. In contrast, the latitude analysis is a stratified analysis which examines the above seasonal variations in two separate latitude regions (lower and higher latitudes in the northern hemisphere). The results of such an analysis look for differences in the distribution of methylation signals across the seasons in two separate latitude subgroups which are likely to be different from that of the primary analysis. However, the DMR mapped to HTR2A was present both in the winter- and spring-born children of the preliminary childhood analysis as well as the winter-born children of the higher latitude childhood analysis. Alternatively, the non-overlapping methylation signals observed in the latitude subgroups, despite smaller sample sizes and stringent FDR cut offs, are likely to be the enriched latitude-specific signals which were not visible in the primary analysis.Several of the differentially methylated probes (DMPs) and DMRs identified in our analyses mapped to genes with well characterised functions. We highlight below some of the genes mapped to DMPs or DMRs identified in the at-birth and childhood analyses of the higher latitude subgroup which are likely to be associated with outcomes relevant to season of birth.LAX1 gene (Lymphocyte Transmembrane Adaptor 1), has been shown to be associated with severity of certain symptoms of schizophrenia (SZ) in a case–control study [LAX1 is also the mapped gene for one of the top-ranked at-birth DMRs  spanning six CpGs including cg12022621 . In the general population in the northern hemisphere, individuals born in late winter and early spring have an increased risk of developing SZ later in life , 50, 51.ol study . LAX1 isng-borns –59.ELF1N, SEMA5B, GPRC5C, SLC17A9, TOX2, PRSS50, AZU1, KIAA0319, PSORS1C3, GNAS, GNAS-AS1, DDC, CFAP46, MEG3, TNXB, ZKSCAN4, PLCH2, NPY, NRBP1, LTB4R and LTB4R2 in the winter-born babies , and LTB4R (winter-born), both of which are known to be linked to the autoimmune disease psoriasis [MIR-1914, MIR-647 and MAP3K8 (common wart) and TNF (psoriasis)  [LTB4R, leukotriene B4 receptor, appears to be the most epigenetically divergent gene in the peripheral blood of humans. LTB4R has been linked to a variety of inflammatory diseases such as asthma [N = 175).Several genes mapped to DMRs of at-birth blood samples of the winter-born of the higher latitude, not found in the lower latitude, had links to immunity and inflammation (iseases) , 73–76. s asthma , allergis asthma , inflamms asthma , atheross asthma , inflamms asthma  and psors asthma . This iss asthma . HoweverC7orf50 and DMR containing this CpG were reported to be associated with prenatal exposure to particulate air pollution in a meta-analysis by Gruzieva et al. [A CpG, cg003488551, mapped to a et al. . Major aa et al. . It is pGNAS/GNAS-AS1, MEG3 and MEST (PEG1). Almost all the CpGs found in the DMRs of these imprinted genes were hyper-methylated. In addition to being season of birth and latitude specific (only in the summer-born babies of the higher latitude), they were not found in the older children from the higher latitude subgroup. However, a DMR associated with the MEST gene (mesoderm-specific transcript) was present both at birth (summer-born) and in early childhood (spring-born) from the higher latitude subgroup. Many imprinted genes function as regulators of embryonic or neonatal growth and may therefore influence a spectrum of heritable outcomes later in life. The majority of imprinted genes are expressed in the brain, and methylation of these genes in their imprinting control regions (ICRs) has been implicated in neuropsychiatric disorders . For exiewed in ). Furtheiewed in . A previhildhood .Metastable epialleles are variably methylated loci with cross-tissue methylation signatures indicative of establishment in the early embryo . They, tIn the at-birth meta-analyses, there were only a few robust but weak genome-wide associations between CpG methylation and season of birth. DMR analysis is believed to be statistically more powerful than the analysis of individual probes as it combines methylation signals from nearby CpGs to give more reliable signals for associations between DNAm and exposures. It is possible that the seasonal variations in exposures influence DNAm via groups of CpG sites over an extended region as in the DMRs where contiguous differential methylation may be maintained. Our findings on the birth season-dependent variations of regional epigenetic signals concur with the findings of a study by Dopico et al. which demonstrated the existence of seasonal variations in gene expression profiles over a year in ethnically and geographically diverse populations . They atOur study investigated associations between season of birth and DNAm on a large scale with 9358 at-birth and 3610 childhood samples. Analyses with such a large sample size, especially for the at-birth samples, make it possible to interpret results with more confidence. The cohort-specific EWAS analyses were robust and adjusted for several pre-specified potential confounders, including cell type proportions. The cohorts originated from geographically diverse locations in terms of latitude in the northern hemisphere: 32.7–71.2°N and 36.7–58.7°N for the at-birth and childhood samples. This enabled us to carry out latitude stratifications to investigate season of birth associations of DNAm. Of the 27 cohorts analysed in this study, more than 95% of the participants were of European ancestry. It remains to be seen whether our results are generalizable to other populations.N = 3569 vs. at-birth: N = 9358) made it harder to interpret with certainty the absence of at-birth DNAm signals in childhood data. Another limitation of our study is that the at-birth and childhood data were not from the same children for most of the cohorts (21/27 studies). A longitudinal study which follows up the same children at different latitudes in sufficient numbers is necessary to detect the persistence of at-birth DNAm signals from birth to childhood. The latitude analyses of this study have not been adjusted for longitude. The same latitude can have geographic locations that have very different climates, e.g. New York and Madrid (40°N). Furthermore, the choice of autumn as a reference season may have masked some of the other significant associations between season of birth and DNAm. This study was initiated as a follow-on from an earlier study on seasonality effects on asthma and allergy outcomes which showed the strongest effects on allergy phenotypes with autumn as the reference season [This study has limitations. This study was designed only to examine the associations between DNAm and season of birth as an exposure and not the factors for which season of birth is a proxy (see above). Heterogeneity of the age range in the childhood population in this study and its smaller sample size  and suggestive evidence of a latitude  effect. Findings in this study add to the understanding of a potential epigenetic role in the seasonality of human disease. Our study suggests the existence of a circannual periodicity in DNAm patterns, much like the seasonal periodicity observed in gene expression profiles.Additional file 1. Table S1: “Summary of the studies in the meta-analysis for the association between Season of Birth and DNA methylation at birth and in children (age: 1 to 11 years)”. Baseline summary of participants from each of the individual cohorts.Additional file 2. “Cohort-specific methods and declarations ”. Method description, Funding and Acknowledgements from the participating cohorts.Additional file 3. “PACE analysis plan for Season of Birth and methylation profiles in children (6 June 2018)”. Analysis plan that was circulated amongst the participant cohorts for the Season of Birth study.Additional file 4. Table S2: “Models used in this meta-analysis study”. Inflation (lambda) and bias information of the models. Table S3: “Comparison of magnitude and direction of the FDR-significant DNA methylation signals identified in the at-birth and childhood meta-analyses”.Additional file 5. Table S4: “Direction of differential methylation of CpGs in DMRs of the at-birth and childhood analyses .Additional file 6. Table S5: “Genes mapped to DMP/DMR identified in at-birth samples of babies born in the latitude ≥ 50°N and some examples of their associations with biological functions”. Provides examples of known functional associations of genes mapped to significant CpG sites or differentially methylated regions identified in this study.Additional file 7. Table S6: “Season of birth-associated differentially methylated regions (DMRs) at birth in babies born in latitudes < 50°N”. Differentially methylated regions and mapped genes identified in the at-birth samples of babies born in latitudes < 50°N . Table S7: “Season of birth associated with differentially methylated regions (DMRs) in children born in latitudes ≥ 50°N”.Additional file 8. Table S8: “Genes mapped to DMR identified in the childhood samples of children born in the latitude ≥ 50°N and some examples of their associations with biological functions”. Provides examples of known functional associations of genes mapped to significant differentially methylated regions identified in this study.Additional file 9. “Trait Enrichment Analysis (EWAS Atlas)”. Trait names and the odds ratios for their association with CpG sites for all the models meta-analysed in this study.


