Gastroschisis prevalence patterns in 27 surveillance programs from 24 countries, International Clearinghouse for Birth Defects Surveillance and Research, 1980-2017

BACKGROUND

Gastroschisis is a serious birth defect with midgut prolapse into the amniotic cavity. The objectives of this study were to evaluate the prevalence and time trends of gastroschisis among programs in the International Clearinghouse for Birth Defects Surveillance and Research (ICBDSR), focusing on regional variations and maternal age changes in the population.

METHODS

We analyzed data on births from 1980 to 2017 from 27 ICBDSR member programs, representing 24 countries and three regions (Europe+ (includes Iran) , Latin America, North America). Cases were identified using diagnostic codes (i.e., 756.7, 756.71, or Q79.3). We excluded cases of amniotic band syndrome, limb-body wall defect, and ruptured omphalocele. Programs provided annual counts for gastroschisis cases (live births, stillbirths, and legally permitted pregnancy terminations for fetal anomalies) and source population (live births, stillbirths), by maternal age.

RESULTS

Overall, gastroschisis occurred in 1 of every 3268 births (3.06 per 10,000 births; 95% confidence intervals [CI]: 3.01, 3.11), with marked regional variation. European+ prevalence was 1.49 (95%CI: 1.44, 1.55), Latin American 3.80 (95%CI: 3.69, 3.92) and North American 4.32 (95%CI: 4.22, 4.42). A statistically significant increasing time trend was observed among six European+ , four Latin American, and four North American programs. Women <20 years of age had the highest prevalence in all programs except the Slovak Republic.

CONCLUSIONS

Gastroschisis prevalence increased over time in 61% of participating programs, and the highest increase in prevalence was observed among the youngest women. Additional inquiry will help to assess the impact of the changing maternal age proportions in the birth population on gastroschisis prevalence.

Is gastroschisis associated with county-level socio-environmental quality during pregnancy?

BACKGROUND

Gastroschisis prevalence more than doubled between 1995 and 2012. While there are individual-level risk factors (e.g., young maternal age, low body mass index), the impact of environmental exposures is not well understood.

METHODS

We used the U.S. Environmental Protection Agency's Environmental Quality Index (EQI) as a county-level estimate of cumulative environmental exposures for five domains (air, water, land, sociodemographic, and built) and overall from 2006 to 2010. Adjusted odds ratios (aOR) and 95% confidence interval (CI) were estimated from logistic regression models between EQI tertiles (better environmental quality (reference); mid; poorer) and gastroschisis in the National Birth Defects Prevention Study from births delivered between 2006 and 2011. Our analysis included 594 cases with gastroschisis and 4105 infants without a birth defect (controls).

RESULTS

Overall EQI was modestly associated with gastroschisis (aOR [95% CI]: 1.29 [0.98, 1.71]) for maternal residence in counties with poorer environmental quality, compared to the reference (better environmental quality). Within domain-specific indices, only the sociodemographic domain (aOR: 1.51 [0.99, 2.29]) was modestly associated with gastroschisis, when comparing poorer to better environmental quality.

CONCLUSIONS

Future work could elucidate pathway(s) by which components of the sociodemographic domain or possibly related psychosocial factors like chronic stress potentially contribute to risk of gastroschisis.

Neighborhood Deprivation and Neural Tube Defects

BACKGROUND

Individual measures of socioeconomic status (SES) have been associated with an increased risk of neural tube defects (NTDs); however, the association between neighborhood SES and NTD risk is unknown. Using data from the National Birth Defects Prevention Study (NBDPS) from 1997 to 2011, we investigated the association between measures of census tract SES and NTD risk.

METHODS

The study population included 10,028 controls and 1829 NTD cases. We linked maternal addresses to census tract SES measures and used these measures to calculate the neighborhood deprivation index. We used generalized estimating equations to calculate adjusted odds ratios (aORs) and 95% confidence intervals (CIs) estimating the impact of quartiles of census tract deprivation on NTDs adjusting for maternal race-ethnicity, maternal education, and maternal age at delivery.

RESULTS

Quartiles of higher neighborhood deprivation were associated with NTDs when compared with the least deprived quartile (Q2: aOR = 1.2; 95% CI = 1.0, 1.4; Q3: aOR = 1.3, 95% CI = 1.1, 1.5; Q4 (highest): aOR = 1.2; 95% CI = 1.0, 1.4). Results for spina bifida were similar; however, estimates for anencephaly and encephalocele were attenuated. Associations differed by maternal race-ethnicity.

CONCLUSIONS

Our findings suggest that residing in a census tract with more socioeconomic deprivation is associated with an increased risk for NTDs, specifically spina bifida.

Are individual-level risk factors for gastroschisis modified by neighborhood-level socioeconomic factors?

BACKGROUND

Two strong risk factors for gastroschisis are young maternal age (<20 years) and low/normal pre-pregnancy body mass index (BMI), yet the reasons remain unknown. We explored whether neighborhood-level socioeconomic position (nSEP) during pregnancy modified these associations.

METHODS

We analyzed data from 1269 gastroschisis cases and 10,217 controls in the National Birth Defects Prevention Study (1997-2011). To characterize nSEP, we applied the neighborhood deprivation index and used generalized estimating equations to calculate odds ratios and relative excess risk due to interaction.

RESULTS

Elevated odds of gastroschisis were consistently associated with young maternal age and low/normal BMI, regardless of nSEP. High-deprivation neighborhoods modified the association with young maternal age. Infants of young mothers in high-deprivation areas had lower odds of gastroschisis (adjusted odds ratio [aOR]: 3.1, 95% confidence interval [CI]: 2.6, 3.8) than young mothers in low-deprivation areas (aOR: 6.6; 95% CI: 4.6, 9.4). Mothers of low/normal BMI had approximately twice the odds of having an infant with gastroschisis compared to mothers with overweight/obese BMI, regardless of nSEP (aOR range: 1.5-2.3).

CONCLUSION

Our findings suggest nSEP modified the association between gastroschisis and maternal age, but not BMI. Further research could clarify whether the modification is due to unidentified biologic and/or non-biologic factors.

Neighborhood-level Socioeconomic Position During Early Pregnancy and Risk of Gastroschisis

BACKGROUND

Neighborhood-level socioeconomic position has been shown to influence birth outcomes, including selected birth defects. This study examines the un derstudied association between neighborhood-level socioeconomic position during early pregnancy and the risk of gastroschisis, an abdominal birth defect of increasing prevalence.

METHODS

We conducted a case-control study of 1,269 gastroschisis cases and 10,217 controls using data from the National Birth Defects Prevention Study (1997-2011). To characterize neighborhood-level socioeconomic position, we conducted a principal component analysis to construct two indices-Neighborhood Deprivation Index (NDI) and Neighborhood Socioeconomic Position Index (nSEPI). We created neighborhood-level indices using census socioeconomic indicators corresponding to census tracts associated with addresses where mothers lived the longest during the periconceptional period. We used generalized estimating equations to estimate odds ratios (ORs) and 95% confidence intervals (CIs), with multiple imputations for missing data and adjustment for maternal race-ethnicity, household income, education, birth year, and duration of residence.

RESULTS

Mothers residing in moderate (NDI Tertile 2 aOR = 1.23; 95% CI = 1.03, 1.48 and nSEPI Tertile 2 aOR = 1.24; 95% CI = 1.04, 1.49) or low socioeconomic neighborhoods (NDI Tertile 3 aOR = 1.28; 95% CI = 1.05, 1.55 and nSEPI Tertile 3 aOR = 1.32, 95% CI = 1.09, 1.61) were more likely to deliver an infant with gastroschisis compared with mothers residing in high socioeconomic neighborhoods.

CONCLUSIONS

Our findings suggest that lower neighborhood-level socioeconomic position during early pregnancy is associated with elevated odds of gastroschisis. Additional epidemiologic studies may aid in confirming this finding and evaluating potential mechanisms linking neighborhood-level socioeconomic factors and gastroschisis.

