Background: Depending on the epidemiological context of each country, three vaccines are recommended by the World Health Organization (WHO) to be administered as soon as possible after birth (birth vaccines); namely, BCG, zero dose of oral polio vaccine (OPV0), and birth dose of hepatitis B vaccine (HepB-BD). The timely administration of these vaccines immediately after birth might pose significant challenges in sub-Saharan Africa, where about half of childbirths occur outside health facilities. We therefore conducted a systematic review and meta-analysis to estimate the coverage rate of these vaccines at a specific timing in neonates in sub-Saharan Africa. Methods: We searched PubMed, Embase, CINAHL, and Web of Science for studies conducted in sub-Saharan Africa and published up to March 31, 2017, which provided a coverage rate of the birth vaccines at any specific time points within 28 days after birth. Two investigators independently screened the titles and abstracts and extracted data from the eligible full-text articles. This study was registered in PROSPERO (CRD42017071269). Results: Of 7283 articles identified, we finally included 31 studies with 204,111 infants in the meta-analysis. The pooled coverage rates at day 0–1 after birth were 14.2% (95% CI: 10.1–18.9) for BCG and 1.3% (0.0–4.5) for HepB-BD. No data were available for OPV0 at day 0–1. The coverage at day 28 was 71.7% (63.7–79.2) for BCG, 60.8% (45.8–74.7) for HepB-BD, and 76.1% (67.1–84.0) for OPV0. No significant difference in the vaccine coverage was observed between infants born in healthcare facilities and those born outside facilities. Conclusions: The rates of vaccine coverage immediately after birth were very low for BCG and HepB-BD, and no data for OPV0. We need additional data to better define barriers and facilitators for the timely administration of the birth vaccines in sub-Saharan Africa, since the delay in its provision may increase the burden of these vaccine-preventable diseases. Vaccination is a highly cost-effective intervention to reduce morbidity and mortality on a global scale . It is eSub-Saharan Africa is a region with the highest risk of infant mortality; 53 out of 1000 births die within the first month of life in 2018 . Among tThis systematic review followed a protocol registered at PROSPERO (CRD42017071269) and was reported according to the Preferred Reporting Items for a Systematic Review and Meta-Analysis (PRISMA) guidelines .The following four databases were searched for articles published up to 31st March 2017: PubMed, EMBASE, CINAHL, and Web of Science. The search strategy was structured around three concepts: (i) BCG, OPV, or hepatitis B vaccine, AND (ii) vaccination coverage, AND (iii) sub-Saharan Africa. The detailed search strategy is presented in the We included both observational and intervention studies which provided an estimate of the coverage of the birth vaccines at specific time points in sub-Saharan Africa. We defined BCG, OPV0, and HepB-BD as the birth vaccines. The vaccination status of each individual needed to be ascertained through written documents including a vaccination card or registry. We did not consider studies that ascertained vaccination status solely through caregiver’s recalls. We excluded studies that only reported the coverage beyond 28 days.Two authors (O.B. and K.M.) independently screened the titles and abstracts of articles identified from the database search. Disagreements were resolved by the third reviewer (Y.S.). For potentially eligible articles, full-text papers were obtained and independently processed for data extraction by two authors (O.B. and K.M.). For each selected study, a pre-piloted standardized form was used to extract the following data: author names, year, country, study area , study design, study settings , source of vaccination information , percentage of study participants having a valid source of vaccination information (percentage ascertained), children’s age at the coverage assessment, maternal characteristics , place of birth, birth weight, type of vaccine, timing assessed for vaccination coverage, and percentage of neonates receiving each vaccine at each time point. Following the WHO’s instruction, we considered the timely administration within 24 h after birth if the vaccine was given within the first day of life  . Corresp2 statistic [a priori: study location ; place of birth ; birth weight; maternal education level; and maternal age. We reported these subgroup analyses irrespective of the type of the birth vaccines.Our primary outcome of interest was the proportion of infants who have received each type of the birth vaccines by certain time points within 28 days after birth. We obtained this by dividing the number of infants vaccinated by the specific time point by the total number of infants assessed. We excluded infants without a valid source of vaccination information from the denominator of these analyses. To pool the proportions, we carried out a meta-analysis using a command ‘metaprop’ with STATA 16.0  , then, ptatistic . To assen = 26); not in sub-Saharan Africa (n = 9); not enough information (n = 15); no full text available (n = 5); or not assessing timeliness within 28 days of birth (n = 68). Finally, 31 articles were included in the meta-analysis , The Gambia (n = 2), Ghana (n = 3), Guinea Bissau (n = 2), and Nigeria (n = 7)), one study from Central Africa (Democratic Republic of Congo (n = 1)), 12 studies from East Africa (Ethiopia (n = 1), Kenya (n = 5), Malawi (n = 1), Tanzania (n = 2) and Uganda (n = 3)), and 3 studies from Southern Africa (South Africa (n = 3)). There was one study that integrated results of Demographic Health Surveys from 29 countries across sub-Saharan Africa [n = 5), day 7 (n = 13), day 14 (n = 13), and day 28 (n = 17).The characteristics of the included studies are summarized in n Africa . Out of n Africa . The perA detailed description of the risk of bias of each of the included studies was presented in the 2 >98%, p < 0.001).A total of 204,111 children from 31 studies were included in the meta-analysis. Meta-analysis could be performed at four different time points: day 0–1, day 7, day 14, and day 28. The pooled coverages increased with an increase in infants’ age . Five stp = 0.5) (p = 0.3)  in those born at health facilities and 0.6% (0.1–1.7%) in those born outside health facilities A. At dayp = 0.5) B. Such ap = 0.3) C.In this systematic review and meta-analysis evaluating the timeliness of the birth vaccines in sub-Saharan Africa, the pooled rates of vaccine coverage at the age of four weeks were modest: BCG (71.7%), OPV0 (76.1%), and HepB-BD (60.8%). However, the pooled rates at birth within the first date of life were far from satisfaction: BCG (14.2%) and HepB-BD (1.3%). The coverage on day 7 was still low, with more than half of the infants remaining unvaccinated. In addition, in most of these meta-analyses, we identified strong evidence for heterogeneity across the studies. We expected such a wide geographical and temporal variation in the vaccine coverages because of the social, cultural, economic, and political differences between the contexts of the included studies in terms of vaccination practices.The timely administration is critical in conferring the expected effects of the birth vaccines to the children. BCG given shortly after birth is especially important in areas with a high incidence of tuberculosis where there is an elevated risk of early exposure to mycobacterium tuberculosis . It is kOur study highlighted the limited number of studies in the region assessing the coverage of birth vaccines, suggesting a potentially low interest and commitment to the timely birth dose vaccination in sub-Saharan Africa. Although administration as soon as after birth is recommended by the WHO, only five included studies focused on this time point. Moreover, the number of studies assessing HepB-BD was far more limited compared to the other two vaccines. In Africa, only 12 out of 48 countries integrated HepB-BD in the routine infant immunization schedule . TherefoTimely administration of birth vaccines is especially challenging in sub-Saharan Africa where about half of women give birth at home ,56. Indea priori sources of heterogeneity, we could only assess “place of birth” in the subgroup analyses. A great majority of the included studies did not report the completeness of the study population; care must be therefore taken to interpret the results in terms of representativeness of the study population. Moreover, we excluded study participants without a valid source of vaccination information from our meta-analyses. Since these infants who do not possess the vaccination card at the time of a survey are less likely to have received the vaccine in a timely manner, we might have over-estimated the coverage at each specific time point. Finally, this was a meta-analysis of aggregate data, pooling cumulative incidences of being vaccinated by the certain time points. We therefore could not assess the exact timing of vaccine administration in each individual.Our study has several limitations. Since there was a wide variation in time points to assess vaccine coverage according to the different studies, the number of studies at each time point was limited. Of six Although the majority of neonates received the birth vaccines by the first month of life, only a few received them at birth. We need additional data to better define barriers and facilitators for the administration of these vaccines at birth in sub-Saharan Africa, and this may allow us to develop evidence-based interventions to improve the coverage and timeliness of these life-saving vaccines.