Canada’s first alongside midwifery unit (AMU) was intentionally informed by evidence-based birth environment design principals, building on the growing evidence that the built environment can shape experiences, satisfaction, and birth outcomes.To assess the impact of the built environment of the AMU for both service users and midwives. This study aimed to explore the meanings that individuals attribute to the built environment and how the built environment impacted people’s experiences.We conducted a mixed-methods study using a grounded theory methodology for data collection and analysis. Our research question and data collection tools were underpinned by a sociospatial conceptual approach. All midwives and all those who received midwifery care at the unit were eligible to participate. Data were collected through a structured online survey, interviews, and focus group.Fifty-nine participants completed the survey, and interviews or focus group were completed with 28 service users and 14 midwives. Our findings demonstrate high levels of satisfaction with the birth environment. We developed a theoretical model, where “making space” for midwifery in the hospital contributed to positive birth experiences and overall satisfaction with the built environment. The core elements of this model include creating domestic space in an institutional setting, shifting the technological approach, and shared ownership of the unit.Our model for creating, shifting, and sharing as a way to make space for midwifery can serve as a template for how intentional design can be used to promote favorable outcomes and user satisfaction. Canada’s first alongside midwifery unit (AMU) opened in Markham Stouffville Hospital, Ontario, in July 2018. The AMU is a physically separate birthing unit governed and staffed by midwives. The unit is in close proximity to the labor and delivery (L&D) unit, so that in the event of an emergency, patients can be easily moved. For more detail on the setup and function of the AMU, see Compared to conventional hospital units, the AMU was purposefully designed aesthetically as a “home-like” environment and was equipped to provide comprehensive intrapartum care. While we describe the AMU as “home-like” and much of the literature describes creating domestic birth spaces, we explicitly recognize that the concept of “home” is not universal. It is important to deconstruct this term which is pervasive in the research. In general, “home-like” is used to imply a place of safety, security, autonomy, and domesticity; however, this may not be true for all childbearing people, and for some, home may be an unsafe place . The intThe physical environment significantly influences service user’s feelings of safety, relaxation, sense of comfort, well-being, control, stress levels, satisfaction, and outcomes during birth . FurtherFor healthcare providers, improving workplace design in healthcare settings has been shown to reduce stress, enhance safety, productivity, job satisfaction, and quality of care. This includes attention to the layout and configuration of the unit and birth room, the flexibility of the space, light and color, visual and sensory elements, a social room for healthcare providers, and incorporating elements of nature .The design of the birth environment has been shown to influence job satisfaction and the way healthcare professionals provide care, which in turn may also impact birth outcomes . TraditiThe purpose of this study was to assess the impact of the built environment of the first Canadian AMU for midwifery service users, along with the midwives who work there. Our specific objectives were to explore the meanings that individuals attribute to the built environment and to explore how this influences satisfaction with birth space.We conducted an explanatory, sequential mixed methods using a grounded theory methodology. This study was one component of a concurrent, multiphase, mixed-methods evaluation of the AMU, involving both midwives and midwifery service users. Ethics approval was granted by both the Markham Stouffville Hospital (Protocol #78-1808) and Hamilton Integrated Research Ethics Boards (Protocol # 5050 and 5056).Our study was informed by a sociospatial conceptual view of the birth environment. From this perspective, the birth environment is defined as not only a physical space but also a place that has meaning and value invested within it by the people who interact with it. The birth environment is shaped by what is physically in the room, such as the design elements, equipment, and the architecture, but also by broader sociocultural expectations, norms, and influences, which are constructed in part by the thoughts, feelings, and responses of the people who use and interact with the environment . We usedOur study population included midwifery service users and midwives. Everyone admitted to the AMU, including individuals whose care was later transferred to an obstetrician on the L&D unit during the intrapartum period, was eligible to participate in the study . We recrMidwifery service users completed an online survey, followed by an individual interview. Midwives participated in either an individual interview or a focus group. The survey and interview questions for all participants, developed by our research team, explored experiences of the built environment of the AMU, including how they used the space, their satisfaction, and evaluation of the equipment available to them. Individual interviews, completed via telephone, and the focus group, conducted in person, were conducted by an experienced researcher and audio recorded. We obtained informed consent from all individuals prior to their participation in all surveys, interviews, and focus groups.In keeping with grounded theory approaches, we conducted data analysis concurrently with data collection to facilitate the iterative process of constant comparison . DecisioThe data were analyzed sequentially. First, we analyzed the quantitative survey data. Descriptive statistics were used to present the survey data using Microsoft Excel. The Likert scales were collapsed into a three-point scale  and summarized into percentage proportions. Next, we used grounded theory to analyze our qualitative data. Specifically, data collected from interviews were transcribed verbatim, read line-by-line, and open coded by three researchers. To ensure reliability between coders, codes were reviewed as a team to ensure agreement. We created categories by identifying relationships between related open codes; next, we clustered categories together to form themes . These tFifty-nine service users completed the survey. Twenty-eight services users and 11 midwives participated in interviews and three midwives participated in one focus group .The majority of midwifery service-user participants had postsecondary education, earned a total household income above US$100,000 per year, and were similar in age . ParticiThe survey findings indicated that service users were highly satisfied with their experiences in the AMU and with elements of the built environment. Components of their experiences that were rated as highly satisfying included: the check-in/welcome experience (93.6%), atmosphere (97.9%), physical space (93.4%), the tools and equipment available (83.2%), and the accommodations made for family members 84.0%; . In termOur interview findings confirmed and expanded on the survey findings and supported the development of a theoretical model, whereby “making space” for midwifery in the hospital contributed to positive experiences and overall satisfaction with the built environment of the AMU. “Making space” is accomplished through three crucial steps: creating a domestic space in an institutional setting, shifting the technological approach, and sharing ownership of the space . We use The AMU was designed to look and feel cozy, relaxing, comfortable, and intentionally different from the traditional hospital environment, which participants described as “cold and sterile.” Despite being located within the hospital, the atmosphere, aesthetics, spaciousness, and the ways it supported family members all contributed to the AMU feeling more domestic than institutional. The atmosphere was described by midwives as being quiet, calm, spa-like, and very welcoming to families.Service users chose similar words to describe the atmosphere and went further to articulate that it felt private and intimate and noted the atmosphere was very different from a hospital ward. Multiparous people who had previously given birth on the traditional labor unit noted that the AMU was calmer in comparison. The AMU aesthetics included soft wall colors, nature murals, artwork, birth affirmations, and soft furniture . ServiceBoth service users and midwives enjoyed the spaciousness of the AMU and birthing rooms. The AMU was less crowded and busy than the traditional labor unit due to fewer people, fewer visible supplies, and medical equipment, resulting in more open spaces . The midA major design element of the AMU was to create an environment that felt more like a domestic space than a hospital. Service users commonly described the AMU as “the best of both worlds,” meaning the best of homebirth and hospital birth combined. This referred to the ability to have a home-like environment while still being in the hospital, with quick, easy access to obstetrical care if needed, unlike at a planned homebirth. The space also accommodated and supported partners and families through the family lounge and kitchen, comfortable furniture, and the birthing room being large enough to comfortably