Exome-wide assessment of isolated biliary atresia: A report from the National Birth Defects Prevention Study using child-parent trios and a case-control design to identify novel rare variants

The etiology of biliary atresia (BA) is unknown, but recent studies suggest a role for rare protein-altering variants (PAVs). Exome sequencing data from the National Birth Defects Prevention Study on 54 child-parent trios, one child-mother duo, and 1513 parents of children with other birth defects were analyzed. Most (91%) cases were isolated BA. We performed (1) a trio-based analysis to identify rare de novo, homozygous, and compound heterozygous PAVs and (2) a case-control analysis using a sequence kernel-based association test to identify genes enriched with rare PAVs. While we replicated previous findings on PKD1L1, our results do not suggest that recurrent de novo PAVs play important roles in BA susceptibility. In fact, our finding in NOTCH2, a disease gene associated with Alagille syndrome, highlights the difficulty in BA diagnosis. Notably, IFRD2 has been implicated in other gastrointestinal conditions and warrants additional study. Overall, our findings strengthen the hypothesis that the etiology of BA is complex.

Society for Birth Defects Research and Prevention 2022-2027 strategic plan

BACKGROUND

The sixth Strategic Planning Session of the Society for Birth Defects Research and Prevention (BDRP) was held on April 24-25, 2022, in Alexandria, VA.

METHODS

This effort built upon previous strategic planning sessions, conducted every 5 years.

RESULTS

The overall process was designed to identify BDRP's vision, purpose, culture, and potential, as well as to communicate the value that BDRP brings to its members, volunteers, partners, and the greater community.

CONCLUSIONS

The BDRP 2022-2027 Strategic Plan provides the BDRP leadership, members, and staff with a clearly articulated framework and direction to support long-term sustainability and growth of the society.

Prevalence and mortality among children with anorectal malformation: A multi-country analysis

PURPOSE

We examined the total prevalence, trends in prevalence, and age-specific mortality among individuals with anorectal malformation (ARM) METHODS: We conducted a retrospective cohort study using data from 24 population- and hospital-based birth defects surveillance programs affiliated with the International Clearinghouse for Birth Defects Surveillance and Research (ICBDSR) from 18 countries and for births from 1974 to 2014. We estimated pooled and program-specific total prevalence per 10,000 total births. Poisson regression was used to assess time trends in prevalence from 2001 to 2012 when most programs contributed data. We calculated selected age-specific proportions of deaths, stratified by case status RESULTS: The pooled total prevalence of ARM was 3.26 per 10,000 total births (95% Confidence Interval = 3.19, 3.32) for birth years 1974-2014. About 60% of cases were multiple or syndromic. Prevalence of multiple, syndromic, and stillborn cases decreased from 2001 to 2012. The first week mortality proportion was 12.5%, 3.2%, 28.3%, and 18.2% among all, isolated, multiple, and syndromic cases, respectively CONCLUSIONS: ARM is relatively rare, with multiple and syndromic cases showing decreasing prevalence during the study period. Mortality is a concern during the first week of life, and especially among multiple and syndromic cases. Our descriptive epidemiological findings increase our understanding of geographic variation in the prevalence of ARM and can be used to plan needed clinical services. Exploring factors influencing prevalence and mortality among individuals with ARM could inform future studies.

Prepregnancy exposure to dietary arsenic and congenital heart defects

INTRODUCTION

Arsenic crosses the placenta and accumulates in fetal tissues. In the United States, diet is the predominant route of arsenic exposure, but epidemiologic data are sparse regarding this exposure and development of birth defects. Using data from a large case-control study, we explored associations between maternal dietary arsenic exposure and congenital heart defects (CHDs), the most prevalent birth defects.

METHODS

We used maternal self-reported dietary assessments and arsenic concentration estimates in food items to estimate average daily exposure to dietary arsenic during the year before pregnancy for mothers of 10,446 unaffected control children and 6,483 case children diagnosed with CHDs. Using tertiles of dietary exposure to total arsenic (all species) and inorganic arsenic, we applied logistic regression analysis to estimate associations for middle and high tertiles, compared with the low tertile.

RESULTS

Positive associations (odds ratio [OR] ≥ 1.2) for total arsenic were observed in both tertiles for perimembranous ventricular septal defect (VSD) and high tertile only for double outlet right ventricle-transposition of the great arteries (DORV-TGA), partial anomalous pulmonary venous return (PAPVR), and tricuspid atresia. Positive associations were also observed in both tertiles (tricuspid atresia) and high tertile only (DORV-TGA, conoventricular VSD, PAPVR, and pulmonary atresia) for inorganic arsenic. Most remaining associations were near or below unity.

DISCUSSION

Exploration of maternal dietary exposure to total and inorganic arsenic and CHDs produced few positive associations but was limited by available food item concentrations. Future research requires expanded collection of dietary data, improved estimates of concentrations, and consideration of nondietary sources of arsenic exposure.

Interaction of maternal medication use with ambient heat exposure on congenital heart defects in the National Birth Defects Prevention Study

BACKGROUND

Maternal exposure to weather-related extreme heat events (EHEs) has been associated with congenital heart defects (CHDs) in offspring. Certain medications may affect an individual's physiologic responses to EHEs. We evaluated whether thermoregulation-related medications modified associations between maternal EHE exposure and CHDs.

METHODS

We linked geocoded residence data from the U.S. National Birth Defects Prevention Study, a population-based case-control study, to summertime EHE exposures. An EHE was defined using the 90th percentile of daily maximum temperature (EHE90) for each of six climate regions during postconceptional weeks 3-8. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) for associations between EHE90 and the risk of CHDs were estimated by strata of maternal thermoregulation-related medication use and climate region. Interaction effects were evaluated on multiplicative and additive scales.

RESULTS

Over 45% of participants reported thermoregulation-related medication use during the critical period of cardiogenesis. Overall, these medications did not significantly modify the association between EHEs and CHDs. Still, medications that alter central thermoregulation increased aORs (95% CI) of EHE90 from 0.73 (0.41, 1.30) among non-users to 5.09 (1.20, 21.67) among users in the Southwest region, U.S. This effect modification was statistically significant on the multiplicative (P = 0.03) and additive scales, with an interaction contrast ratio (95% CI) of 1.64 (0.26, 3.02).

CONCLUSION

No significant interaction was found for the maternal use of thermoregulation-related medications with EHEs on CHDs in general, while medications altering central thermoregulation significantly modified the association between EHEs and CHDs in Southwest U.S. This finding deserves further research.

Health Care Usage Among Adolescents With Congenital Heart Defects at 5 Sites in the United States, 2011 to 2013

Background

We sought to characterize health care usage for adolescents with congenital heart defects (CHDs) using population‐based multisite surveillance data.

Methods and Results

Adolescents aged 11 to 18 years with ≥1 CHD‐related diagnosis code and residing in 5 US sites were identified in clinical and administrative data sources for the years 2011 to 2013. Sites linked data on all inpatient, emergency department (ED), and outpatient visits. Multivariable log‐binomial regression models including age, sex, unweighted Charlson comorbidity index, CHD severity, cardiology visits, and insurance status, were used to identify associations with inpatient, ED, and outpatient visits. Of 9626 eligible adolescents, 26.4% (n=2543) had severe CHDs and 21.4% had Charlson comorbidity index >0. At least 1 inpatient, ED, or outpatient visit was reported for 21%, 25%, and 96% of cases, respectively. Cardiology visits, cardiac imaging, cardiac procedures, and vascular procedures were reported for 38%, 73%, 10%, and 5% of cases, respectively. Inpatient, ED, and outpatient visits were consistently higher for adolescents with severe CHDs compared with nonsevere CHDs. Adolescents with severe and nonsevere CHDs had higher health care usage compared with the 2011 to 2013 general adolescent US population. Adolescents with severe CHDs versus nonsevere CHDs were twice as likely to have at least 1 inpatient visit when Charlson comorbidity index was low (Charlson comorbidity index =0). Adolescents with CHDs and public insurance, compared with private insurance, were more likely to have inpatient (adjusted prevalence ratio, 1.5 [95% CI, 1.3–1.7]) and ED (adjusted prevalence ratio, 1.6 [95% CI, 1.4–1.7]) visits.