To assess the birth prevalence and spatial distribution of congenital heart disease (CHD) in China by conducting a complete overview and using spatial epidemiological methods. Unrestricted searches were conducted on seven electronic databases, with an end-date parameter of May 2019. Data on the birth prevalence of CHD and its subtypes were collected and combined using either the random-effect model or fixed-effect model. Subgroup sensitivity analyses were performed to explore potential heterogeneity moderators. The three-dimensional trend analysis and a visualization of CHD birth prevalence among different provinces were performed to describe the spatial distribution characteristics. Total 617 studies involving 76,961,354 births and 201,934 CHD individuals were included. Overall, total CHD birth prevalence increased continuously over time, from 0.201‰ in 1980–1984 to 4.905‰ in 2015–2019. The study on the high-income provinces, population-based monitoring model, male births, and urban regions reported a significantly higher prevalence of total CHD compared with upper-middle-income provinces, hospital-based monitoring model, female births, and rural regions, respectively. National CHD birth prevalence increased gradually from western region to eastern region, but decreased gradually from southern to northern region. Relevant heterogeneity moderators including gender, geographic region, income levels, and monitoring models have been identified by subgroup analyses. Sensitivity analysis yielded consistent results. Total CHD birth prevalence in China increases continuously in the past 40 years. Significant differences in gender, geographical regions, income levels, and monitoring models were found. In the future, population wide prospective birth defect registries covering the entire Chinese population need to determine the exact birth prevalence.The online version of this article (10.1007/s10654-020-00653-0) contains supplementary material, which is available to authorized users. Congenital heart disease (CHD) is typically defined as clinically significant structural heart and/or great vessels disease present at birth . CHD is According to the statistics from Ministry of Health of China in 2012, CHD accounts for 40.95% of all birth defects in China . Given tAlthough the Chinese government began to monitor the birth prevalence of birth defects as early as 1986 , there hIt is important to have reliable information about national CHD birth prevalence, because this can contribute to better understanding the impact of CHD on child health, providing the basic data for further research and prevention of CHD, and guiding future health resource allocation and advocacy efforts. In addition, dedicated care could be better planned and provided. Therefore, we performed a meta-analysis for the first time to provide a complete nationwide overview of the reported birth prevalence and spatial distribution of CHD and its specific subtypes in China from 1980 to 2019.We reported this systematic review and meta-analysis according to the statement of the proposed preferred reporting items for systematic reviews and meta-analyses (PRISMA) .We systematically searched PubMed, Embase, Web of Science, China National Knowledge Infrastructure, Wanfang Database, Weipu and China Biology Medicine disc databases on May 31, 2019 to identify relevant studies assessing the birth prevalence of CHD among Chinese population. No time restriction for publication dates was used. We used and combined the following search terms:  AND  AND (China OR Chinese). Terms covering “CHD”, “birth defect”, “prevalence” “incidence” and “China” were adjusted for each database. We reviewed the reference lists of all retrieved articles and recent reviews to reduce omissions.In the present review, the outcomes of interest were CHD. The CHD diagnoses were identified according to the CHD codes of the International Statistical Classification of Diseases and Related Health Problems 10th Revision (ICD-10). We not only focused on the birth prevalence of total CHD, but also focused on the birth prevalence of specific subtypes of CHD. Total 21 commonly anatomical subtypes of CHD including atrial septal defect (ASD), ventricular septal defect (VSD), patent ductus arteriosus (PDA), tetralogy of Fallot (TOF), transposition of the great arteries (TGA), pulmonary stenosis (PS), atrioventricular septal defect, tricuspid atresia or stenosis, double outlet right ventricle, endocardial cushion defect, single ventricle, truncus arteriosus, hypoplastic left heart syndrome, pulmonary atresia, aortic stenosis, coarctation of the aorta, dextrocardia, ebstein anomaly, mitral insufficiency/regurgitation, total anomalous pulmonary venous return, and interrupted aortic arch were considered. Additionally, CHD could be also divided into mild lesions, severe lesions, cyanotic lesions and acyanotic lesions according to previous studies , 12 (detAccording to China Birth Defect Monitoring Scheme (CBDMS) , birth dWe first performed an initial screening of titles or abstracts. A second screening was based on full-text review. Studies were considered eligible if they fulfilled the following criteria: (1) study participants were Chinese peoples; (2) studies published in Chinese or English language; (3) the reported monitoring scheme of CHD was consistent with CBDMS requirements; (4) the birth prevalence of CHD or its subtypes was reported ; (5) the monitoring periods was from 28 weeks of gestation to 7 days or 42 days after birth; and (6) studies belonged to high quality studies after quality assessment. We excluded review papers, case–control studies, non-peer-reviewed local or government reports, conference abstract and presentation in the present review. We also excluded these studies that focused on the birth prevalence of CHD among specific populations, such as mothers with CHD, diabetes, hypertension, or other diseases that were significantly associated with the occurrence of CHD in offspring. If there were many studies based on the same research database, only the one that reported the most detailed data was included. Additionally, we assessed potential studies to ensure that there was no duplication of case series.Data extraction and quality assessment were done twice independently by two authors (ZLJ and QJB) to reduce the bias and errors of reviewers. Disagreements were resolved through discussions between investigators until a consensus was reached. The following study characteristics were recorded: publication year, geographic region, time period during which the study was performed, monitoring models of CHD , diagnostic method of CHD, number of monitoring participants, number of CHD cases, birth prevalence of total CHD and its specific subtypes, and quality score. Studies were grouped according to 5-year time periods since 1980 to demonstrate time trends. Time period is taken as the period in which the study was performed. Additionally, studies were further grouped according to geographic region   was applied for map construction. The combined birth prevalence and the corresponding 95% confidence intervals (CI) were calculated using either fixed-effect models or, in the presence of heterogeneity, random-effect models. Heterogeneity tests were performed using the Cochran Q test (ogeneity ) and I2 P < 0.05; otherwise, the pattern was considered to be nonclustered  compared with upper-middle-income areas [1.538 per 1000 births ] .Significant geographical differences were found Fig. . The higP = 0.115); additionally, local spatial autocorrelation analysis  also indicated that there was no aggregation among 32 provinces . Time trend analysis showed that total CHD birth prevalence in different geographical regions  increased substantially over time .Global Moran’s I spatial autocorrelation analysis  showed that the birth prevalence of total CHD in different provinces didn’t have spatial clustering  adopted population-based monitoring model to monitor the occurrence of CHD; the remaining studies (91.9%) adopted hospital-based monitoring model. Overall, total CHD birth prevalence was significantly higher among population-based monitoring model [3.373 per 1000 births ] compared with hospital-based monitoring model [2.441 per 1000 births ]. Time trend analysis showed that total CHD birth prevalence among different monitoring models increased substantially over time .The birth prevalence of specific subtypes of CHD is summarized in Table Our study also showed that the birth prevalence of mild lesions [4.581 per 1000 births ] was significantly higher than severe lesions [0.762 per 1000 births ]; similarly, the birth prevalence of acyanotic lesions [4.781 per 1000 births ] was also significantly higher than cyanotic lesions [0.608 per 1000 births ]. Time trend analysis suggested that the birth prevalence of mild lesions and acyanotic lesions significantly increased over time, but the birth prevalence of severe lesions and cyanotic lesions remained a stable status over time  . Birth prevalence estimates did not change significantly after exclusion of any single study. However, both the funnel plot  and egger’s regression test (P < 0.01) indicated the evidence of publication bias.Significant heterogeneity was observed within pooled estimates for gender, geographic region, monitoring models and income levels  and acyanotic lesions (70.1%). Additionally, VSD, ASD, PDA, TOF, TGA, tricuspid atresia or stenosis and PS were identified as the first seven most frequent subtypes.Obviously, total CHD birth prevalence in China 2.502‰) from 1980 to 2019 was relatively lower compared with both the worldwide prevalence (8.2‰) and the Asia prevalence (9.3‰) reported by previous two studies .502‰ fro. We specThird, presently, many countries adopted population-based monitoring model to monitor the prevalence of CHD , but ChiPresently, the reasons for the substantial increase of reported CHD birth prevalence in China are still uncertain. A universal viewpoint is that improved diagnostic and screening methods themselves, parental lifestyles, genetic and environmental factors associated birth defects, or a combination of these factors, bring about increased birth prevalence of CHD. Increase of CHD birth prevalence may be a result of widely used of echocardiography in clinical practice , making An additional possibility is that the changes in environmental exposures over time may be associated with substantial increase of CHD. For example, it has reported that the industrialization and urbanization over the past century have had effects on CHD birth prevalence . NowadayIn our review, the important geographical differences for CHD birth prevalence were found. The southern region and eastern region in China experienced higher birth prevalence for total CHD compared with other regions. The total birth prevalence rate of the national CHD gradually increased from the western region to the eastern region, and gradually decreased from the southern region to the northern region, which was positively related to the economic development. However, a study conducted at the Qinghai Women and Children Hospital in Xining indicated that the birth prevalence of CHD at high altitude areas was significantly higher than that at low altitude regions . There aPresent study showed that the CHD birth prevalence in urban areas was higher than that in rural areas, which contradicts the report by Li Dai et al. . The pheImportant population differences were found. Reported birth prevalence of CHD in male births was higher than that in female births, which is consistent with some previous studies , 30. TheThis study has some limitations. First, although we investigated all available literatures of CHD birth prevalence in China, and