accommodate their presence. Families also expressed feeling welcome in the space by AMU staff, noting that the space was set up to support their involvement in the birthing experience.Overall, the ambiance, aesthetics, and family-orientation created a domestic space that contributed to feelings of comfort and relaxation.The design of the AMU moved away from the biomedical and technological focus of childbirth characterized by a reliance on technology. This shift occurred by removing from the birth space much of the technology that was not routinely used. The primary motivation for this was to decrease access to unnecessary equipment and therefore demonstrate respect for judicious rather than routine use of technology. Put simply, if the continuous fetal heart rate monitor is present in the room, it will be used. However, this removal of equipment had two consequences. First, it reduced the amount of unnecessary equipment, which created more open space for people to move about and labor freely. Second, it allowed for the introduction of nontechnology-based labor and birth tools and equipment. For example, since the traditional equipments, such as the fetal heart monitor, obstetric bed, and neonatal warmer. were brought in only when needed, items to support physiologic birth, such as bars, slings, mats, and birth stools, were prioritized and visible. On the traditional labor ward, these tools had previously not been available, not accessible due to space limitations. By comparison, in the purpose-built AMU, these tools and equipment were at the midwife’s fingertips and promoted their use to support physiologic birth . The tooService users enjoyed and appreciated the variety of resources available since it gave them more opportunities to find the right tool or position while coping with contractions. However, some service users felt they needed better education about the tools, how to use them, how they were beneficial in labor, and at what stages in labor they were helpful. Without this information, clients often refrained from using the equipment at all. For example, some service users reported not knowing about the ability to control the lighting and music in the room.Overall, both service users and midwives reported that removing and modifying the technology and equipment in the birthing room created a space that was flexible and usable. Midwives had the ability to remove, move, or add equipment as necessary to accommodate the needs of each individual. The open space facilitated mobility, freedom of movement, and the ability to use more of the space.A unique design feature of the AMU birth spaces was the replacement of traditional hospital beds with a queen-sized murphy bed that was folded down from the wall only when in use . This shWe found that all users of the space, service users, midwives, and family described a sense of individual ownership over the space. For midwives, this stemmed from the space being solely for midwifery care and governed and run by midwives. The governance of this space was an important aspect of ownership, as midwives were able to create their own care standards based on evidence-based midwifery approaches to care. Midwives recounted how this facilitated a sense of power and autonomy, knowing that the space was designed specifically to support their philosophy of care and validated their work. Service users supported this sentiment, valuing a space that was designed to promote the type of care and birth philosophies they were seeking when choosing midwifery care. Features like the staff room and meeting rooms gave midwives a sense of belonging and camaraderie that had been missing since they had never previously had dedicated spaces in the hospital.Those birthing on the unit demonstrated multidimensional ownership of the space, by taking control of their physical surroundings and their birth experience. In the birthing room, they had flexibility to modify the space, including the equipment, labor tools, and furniture. They also had the ability to personalize the lighting and music and were encouraged to bring personal items to make the space more comfortable, such as LED candles, pictures, and curated music playlists. The birthing room was described as a space that became their own, almost an extension of their home. The built environment also facilitated greater ownership over the birth experience. This was achieved by using a variety of birthing tools, hydrotherapy, and movement into various positions for laboring and pushing, and ambulating in the room and in the hallways. Midwifery service users expressed feeling a sense of control over their experience as a result of having more options. The midwives noted that ownership and customization of the space contributed to relaxation, improved outcomes, and an overall better birth experiences for service users.Finally, family members also shared in this sense of ownership since they were able to be an integral part of the birth experience. All participants expressed appreciation that families had enough space in the birthing room to settle in and be comfortable, without feeling crowded and that spaces such as the lounge and kitchen accommodated families. Additionally, the midwives believed that partners were more involved in labor support on account of the increased space and room for movement.This study, underpinned by a sociospatial conceptual approach, used grounded theory to explore the impact of the built environment of Canada’s first AMU from the perspective of both midwives and service users. The findings revealed that the intentional design elements of the unit facilitated positive experiences and contributed to greater satisfaction with the birth experience. We attribute these positive experiences to three key ways of “making space” for midwifery-led birth—creating a domestic space in an institutional setting, shifting the technological approach, and sharing ownership of the AMU . These fOur results support previous research, which emphasized the importance of ownership and control in the birthspace . The birThe flexibility of the space was a key component to participants’ satisfaction, making it easier for midwives to fully promote physiological birth and giving birthing people ownership and options . It is iOur findings stress the impact and importance of midwives feeling a sense of ownership and belonging in the birthspace. Previous findings from As now neither a visitor in clients’ homes, nor guest in the labor ward, midwives working on the AMU exist in a liminal space, which As Canada’s first AMU, this analysis is critical for identifying factors that should be considered when designing future birth spaces to optimize the environment for all. Our model for creating, shifting, and sharing as a way to make space for midwifery approaches can serve as a template for other centers looking at intentional design to promote favorable outcomes and user satisfaction.This model of care and the intentional design of the birth environment may be an important component to midwifery retention, which is an ongoing problem globally. In a recent study in Western Canada, one third of midwives surveyed had seriously considered leaving the profession . The litThere are further implications to using “home-like” as a design goal. From an equity lens, there may be a benefit to the unit having a stereotypical “home-like” aesthetic, as it provides an alternative to homebirth for those who don’t have a home-space that provides the same safety, comfort, ambiance, and spaciousness as the AMU.Our mixed-methods approach strengthened the study as we were able to confirm our findings through data triangulation. Limitations of the study stem from the fact that we did not collect data from patients with other care providers at the same hospital, nor did we investigate midwifery service user’s experiences in the traditional labor ward prior to the opening of the midwifery unit. Also, our findings may not be generalizable to other communities due to the specific demographics of the midwifery population who participated.The built environment of AMU resulted in positive experiences and satisfaction among all participants. The domestic environment was relaxing and comfortable for those in labor, while still maintaining proximity to emergency care. This purpose-built space designed with equipment and resources to support midwife-led care encouraged flexibility and choice for those giving birth. Finally, the built environment led to a greater sense of ownership for all those giving and receiving care. This went beyond the space and how it is designed, to include how it was used and co-created by midwives, service users, and their families.To optimize the birth environment for all, institutional birth settings should consider incorporating domestic elements and demedicalizing the space to promote midwifery approaches to care which support physiologic birth.Midwifery ownership and self-governance contribute to how the space is used and co-created with service users. This agency and ownership foster a sense of belonging, which is an important contributor to healthcare provider job satisfaction.A positive built environment for the birth setting may have a meaningful impact on addressing attrition and retention in the midwifery profession through decreased stress and increased job satisfaction.Optimizing the birth environment can improve childbirth satisfaction among women and birthing people and their families. But service users need to be informed about how to optimally interact and make use of the space during the antenatal period.