Conclusions

High resource usage by adolescents with CHDs indicates a substantial burden of disease, especially with public insurance, severe CHDs, and more comorbidities.

Evaluation of effects of continued corticosteroid treatment on cardiac and pulmonary function in non-ambulatory males with Duchenne muscular dystrophy from MD STARnet

INTRODUCTION/AIMS

Corticosteroids have been shown to improve muscle strength and delay loss of ambulation (LOA) in Duchenne muscular dystrophy (DMD) and are considered standard of care despite significant side-effects. The objective of this study is to evaluate whether corticosteroid treatment after LOA is beneficial for cardiac or pulmonary functions among boys with DMD.

METHODS

We used the Muscular Dystrophy Surveillance, Tracking, and Research Network (MD STARnet) to characterize associations between corticosteroid use and onset of abnormal left ventricular (LV) function or abnormal percent predicted forced vital capacity (ppFVC) among 398 non-ambulatory boys with DMD. Kaplan-Meier curve estimation was used to compare time to onset by corticosteroid use groups; Cox proportional hazards modeling was used to estimate hazard ratios (HRs) and corresponding 95% confidence intervals.

RESULTS

We found no differences in time to onset of abnormal LV function by corticosteroid use groups. We observed a longer time from LOA to first abnormal ppFVC in boys that were treated with corticosteroid ≥1 y beyond LOA compared with those with no corticosteroid use or those who stopped corticosteroid use within 1 y of LOA.

DISCUSSION

Our findings show no association of corticosteroid use beyond LOA with the onset of abnormal LV function, but a significant association with a delay in onset of abnormal ppFVC. Prospective studies of corticosteroid use in boys with DMD who have lost ambulation may identify benefits and can better elucidate risks, allowing for more effective counseling of patients on continuing treatment after LOA.

Exome sequencing identifies genetic variants in anophthalmia and microphthalmia

Anophthalmia and microphthalmia (A/M) are rare birth defects affecting up to 2 per 10,000 live births. These conditions are manifested by the absence of an eye or reduced eye volumes within the orbit leading to vision loss. Although clinical case series suggest a strong genetic component in A/M, few systematic investigations have been conducted on potential genetic contributions owing to low population prevalence. To overcome this challenge, we utilized DNA samples and data collected as part of the National Birth Defects Prevention Study (NBDPS). The NBDPS employed multi-center ascertainment of infants affected by A/M. We performed exome sequencing on 67 family trios and identified numerous genes affected by rare deleterious nonsense and missense variants in this cohort, including de novo variants. We identified 9 nonsense changes and 86 missense variants that are absent from the reference human population (Genome Aggregation Database), and we suggest that these are high priority candidate genes for A/M. We also performed literature curation, single cell transcriptome comparisons, and molecular pathway analysis on the candidate genes and performed protein structure modeling to determine the potential pathogenic variant consequences on PAX6 in this disease.

A Multicountry Analysis of Prevalence and Mortality among Neonates and Children with Bladder Exstrophy

OBJECTIVE

 Bladder exstrophy (BE) is a rare but severe birth defect affecting the lower abdominal wall and genitourinary system. The objective of the study is to examine the total prevalence, trends in prevalence, and age-specific mortality among individuals with BE.

STUDY DESIGN

 We conducted a retrospective cohort study. Data were analyzed from 20 birth defects surveillance programs, members of the International Clearinghouse for Birth Defects Surveillance and Research in 16 countries. Live births, stillbirths, and elective terminations of pregnancy for fetal anomaly (ETOPFA) diagnosed with BE from 1974 to 2014. Pooled and program-specific prevalence of BE per 100,000 total births was calculated. The 95% confidence intervals (CI) for prevalence were estimated using Poisson approximation of binomial distribution. Time trends in prevalence of BE from 2000 to 2014 were examined using Poisson regression. Proportion of deaths among BE cases was calculated on the day of birth, day 2 to 6, day 7 to 27, day 28 to 364, 1 to 4 years, and ≥5 years. Mortality analysis was stratified by isolated, multiple, and syndromic case status.

RESULTS

 The pooled total prevalence of BE was 2.58 per 100,000 total births (95% CI = 2.40, 2.78) for study years 1974 to 2014. Prevalence varied over time with a decreasing trend from 2000 to 2014. The first-week mortality proportion was 3.5, 17.3, and 14.6% among isolated, multiple, and syndromic BE cases, respectively. The majority of first-week mortality occurred on the first day of life among isolated, multiple, and syndromic BE cases. The proportion of first-week deaths was higher among cases reported from programs in Latin America where ETOPFA services were not available.

CONCLUSIONS

 Prevalence of BE varied by program and showed a decreasing trend from 2000 to -2014. Mortality is a concern among multiple and syndromic cases, and a high proportion of deaths among cases occurred during the first week of life.

KEY POINTS

· Total prevalence of BE was 2.58 per 100,000 births.. · Prevalence decreased from 2000 to 2014.. · The first-week mortality was 9.3%..

Analysis of early neonatal case fatality rate among newborns with congenital hydrocephalus, a 2000-2014 multi-country registry-based study

BACKGROUND

Congenital hydrocephalus (CH) comprises a heterogeneous group of birth anomalies with a wide-ranging prevalence across geographic regions and registry type. The aim of the present study was to analyze the early neonatal case fatality rate (CFR) and total birth prevalence of newborns diagnosed with CH.

METHODS

Data were provided by 25 registries from four continents participating in the International Clearinghouse for Birth Defects Surveillance and Research (ICBDSR) on births ascertained between 2000 and 2014. Two CH rates were calculated using a Poisson distribution: early neonatal CFR (death within 7 days) per 100 liveborn CH cases (CFR) and total birth prevalence rate (BPR) per 10,000 births (including live births and stillbirths) (BPR). Heterogeneity between registries was calculated using a meta-analysis approach with random effects. Temporal trends in CFR and BPR within registries were evaluated through Poisson regression modeling.

RESULTS

A total of 13,112 CH cases among 19,293,280 total births were analyzed. The early neonatal CFR was 5.9 per 100 liveborn cases, 95% confidence interval (CI): 5.4-6.8. The CFR among syndromic cases was 2.7 times (95% CI: 2.2-3.3) higher than among non-syndromic cases (10.4% [95% CI: 9.3-11.7] and 4.4% [95% CI: 3.7-5.2], respectively). The total BPR was 6.8 per 10,000 births (95% CI: 6.7-6.9). Stratified by elective termination of pregnancy for fetal anomalies (ETOPFA), region and system, higher CFR were observed alongside higher BPR rates. The early neonatal CFR and total BPR did not show temporal variation, with the exception of a CFR decrease in one registry.

CONCLUSIONS

Findings of early neonatal CFR and total BPR were highly heterogeneous among registries participating in ICBDSR. Most registries with higher CFR also had higher BPR. Differences were attributable to type of registry (hospital-based vs. population-based), ETOPFA (allowed yes or no) and geographical regions. These findings contribute to the understanding of regional differences of CH occurrence and early neonatal deaths.

Pre-pregnancy exposure to arsenic in diet and non-cardiac birth defects

OBJECTIVES

To explore associations between maternal pre-pregnancy exposure to arsenic in diet and non-cardiac birth defects.