checked for bias caused by regions, surveillance models and income levels, some residual bias may be present in our estimates. It remains uncertain whether the difference in the detected birth prevalence of CHD presents real or just methodological. Second, when assessing the birth prevalence and time-trends of specific CHD subtypes, we only relied on a small quantity of studies (22 studies). Meantime, the application of different versions of ICD codes in included studies  may have a weak influence on the recording of CHD subtypes. Also, discrepancies in antenatal or postnatal diagnosis of birth defects between surveillance institutes may affect the detection rate and introduce potential biases.Third, the heterogeneity in our study was substantial. Although subgroup analyses have been conducted according to gender, geographic regions, income level and surveillance models, significant evidence of heterogeneity was still observed among subgroups. However, the heterogeneity was expected and inevitable considering the differences in the obstetric management, diagnosis of CHD, length of follow up, ethnic background, socioeconomic situation, study population, food and life habits, prenatal care services, and referral systems. Fourth, because some studies did not provide annual data on the birth prevalence of CHD, we adopted this way that a same study  could be counted twice (2000–2004 and 2005–2009) when performing the time trend analysis, which may have a slight impact on the results of time trend analysis. Furthermore, potential publication bias could influence the findings. In this study, both the funnel plot and egger’s regression test indicated the evidence of publication bias. The asymmetry of funnel plots may be due to small-study effects, especially when there was evidence of substantial heterogeneity across studies . BesidesTotal CHD birth prevalence in China increases continuously in the past forty years. Significant differences in gender, geographical regions, income levels, and monitoring models were found for birth prevalence of CHD. It remains uncertain whether detected differences in birth prevalence of CHD represent true or merely methodological differences. In the future, population wide prospective birth defect registries covering the entire Chinese population need to determine the exact birth prevalence.Supplemental Figure 1: Total CHD birth prevalence over time in different genders in China. The solid line is the estimated birth prevalence, and dotted lines represent the 95% confidence interval. (PNG 34 kb)Supplemental Figure 2: Geographical distribution of total CHD birth prevalence in different genders. (PNG 192 kb)Supplemental Figure 3: Total CHD birth prevalence over time in urban and rural areas in China. The solid line is the estimated birth prevalence, and dotted lines represent the 95% confidence interval. (PNG 31 kb)Supplemental Figure 4: Geographical distribution of total CHD birth prevalence in urban and rural areas. (PNG 190 kb)Supplemental Figure 5: Total CHD birth prevalence over time in different income levels in China. The solid line is the estimated birth prevalence, and dotted lines represent the 95% confidence interval. (PNG 40 kb)Supplemental Figure 6: Global Moran’s I spatial autocorrelation analysis of total CHD birth prevalence in China. (PNG 186 kb)Supplemental Figure 7: Local spatial autocorrelation analysis of total CHD birth prevalence in China. (JPEG 233 kb)Supplemental Figure 8: Total CHD birth prevalence over time in different geographic regions (south-north direction) in China. (PNG 44 kb)Supplemental Figure 9: Total CHD birth prevalence over time in different geographic regions (west-east direction) in China. The solid line is the estimated birth prevalence, and dotted lines represent the 95% confidence interval. (PNG 38 kb)Supplemental Figure 10: Total CHD birth prevalence over time in different monitoring models in China. The solid line is the estimated birth prevalence, and dotted lines represent the 95% confidence interval. (PNG 41 kb)Supplemental Figure 11: Funnel plots with 95% confidence limits of included studies. (PNG 50 kb)Supplemental Table 1 (DOCX 18 kb)Supporting information file 1 (DOCX 13 kb)Supplemental Excel: The characteristics of the included studies. (XLSX 239 kb)Below is the link to the electronic supplementary material.


The study of fish that generate electric fields around their bodies in order to interact with their environment continues to generate intense interest in the research community. While it has been known since ancient times that some fish can generate electricity . Such bursts have been shown to reliably encode electro-communication stimuli that occur during agonistic encounters (Marsat et al., Metzen provides a review of how natural electrocommunication stimuli are processed across successive brain areas in order to give rise to perception and behavioral responses. Interestingly, Field et al. suggest an important new function for natural electro-communication stimuli toward actually avoiding the deleterious effects of jamming stimuli, a function that was previously thought to be carried out by the jamming avoidance response. Specifically, when two fish are located within close proximity of one another, interference between their electric fields can create a jamming signal that interferes with the animal's ability to electrolocate other relevant stimuli such as prey or object boundaries (Ramcharitar et al., Fortune et al. in their investigation of how evolutionary loss of vision affects electroreception in different species of glass knifefishes and, in particular, demonstrate lack of jamming avoidance responses despite social conditions that would normally trigger such behavior based on previous studies.In general, processing of sensory input by the brain is achieved through a combination of neural circuits as well as ion channels embedded in the cell membrane. Toward the former end, s Cajal, , on actuFortune et al. also demonstrate that blind electric fish display more territoriality and dominance than their seeing cousins. Raab et al. provide some critical field data as to dominance and exploration behavior. Such field data will no doubt be key toward guiding future studies as to how these animals actively acquire information about their environments in natural settings. A study by Yu et al. investigates how an important aspect of electrosensory stimuli experienced by electric fish during social interactions, namely contrast, strongly depends on the relative distance and orientation between animals. In particular, Yu et al. reveal that contrast routinely reaches much higher values than are typically used in laboratory settings (see e.g., Marsat et al., Interestingly, Pouso et al. report, for the first time in electric fish, that distinct classes of vasotocin neurons within the pre-optic area are preferentially activated by social stimuli in courting males, and that these changes are associated with the production of electric courtship signals as well as locomotor activity related to courtship.In addition to research on the sensory processing of electric signals during social encounters, it is also critical to investigate the central networks and peripheral mechanisms that regulate electric signaling in social contexts to fully understand the social communication functions of electric signals. Toward this end, Catania reviews recent advances showing how electric eels adapt the characteristics of their strongly electric fields for different behavioral contexts ranging from stunning prey to self-defense. Interestingly, electric eels also use their strong electric field to actually track prey, which was until recently thought to be achieved exclusively through the weak electric field.Finally, it is important to remember that the most widely recognized electric fish, the Electric Eel, not only uses weak electric fields to sense the environment but also uses strong electric fields as a weapon to stun and capture prey. Taken together, the manuscripts in this collection help to illustrate the many historical advances and current progress that research with electric fish contributes to neuroethology and integrative neurobiology. This collection also serves to highlight the vast range of unresolved questions yet to be experimentally addressed.MC and MM wrote the manuscript. All authors contributed to the article and approved the submitted version.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Objective: Fecal calprotectin (FC) has been widely used for a clinical marker of intestinal inflammation in children and adults. However, the clinical usefulness has not been determined in neonates. The purpose of this study was to investigate the change of FC and associated clinical factors in neonates.Methods and Materials: In total, 146 neonates among 472 admissions to our NICU between 2018 and 2019 were included, and 242 stool samples were collected. FC was measured in the first, second, and third–fourth week after birth, respectively, using commercial ELISA. The clinical characteristics were reviewed from medical records. Statistical analyses were performed to analyze associated factors regarding on changes of fecal calprotectin.Results: A wide range from 5.5 to 6,000 mg/kg of FC was observed in neonates. FCs during neonatal period were not correlated with the gestational age at birth or birth weight. The meconial calprotectin was higher than FCs after 2 weeks of age . Meconial calprotectin was associated with birth weight and meconium stained amniotic fluid. FC during the neonatal period decreased with postnatal week  and breast milk .Conclusion: Fecal calprotectin tended to decrease with postnatal week during the neonatal period, and breast milk could affect more decrease of FC. Calprotectin is a 36.5-kDa calcium- and zinc-binding protein found mostly in neutrophils, monocytes, and macrophages and involved in the regulation of inflammation , 2. ThisAmong 472 admissions at the neonatal intensive care unit (NICU) in our hospital between May 2018 and October 2019, stool samples for FC were collected prospectively from 146 neonates born at 25–40 weeks of gestation, with parent's consent. In total, 242 stool samples were collected, with 134 in the first, 67 in the second, and 41 in the third–fourth weeks of life. Stool samples were stored at 4°C without preservative and measured within 5 days of collection using commercial ELISA  following the manufacturer's instruction. Two or more serial stools were collected from 64 among 146 neonates.The clinical characteristics were retrospectively reviewed from medical records. The prenatal and perinatal clinical factors were investigated as follows.(1) Multiple gestation such as two or more fetuses in one pregnancy.(2) Meconium-stained amniotic fluid (AF) such as meconium pass before giving birth.(3) Prolonged premature rupture of membrane (PPROM) such as rupture of amniotic membrane over 18 h before birth.(4) Maternal hypertensive condition such as essential hypertension, pregnancy-induced hypertension (PIH), eclampsia, or preeclampsia.(5) Respiratory distress syndrome (RDS) of newborn such as ground glass opacity of lungs on chest X-ray with tachypnea and/or desaturation.(6) Use of antibiotics such as any kind of antibiotic treatment for suspicious or culture-proven sepsis during the neonatal period.(7) Neonatal jaundice such as unconjugated hyperbilirubinemia that needs phototherapy in preterm and term neonates .(8) Intestinal distress such as gastrointestinal symptoms or signs leading to interrupted enteral feeding and suspected or definite NEC based on modified Bell's classification .(9) Days of full feeding such as postnatal days until fed enterally with 120 ml/kg/day.