Intrauterine growth restriction and prematurity determine low birth weight. Thecombination of the three conditions results in different neonatal phenotypesthat interfere with child survival. Neonatal prevalence, survival and mortalitywere estimated according to neonatal phenotypes in the cohort of live births in2021 in the state of Rio de Janeiro, Brazil. In this study, live births ofmultiple pregnancies, with congenital anomalies and inconsistencies in theinformation of weight and gestational age were excluded. The Intergrowth curvewas used to classify weight adequacy. Mortality  and survival (Kaplan-Meier) were estimated. In total, 6.8%, 5.5%, and 9.5%of the 174,399 live births were low birth weight, small for gestational age(SGA), and premature, respectively. Considering low birth weight live births,39.7% were SGA and 70% were premature. The neonatal phenotypes wereheterogeneous according to maternal, delivery, pregnancy, and newborncharacteristics. The mortality rate per 1,000 live births was high for low birthweight premature newborns, both SGA (78.1) and AGA , at all specific ages. Reductions in the survival rate were observedwhen comparing non-low birth weight and AGA term live births. The estimatedprevalence values were lower than those of other studies, partly due to theexclusion criteria adopted. The neonatal phenotypes identified children who weremore vulnerable and at higher risk of death. Prematurity contributed more tomortality than SGA, and its prevention is necessary to reduce neonatal mortalityin the state of Rio de Janeiro. Birth weight remains one of the most important markers of maternal and child health,and 2,500g remains the cutoff point to define low birth weight In 2014, the estimated prevalence of prematurity - births under 37 weeks ofgestational age -worldwide was 10.6%, ranging from 8.4% in Europe to 13.4% in NorthAfrica, and 9.8% in Latin America Birth in Brazil study, using data from a similarperiod and population percentiles developed with the data itself, reported 11.1%prevalence Regarding fetal growth restriction, the prevalence of infants small for gestationalage (SGA) is often used as proxy, considering the 10th percentile of growth curvesas the cutoff. The estimate for low- and middle-income countries, in 2012, based onthe Intergrowth curve, was 19.3%, with 34.2% as the highest value, found in SouthAsia ,Birth in Brazil, the highest attributable fractionswere nulliparity, hypertensive syndrome during pregnancy, low gestational weightgain, and smoking Social and health care inequities such as unfavorable socioeconomic conditions,absence of a partner, extremes of age, non-white skin/color, low maternal schooling,smoking, newborn with previous low weight, hypertensive syndrome during pregnancy,chronic morbidities (lupus and kidney disease), low gestational weight gain, andinadequate prenatal care were associated with fetal growth restriction in thecountry This study estimated the prevalence of low birth weight, fetal growth restriction,prematurity, as well as survival rates and specific neonatal mortality by ageaccording to these phenotypes in the 2021 live birth cohort in the state of Rio deJaneiro, Brazil.This is a retrospective cohort study of live births in 2021 in the state of Rio deJaneiro followed from birth to 27 full days of life. The outcome was specificneonatal death  Data were obtained from the Brazilian Information Systems on Live Births  and Brazilian Mortality Information System  of the Rio de Janeiro State Health Department. The databases,provided in June 2022, in physical digital format (CD-ROM), without nominal andresidential identification, were deterministically related using number of theDeclaration of Live Birth as key variable. The losses were about 12% and notselective regarding age at death and maternal and neonatal characteristics Eligible newborns had birth weight ≥ 500g, gestational age ≥ 22 weeks, and werechildren of single pregnancy. Records with values of inconsistent weight forgestational age, that is, values outside the consistent ranges of the lowest 3rdpercentile value and the highest 97th percentile value ,,To classify the newborn according to fetal growth, the adequacy of birth weight forgestational age was used, considered a proxy for this estimate. Although the use ofadequacy of weight is criticized for not presenting a perfect correspondence withfetal growth For the following analyses, in which growth restriction and prematurity were thevariables of interest, LGA newborns were excluded. The resulting population wasclassified as: (1) birth weight - not low birth weight  and low birthweight ; (2) gestational age - term (≥ 37 weeks) and prematurity (<37 weeks); (3) adequacy of weight for gestational age - AGA and SGA. The resultingcombinations were eight: (a) not low birth weight , (b) low birth weight . The reference category was not low birth weight term SGA, due to the lowerrisk of death.After classification, live births were described according to maternalcharacteristics. Sociodemographic variables included age group ; skin color , and schooling . Parity was evaluated according to the number of previous deliveries(zero: primiparous and ≥ 1: multiparous). The adequacy of access to prenatal carei  per 1,000live births, the relative risks and the 95%CI according to the combinations oflow weight, prematurity, and adequacy of weight for gestational age wereestimated.Absolute and percentage distributions of the variables, adequacy of weight andgestational age, prematurity, and low weight were described for neonatalsurvivors and by age at death. Mean and the respective 95% confidence intervals(95%CI) were calculated for the variables weight and gestational age accordingto phenotype. Pearson’s chi-square test, Fisher’s exact test and ANOVA were used. The rate of specific neonatalmortality by age https://www.stata.com).The Kaplan-Meier method was used to analyze the survival curves th, 2020).This study was approved by the Ethics Research Committee of the FluminenseFederal University  . Among tThe highest proportions of mothers ≥ 35 years old were among preterm live births,regardless of the adequacy of weight for gestational age. On the other hand, thehighest proportion of adolescents were among not low birth weight and SGA full termlive births. The lowest schooling level was observed among mothers of SGA and termlive births, both low birth weight and not low birth weight. Black skin colorpresented a higher percentage between SGA with low birth weight and preterm livebirths. Inadequate prenatal care predominated among low birth weight live births,especially SGA and preterm. Cesarean section and non-cephalic presentation weremostly observed in preterm live births, especially with low birth weight and SGA.Asphyxia occurred mostly in preterm live births, with low weight, regardless ofadequacy of weight and age. Boys predominated among preterm and girls among lowbirth weight live births .SupplementaryMaterialhttps://cadernos.ensp.fiocruz.br/static//arquivo/supl-een231022_3491.pdf).Mean weight and gestational age showed significant differences between the sevenphenotypes analyzed. Particularly, for the two phenotypes of term and low weightlive births, the mean gestational age of SGA live births was about one week higherthan AGA live births (p < 0.00001) . Low birThe analysis of neonatal mortality showed higher rates for preterm newborns with lowbirth weight, both SGA and AGA, at all specific ages of neonatal death. In the notlow birth weight group, prematurity increased mortality rates more than SGA. Thehighest risk of neonatal death was among SGA preterm newborns with low birth weight, followed by AGA preterm newborns with low birth weight. Regarding the specific age at death, SGA pretermnewborns with low birth weight had the highest mortality from 1 to 6 days , and AGA preterm newborns with low birth weight from 7 to 27 days. All combinations showed high mortality rates whencompared to the not low birth weight AGA category. The highest relative risk (RR =79) was observed for mortality from 1 to 6 days of preterm SGA low birth weight libebirths .Neonatal survival rate was higher than 92% in the live birth cohort. The survivalproportions of low birth weight and not low birth weight newborns were,respectively, 94.74%  and 99.85% ; pretermand term, 95.41%  and 99.85% ; and SGA andAGA, 98.66%  and 99.55%  The smallestdifference in estimated survival was between AGA and SGA live births (0.84%) andabout 5% between term and preterm live births, and not low birth weight and lowweight. When