DESIGN

This is a population-based, case-control study using maternal responses to a dietary assessment and published arsenic concentration estimates in food items to calculate average daily total and inorganic arsenic exposure during the year before pregnancy. Assigning tertiles of total and inorganic arsenic exposure, logistic regression analysis was used to estimate OR for middle and high tertiles, compared to the low tertile.

SETTING

US National Birth Defects Prevention Study, 1997-2011.

PARTICIPANTS

Mothers of 10 446 children without birth defects and 14 408 children diagnosed with a non-cardiac birth defect.

RESULTS

Maternal exposure to total dietary arsenic in the middle and high tertiles was associated with a threefold increase in cloacal exstrophy, with weak positive associations (1·2-1·5) observed either in both tertiles (intercalary limb deficiency) or the high tertile only (encephalocele, glaucoma/anterior chamber defects and bladder exstrophy). Maternal exposure to inorganic arsenic showed mostly weak, positive associations in both tertiles (colonic atresia/stenosis, oesophageal atresia, bilateral renal agenesis/hypoplasia, hypospadias, cloacal exstrophy and gastroschisis), or the high (glaucoma/anterior chamber defects, choanal atresia and intestinal atresia stenosis) or middle (encephalocele, intercalary limb deficiency and transverse limb deficiency) tertiles only. The remaining associations estimated were near the null or inverse.

CONCLUSIONS

This exploration of arsenic in diet and non-cardiac birth defects produced several positive, but mostly weak associations. Limitations in exposure assessment may have resulted in exposure misclassification. Continued research with improved exposure assessment is recommended to identify if these associations are true signals or chance findings.

Factors associated with maternal consent for use of residual newborn bloodspots in the National Birth Defects Prevention Study

PURPOSE

We investigated factors associated with maternal consent to use residual newborn dried bloodspots (DBS) in a national case-control study of birth defects.

METHODS

A subset of sites in the National Birth Defects Prevention Study (NBDPS; 1997-2011) asked participants to provide consent for investigators to retrieve DBS from local newborn screening programs to use for research on risk factors for birth defects. We assessed whether consent differed by factors including maternal age, education, parity, body mass index, language of interview, country of birth, and case-control status.

RESULTS

Of 5,850 mothers of cases and 2,534 mothers of controls, 57% provided consent for the DBS component. Mothers of cases were more likely to participate than mothers of controls (61% vs. 52%), as were mothers who self-reported white race, >12 years of education, and born in the United States.

CONCLUSIONS

Retrieval of DBS can be integrated into retrospective studies of neonatal outcomes including birth defects. In NBDPS, participation in the DBS component was moderate and varied by some sociodemographic factors. Further research is needed to better understand families' perspectives on using residual DBS for secondary research. Representative participation is important to reduce the potential for selection bias in future studies using DBS for children's health research.

Exome sequencing identifies variants in infants with sacral agenesis

BACKGROUND

Sacral agenesis (SA) consists of partial or complete absence of the caudal end of the spine and often presents with additional birth defects. Several studies have examined gene variants for syndromic forms of SA, but only one has examined exomes of children with non-syndromic SA.

METHODS

Using buccal cell specimens from families of children with non-syndromic SA, exomes of 28 child-parent trios (eight with and 20 without a maternal diagnosis of pregestational diabetes) and two child-father duos (neither with diagnosis of maternal pregestational diabetes) were exome sequenced.

RESULTS

Three children had heterozygous missense variants in ID1 (Inhibitor of DNA Binding 1), with CADD scores >20 (top 1% of deleterious variants in the genome); two children inherited the variant from their fathers and one from the child's mother. Rare missense variants were also detected in PDZD2 (PDZ Domain Containing 2; N = 1) and SPTBN5 (Spectrin Beta, Non-erythrocytic 5; N = 2), two genes previously suggested to be associated with SA etiology. Examination of variants with autosomal recessive and X-linked recessive inheritance identified five and two missense variants, respectively. Compound heterozygous variants were identified in several genes. In addition, 12 de novo variants were identified, all in different genes in different children.

CONCLUSIONS

To our knowledge, this is the first study reporting a possible association between ID1 and non-syndromic SA. Although maternal pregestational diabetes has been strongly associated with SA, the missense variants in ID1 identified in two of three children were paternally inherited. These findings add to the knowledge of gene variants associated with non-syndromic SA and provide data for future studies.

Modeling complex effects of exposure to particulate matter and extreme heat during pregnancy on congenital heart defects: A U.S. population-based case-control study in the National Birth Defects Prevention Study

BACKGROUND/OBJECTIVE

Research suggests gestational exposure to particulate matter ≤2.5 μm (PM2.5) and extreme heat may independently increase risk of birth defects. We investigated whether duration of gestational extreme heat exposure modifies associations between PM2.5 exposure and specific congenital heart defects (CHDs). We also explored nonlinear exposure-outcome relationships.

METHODS

We identified CHD case children (n = 2824) and non-malformed live-birth control children (n = 4033) from pregnancies ending between 1999 and 2007 in the National Birth Defects Prevention Study, a U.S. population-based multicenter case-control study. We assigned mothers 6-week averages of PM2.5 exposure during the cardiac critical period (postconceptional weeks 3-8) using the closest monitor within 50 km of maternal residence. We assigned a count of extreme heat days (EHDs, days above the 90th percentile of daily maximum temperature for year, season, and weather station) during this period using the closest weather station. Using generalized additive models, we explored logit-nonlinear exposure-outcome relationships, concluding logistic models were reasonable. We estimated joint effects of PM2.5 and EHDs on six CHDs using logistic regression models adjusted for mean dewpoint and maternal age, education, and race/ethnicity. We assessed multiplicative and additive effect modification.

RESULTS

Conditional on the highest observed EHD count (15) and at least one critical period day during spring/summer, each 5 μg/m3 increase in average PM2.5 exposure was significantly associated with perimembranous ventricular septal defects (VSDpm; OR: 1.54 [95% CI: 1.01, 2.41]). High EHD counts (8+) in the same population were positively, but non-significantly, associated with both overall septal defects and VSDpm. Null or inverse associations were observed for lower EHD counts. Multiplicative and additive effect modification estimates were consistently positive in all septal models.

CONCLUSIONS

Results provide limited evidence that duration of extreme heat exposure modifies the PM2.5-septal defects relationship. Future research with enhanced exposure assessment and modeling techniques could clarify these relationships.

Parents' report on the health care management of spina bifida in early childhood

PURPOSE

This study aimed to describe health care use by type of health providers and care settings visited by children with spina bifida (SB) and to compare this use between children with and without a shunt.

METHODS

Health care use data were extracted from a larger study on the health and functioning of children with SB aged 3-6 years. The present study focused on the medical information subsection of a parent-reported survey related to SB care, general care, specialty care (e.g., neurosurgery), emergency care, and complications related to SB and shunts.

RESULTS

Parents of 101 children with SB participated. Most of the children were male with myelomeningocele and had a shunt. They visited a health care provider for SB care an average of 7.4 times and a specialist an average of 11.9 times in the previous 12 months. Most visited a multidisciplinary clinic for SB-related care and a private physician's office for general care. Children with a shunt had more SB-related medical visits, more visits to a specialist, and a greater number of different types of specialists than those without it. Frequency of emergency room visits did not differ between the two groups. Health providers informed parents about headaches, vomiting, and fever as signs of complications, and some parents did report shunt-related complications.

CONCLUSION

SB is a complex medical condition requiring that children receive medical care from various medical specialists, especially for children with a shunt. Findings on health care use suggest high levels of monitoring and care coordination that parents navigate to care for their child.