(10) Breast milk (BM) feeding such as being fed with BM exclusively or partially with BM being >1/2 of the total amount of feeding volume.t-test or the Mann–Whitney U-test. Correlation between FC and continuous variables was performed by the Spearman rho test. The categorical data were presented as the number and proportion (%). Multivariable linear or nonlinear logistic regression analysis was conducted to investigate an association between clinical factors and the level of FC. We also checked the multicollinearity between the factors for adjustment using correlation coefficients and excluded one when the coefficient was more than 0.7. The changes in FC concentration according to clinical factors during the neonatal period were investigated using a linear mixed model (LMM) or generalized linear mixed-effect model (GLMM), a repeated-measures covariance pattern model with unstructured covariance within the subjects. The P-value was set as <0.05.Statistical analyses were conducted using SPSS® version 25.0 , and GraphPad Prism 6  was used for graphics. Normality of the continuous values was tested by Kolmogorov–Smirnov and Shapiro–Wilk tests. The continuous variables were presented as the mean and standard deviation (SD) or median and interquartile range (IQR). Comparisons of FC according to clinical factors were performed by independent The protocol of this study was reviewed and approved by the institutional review board of our hospital (GNUH 2020-02-004). Informed consent was waived by the board.4/7-403/7). Among them, preterm neonates born before 37 weeks of gestation were 109 (74.7%). Mean BW was 2.2 ± 0.8 kg (range: 0.6–4.3), and low-birth-weight infants weighing less than 2.5 kg were 93 (63.7%). Twenty-eight (19.2%) were born vaginally. Males were 68 (46.6%). Mean Apgar score at 5 min was 8.8 ± 1.3. Obstetric problems occurred in 89 pregnancies, which were maternal hypertensive disorder , gestational diabetes mellitus , PPROM , and meconium pass in utero  in that order. Forty-three neonates (29.5%) among 146 neonates were born as twins or triplets.The clinical characteristics were described in Chief complaints at admission among 146 neonates were prematurity (59.6%), maternal condition affecting baby's health (17.5%), and low BW or being small for gestation (13.8%), in that order. Rates of BM feeding was 75.3% (110 of 146 neonates), and mean time to achieve full feeding with enteral route was 9.7 ± 12.0 days. Intestinal distress leading to the interruption of enteral or oral feeding including NEC, occurred in 17 of 146 neonates (11.6%). Mean hospital stays were 26.3 ± 25.9 days and weighed mean 2.8 ± 0.6 kg at discharge from the NICU. Two infants died from sepsis at the 24th and 74th days after birth.FCs were measured in the first, second, and third–fourth weeks after birth, and a total of 242 FCs were measured from 146 neonates. The FC of the first week was mean 418.06 ± 864.89 mg/kg of stool and was collected from 134 neonates on mean day of 2.14 ± 1.87 after birth . The second-week FC was mean 243.12 ± 328.80 mg/kg of stool and was collected from 67 neonates on mean day of 10.03 ± 0.43 after birth . The third–fourth week FC was mean 259.58 ± 368.18 mg/kg of stool and was collected on mean day of 21.29 ± 1.07 after birth . The lowest level of FC was 5.5, and the highest one was over 6,000 mg/kg. Changes of FC in individual subject are shown in r = −0.125, P = 0.151) or BW .The mean concentration of FC during neonatal period was 341.68 ± 687.39 mg/kg, in total. FCs were not correlated with the gestational age . We performed stepwise multivariable linear or nonlinear regression analysis to investigate associating prenatal or perinatal factors with meconial calprotectin. Of them, lower BW  and meconium-stained AF  were associated with high concentration of meconial calprotectin  and BW was different according to gender in this study .The first-week FC was measured by meconium since feces were collected at mean 2.14 ± 1.87 days after birth . Meconial calprotectin was higher than later FCs , 2. Mecorotectin . GA and P = 0.008), antibiotics , and BM , antibiotics , and postnatal week  were associated factors with decreased changes of FC during the neonatal period compared with each reference , 5′-Apgar score  or postnatal days in the first week  unlike previous studies . Even though there was a selection bias on statistical analysis according to antibiotic treatment in this study, the result that neonates with high meconial calprotectin did not receive antibiotics in later FCs might indirectly suggest that calprotectin may be involved in the regulation of inflammation (Use of prenatal or perinatal antibiotic treatments could negatively or positively affect FC in newborns , 28. In Studies of calprotectin as a marker of intestinal disease in neonates were reported given its utility in inflammatory bowel disease , 29–33. Our limitations were being an observational study in one hospital and enrollment of a small number of neonates with diverse clinical conditions. Thus, our results could not reflect the time trend of FC in healthy neonates. FC values tended to decrease with increasing GA or BW albeit being statistically insignificant , which mIn conclusion, FC during the neonatal period decreased with time regardless of GA at birth, BW, or other diseases. BM may contribute to lower FC levels. Decrease of FC with postnatal week and BM may be associated with transition of feces or establishment of intestinal microbiota. Regarding intestinal inflammation in neonates like NEC, clinical usefulness of FC was questionable unlike children and adults. We observed dynamic changes of FC during the neonatal period, and caution is necessary when FC is interpreted in neonates.All datasets generated for this study are included in the article/supplementary material.The studies involving human participants were reviewed and approved by the Institutional Review Board of the Gyeongsang National University Hospital. Written informed consent to participate in this study was provided by the participants' legal guardian/next of kin.JP: Designing and conducting the study, and drafting the manuscript. JC: Conducting the study. CC: Presenting the study and collecting data. SO: Collecting data and stool samples. HD: Collecting data and stool samples. J-HS: Interpreting data. JL: Interpreting data. C-HP: Designing the study and collecting data. H-OW: Interpreting data. H-SY: Interpreting data. All authors contributed to the article and approved the submitted version.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Although cardiometabolic outcomes were comparable in preterm SGA and AGA infants, the growth velocity at different time periods resulted in different cardiometabolic and neurocognitive outcomes. Thus, ensuring an optimal growth velocity at early neonatal period could promote good neurocognitive outcomes, while adequate growth after 1 year could prevent adverse cardiometabolic outcomes in preterm infants.Prematurity, size at birth, and postnatal growth are important factors that determine cardiometabolic and neurodevelopmental outcomes later in life. In the present study, we aimed to investigate the associations between the size at birth and growth velocity after birth with cardiometabolic and neurodevelopmental outcomes in preterm infants. Fifty-six preterm infants born at < 32 weeks of gestation or having a birth weight of < 1500 g were enrolled and categorized into small for gestational age (SGA) and appropriate for gestational age (AGA) groups. Anthropometric and cardiometabolic parameters were assessed at school-age, and the Korean Wechsler Intelligence Scale for Children, fourth edition (K-WISC-IV) was used for assessing the intellectual abilities. The growth velocity was calculated by changes in the weight z-score at each time period. Multivariate analysis was conducted to investigate the associations of growth velocity at different periods with cardiometabolic and neurodevelopmental outcomes. Forty-two (75%) were classified as AGA and 25% as SGA. At school-age, despite the SGA children showing significantly lower body weight, lean mass index, and body mass index, there were no differences in the cardiometabolic parameters between SGA and AGA groups. After adjusting for gestational age, birth weight z-score, weight z-score change from birth to discharge and sex, change in weight z-score beyond 12 months were associated with a higher systolic blood pressure, waist circumference, and insulin resistance. Full-scale intelligent quotient (β = 0.314,  Though no consensus has been made on the diagnostic criteria in the pediatric population, it presents as a combination of central obesity, hypertension, high triglyceride levels, and low high-density lipoprotein cholesterol levels, and glucose intolerance. After Barker5. According to a Polish study2, children at pre-pubertal age who were born as SGA at term showed a high prevalence of particular components of metabolic syndrome. Numerous studies have also identified the effects of preterm birth on metabolic outcomes11. A recent systematic review and meta-analysis reported that preterm birth was associated with higher fat mass, blood glucose, insulin resistance, and total cholesterol level in adults7.Several studies have reported SGA as a risk factor for adverse metabolic consequences in later life of term infants12 reported the risk of metabolic syndrome in preterm and/or SGA children. Lower insulin sensitivity at pre-pubertal age13 and elevated blood pressure after 31 years of follow-up14 were observed in preterm infants born as SGA, as compared to appropriate for gestational age (AGA) group. In contrast, other studies demonstrated no differences in the cardiometabolic outcomes between the two groups of preterm infants16; like Darendelier et al. reported that there were no differences in insulin resistance and body composition during the pre-pubertal period between preterm SGA and AGA17.The role of SGA in metabolic outcomes in later life among preterm infants has been demonstrated in several studies. Huang et al.18. On the contrary, slow weight gain was found to result in adverse neurodevelopmental outcomes in term SGA infants19. Likewise, the influence of postnatal growth on an increased risk of metabolic syndrome in preterm infants has been demonstrated as well21. In addition, unfavorable neurodevelopmental outcomes following poor growth have also been reported in this population23. However, the optimal intrauterine and extrauterine growth patterns related to cardiometabolic and neurocognitive outcomes have not been established in preterm infants so far.Accelerated growth is another important risk factor for metabolic syndrome in the later part of life in term SGA infantsIn this study, the prevalence of adverse cardiometabolic findings at school-age was evaluated among very preterm infants born as AGA and SGA. Moreover, to investigate the role of growth velocity at different periods on health outcomes of preterm infants, the associations between postnatal growth velocity at different periods with the health status at school-age were analyzed in the study population, including cardiometabolic and neurodevelopmental outcomes.24 or periventricular leukomalacia (PVL) were excluded. SGA was defined as a birth weight of < 10th percentile for age by the Fenton growth chart25. The participants were assigned to two groups, SGA and AGA, based on the birth weight. This study was approved by the Institutional Review Board of Seoul National University Hospital. Written informed consent was obtained from the parents of all participants. All methods were performed in accordance with the guideline of the Human Research Protection Program.This was a retrospective cohort