the three conditions are combined, significant reductions in neonatalsurvival are observed, especially for preterm newborns with low birth weight, bothfor AGA and SGA, the latter being the one with the lowest survival, when compared tonot low birth weight and AGA term newborns (p < 0.001). In the cohort of live births from the state of Rio de Janeiro, in 2021, excludingcongenital anomalies, the prevalence of prematurity was 9.8%, 6.8% for low birthweight, and 5.5% for SGA. The risk of neonatal death was more influenced byprematurity than by fetal growth restriction, regardless of the phenotypes analyzed.The highest risk of neonatal death occurred in the combination of the threeconditions - low birth weight, SGA and preterm live births.,Birth in Brazil - a survey based on hospitalrecords, between 2011 and 2012 - and estimated the adequacy of weight forgestational age by a curve generated with the data, without using exclusion criteriafor live births. Paixão et al. The prevalence of SGA newborns (without exclusion criteria and using the Intergrowthcurve) was equal to the one of this study in the cohort of pregnant women from 2009to 2012 in the capital of Rio de Janeiro ,,,,,,,,,Among the factors that may affect the comparability of phenotype studies arepopulation and methodological factors. The population distribution of gestationalages, birth weight, and fetal growth restriction varies between countries andregions within a same country MaterialSuplementar:https://cadernos.ensp.fiocruz.br/static//arquivo/supl-een231022_3491.pdf).Preterm newborns have a higher risk of morbidity and mortality than full-termnewborns with a gestational age greater than 39 weeks (not preterm) Although the prevalence rates in the state of Rio de Janeiro were different fromthose of the study by Paixão et al. ,In African countries, prematurity, alone or combined with fetal growth restriction,presented a higher risk of infant mortality, especially in the neonatal component,The concentration of deaths of newborns with higher risk phenotypes in the earlycomponent of neonatal mortality of this study corroborates the national pattern ofthe retrospective cohort of live births followed for longer, up to five incompleteyears (2011 to 2018) ,Furthermore, the conditions of greater sociodemographic vulnerability were present inthe three outcomes. Adolescence and low schooling were more related to fetal growthrestriction in full-term infants, corroborating studies in other low- andmiddle-income countries ,,This study presents some limitations due to losses, since information was eitherlacking or inconsistent regarding weight for gestational age. A possible lack ofmeasurement accuracy, particularly of gestational age A strong point of the study was highlighting the representativeness of the resultsconsidering the reconstitution of the cohort of live births from the data availablein the health information systems that have good national coverage and, mostly, inthe state of Rio de Janeiro ,Therefore, the estimated prevalence rates of the conditions of risk of low weightneonatal death, SGA, and prematurity showed lower values compared to other studies,partly due to methodological nuances. Furthermore, population differences may havecontributed to different phenotypic combinations, as reported in other studies ,,Phenotypes resulting from the combination of these conditions identified morevulnerable children in the present study, highlighting the contribution ofprematurity. Fetal growth restriction and prematurity share causes and consequencesand are interlinked in the determination of low weight and, consequently, neonatalmorbidity and mortality


Iron deficiency (ID) in very preterm infants born at 28–32 weeks of gestational age (GA) can lower mental and motor test scores. This study aimed to determine whether the rapid growth of very preterm infants might be associated with ID. Among 134 very preterm born between January 2014 and December 2020 at Jeonbuk National University Hospital and discharged home, 93 were included in this study. Rapid BMI increase (RBI) was defined as a z-score difference of > 1 standard deviation between birth and 8 months. ID occurred in 23 of 93 (24.7%) infants at 8 months of corrected age (CA). ID was more common in the RBI group (50%) than in the non-RBI group (18.7%). In the multivariate logistic regression corrected for GA, infants small for gestational age (SGA)  and RBI by z-score  were identified as independent risk factors for ID at 8 months of CA. Conclusively, both SGA and RBI in the early life of very preterm were risk factors for ID at 8 months of CA. Preterm infants are at risk of ID because of a combination of physiological factors such as lower storage iron concentrations at birth and shorter half-life of red blood cells. In neonates, ID can result in lower mental and motor test scores, and it can be prevented by iron supplementation3. Iron supplementation from 6 weeks to 6 months can reduce the risk of ID and ID anemia (IDA) in these infants, without short-term adverse effects on morbidity or growth4. Assessing the nutritional status of very preterm infants and iron testing during follow-up visits is important.Iron deficiency (ID) remains a serious health problem in children, even if it is not accompanied by anemia. The prevalence of ID among newborns fluctuates considerably across different studies; however, it remains alarmingly high. For instance, a prospective cohort study conducted on very-low-birth-weight infants (VLBWI) in Brazil reported a prevalence of 48.0% at 1 year of corrected age (CA), whereas studies on European term infants aged 1–3 years reported a prevalence ranging from 5 to 20%5. The optimal catch-up growth rate is unknown, except that the catch-up completion point is 18–24 months. However, rapid growth in very preterm infants, rather than skeletal maturity, tends to increase the risk of overweight status and obesity7. Moreover, whether excessively fast catch-up growth leads to good outcomes in very preterm infants is unclear because their postnatal growth rate is similar to their intrauterine growth rates. Thus, this study aimed to determine whether the rapid growth of very preterm infants is an ID-associated factor.Very preterm infants born at 28–32 weeks of gestational age (GA) experience catch-up growth by 18–24 months of CA. Successful catch-up growth in very preterm infants positively affects neurocognitive long-term outcomesThis study included very preterm infants discharged from the neonatal intensive care unit (NICU) of JeonBuk National University Hospital (JBUH) between January 2014 and December 2020 based on the data collected from the electronic medical records. Patients who were diagnosed with hemoglobinopathy and/or were not followed-up at 8 months of CA and those without available data on physical examination findings, diet, and blood test results on the medical chart were excluded from the analysis. Among 134 very preterm infants born between January 2014 and December 2020 at JBUH and discharged home, 93 were included in this study.3+) should be provided to very preterm patients at 2–4 weeks of age and maintained until at least 8 months regardless of their diet. The guardians were instructed to increase the amount of iron supplementation (2.5 mg/kg) according to the body weight of infants. Human milk fortifier or premature infant formula must be continued at least until full-term. Thereafter, the diet is provided based on the infant’s condition. Weaning should be started at the CA of 4–6 months and must begin with rice cereal and include iron-fortified food and beef to facilitate iron supplementation. For the first year, follow-up is performed at 4 (3–4), 8 (6–8), and 12 (10–12) months of CA. At each follow-up, the patient’s length, weight, and head circumference growth are measured. At birth, anthropometric parameters were measured at least twice by two nurses and measured again in the NICU if the obtained values differed by > 10%. The length and weight of infants visiting the outpatient clinic were measured with a length board using the gold standard method8. The infants also underwent physical and neurodevelopmental examinations. Developmental abnormalities in aspects such as motor, cognitive, and language skills were identified using a part of the Korean Infant Development Test9. Diet was also investigated to determine whether solid food including meat is started and whether iron supplementation according to weight (2.5 mg/kg) and cholecalciferol supplementation (400 IU/day) are adhered to. At 