Exome sequencing of child-parent trios with bladder exstrophy: Findings in 26 children

Bladder exstrophy (BE) is a rare, lower ventral midline defect with the bladder and part of the urethra exposed. The etiology of BE is unknown but thought to be influenced by genetic variation with more recent studies suggesting a role for rare variants. As such, we conducted paired-end exome sequencing in 26 child/mother/father trios. Three children had rare (allele frequency ≤ 0.0001 in several public databases) inherited variants in TSPAN4, one with a loss-of-function variant and two with missense variants. Two children had loss-of-function variants in TUBE1. Four children had rare missense or nonsense variants (one per child) in WNT3, CRKL, MYH9, or LZTR1, genes previously associated with BE. We detected 17 de novo missense variants in 13 children and three de novo loss-of-function variants (AKR1C2, PRRX1, PPM1D) in three children (one per child). We also detected rare compound heterozygous loss-of-function variants in PLCH2 and CLEC4M and rare inherited missense or loss-of-function variants in additional genes applying autosomal recessive (three genes) and X-linked recessive inheritance models (13 genes). Variants in two genes identified may implicate disruption in cell migration (TUBE1) and adhesion (TSPAN4) processes, mechanisms proposed for BE, and provide additional evidence for rare variants in the development of this defect.

Are paternal or grandmaternal age associated with higher probability of trisomy 21 in offspring? A population-based, matched case-control study, 1995-2015

BACKGROUND

Fetal aneuploidy risk increases with maternal age, but the majority of pregnancies complicated by trisomy 21 occur in younger women. It has been suggested that grandmaternal and/or paternal age may also play a role.

OBJECTIVES

To assess the association between grandmaternal and paternal age and trisomy 21.

METHODS

For the grandmaternal assessments, we included all offspring with trisomy 21 in a statewide birth defects surveillance system (1995-2015) that could be linked to 3-generation matrilineal pedigrees in the Utah Population Database. Ten sex/birth year-matched controls were selected for each case (770 cases and 7700 controls). For the paternal assessments, our cohort included all trisomy 21 cases (1995-2015) where both the mother and father resided in Utah at the time of birth (1409 cases and 14 090 controls). Ages were categorised by 5-year intervals (reference: 25-29 years). Conditional logistic regression, adjusting for potential confounding factors, was used to model the association between grandmaternal and paternal age and trisomy 21.

RESULTS

No association between grandmaternal age and trisomy 21 was detected, whether age was assessed continuously (adjusted odds ratio [OR] 1.01, 95% confidence interval [CI] 0.98, 1.03) or categorically after adjusting for grandmaternal and grandpaternal race/ethnicity and grandpaternal age. Compared to fathers aged 20-29 years, fathers <20 years (OR 3.15, 95% CI 1.99, 4.98) and 20-24 years (OR 1.39, 95% CI 1.11, 1.73) had increased odds of trisomy 21 offspring, after adjusting for maternal and paternal race/ethnicity and maternal age. Results were consistent after excluding stillbirths, multiples, and trisomy 21 due to translocation or mosaicism.

CONCLUSIONS

Maternal age is an important risk factor for trisomy 21 offspring; however, this population-based study shows that that young paternal age is also associated with trisomy 21, after taking into account maternal age and race/ethnicity.

High throughput screening for expanded CTG repeats in myotonic dystrophy type 1 using melt curve analysis

Background

Myotonic dystrophy type 1 (DM1) is caused by CTG repeat expansions in the DMPK gene and is the most common form of muscular dystrophy. Patients can have long delays from onset to diagnosis, since clinical signs and symptoms are often nonspecific and overlapping with other disorders. Clinical genetic testing by Southern blot or triplet‐primed PCR (TP‐PCR) is technically challenging and cost prohibitive for population surveys.

Methods

Here, we present a high throughput, low‐cost screening tool for CTG repeat expansions using TP‐PCR followed by high resolution melt curve analysis with saturating concentrations of SYBR GreenER dye.

Results

We determined that multimodal melt profiles from the TP‐PCR assay are a proxy for amplicon length stoichiometry. In a screen of 10,097 newborn blood spots, melt profile analysis accurately reflected the tri‐modal distribution of common alleles from 5 to 35 CTG repeats, and identified the premutation and full expansion alleles.

Conclusion

We demonstrate that robust detection of expanded CTG repeats in a single tube can be achieved from samples derived from specimens with minimal template DNA such as dried blood spots (DBS). This technique is readily adaptable to large‐scale testing programs such as population studies and newborn screening programs.

Population-Based Prevalence of Myotonic Dystrophy Type 1 Using Genetic Analysis of Statewide Blood Screening Program

OBJECTIVE

To determine whether the genetic prevalence of the CTG expansion in the DMPK gene associated with myotonic dystrophy type 1 (DM1) in an unbiased cohort is higher than previously reported population estimates, ranging from 5 to 20 per 100,000 individuals.

METHODS

This study used a cross-sectional cohort of deidentified dried blood spots from the newborn screening program in the state of New York, taken from consecutive births from 2013 to 2014. Blood spots were screened for the CTG repeat expansion in the DMPK gene using triplet-repeat primed PCR and melt curve analysis. Melt curve morphology was assessed by 4 blinded reviewers to identify samples with possible CTG expansion. Expansion of the CTG repeat was validated by PCR fragment sizing using capillary electrophoresis for samples classified as positive or premutation to confirm the result. Prevalence was calculated as the number of samples with CTG repeat size ≥50 repeats compared to the overall cohort.

RESULTS

Of 50,382 consecutive births, there were 24 with a CTG repeat expansion ≥50, consistent with a diagnosis of DM1. This represents a significantly higher DM1 prevalence of 4.76 per 10,000 births (95% confidence interval 2.86-6.67) or 1 in every 2,100 births. There were an additional 96 samples (19.1 per 10,000 or 1 in 525 births) with a CTG expansion in the DMPK gene in the premutation range (CTG)_35-49.

CONCLUSION

The prevalence of individuals with CTG repeat expansions in DMPK is up to 5 times higher than previous reported estimates. This suggests that DM1, with multisystemic manifestations, is likely underdiagnosed in practice.

Site, frequency, and duration of pain in young children with spina bifida

PURPOSE

To investigate the: (1) percent of children with spina bifida (SB) complaining of pain, (2) frequency, duration, and cause of pain by sex, level of lesion type of SB, and ambulation status, (3) body sites reported to hurt, by variables in objective 2, and (4) associations between physical and mental/emotional health between caregiver and child.

METHODS

Cross-sectional study of 101 caregivers of children (3 to 6 years old) with SB. Survey data and information from medical records were included. Pearson chi-square, one-way ANOVA, Fisher's exact test, logistic regressions, and bivariate correlations were used.

RESULTS

Seventy percent reported that their child complained of pain, which did not significantly differ by sex, level of lesion, type of SB, or ambulation status. Most (86%) were reported to have experienced pain for less than 24 hours. The most frequently reported pain site was the head, followed by the abdomen and the lower body. Number of pain sites was moderately correlated with frequency of pain complaints. Correlations between how caregivers reported their own physical/mental/emotional health and how they rated that of their children ranged from weak (r = 0.22) to moderate (r = 0.55).

CONCLUSION

Almost seven of ten children reportedly complained of pain ranging from at least once a month to everyday. Pain needs to be routinely assessed and treated in this population.

Prevalence and mortality in children with congenital diaphragmatic hernia: a multicountry study

PURPOSE

This study determined the prevalence, mortality, and time trends of children with congenital diaphragmatic hernia (CDH).

METHODS

Twenty-five hospital- and population-based surveillance programs in 19 International Clearinghouse for Birth Defects Surveillance and Research member countries provided birth defects mortality data between 1974 and 2015. CDH cases included live births, stillbirths, or elective termination of pregnancy for fetal anomalies. Prevalence, cumulative mortality rates, and 95% confidence intervals (CIs) were calculated using Poisson regression and a Kaplan-Meier product-limit method. Joinpoint regression analyses were conducted to assess time trends.