study. Preterm infants born at < 32 weeks of gestation or having a birth weight of < 1,500 g and who were admitted to the neonatal intensive care unit (NICU) at Seoul National University Children’s Hospital between 2008 and 2009 were enrolled in the cohort at a chronological age of 6–8 years. Among 266 infants who were born below 32 weeks’ gestation or 1,500 g at birth, families of 136 infants were contacted, and 60 of them consented to participate in the cohort. Of the 60 infants in the cohort, four with grade IV intraventricular hemorrhage (IVH), according to the classification by Papile et al.Data on perinatal factors, including birth weight, gestational age (GA), delivery mode, sex, and multiple births were reviewed. Data on neonatal outcomes, such as treated patent ductus arteriosus (PDA), respiratory distress syndrome (RDS), moderate to severe bronchopulmonary dysplasia (BPD), and sepsis were collected. Information on the duration of breast milk feeding and additional calorie intake other than fortifier was also reviewed. Body weight at discharge, corrected age (CA) of 4 months, chronological age at 12 and 24 months, and school-age were measured. The z-scores of body weight were calculated according to the World Health Organization growth charts.26. The Korean national growth charts for children and adolescents released in 2007 were used to calculate the percentile of WC. The parents filled questionnaires related to the recent daily calorie intake and physical activity.At school-age, anthropometric parameters, including weight, waist circumference (WC), and height were assessed. The fat mass was measured using the InBody Test . The body mass index (BMI) was calculated by dividing weight in kilograms by height in meters squared, and the fat mass index (FMI) was obtained by dividing the fat mass in kilograms by height in square meters. Lean mass index (LMI) was calculated by dividing the lean mass by the square of height. The blood pressure (BP) (systolic and diastolic) was also measured with an automated device at the left arm using an appropriate-sized cuff. The BP was measured twice, and the average value of the two readings was recorded. The BP was interpreted using the normative BP table proposed by Lee et al.The blood sample of each participant was obtained by venipuncture after 8 h of fasting. The homeostasis model assessment of insulin resistance (HOMA-IR) representing the insulin resistance was evaluated after estimating fasting plasma insulin and glucose levels. Then, the values were applied to the following equation: HOMA-IR = fasting plasma insulin (mU/mL) × fasting plasma glucose (mg/dL) / 405. The lipid profiles including total cholesterol, triglyceride, high-density lipoprotein cholesterol (HDL-C), leptin, and adiponectin were also estimated. The intellectual abilities at 6 years of age, including verbal comprehension, perceptual reasoning, working memory, and processing speed, were tested using the Korean Wechsler Intelligence Scale for Children, fourth edition (K-WISC-IV), administered by a trained assessor.p values were calculated after adjusting for GA, birth weight z-score, weight z-score change from birth to discharge, and sex. Multivariate linear regression analysis was also used to determine the effect of weight gain at different epochs on each index scale of K-WISC-IV after adjusting for factors that could influence neurocognitive outcomes, such as GA, birth weight z-score, weight z-score change from birth to discharge, sex, and IVH30. A p value of < 0.05 was considered statistically significant. STATA 12.0 for Windows  was used to analyze all data.The data are presented as median (interquartile ranges) or count (percentage). The Wilcoxon rank-sum test was conducted to compare the continuous variables and Fisher’s exact test was used for the categorical variables. Multivariate linear regression analysis was conducted to investigate the association between the changes in the z-score at each epoch with the cardiometabolic factors at school-age. Regression coefficients beta (β) with Written informed consent was obtained from the participants of the study.p < 0.001), and RDS was more prevalent in the AGA group  (Table p < 0.001).Among the 56 school-aged children born prematurely, 14 were born as SGA. The gestational age was higher in the SGA group than that in the AGA group , there were no differences in the changes of z-scores during the other epochs. In both groups, the catch-up of weight z-score was mostly achieved during the period from discharge to 4 months CA.The weight z-scores were lower in the SGA group from birth to school-age Table . AlthougIn the multivariate linear regression analysis after adjustment for GA, birth weight z-score, weight z-score change from birth to discharge, and sex, cardiometabolic outcomes were not associated with z-score changes before 12 months after birth Table . Only thp = 0.036) and perceptual reasoning index  at school-age   and later outcomes were found in a young adult study, while the effect of later growth (> 1 year of age) was found at a relatively young age, including the present study.To clarify the role of growth velocity in the development of cardiometabolic abnormalities in the study population, multivariate analysis was conducted adjusting the birth weight z-score. The result showed that the growth velocity beyond 12 or 24 months of age was correlated with several cardiometabolic outcomes in our study. The critical period of growth for the later health outcomes in preterm infants has not yet been established. Several studies have reported the association of early postnatal growth patterns, especially until 3 months of CA, and unfavorable health outcomes in the later part of life. A Dutch national prospective follow-up study reported that early postnatal growth from birth to CA of 3 months in very preterm infants was associated with higher BMI, fat mass, and percentage of body fat at age 19 years37. According to Ehrenkranz et al., better weight growth during NICU stay reduced the incidence of cerebral palsy and poor neurocognitive outcomes at 18 − 22 months’ of CA38.In terms of neurodevelopmental outcomes, changes in weight z-score during NICU stay had a positive correlation with full scales of K-WISC-IV, especially with the perceptional reasoning index in our study. On the other hand, there was no association between neurocognitive outcomes and z-score of birth weight or growth after discharge. Early postnatal growth of preterm infants is important for favorable neurodevelopmental outcomes. The association of in-hospital weight gain of preterm infants and improvement of mental processing composite score of the Kaufmann Assessment Battery at 5 years of age was demonstrated by Franz et al.21. Another study reported that linear growth from term to 4 months was related to better cognitive outcomes at 8 years and 18 years of age, while the risk of becoming overweight or obese was increased at 8 years of age39. However, these previous studies did not consider the role of postnatal growth in the NICU.The trade-off phenomenon by postnatal growth in preterm infants has been well demonstrated in two multi-center longitudinal studies from the Infant Health and Development Project in the US. In the first study, rapid weight gain from term to age 4 months was associated with better cognitive outcomes at school-age and higher BP42 and neurodevelopmental outcomes44. Deprivation followed by a relatively enriched environment is a pivotal hypothesis of the developmental origin of adult disease1. The postnatal period during NICU stay in preterm infants could be understood as a deprived environment because many very preterm infants experience extrauterine growth restriction during this period46, and it might be considered in the analysis as an effect of growth after the neonatal period on later health outcomes.In the present study, the growth during NICU stay was calculated and adjusted because postnatal growth before term equivalent age plays an important role in cardiometabolic outcomes49.The results of the present study might provide some clues to set an optimal growth target and accordant nutritional interventions for preterm infants because many term SGA studies reported postnatal growth as a double-edged sword between health in later life and neurodevelopmental outcomes. However, if growth at different periods affects different aspects of later health outcomes, nutritional interventions could be focused at a time when these could lead to favorable outcomesThere are limitations to generalizing the results of the present study. This is a single-center study with a small number of children. Only 22.5% of the original birth population constituted the study cohort, and 14 out of 56 preterm infants were born as SGA. Moreover, control group was not included in the current study. Therefore, the statistical power of the present study was low. However, the growth pattern of preterm and term infants should be compared with caution because most preterm infants experience postnatal growth restriction immediately after birth and growth standards regarding later health outcomes have not been established. In this respect, the purpose of the current study was confined to the evaluation of the association between growth velocity and health outcomes among preterm population.51. SGA could originate from factors other than obstetric and fetal problems, such as genetic causes  and maternal weight gain during pregnancy52. However, SGA could be used as a proxy of IUGR, and many studies also reported adverse cardiometabolic outcomes in the SGA population32.In the present study, intrauterine growth restriction (IUGR) was not assessed among the study population. Although IUGR is often used interchangeably with SGA, their definitions and etiologies are different. In addition, an IUGR fetus may be born as either SGA or AGA and vice versa. IUGR is defined as a lower-than-normal fetal growth rate, considering the growth potential by fetal race and sex, whilst SGA is determined by size at birth, such as weight and height according to the sexAlthough growth velocity during NICU stay was associated with favorable later neurocognitive outcomes, optimal standards for growth could not be driven from this study only. Prospective studies with larger populations are required to establish optimal growth standards for adulthood health outcomes, including both metabolic and neurodevelopmental outcomes. Moreover, longitudinal follow-up study evaluating the components of the metabolic syndrome and actual diagnosis of the disease at older age is needed.In the present study, among preterm infants, more rapid weight gain during NICU stay was associated with better neurocognitive outcomes. On the contrary, better weight gain beyond 12 months or 24 months of age was related to adverse cardiometabolic outcomes at school-age. As growth at different periods affects different outcomes in the later part of life, nutritional interventions and monitoring of growth might be established based on the age of the preterm infants.Supplementary Information