8 months of CA, blood test was also performed to confirm recovery from physiological anemia10. The examination included serum ferritin and iron levels, total iron binding capacity, calculated transferrin saturation (TS), and mean corpuscular volume (MCV). A retrospective study of patients discharged from the NICU based on the follow-up protocol of JBUH was conducted.JBUH has a policy for the follow-up of very preterm infants. The preterm infant formula (16%), regular formula, and breast milk with fortifier provided in the NICU contained 0.24 mg, 0.66 mg, and 1.44 mg of iron per 100 mL, respectively. Iron supplementation  were defined as below the 10th percentile at birth and 8 months of CA, respectively13. Rapid growths based on height, weight, head circumference, and BMI were defined as a z-score difference of > 1 standard deviation (SD) between birth and 8 months with consideration of catch-up growth15. ID was defined by two or more of the following parameters: ferritin level < 12 mcg/L, MCV < 71 fL, and TS < 10%. Anemia was defined as a hemoglobin level of < 10.5 g/dL at 8 months of CA16. IDA was diagnosed when both ID and anemia criteria were met.Weight, length, and head circumference data at birth and 8 months of CA were collected from the medical records. Z-scores of collected anthropometric data by GA were calculated based on the Intergrowth 21 chartThe perinatal characteristics of preterm infants on NICU admission and their status at discharge were collected. The perinatal characteristics included Apgar score, GA, sex, and neonatal and maternal disease. The diseases observed in premature infants during NICU admission included respiratory distress syndrome (RDS), intraventricular hemorrhage, necrotizing enterocolitis, bronchopulmonary dysplasia, duration of ventilation, sepsis, and retinopathy of prematurity. The maternal diseases associated with anemia included pregnancy-induced hypertension, maternal diabetes mellitus, and abnormal placenta. Data on hemoglobin levels and MCV at discharge were also collected. Further, information on abnormal neurodevelopment, feeding type, and solid food initiation at 8 months of CA was obtained. Feeding types were classified into exclusive breastfeeding, formula feeding, and mixed feeding.2 or Fisher’s exact tests for proportions were performed. A logistic regression model was used to determine the risk factors for ID at a CA of 8 months. GA and other factors with statistical significance based on ID were included as variables in the multivariate regression analysis with backward stepwise variable selection. The risk factors for the outcomes were evaluated based on the odd ratios and confidence intervals. All statistical analyses were conducted using R version 4.1.1 . P-values of < 0.05 were considered statistically significant.The exposure and outcome were Rapid BMI Increase (RBI) and ID at 8 months of CA, respectively. The very preterm infants included in the study were divided into two groups according to RBI. The values measured at birth and 8 months of CA and iron status from blood tests at 8 months of CA were compared. Continuous variables are reported as the mean and standard deviation. Categorical variables are reported as frequencies and percentages. Demographic factors and outcomes between groups were compared using the analysis of variance. The χThis study was approved by the Institutional Review Board of Jeonbuk National University Hospital (IRB No. 2016-07-018-002) and conducted following the Declaration of Helsinki. The need for informed consent was waived by the ethics committee/institutional review board of Jeonbuk National University Hospital.Among the 41 patients who were excluded, 17 were lost during follow-up, and 12 did not have data on physical measurements at the CA of 8 months due to early follow-up. The remaining 12 patients were excluded from the analysis due to blood test refusal. All patients underwent blood tests with iron profile and CRP levels, which are used to diagnose ID.The mean GA and birth weight of 93 very preterm infants included in the study were 30.1 ± 1.1 weeks and 1419.1 ± 291.5 g, respectively. A total of 41 patients were excluded from the study, and there was no difference in gestational age and birth weight between the included  and the excluded group . At 8 months of CA, IDA and ID occurred in 5 of 93 (5.4%) and 23 of 93 (24.7%) infants, respectively. Between birth and 8 months of CA, 18 (19.4%) infants showed RBI, of which 9 (50%) had concurrent ID. Among 75 (80.6%) infants in the non-RBI group, 14 (18.7%) had ID. Anemia at 8 months of CA was not present in very preterm infants with normal iron status. All infants with anemia were confirmed to have IDA (Fig. The clinical characteristics of very preterm infants were compared according to RBI. The group with RBI had a greater GA and a higher incidence of RDS. Except for these differences, perinatal characteristics, morbidity, and duration of NICU admission did not differ significantly according to RBI. All infants were discharged without any respiratory or dietary assistance. There was no significant difference between the two groups in terms of hemoglobin levels, MCV, and the incidence rate of anemia. All infants survived up to 8 months of CA. No difference was found in terms of neurodevelopment and feeding type at the 8-month follow-up visit Table . The cliNo difference in length, weight, or head circumference at birth was found between the RBI and non-RBI groups. BMI at birth was lower in the RBI group than in the non-RBI group. At 8 months of CA, no difference was noted in the head circumference or length. However, the RBI group weighed more than the non-RBI group. When differences in z-scores between birth and 8 months of CA were evaluated, a difference in weight was found. When changes in z-scores between birth and 8 months of CA were compared according to RBI, a statistically significant difference in weight but not in length was noted. Ferritin, MCV, serum iron, and transferrin saturation values indicating iron status at 8 months of CA were generally lower in the RBI group than the non-RBI group, although not significantly lower. However, when ID was classified by applying diagnostic criteria, more infants with RBI were diagnosed with ID than those without RBI. No difference was found in the frequency of anemia according to RBI. Then, anthropometric data of very premature infants were compared according to ID at 8 months of CA. No significant difference was found in length, weight, head circumference, or BMI at birth or 8 months of CA Table .Table 2ALogistic regression analysis was performed to identify the risk factors of ID at 8 months of CA. The ID group had more infants with RBI and SGA than those without ID. EUGR, feeding type, and solid food initiation at 8 months of CA did not differ significantly according to ID (Supplemental Table 17. ID at infancy was associated with a faster growth between 0 and 12 months20. Inappropriate provision of iron supplementation according to the rapidly increasing weight of infants may also increase the risk of ID.RBI between birth and 8 months of CA was identified as a risk factor for ID at 8 months of CA. Among the criteria for rapid growth in very preterm infants, RBI was found to be an independent risk factor for ID. Since RBI is the catch-up in the growth of very preterm infants, it may result from a rapid increase in relative weight without maintaining an overall balance in growth. The mean iron requirements for growth include blood volume expansion and body mass gain. As the infant grows and blood volume expands, hemoglobin requires increased amounts of iron1. Prophylactic iron supplementation in premature infants reduced the prevalence of anemia at 12 months of CA21. Adequate iron supplementation was ensured via follow-up during infancy among very preterm infants. Iron supplementation at 2 mg/kg/day until 6 months of life in marginally LBW infants is an effective intervention to prevent early IDA12. In a recent retrospective study of very preterm infants, early iron prophylaxis was performed at 2–4 weeks of chronological age. However, ID was confirmed in 32% of very preterm infants before 6 months of CA22. Considering that a similar rate of ID was also observed in this study, very preterm infants require a higher iron supply to prevent ID compared with term or moderate preterm infants.In this study, ID/IDA occurred in 24.7%/5.4% of very preterm infants. In a prospective study in Brazil targeting a similar cohort, the rates of anemia and ID in very