RESULTS

The prevalence of CDH was 2.6 per 10,000 total births (95% CI: 2.5-2.7), slightly increasing between 2001 and 2012 (average annual percent change = 0.5%; 95% CI:-0.6 to 1.6). The total percent mortality of CDH was 37.7%, with hospital-based registries having more deaths among live births than population-based registries (45.1% vs. 33.8%). Mortality rates decreased over time (average annual percent change = -2.4%; 95% CI: -3.8 to 1.1). Most deaths due to CDH occurred among 2- to 6-day-old infants for both registry types (36.3%, hospital-based; 12.1%, population-based).

CONCLUSIONS

The mortality of CDH has decreased over time. Mortality remains high during the first week and varied by registry type.

A multi-country study of prevalence and early childhood mortality among children with omphalocele

BACKGROUND

Omphalocele is the second most common abdominal birth defect and often occurs with other structural and genetic defects. The objective of this study was to determine omphalocele prevalence, time trends, and mortality during early childhood, by geographical region, and the presence of associated anomalies.

METHODS

We conducted a retrospective study with 23 birth defect surveillance systems in 18 countries who are members of the International Clearinghouse for Birth Defects Surveillance and Research that submitted data on cases ascertained from 2000 through 2012, approximately 16 million pregnancies were surveyed that resulted in live births, stillbirths, or elective terminations of pregnancy for fetal anomalies (ETOPFA) and cases with omphalocele were included. Overall prevalence and mortality rates for specific ages were calculated (day of birth, neonatal, infant, and early childhood). We used Kaplan-Meier estimates with 95% confidence intervals (CI) to calculate cumulative mortality and joinpoint regression for time trend analyses.

RESULTS

The prevalence of omphalocele was 2.6 per 10,000 births (95% CI: 2.5, 2.7) and showed no temporal change from 2000-2012 (average annual percent change = -0.19%, p = .52). The overall mortality rate was 32.1% (95% CI: 30.2, 34.0). Most deaths occurred during the neonatal period and among children with multiple anomalies or syndromic omphalocele. Prevalence and mortality varied by registry type (e.g., hospital- vs. population-based) and inclusion or exclusion of ETOPFA.

CONCLUSIONS

The prevalence of omphalocele showed no temporal change from 2000-2012. Approximately one-third of children with omphalocele did not survive early childhood with most deaths occurring in the neonatal period.

Congenital diaphragmatic hernia and maternal dietary nutrient pathways and diet quality

INTRODUCTION

We examined the association of congenital diaphragmatic hernia (CDH) with maternal dietary intake, using semi-Bayes hierarchical models and principal components analysis to consider intake of nutrients that contribute to one-carbon metabolism and oxidative stress pathways, and a diet quality index.

METHODS

We included data on 825 cases and 11,108 nonmalformed controls born from 1997-2011 whose mother participated in the National Birth Defects Prevention Study (NBDPS), a multisite, population-based case-control study. Exposure data were from maternal telephone interviews, which included a food frequency questionnaire. Adjusted odds ratios (aOR) and 95% confidence intervals (CI) were generated from logistic regression models that included nutritional factors as continuous variables and were adjusted for maternal energy intake, race-ethnicity, parity, and vitamin supplement intake.

RESULTS

In the semi-Bayes hierarchical model that included all nutrients and confounders, riboflavin was the only nutrient for which the 95% CI excluded 1.0; the aOR for a 1 SD increase was 0.83. The aORs were 0.79 (95% CI 0.69-0.91) for the one-carbon metabolism pathway score, 0.90 (95% CI 0.80-1.01) for oxidative stress, and 0.85 (95% CI 0.77-0.93) for diet quality (the aORs correspond to a 1 SD increase).

CONCLUSIONS

The findings from this study provide some support for the hypothesis that better prepregnancy nutrition is associated with reduced risk for CDH. These results provide etiologic clues but should be interpreted with caution given the novelty of the investigation.

Pre-pregnancy dietary arsenic consumption among women in the United States

BACKGROUND

Arsenic is associated with several adverse health outcomes, including some birth defects. Although diet is the predominant route of arsenic exposure in the United States (U.S.), limited data exist regarding pre-pregnancy dietary arsenic consumption among U.S. women.

METHODS

Using data collected in the National Birth Defects Prevention Study (NBDPS), we estimated daily dietary arsenic consumption during the year before pregnancy for 10,886 mothers of nonmalformed control children delivered from 1997-2011. Responses to the NBDPS dietary assessment and food item estimates of total and inorganic arsenic were used to estimate consumption. Associations between total and inorganic arsenic consumption and selected maternal characteristics were estimated using multinomial logistic regression.

RESULTS

Estimates of mean maternal total and inorganic dietary arsenic consumption were 14.9 and 5.2 μg/day, respectively. Several positive and inverse associations with confidence intervals that excluded the null were observed. Comparing mothers in the middle or high total arsenic consumption tertiles to those in the low tertile, we observed positive associations (odds ratios = 1.3-3.8) for maternal age (≥30 years), lower (0-8 years) or higher (>12 years) education, race/ethnicity (non-Hispanic Black, Hispanic, other), and early pregnancy drinking with no binge episodes, and inverse associations (odds ratios = 0.4-0.8) for age (<25 years), body mass index (≥30.0 kg/m² ), and early pregnancy smoking. Findings tended to be similar for inorganic arsenic consumption.

CONCLUSIONS

These contemporary estimates of pre-pregnancy dietary arsenic consumption among U.S. women show associations between both total and inorganic dietary arsenic consumption and several maternal characteristics, improving characterization of the public health impact of this exposure.

Associations between fine particulate matter, extreme heat events, and congenital heart defects

Previous research reports associations between air pollution measured during pregnancy and the occurrence of congenital heart defects (CHDs) in offspring. The objective of this research was to assess if exposure to extreme heat events (EHEs) during pregnancy may modify this association.

METHODS

The study population consisted of 4,033 controls and 2,632 cases with dates of delivery between 1999 and 2007 who participated in the National Birth Defects Prevention Study, a multi-site case-control study in the United States. Daily data from the closest stationary fine particulate matter (PM2.5) monitor within 50 km from the maternal residence were averaged across weeks 3-8 post-conception. EHEs were defined as maximum ambient temperature in the upper 95th percentile for at least 2 consecutive days or the upper 90th percentile for 3 consecutive days. Logistic regression models were adjusted for maternal age, ethnicity, education, and average humidity. Relative excess risks due to interaction (RERI) were calculated.

RESULTS

Compared with women with low PM2.5 exposure and no exposure to an EHE, the odds of a ventricular septal defect in offspring associated with high PM2.5 exposure was elevated only among women who experienced an EHE (odds ratio [OR] 2.14 95% confidence interval [CI] 1.19, 3.38 vs. OR 0.97 95% CI 0.49, 1.95; RERI 0.82 95% CI -0.39, 2.17). The majority of observed associations and interactions for other heart defects were null and/or inconclusive due to lack of precision.

CONCLUSIONS

This study provides limited evidence that EHEs may modify the association between prenatal exposure to PM2.5 and CHD occurrence.

Analysis of Mortality among Neonates and Children with Spina Bifida: An International Registry-Based Study, 2001-2012

BACKGROUND

Medical advancements have resulted in better survival and life expectancy among those with spina bifida, but a significantly increased risk of perinatal and postnatal mortality for individuals with spina bifida remains.

OBJECTIVES

To examine stillbirth and infant and child mortality among those affected by spina bifida using data from multiple countries.

METHODS

We conducted an observational study, using data from 24 population- and hospital-based surveillance registries in 18 countries contributing as members of the International Clearinghouse for Birth Defects Surveillance and Research (ICBDSR). Cases of spina bifida that resulted in livebirths or stillbirths from 20 weeks' gestation or elective termination of pregnancy for fetal anomaly (ETOPFA) were included. Among liveborn spina bifida cases, we calculated mortality at different ages as number of deaths among liveborn cases divided by total number of liveborn cases with spina bifida. As a secondary outcome measure, we estimated the prevalence of spina bifida per 10 000 total births. The 95% confidence interval for the prevalence estimate was estimated using the Poisson approximation of binomial distribution.