Preterm birth, defined as delivery at less than 37 weeks’ gestation, is one of the most pressing clinical problems in obstetrics worldwide . DespitePreterm birth is not only the major contributor to neonatal morbidity and mortality globally, it also accounts for the increasing numbers of intergenerational non-communicable diseases. It is estimated that 106 million disability-adjusted life years are lost annually to preterm birth. Thus, preterm birth is a high priority public health problem and it is essential to reduce the rate of preterm birth in order to achieve the health-related Millennium Developmental goals set forth by the WHO in 2000 .These goals can only be achieved if understanding of the pathogenesis of the multifactorial nature of preterm birth improves. Hence, a significant number of research endeavors aim to unearth markers and mediators accounting for the onset of preterm birth. In this special issue, we have compiled a comprehensive update on clinical, socioeconomic, and pathophysiological aspects currently known to be involved in preterm birth. Deindl and Diemert highlight features of the heterogeneity of the syndrome and focus on its connection with health care structures. The authors further summarize the structural modalities required for the prevention of preterm birth by discussing various care levels of hospitals .To date, the accurate prediction and subsequently prevention of preterm birth is not yet within reach. Clearly, such prediction-based prevention of preterm birth is a highly desired goal and, thus, pursued by a number of researcher and clinicians. Pizzella et al. put forward evolving techniques to predict preterm birth, focusing on cervical imaging technologies. Currently used and emerging imaging techniques such as brightness-mode ultrasound, Raman spectroscopy, and photoacoustic endoscopy are discussed in the light of their advantages and disadvantages in assessing cervical remodeling. The authors propose that a combination of several imaging approaches, combined with clinical epidemiologic characteristics, holds the potential to accurately predict preterm birth . Along tSince dysfunctions of maternal immune adaptations have been linked to the onset of preterm birth, Green and Arck examine the current knowledge of the bidirectional communication between fetal and maternal systems and its role in the immunopathogenesis of preterm birth . Much reMenon et al. also acknowledge the importance of fetal-maternal immune tolerance and focus in their review article on inflammation of fetal membranes associated with preterm birth and preterm pre-labor rupture of the membranes. Both arise from distinct pathophysiologic pathways but share inflammation as a common underlying mechanism. Their review summarizes the mechanisms of fetal membrane cellular senescence, transitions, and the generation of inflammation that contributes to term and preterm parturitions .Humberg and colleagues follow-up on these aspects and discuss sustained inflammation in the context of preterm birth and resulting consequences for the neonate. Here, the onset of chorioamnionitis is suggested to act as a first inflammatory hit. Postnatal confrontation of the prematurely born neonate with a drastically altered antigen exposure, such as hospital-specific microbes, artificial devices, drugs, nutritional antigens, and hypoxia or hyperoxia can then create a second inflammatory hit .Blois and colleagues introduce galectins, an evolutionary conserved family of glycan-binding proteins, a pivotal mediator controlling fetal-maternal immune tolerance. In their review, the functional role of galectins in shaping cellular circuits that characterize a healthy pregnancy is comprehensively discussed. Moreover, the current understanding of galectins in term and preterm labor and the contribution of galectin-glycan circuits as key immunological pathways sustaining maternal tolerance and preventing microbial infections is proposed. This deeper understanding of the glycoimmune pathways regulating early events in preterm birth could provide a broad translational potential for the treatment of preterm birth .Bayar et al. follow-up on microbial challenges, but also microbiome-mediated health advantages during pregnancy. In their review article, the complex interplay between the vaginal microbiome in pregnancy and its association with preterm birth is discussed in depth. Advances resulting from an improved understanding of the human microbiome are proposed, such as an improved awareness of the functional role of vaginal microbiota in both health and in disease .Fetal medicine opens a new territory by treating the fetus as a patient. Hence, fetal therapy can improve perinatal survival or prevent severe long-term handicap. In utero fetal interventions can be divided into ultrasound-guided minimally invasive procedures, fetoscopic procedures, and open hysterotomy procedures, which carry an inherent risk of ruptured membranes and preterm birth. Therefore, Valenzuela et al. comprehensively discuss fetal therapies and their influence on preterm birth. They summarize the conditions that may benefit from fetal therapy and review the current therapies on offer in the light of their risk of ruptured membrane and preterm birth .In summary, preterm birth has dire consequences for mother, child, and society in general. Babies who survive preterm birth often face disabilities, such as cerebral palsy, lung disease, blindness, and deafness. Continuous research endeavors addressing these not only persistent but also growing inequalities are urgently needed. With the present special issue addressing key features of the pathogenesis as well as clinical consequences of preterm birth, we sought to provide an updated platform summarizing current insights and future directions. This shall aid researcher and clinicians alike to continue striving for a deeper knowledge of preterm birth in order to lowering its rate globally.


Policy-makers are increasingly seeking rigorous evidence on the impact of programs that go beyond typical health care settings to improve outcomes for low-income families during the critical period around the transition to parenthood and through early childhood.This study is a randomized controlled trial evaluating the impact of the Nurse-Family Partnership’s expansion in South Carolina. The scientific trial was made possible by a “Pay for Success” program embedded within a 1915(b) Waiver from Medicaid secured by the South Carolina Department of Health and Human Services. This protocol describes study procedures and defines primary and secondary health-related outcomes that can be observed during the intervention period (including pregnancy through the child’s first 2 years of life). Primary study outcomes include (1) a composite indicator for adverse birth outcomes including being born small for gestational age, low birth weight (less than 2500 g), preterm birth (less than 37 weeks’ gestation), or perinatal mortality , (2) a composite outcome indicating health care utilization or mortality associated with major injury or concern for abuse or neglect occurring during the child’s first 24 months of life, and (3) an indicator for an inter-birth interval of < 21 months. Secondary outcomes are defined similarly in three domains: (1) improving pregnancy and birth outcomes, (2) improving child health and development, and (3) altering the maternal life course through changes in family planning.Evidence from this trial on the impact of home visiting services delivered at scale as part of a Medicaid benefit can provide policy-makers and stakeholders with crucial information about the effectiveness of home visiting programs in improving health and well-being for low-income mothers and children and about novel financing mechanisms for cross-silo interventions.AEARCTR-0001039). ClinicalTrials.gov NCT03360539. Registered on 28 November 2017.The trial was registered prospectively on the American Economic Association Trial Registry  on 16 February 2016 ( We present the full SPIRIT Checklist in Additional file Millions of children in the USA live in households experiencing poverty , and neaOne of the established models for reaching low-income families to address a range of challenges in early life is nurse home visiting during pregnancy and early childhood. From 1978 to 1995, three modest-scale randomized controlled trials were conducted in Elmira, New York; Memphis, Tennessee; and Denver, Colorado, to estimate the impact of the Nurse-Family Partnership (NFP) on the outcomes of low-income families over multiple decades –22. The The extent to which evidence from these early trials of NFP applies within a modern context is an important policy question. Over the past decades, the health care and social safety net landscapes have changed substantially, as have the composition, health status, and experiences of low-income families. The scale of NFP has also increased substantially; earlier trials represent the impact of the program on a small scale within narrowly defined populations. Earlier trials were also conducted before current practices in pre-registration of outcomes for clinical trials and accounting for multiple inferences were developed. Recent evidence on the impact of similar nurse-led home visiting programs has been mixed , 25, andOur ongoing experiment in South Carolina represents a rare opportunity to understand the effects of NFP when scaled up to serve a broader population in today’s context. The South Carolina Department of Health and Human Services (SCDHHS) is offering NFP services to first-time, Medicaid-eligible mothers by leveraging Medicaid funding via a Medicaid 1915(b) Waiver and philanthropic funding. The financing operates through a Pay for Success (PFS) model, where program costs are initially covered via philanthropic and Medicaid funding, and later SCDHHS will make success payments if our randomized controlled trial provides impact estimates that exceed the impact thresholds that were defined in the PFS contract before the trial began .Home visiting programs have been hypothesized to affect a diverse range of outcomes, including prenatal, maternal, and neonatal health, infant and child health and development, morbidity and mortality, mental health, substance abuse, family planning, nutrition, neglect and maltreatment, home environment and parenting skills, crime, educational attainment, public spending, family economic self-sufficiency, access to healthcare, community resource connections, and social competence . This prLow-income families face particular challenges and disadvantages during the critical period around pregnancy, birth, transition to parenthood, and early childhood. These include relatively worse access to and quality of health care , 30 and This study is an individually randomized controlled parallel group trial.The study was approved by the Harvard T.H. Chan School of Public Health Institutional Review Board (IRB15-2939). Permissions were also obtained from cooperating institutions. The following IRBs have approved Harvard’s oversight of this research study: Massachusetts Institute of Technology, South Carolina Department of Health and Environmental Control (DHEC), IRB00000092 , McLeod Health System, IRB00004313, Greenville Health System, and Spartanburg Regional Health System, IRB00001369.NFP is a prenatal and infancy home visiting program for low-income, first-time mothers, and their families. Registered nurses enroll pregnant women who have completed less than 28 weeks’ gestation. NFP attempts to enroll women early in pregnancy so that home visits can take place throughout the pregnancy. This enables nurse home visitors to monitor pregnancy health at home, encourage utilization of high-quality health care during pregnancy, and help pregnant women make informed choices about their own health and the health of their baby. Nurses continue regular visits with the family until the child is 2 years old. Families may choose to discontinue participation in nurse home visiting services at any point. During the study period, mothers enrolled in the NFP program were eligible for up to 40 home visits divided into up to 15 visits during the prenatal period, up to 8 visits during the postpartum period (within the 60 days after delivery), and up to 17 visits during the child’s first 24 months of life that were covered by the