LBW infants at 1 year of CA were 26.4% and 48.0%, respectively23. Iron sufficiency measured based on reticulocyte hemoglobin levels at discharge from the NICU was confirmed to be 20% and increased to 39% after educational efforts and standardized guidelines were applied24. Although the reticulocyte hemoglobin level was not measured in this study, with consideration of hemoglobin levels at discharge, iron supplementation is required from the early period of birth.Reticulocyte hemoglobin levels were used to differentiate ID from other causes of anemia25. Since ID is common in late preterm infants at approximately 6 weeks of age, low birth weight and low serum ferritin levels within the first week of life are associated with a high risk of iron depletion, requiring iron supplementation in the early stages of life26. A previous study on late preterm infants also revealed that infants with SGA had lower ferritin levels and total body iron stores27. Thus, neonates with SGA require a large amount of iron supply.SGA in very preterm infants was also considered a risk factor of ID at 8 months of CA. In a recent prospective study of neonates under 33 weeks of age or those with SGA, ID was confirmed in the cord blood immediately after birth in 16% of patients and at 1 month of age in 32%5. However, when normal-weight children gain weight rapidly, they have an increased risk of becoming overweight and obese rather than developing skeletal maturity7. In a single center study in which 834 premature infants were followed-up for 1 year21. A rapid increase in BMI in SGA newborns can increase the risk of persistent obesity14. The optimal pattern for infant weight growth is thought to be different among populations28. Therefore, the criteria for rapid growth that can lead to a worse poor prognosis must be presented.After birth, the rapid catch-up in weight and head circumference of premature infants has a positive effect on neurocognitive prognosis. Pediatricians try to keep the growth as fast as possible because the association among later adiposity, insulin resistance, and cardiovascular diseases, which can result from rapid weight growth, is unknown6. Thus far, the concept of growth in premature infants has mainly focused on comparing outcomes according to whether growth is slow5. Considering the catch-up growth of very preterm infants, setting the standard for rapid growth in infancy after birth to when the z-score has increased by ≥ 1 SD among various criteria appears reasonable. Previous studies of full-term children have reported rapid growth in 21.8% and 28.7%7. In this study, the population of premature infants was small, which could have been due to the set conservative standard for catch-up growth in very preterm infants. Because the catch-up growth of very preterm infants should be a range of growth in infants without diseases, the BMI presented in this study can be considered the upper limit of catch-up growth.Rapid growth in the neonatal period has different definitions, and the relative z-score is mainly used. Stetter defined rapid growth in the neonatal period as an increase in the z-score of ≥ 1 SD from birth to 4 months of age and suggested that meeting this criterion as a newborn is associated with obesity as a child and young adultThis study had some limitations. First, the ID risk factor analysis could not include compliance with recommended iron supplementation amounts, which should be checked through follow-up observations at 4 and 8 months of CA. Moreover, statistical analysis was difficult because of the subjectivity of parents’ answers rather than quantitative indicators. Second, the iron status at birth could not be confirmed. Considering the relationship between SGA and iron status at birth reported in previous studies, ID due to decreased iron storage was reflected in SGA infants. Third, the TfR was not included in the previously presented diagnostic criteria of ID because it could not be tested in our hospital. Although ID was judged to be underestimated, its prevalence being similar to its diagnostic criteria indicated that it might have a small effect on the results of this study. Finally, data were insufficient data, including dietary data between discharge and 8 months of CA, because of the retrospective design.29.The rapid growth of premature infants is thought to have a similar effect. Adequate iron supply must be maintained to prevent ID in premature infants, which were previously identified as causes of ID and IDAIn this study, the RBI of very preterm infants in early life and SGA were risk factors for ID at 8 months of CA. Consequently, it underscores the need for tailored nutritional strategies for this vulnerable subgroup. Further prospective studies of ID based on proper BMI increases of very preterm infants are needed.Supplementary Table 1.Supplementary Table 2.


It has been suggested that maternal type 1 diabetes (T1D) increases the risk of autism spectrum disorder (ASD) in the offspring. However, it is unclear whether this risk is mediated by pre-term birth, affecting around one-third of pregnancies with T1D, and whether maternal levels of glycated haemoglobin (HbA1c) impact the risk.A cohort of 1.4 million Swedish children born between 1998 and 2015, and their parents. Maternal T1D and HbA1c before or in early pregnancy, gestational and ASD diagnoses were obtained from Swedish national registers. Relative risk (RR) and 95% CIs of ASD were estimated by hazard ratios (HRs) from Cox regression or RR from log-binomial regression.Of 1 406 650 children, 8003 (0.6%) were born to mothers with T1D, 24 941 (1.8%) were diagnosed with ASD and 81 915 (5.8%) were born pre-term. The risk of ASD was increased in offspring of mothers with T1D was HR = 1.40 (1.21–1.61). The RR for each +5-mmol/mol excess HbA1c was estimated at HR = 1.03 (0.97–1.10). The T1D effect on ASD mediated through pre-term birth was estimated at RR = 1.06 (1.05 to 1.08), corresponding to 22% (16% to 41%) of the total effect. T1D in pregnancy was associated with increased ASD risk in the offspring. Twenty percent of the total effect was accounted for by pre-term birth. HbA1c was not associated with ASD risk, beyond the risk associated by the T1D diagnosis itself.Awareness of ASD in the offspring of mothers with T1D may be warranted, especially considering the additional effect of pre-term birth. Key MessagesIn this cohort study of 1.4 million Swedish children and close to 30 000 autism cases, we found a 1.4-fold increased risk of autism in the offspring of mothers with type 1 diabetes diagnosed before child birth.We did not find any support for the notion that increasing glycated haemoglobin (HbA1c) levels before or during early pregnancy would increase the risk further.Approximately 20% of the total risk of autism spectrum disorders in the offspring was mediated through the pathway of pre-term birth.Type 1 diabetes (T1D) in pregnancy increases risks of pre-term birth,,Autism spectrum disorder (ASD) is characterized by impairment in social communication and repetitive and restricted behaviours.,,Studies on the association between maternal diabetes and ASD reported mixed results.The study objective is to test the hypothesis that maternal T1D increases the risk of ASD in the offspring. We controlled for important confounding, examined the potential modifying role of pre-term birth and investigated whether ASD risk can be linked to maternal blood glucose levels, measured as glycated haemoglobin (HbA1c).The study population included all children born alive in Sweden between 1998 and 2015 to mothers from the Nordic countries  as recorded in the Swedish Medical Birth register (MBR). MBR records data on all pregnancies and deliveries in Sweden since 1973, with almost complete coverage. In Sweden, healthcare is free of charge and accessible to all citizens, which minimizes the risk of selection bias. Individual-level information from the Swedish national registries is linked by the unique personal identification numbers of all citizens.IJE online).In Sweden, all infants and pre-school children regularly undergo routine medical and developmental examinations. At age 4 years, a developmental assessment  is performed. Children with suspected developmental disorders are referred for further investigation by a specialized team at a child psychiatry unit or habilitation service. Diagnostic information is reported to the Swedish National Patient Register (NPR). The NPR includes all psychiatric inpatient diagnoses in Sweden since 1973, somatic diseases since 1987 and