RESULTS

Between years 2001 and 2012, the overall first-week mortality proportion was 6.9% (95% CI 6.3, 7.7) and was lower in programmes operating in countries with policies that allowed ETOPFA compared with their counterparts (5.9% vs. 8.4%). The majority of first-week mortality occurred on the first day of life. In programmes where information on long-term mortality was available through linkage to administrative databases, survival at 5 years of age was 90%-96% in Europe, and 86%-96% in North America.

CONCLUSIONS

Our multi-country study showed a high proportion of stillbirth and infant and child deaths among those with spina bifida. Effective folic acid interventions could prevent many cases of spina bifida, thereby preventing associated childhood morbidity and mortality.

Exome sequencing of family trios from the National Birth Defects Prevention Study: Tapping into a rich resource of genetic and environmental data

BACKGROUND

The National Birth Defects Prevention Study (NBDPS) is a multisite, population-based, case-control study of genetic and nongenetic risk factors for major structural birth defects. Eligible women had a pregnancy affected by a birth defect or a liveborn child without a birth defect between 1997 and 2011. They were invited to complete a telephone interview to collect pregnancy exposure data and were mailed buccal cell collection kits to collect specimens from themselves, their child (if living), and their child's father. Over 23,000 families representing more than 30 major structural birth defects provided DNA specimens.

METHODS

To evaluate their utility for exome sequencing (ES), specimens from 20 children with colonic atresia were studied. Evaluations were conducted on specimens collected using cytobrushes stored and transported in open versus closed packaging, on native genomic DNA (gDNA) versus whole genome amplified (WGA) products and on a library preparation protocol adapted to low amounts of DNA.

RESULTS

The DNA extracted from brushes in open packaging yielded higher quality sequence data than DNA from brushes in closed packaging. Quality metrics of sequenced gDNA were consistently higher than metrics from corresponding WGA products and were consistently high when using a low input protocol.

CONCLUSIONS

This proof-of-principle study established conditions under which ES can be applied to NBDPS specimens. Successful sequencing of exomes from well-characterized NBDPS families indicated that this unique collection can be used to investigate the roles of genetic variation and gene-environment interaction effects in birth defect etiologies, providing a valuable resource for birth defect researchers.

Drinking water disinfection byproducts and risk of orofacial clefts in the National Birth Defects Prevention Study

BACKGROUND

Maternal exposure to drinking water disinfection byproducts (DBP)s may contribute to orofacial cleft (OFC) development, but studies are sparse and beset with limitations.

METHODS

Population-based, maternal interview reports of drinking water filtration and consumption for 680 OFC cases (535 isolated) and 1826 controls were linked with DBP concentration data using maternal residential addresses and public water system monitoring data. Maternal individual-level exposures to trihalomethanes (THM)s and haloacetic acids (HAA)s (µg/L of water consumed) were estimated from reported consumption at home, work, and school. Compared to no exposure, associations with multisource maternal exposure <1/2 or ≥1/2 the Maximum Contaminant Levels (MCL)s for total THMs (TTHM)s and HAAs (HAA5) or Maximum Contaminant Level Goals (MCLG)s for individual THMs and HAAs (if non-zero) were estimated for all OFCs and isolated OFCs, cleft palate (CP), and cleft lip ± cleft palate (CL/P) using logistic regression analyses.

RESULTS

Compared to controls, associations were near or below unity for maternal TTHM, HAA5, and individual THM exposures with all OFCs and isolated OFCs, CP, and CL/P. Associations also were near or below unity for individual HAAs with statistically significant, inverse associations observed with each OFC outcome group except CL/P.

CONCLUSIONS

This study examined associations for maternal reports of drinking water filtration and consumption and maternal DBP exposure from drinking water with OFCs in offspring. Associations observed were near or below unity and mostly nonsignificant. Continued, improved research using maternal individual-level exposure data will be useful in better characterizing these associations.

Risk of gastroschisis with maternal genitourinary infections: the US National birth defects prevention study 1997-2011

OBJECTIVE

To assess the association between occurrence and timing of maternal self-reported genitourinary tract infection (urinary tract infections [UTIs] and/or sexually transmitted infection [STI]) and risk for gastroschisis in the offspring.

DESIGN

Population-based case-control study.

SETTING

National Birth Defects Prevention Study, a multisite study in the USA.

PARTICIPANTS

Mothers of 1366 gastroschisis cases and 11 238 healthy controls.

MAIN OUTCOME MEASURES

Crude and adjusted ORs (aORs) with 95% CIs.

RESULTS

Genitourinary infections were frequent in case (19.3%) and control women (9.9%) during the periconceptional period (defined as 3 months prior to 3 months after conception). UTI and/or STI in the periconceptional period were associated with similarly increased risks for gastroschisis (aOR 1.5, 95% CI 1.3 to 1.8; aOR 1.6, 95% CI 1.2 to 2.3, respectively). The risk was increased with a UTI before (aOR 2.5; 95% CI 1.4 to 4.5) or after (aOR 1.7; 95% CI 1.1 to 2.6) conception only among women ≥25 years of age. The risk was highest among women <20 years of age with an STI before conception (aOR 3.6; 95% CI 1.5 to 8.4) and in women ≥25 years of age, the risk was similar for before (aOR 2.9; 95% CI 1.0 to 8.5) and after (aOR 2.8; 95% CI 1.3 to 6.1) conception. A specific STI pathogen was reported in 89.3% (50/56) of cases and 84.3% (162/191) of controls with Chlamydia trachomatis the most common (25/50 cases, 50%; 58/162 controls, 36%) and highest among women <20 years of age (16/25 cases, 64%; 22/33 controls, 67%).

CONCLUSIONS

UTI and/or STI were associated with an increased risk for gastroschisis, with the strength of the association varying by maternal age and timing of infection.

An evolutionary and developmental biology approach to gastroschisis

Recent advances have now made it possible to speak of gastroschisis narrowly in morphogenetic terms invoking the Rittler-Beaudoin (R-B) model. This proceeds from the appreciation of gastroschisis as a congenital intestinal herniation (without cover or liver) within the primordial umbilical ring, mostly to the right side of a normally formed umbilical cord. Presently, it is unresolved whether this visceral prolapse represents failure of ring closure before return of the physiological hernia into the abdomen or rupture of the delicate amniotic/peritoneal membrane at the ring's edge to the right of the cord. Animal observations and experiments will be required to address this question effectively. If gastroschisis is, in fact, a primary malformation with the primordial umbilical ring as the developmental field involved, then homology implies potential gastroschisis in all amniotes with corresponding nourishment from yolk sac (aka omphalomesenteric) vessels going into the embryo and excretory products out via the ancient umbilical connection. It also implies homology of corresponding morphogenetic signal transduction cascades. We review the history of gastroschisis, its presumed pathogenesis, and the developmental biology of the amniotic umbilical ring from this perspective. Therefore, based on the animal and human evidence to date, we propose that gastroschisis is a primary midline malformation that involves the umbilical canal from amniotic to peritoneal space and its primordial umbilical ring, either through nonclosure or rupture of the membrane covering the area, mostly to the right, between the cord and the edge of the ring.