Medicaid waiver (described below). When convenient for the mother, the nurses could conduct telehealth visits instead of doing visits in the home. Services are provided in English and Spanish and translation services are available for mothers speaking other languages.With a limited Medicaid budget and the desire to improve early childhood outcomes statewide, SCDHHS sought to expand NFP to eligible Medicaid recipients by applying for a 1915(b) Waiver and establishing a “Pay for Success” (PFS) Contract. The Medicaid Waiver authorized South Carolina to expand its current postpartum home visitation services by scaling up NFP. Under the Waiver, an additional 3200 Medicaid beneficiaries and their children were made eligible to enroll in NFP services during the study enrollment period . As part of the Waiver, SCDHHS established a PFS contract with a consortium of local philanthropic agencies to secure the additional funding needed to scale up the program over the 5-year Waiver period. The philanthropic agencies provide the initial capital to scale up NFP ; based on point estimates of the program’s impact on four pre-determined outcomes, SCDHHS will make “success payments” back to the funders, who have agreed to reinvest the money to expand NFP in South Carolina in subsequent years. The four outcomes on which payments will be made are preterm birth, child injury, birth spacing, and the percent of served mothers who live in low-income zip codes. Additional file The first payments are scheduled to be made in April 2021 for all four study outcomes. Payment outcomes were chosen by the signatories to the contract to reflect state-level priorities and major drivers of Medicaid spending. This protocol paper describes health-related primary and secondary outcomes chosen by the research team which are informed by, but distinct from, the outcomes chosen by signatories to the PFS contract.NFP has a well-established delivery system in South Carolina, and there are multiple pathways through which potential clients can be referred. NFP has operated in South Carolina since 2009 and is delivered by 10 different implementing agencies in 32 counties across the state. A map of NFP implementing agency locations in South Carolina is provided in Fig. Individuals are eligible for the study if they (1) are currently pregnant with a gestation period less than 28 weeks, (2) would be first-time mothers, (3) would be income-eligible for Medicaid during pregnancy, (4) are at least 15 years old, (5) live in a catchment area served by NFP nurses, (6) are not incarcerated or living in a lockdown facility, and (7) have enough language fluency that they would be able to benefit therapeutically from the program.Potential study participants are identified through several referral channels. First, referral partners, such as local health care providers, schools, and Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) agencies, directly refer potential clients to an implementing agency with the client’s permission. Second, referrals are made directly from the Medicaid eligibility database to NFP. Finally, during the scale-up of NFP services, NFP had in place an outreach team with outreach coordinators in four regional areas who worked to identify potential clients. In addition to these main channels, some clients are self-referred or referred by a family member or friend or through digital and print advertisements of the program throughout South Carolina.Potential participants are assessed first for eligibility by NFP nurses and then provide written consent to participate in the study. NFP program staff are trained on how to implement the informed consent process by the study team. To minimize coercion and undue influence, program staff review the consent form with potential participants and allow them as much time as they need to read the consent form themselves and ask questions. The consent form  software. We use SurveyCTO, which provides full customization of the baseline survey described in the Prior to randomization, study participants complete a 30-min baseline survey  and a data use agreement with the Children’s Trust Foundation of South Carolina which allows us to track the participation of mothers enrolled in the study in other home visiting programs.We will match mothers enrolled in our study to administrative outcome data using a probabilistic match based on identifying information provided during the baseline survey . We will identify children born into the study by first matching the mother to a birth in vital records. If the birth occurs within 120 days before or after the estimated due date reported on the baseline survey, we will consider the birth as being related to the pregnancy that was in gestation at the time of the baseline survey. Births that occur outside of this window will be considered unmatched  and will not be included in our analysis.NFP’s program strives to impact the lives of mothers and children in three central ways: (1) to improve pregnancy outcomes, (2) to improve child health and development, and (3) to improve economic self-sufficiency. NFP aims to achieve these outcomes through a strength-based approach—which is based on the idea that new mothers will be best able to make changes in their lives when building on their own knowledge and strengths . NFP homNFP’s focus on maternal and newborn health is consistent with the focus of the federal MIECHV program  , 61 whicSecond, home visiting programs, because they focus on improving the safety of the home environment and providing parents with a broad set of tools and resources to help them be more effective parents, have sought to reduce the risk of child injuries and indicators of child abuse and neglect. Home visiting programs have been cited as one of the few interventions where rigorous evidence has demonstrated the potential to improve child outcomes surrounding child maltreatment . An earlFinally, home visiting programs may alter maternal life course and economic opportunity through a variety of channels with the potential for these alterations to change the timing of subsequent births. Home visiting programs often serve a population of first-time low-income mothers who have greater likelihood of unplanned or mis-timed births and who may desire to avoid or delay subsequent pregnancies. Indeed, among the 5655 study participants, 82.7% reported on the baseline survey that their pregnancies were either unplanned or occurred earlier than the mother desired, and only 3.3% of mothers reported desiring less than 2 years of spacing between this birth and any subsequent birth. Home visiting programs may be effective in increasing birth spacing by coordinating continuity of care and ensuring that postpartum mothers have access to family planning services. Home visiting programs also focus on enabling mothers to alter their life course by taking advantage of educational and career opportunities, which may delay subsequent pregnancies. Evidence from previous evaluations of NFP have found substantial impacts on shaping the maternal life course by altering the patterns of subsequent births. In the early evaluation of NFP in Elmira, New York, mothers reported 19% fewer subsequent births by the time their first child reached the age of 15 . In the We define three primary outcomes for this analysis, one for each of the three domains that home visiting programs, including NFP, present as central program objectives or areas where home visiting programs have demonstrated substantial health-related impacts. In addition to these three primary outcomes, we provide a list of pre-specified secondary outcomes in each of these domains in Table First, we will assess the effect of NFP on the likelihood of having an adverse birth outcome. We define an adverse birth outcome as having a preterm birth (less than 37 weeks’ gestation) or a newborn being small for gestational age , havingSecond, we will assess the effect of NFP on the likelihood of experiencing injury, abuse, or neglect during early childhood. This will be defined by a composite outcome indicating a health care encounter or mortality associated with International Classification of Diseases (ICD) codes indicating either a major child injury or suspicion of abuse or neglect. We will identify children who have at least one health care encounter or experience mortality associated with an ICD code that indicates either major injury or suspicion of abuse and neglect. We will identify major injury through the observation of any medical claim or mortality case including an ICD code associated with injury excluding superficial injuries, injuries related to medical care, and injuries stemming from allergic reactions. ICD codes indicating suspected abuse and neglect are derived from Schnitzer et al. 2011) and Hooft et al. 2013) based on validated methods , 70. Dat011 and H based onThird, we will assess the effect of NFP on birth spacing. We define the outcome based on whether a subsequent birth occurs less than 21 months after the birth of the child born from the pregnancy during which the mother was enrolled in the study. Studies examining various pregnancy interval lengths find stronger and more consistent effects on infant health for birth intervals of 6 and 12 months . We seleOur primary study outcomes are not defined identically to outcomes defined in the PFS contract. The outcomes in the PFS contract were defined by the signatories of the contract through the contracting process. We subsequently refined the definitions for the analyses in this protocol paper based on the literature on home visiting and an assessment of which outcomes our study would have sufficient statistical power to detect. Per the PFS contract schedule, the PFS outcomes will also be reported based on a partial sample, whereas the analyses described here will be reported on the full study sample. For these two reasons, we expect that the results of the analysis described in this protocol paper will likely differ from the point estimates we will provide to the PFS contract signatories.Similar to previous NFP trials, we will examine differential impacts of the program among a subgroup of mothers whose circumstances at enrollment place them and their children at increased risk of adverse outcomes , 74, 75.We may also consider the program’s differential impact among other secondary subgroups of particular interest to policy-makers or stakeholders. For example, we may consider how program impacts on birth outcomes differ by maternal race, how outcomes on child injury and suspected abuse and neglect differ for a subgroup identified as experiencing substance abuse disorder, or how birth spacing differs for mothers who had expressed a desire to avoid closely spaced pregnancies. We will fully specify planned subgroups as we develop more detailed pre-analysis plans for specific academic manuscripts. When discussing heterogeneity in treatment impacts, we will clearly indicate whether subgroup analyses were planned and documented in a pre-analysis plan or are exploratory. Finally, for any subgroup analyses, we will correct for multiple hypothesis testing as discussed in “Previous evaluations of NFP have been able to track families with in-person surveys over long periods of time with low to moderate attrition rates, with follow-up rates between 62 and 93% depending on the outcome of interest and the length of follow-up , 65. ThoFor the purposes of statistical power calculations “” sectionYi, such as an indicator for an adverse birth outcome. For subject i, the estimating equation is:We will estimate intent-to-treat (ITT) effects as the primary empirical specification. We will also report local average treatment effects (LATE). The ITT estimates capture