outpatient visits from 2001. The diagnoses in the NPR are assigned by clinical specialists, using, since 1997, the 10th version of the International Coding of Diseases (ICD 10). NPR has been subject to extensive validation efforts.2) at first antenatal visit, gestational age (weeks) and offspring sex were retrieved from the MBR. Gestational age is estimated at the early second-trimester ultrasound examination or, in <1% of births, using the date of last menstrual period. In Sweden, patients with T1D are cared for at university clinics by specialists in diabetes/endocrinology. Diagnosis of T1D is based on criteria according to the International Society for Pediatric and Adolescent DiabetesWomen with T1D were identified in the NPR and the MBR. Data on maternal age at delivery, body mass index  at the first antenatal visit was calculated based on self-reported height and measured weight, and categorized as underweight: BMI < 18.5 kg/m2, normal weight: BMI 18.5–24.9, overweight BMI: 25–29.9 and obesity BMI > 30.Data on glycated haemoglobin (HbA1c mmol/mol) were obtained from the National Diabetes Register (NDR) and recordings within –365 to +90 days from estimated conception were used in the analyses. HbA1c reflects the average level of blood glucose over the last 6–8 weeks and according current guidelines HbA1c should ideally be kept at <48 mmol/mol in early pregnancy.Maternal and paternal socio-economic status (SES) affects overall health and the degree of health-seeking behaviour, and was considered as a potential confounder.Relative risk (RR) of ASD was estimated by hazard ratios (HRs) and associated two-sided 95% Wald CIs calculated from Cox proportional hazards regression models. Each child was followed for incident ASD diagnosis from 1 year of age until the first ASD diagnosis, emigration, death or end of follow-up on 31 December 2017, whichever came first. First, we fitted a ‘crude model’, examining risks associated with maternal T1D adjusted for birth year as a continuous variable. In a second model, we adjusted for potential confounding by additionally including covariates for maternal and paternal age, history of maternal and paternal psychiatric disorders at delivery (yes/no) and maternal and paternal years of education at delivery. Birth year and parental ages entered the models using natural cubic splines with 3 degrees of freedom, except for the analyses stratified by T1D in which the small number of observations only allowed 2 degrees of freedom.IJE online). First, we repeated the analyses in subgroups of children born term/pre-term and in singletons since twins are more often born pre-term and at increased risk of ASD.,IJE online).Since mothers with T1D have an increased risk of pre-term birthWe extended the crude Cox regression model with HbA1c (mmol/mol) data and examined ASD risk associated with HbA1c, above what can be attributed to a T1D diagnosis alone. This was achieved by a parametrization in which we added a continuous variable taking the value zero for women without T1D, and HbA1c minus the average HbA1c for women with T1D for women with T1D. This two-stage risk model allowed us to estimate the risk associated with a T1D diagnosis, as well as the additional excess risk associated with a change in HbA1c in the average T1D mother by fitting a natural cubic spline to the HbA1c data. We compared the distribution of study covariates between mothers with T1D with and without data on HbA1c.We performed a series of complementary analyses; (i) since obesity is a growing problem in pregnant women with T1D and may increase insulin resistance and hyperglycemia, we examined ASD risk in subgroups by maternal BMI; (ii) ASD risk in relation to maternal T1D was also compared in subgroups of small-, appropriate- and large-for-gestational-age offspring; (iii) due to the skewed sex ratio in ASD, we examined risks of ASD in male and female offspring separately and in term and pre-terms; (iv) since T1D duration is closely linked to maternal ageAll analyses were performed using the statistical package R, version 3.6.1  and SAS 9.4 . Computer code is available from the corresponding author by request. We examined the assumption of proportional hazards by visual inspection of weighted Schoenfeld residuals and score tests.IJE online).The study cohort included 1 421 082 children. We excluded 40 children diagnosed with ASD before age 1 year. Only 14 392 (1.0%) did not have complete data on all covariates and were excluded from the statistical analyses. Thus, our analyses included 1 406 650 children, of whom 8003 (0.6%) children were born to mothers with T1D. There were 196 (2.4%) children diagnosed with ASD to mothers with T1D compared with 24 745 (1.8%) in children of mothers without T1D corresponding to 275 cases per 100 000 person-years among offspring of mothers and 184 cases per 100 000 person-years among mothers without T1D. The median length of follow-up was 8.5 person-years for offspring of mothers without T1D and 9.5 person-years for offspring of mothers with T1D (IJE online).The risk of ASD was increased in offspring of mothers with T1D. In the crude model, only adjusted for birth year, the HR for ASD in offspring of mothers with T1D compared with offspring of mothers without T1D was estimated as 1.52 (95% CI: 1.32–1.75). After adjustment for confounding, the HR for ASD was estimated at 1.40 (1.21–1.61), which remained robust when excluding twins . There wIJE online).In pregnancies without T1D, 81 915 (5.8%) of the offspring were born pre-term  comparedIJE online) and corresponding to 22% (16–39%) of the total effect. In subgroups by sex, the percentage mediation from pre-term birth was estimated at 24% (15–73%) for males and 18% (12–33%) for females  and the risk mediated by pre-term birth was estimated at RR = 1.06 (1.05–1.08), unaffected by including an interaction term between T1D and pre-term birth  and distribution at the 10th percentile at 40, median at 58 and the 95th percentile at 85 mmol/mmol. There were no differences in the distribution of confounding factors for T1D mothers with and without data on HbA1c (IJE online). The HR of ASD in the offspring of women with T1D with data on HbA1c compared with the offspring of women T1D was estimated at HR = 1.62 (1.34–1.97), similar to the HR for T1D in the main analysis.HbA1c measured 1 year prior to and until + 90 days from conception was available for 4945 (62%) of the mothers with T1D  or offspring size for gestational age (IJE online). The HRs in the earliest and latest birth cohorts were similar (IJE online). Sex-specific analyses showed slightly higher HR point estimates for ASD in girls than in boys (Supplementary Tables S6 and S7 and IJE online). The risk of ASD associated with advancing maternal age was more pronounced, i.e. steeper, for offspring of mothers with T1D compared with offspring of mothers without T1D (IJE online). For AD, the direct risk of AD from T1D was estimated at RR = 1.19 (0.98–1.46) and the risk mediated by pre-term birth was estimated at RR = 1.09 (1.07–1.10) corresponding to 35% (20–100%) of the total effect. The E-values for the mediated effect indicate that a RR of 1.33 or higher for both pre-term birth and ASD would suffice to explain away the effect mediated through pre-term birth (IJE online).There were no differences in ASD risk by maternal BMI . In Sweden, women with T1D are transferred from the diabetes clinic to specialist antenatal care when pregnancy is recognized and measures of HbA1c in pregnancy are often not registered in the NDR. We lacked information on other potential risk factors for ASD, such as maternal medications, drug abuse and exposure to pollutants.The mechanism underlying the association between T1D and ASD is unclear. Some studies support that hyperglycaemia during fetal life may lead to permanent changes in neuronal networks.T1D in pregnancy was associated with increased risks of ASD in the offspring. Twenty percent of the total effect was accounted for by the pathway through pre-term birth. Higher HbA1c was not associated with higher ASD risk, beyond the association explained by the T1D diagnosis itself.A higher awareness for autism risk in offspring to mothers with T1D may be warranted, especially considering the additional effect of pre-term birth.This study was conducted according to the Helsinki Declaration. The study was approved by the national Swedish ethics review board, Sweden . No individual-level consent was required and all data used were anonymized.dyac116_Supplementary_DataClick here for additional data file.