differences in outcomes between those assigned to the treatment group and those assigned to the control group. The LATE estimates incorporate information on actual program participation, taking advantage of the randomization as an instrument for participation and allowing examination of average characteristics of those participating in the program . We defiwhere “Enrolled in NFP” means having received at least one completed visit from NFP for service delivery. This model will be estimated using two-stage least squares (2SLS), where the first stage is:I(Treatment = 1)i is an indicator variable equal to one if the subject was randomized to the intervention group and zero if the subject was randomized to the control group; Xi is a vector of covariates, specified in more detail below. These covariates should be uncorrelated with the treatment indicator because of the randomization. We include them in the model since they may increase the precision of the estimates. This linear model estimates the local average treatment effect (LATE) of NFP on intervention group members who actually participate in NFP relative to the services consumed by the control group. This estimated effect of NFP is of policy interest because it represents the impact of NFP on those clients who are likely to participate in NFP were the program to expand and offer additional program slots through a lottery. The source of non-compliance that it explicitly captures is that some mothers randomized into the intervention group may never receive NFP services . According to the enrollment protocol, no mothers in the control group should be enrolled in NFP services. To the extent that some sample members in the control group receive services from similar home visiting programs that may also affect outcomes, this model estimates the effect of NFP relative to the mix of other home visiting programs that the control group receives, rather than relative to no home visiting service at all. We may also consider additional secondary specifications that may be of interest to policy-makers including an estimate of local average treatment effects where we consider two potentially relevant alternative definitions of “treatment:” (1) mothers who are still receiving home visits at the time of their anticipated delivery date as reported on the baseline survey and (2) mothers who receive home visits throughout the entire program period of pregnancy and the child’s first 2 years of life.where Existing literature and previous NFP trials have identified a number of characteristics that may be predictive of the three primary study outcomes. Such characteristics include maternal age, indicators of race and ethnicity, health behaviors (smoking and drinking), maternal socioeconomic status, relationship to father of the child, utilization of health services, and mental health. In our impact models, we will include variables from the baseline survey to measure these and other relevant sample characteristics .p values across all primary outcomes and subgroup analyses  using methods developed by Benjamini and Hochberg [Adverse Birth Outcomes: We use vital records data from South Carolina to estimate that approximately 24.3% of study participants will have an adverse birth outcome in our control group. Birth Spacing: Assumptions about the control group mean for the birth spacing outcome come from recently published evidence on the incidence of shortly spaced births in South Carolina [Early childhood injuries or suspected abuse and neglect: The assumptions about the control group mean for the early childhood injury outcome are estimated based on analysis from a sample of hospital discharge data from South Carolina. We anticipate that 18% of families in our sample will experience injury, abuse, or neglect.We calculate minimum detectable differences reported as the percentage point difference between treatment and control groups we will be able to detect, assuming a significance level  of 5% and a statistical power level of 80%. Based on current enrollment trends, we assume 96% of study participants randomized into the treatment group will receive NFP services. Furthermore, we assume that none of the control group receives NFP services. We will account for multiple hypothesis testing across three different outcomes and within one subgroup by calculating and reporting false discovery rate (FDR)-adjusted Hochberg , 83. We Carolina . Early cPlanned analyses will be pre-specified in a publicly archived analysis plan prior to un-blinding the data for analysis. With the exception of contractually required interim reporting on outcomes that are part of the PFS contract (scheduled for April 2021), data will be unblinded sequentially as outcomes can be observed for the full sample  to be enrolled over 4 years (April 2016–2020), with NFP services delivered through the children’s second birthday (2016–2022). At the conclusion of enrollment, 5655 were enrolled in the study. This protocol was first drafted on January 30, 2020, and revised on October 21, 2020, in response to reviewer comments.In this protocol, we outline major objectives of NFP’s home visiting services and define scientific primary and secondary outcomes related to maternal and child health that can be observed during the prenatal period through the first 24 months of life. These outcomes relate to the central goals of home visiting programs to improve pregnancy and birth outcomes, to reduce child injuries and incidence of abuse and neglect, and to help mothers alter their life course by achieving their desired birth spacing.Our evaluation will assess the impacts that might be expected from NFP operating at scale. Previous NFP studies highlighted the impacts of the program on important subgroups, such as unmarried or teenage mothers , 62, 75 The opportunity to apply the scientific rigor of a randomized controlled trial to assess the impact of NFP at scale was made possible by a federal Medicaid waiver and a collaboration between SCDHHS and philanthropic organizations on a Pay for Success contract. This will be the largest randomized trial linked to a Pay for Success project to date, as well as among the largest trials of an early life intervention among low-income mothers in the USA. While the PFS structure enabled this randomized controlled trial, it necessitates a different framework for reporting results than is typical for purely academic studies. First, as independent evaluators to the PFS contract, we are required to report on the PFS outcomes for an incomplete sample prior to the observation of these outcomes for the entire sample. This means that estimates of outcomes used for payments may differ from final scientific output.Second, the primary scientific outcomes we have chosen differ from the PFS outcomes in several ways. While the PFS contract focuses on the costly outcome of preterm birth, we define a composite of adverse birth outcomes that includes preterm birth, low birth weight, or small for gestational age in order to increase power and to detect a broader set of potential pathways to impact around improving birth outcomes. Furthermore, while the PFS birth spacing outcome focuses on subsequent births that occur less than 24 months from the first birth, we pre-specify a scientific outcome of births spaced less than 21 months based on evidence surrounding birth intervals more closely linked to adverse infant health outcomes  and on tRelying on existing administrative data, rather than collecting new primary data, offers several advantages. First, utilizing administrative data reduces concerns about likely differential attrition between treatment and control group members in the years following study enrollment. Second, since the data are already being collected for a purpose separate from the study, the chance of data quality differences between the treatment and control groups is minimized. Finally, administrative data, in general, are less likely than primary data to suffer from recall bias or the impulse to please data collectors, and can often provide more granularity than surveys. Using administrative data to measure our outcomes also enables us to track outcomes robustly over a long time horizon in a large sample. One drawback of relying exclusively on administrative data, however, is that it limits our analysis to the outcomes that are already in existing data sets, which may not include some important outcomes that could be affected by NFP. For example, we will not be able to measure cognitive development in early childhood, as South Carolina does not universally conduct screening before children enter school. In addition, we will not directly observe psychosocial outcomes that are directly related to NFP’s focus on the quality of parenting.A final potential challenge to using administrative data for measuring outcomes is that we will not be able to observe outcomes related to outpatient care delivered by commercial payers or accessed at safety net providers. Furthermore, participation in the NFP program may impact whether families are eligible for Medicaid, either directly through helping families with application and renewal processes or indirectly through income eligibility. This could mean that the sample of mothers whose outcomes will be observed in Medicaid claims data could differ across study arms. We will account for this possibility by comparing enrollment rates in Medicaid across treatment arms, by considering alternative specifications that focus only on discharge records, which can be observed for all study participants, and by conducting bounding exercises  to gaugeBeyond the pre-specified primary and secondary health-related outcomes that we will observe over the period of program implementation discussed in this protocol, the randomized controlled trial provides an opportunity to measure the effect of NFP across a much wider set of outcomes and longer time horizon. In several recent studies, early childhood programs were found to have limited effects in the short to medium run, but notable effects in the very long run –88. HaviEvidence from this trial on the impact of home visiting services delivered at scale as part of a Medicaid benefit can provide policy-makers and stakeholders with crucial information about the effectiveness of the Nurse-Family Partnership program in improving health and well-being for low-income mothers and children. In particular, this study evaluates a program that was previously studied at a relatively small scale including effects seen within a range of distinct subgroups. This evaluation will provide policy-makers with estimates of the NFP’s program when implemented at scale by well-established local service providers. The evaluation also provides an opportunity to measure the comprehensive effects of a health program that operates outside the traditional health care delivery infrastructure and has the potential to impact both health and non-health outcomes.Additional file 1. 2013 SPIRIT Checklist. Standard Protocol Items Recommended for International Trials.Additional file 2. PFS Outcomes and Payment Thresholds. Definition of PFS outcomes and thresholds for “success payments”.Additional file 3. Consent Form. Consent form for Participants enrolled in NFP Trial.Additional file 4. Resources for New Moms and Babies: Greenville County. Example list of resources available to low-income mothers. List provided to both control and treatment group enrollees in the study.Additional file 5. Baseline Survey. Baseline survey administered to all participants enrolled in the trial after informed consent and before randomization.Additional file 6. Home Visitor Survey. Survey administered to all nurse home visitors before enrollment for the trial is complete.