Projected Changes in Maternal Heat Exposure During Early Pregnancy and the Associated Congenital Heart Defect Burden in the United States

Background More intense and longer-lasting heat events are expected in the United States as a consequence of climate change. This study aimed to project the potential changes in maternal heat exposure during early pregnancy (3-8 weeks post conception) and the associated burden of congenital heart defects ( CHD s) in the future. Methods and Results This study expanded on a prior nationwide case-control study that evaluated the association between CHD s and maternal heat exposure during early pregnancy in summer and spring. We defined multiple indicators of heat exposure, and applied published odds ratios obtained for the matching season of the baseline (1995-2005) into the projection period (2025-2035) to estimate potential changes in CHD burden throughout the United States. Increases in maternal heat exposure were projected across the United States and to be larger in the summer. The Midwest will potentially have the highest increase in summer maternal exposure to excessively hot days (3.42; 95% CI, 2.99-3.88 per pregnancy), heat event frequency (0.52; 95% CI, 0.44-0.60) and heat event duration (1.73; 95% CI, 1.49-1.97). We also found large increases in specific CHD subtypes during spring, including a 34.0% (95% CI, 4.9%-70.8%) increase in conotruncal CHD in the South and a 38.6% (95% CI , 9.9%-75.1%) increase in atrial septal defect in the Northeast. Conclusions Projected increases in maternal heat exposure could result in an increased CHD burden in certain seasons and regions of the United States.

Comparing Usual Dietary Intakes Among Subgroups of Mothers in the Year Before Pregnancy

OBJECTIVE

The quantity and quality of dietary intake among women of reproductive age has important public health implications for nutritional status during pregnancy. We described dietary intake during the year before pregnancy among a large, diverse group of US mothers.

METHODS

We examined data from 11 109 mothers who gave birth from 1997 through 2011 and participated in a population-based case-control study, the National Birth Defects Prevention Study, as controls (mothers who had babies without major birth defects). We examined whether subgroups of mothers at elevated risk of adverse pregnancy outcomes were more likely than their reference groups to have high dietary intake (>90th percentile of intake) or low dietary intake (<10th percentile of intake). We examined dietary intake of 22 nutritional factors, which were estimated from responses to a food frequency questionnaire.

RESULTS

Participants who were aged <20, were nulliparous, had

CONCLUSIONS

Strategies are needed to ensure optimal nutrition among all childbearing women.

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Key Words

• adverse pregnancy outcomes
• dietary intake
• elevated risk
• nutritional status
• preconception

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MESH Headings

• Adult
• Age Factors
• Body Mass Index
• Case-Control Studies
• Diabetes Mellitus/epidemiology
• Diet/statistics & numerical data
• Feeding Behavior
• Female
• Humans
• Hypertension/epidemiology
• Mothers/statistics & numerical data
• Nutritional Status
• Parity
• Preconception Care/statistics & numerical data
• Pregnancy
• Pregnancy, Unplanned
• Racial Groups
• Risk Factors
• Socioeconomic Factors
• United States/epidemiology
• Young Adult

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Grants

• U01DD001033 ACL HHS
• EP-D-18-001 EPA
• P30 DK056350 NIDDK NIH HHS
• U01DD001226 ACL HHS
• U01 DD001226 NCBDD CDC HHS
• National Center on Birth Defects and Developmental Disabilities

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Affiliation(s)

Suzan L. Carmichael Division of Neonatology and Developmental Medicine, Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, USA
Chen Ma Division of Neonatology and Developmental Medicine, Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, USA
Marcia L. Feldkamp Division of Medical Genetics, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, UT, USA
Gary M. Shaw
the National Birth Defects Prevention Study Division of Neonatology and Developmental Medicine, Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, USA

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Maternal genitourinary infections and risk of birth defects in the National Birth Defects Prevention Study

BACKGROUND

Genitourinary infections (GUIs) are common among sexually active women. Yet, little is known about the risk of birth defects associated with GUIs.

METHODS

Using data from the National Birth Defects Prevention Study, a multisite, population-based, case-control study, we assessed self-reported maternal GUIs in the month before through the third month of pregnancy (periconception) from 29,316 birth defect cases and 11,545 unaffected controls. We calculated odds ratios (ORs) and 95% confidence intervals to estimate the risk of 52 major structural birth defects associated with GUIs. We also calculated risk of birth defects associated with each type of GUI: urinary tract infection (UTI) and sexually transmitted infection (STI).

RESULTS

In our analysis, 10% (n = 2,972) of case and 9% (n = 1,014) of control mothers reported a periconceptional GUI. A GUI was significantly associated with 11 of the 52 birth defects examined (ORs ranging from 1.19 to 2.26): encephalocele, cataracts, cleft lip, esophageal atresia, duodenal atresia/stenosis, small intestinal atresia/stenosis, colonic atresia/stenosis, transverse limb deficiency, conoventricular septal defect, atrioventricular septal defect, and secundum atrial septal defect. A periconceptional UTI was significantly associated with nine birth defects (ORs from 1.21 to 2.48), and periconceptional STI was significantly associated with four birth defects (ORs ranging from 1.63 to 3.72).

CONCLUSIONS

While misclassification of GUIs in our analysis is likely, our findings suggest GUIs during the periconceptional period may increase the risk for specific birth defects.

A population-based case-control study of the association between weather-related extreme heat events and orofacial clefts

BACKGROUND

Limited epidemiologic research exists on the association between weather-related extreme heat events (EHEs) and orofacial clefts (OFCs). We estimated the associations between maternal exposure to EHEs in the summer season and OFCs in offspring and investigated the potential modifying effect of body mass index on these associations.

METHODS

We conducted a population-based case-control study among mothers who participated in the National Birth Defects Prevention Study for whom at least 1 day of their first two post-conception months occurred during summer. Cases were live-born infants, stillbirths, and induced terminations with OFCs; controls were live-born infants without major birth defects. We defined EHEs using the 95th and the 90th percentiles of the daily maximum universal apparent temperature distribution. We used unconditional logistic regression with Firth's penalized likelihood method to estimate adjusted odds ratios and 95% confidence intervals, controlling for maternal sociodemographic and anthropometric variables.

RESULTS

We observed no association between maternal exposure to EHEs and OFCs overall, although prolonged duration of EHEs may increase the risk of OFCs in some study sites located in the Southeast climate region. Analyses by subtypes of OFCs revealed no associations with EHEs. Modifying effect by BMI was not observed.

CONCLUSIONS

We did not find a significantly increased risk of OFCs associated with maternal exposure to EHEs during the relevant window of embryogenesis. Future studies should account for maternal indoor and outdoor activities and for characteristics such as hydration and use of air conditioning that could modify the effect of EHEs on pregnant women.

Does Maternal Exposure to Secondhand Tobacco Smoke During Pregnancy Increase the Risk for Preterm or Small-for-Gestational Age Birth?

Introduction While associations between active smoking and various adverse birth outcomes (ABOs) have been reported in the literature, less is known about the impact of secondhand smoke (SHS) on many pregnancy outcomes. Methods We examined the relationship between maternal exposure to SHS during pregnancy and preterm (< 37 weeks gestation) and small-for-gestational age (SGA; assessed using sex-, race/ethnic-, and parity-specific growth curves) singleton births using non-smoking controls from the National Birth Defects Prevention Study (1997-2011). Multivariable logistic regression models for household, workplace/school, and combined SHS exposure-controlled for maternal education, race/ethnicity, pre-pregnancy body mass index, and high blood pressure-were used to estimate adjusted odds ratios (aORs) and 95% confidence intervals (CIs). Interaction was assessed for maternal folic acid supplementation, alcohol use, age at delivery, and infant sex. Results Infants of 8855 mothers were examined in the preterm birth analysis with 666 (7.5%) categorized as preterm, 574 moderately preterm (32-36 weeks), and 92 very preterm (< 32 weeks). For the SGA analysis, infants of 8684 mothers were examined with 670 (7.7%) categorized as SGA. The aORs for mothers reporting both household and workplace/school SHS were elevated for preterm (aOR 1.99; 95% CI 1.13-3.50) and moderately preterm birth (32-36 weeks) (aOR 2.17; 95% CI 1.22-3.88). No results for the SGA analysis achieved significance, nor was evidence of interaction evident. Conclusion The findings suggest an association between SHS from multiple exposure sources and preterm birth, but no evidence for association with SGA births. Continued study of SHS and ABOs is needed to best inform public health prevention programs.

Value of sharing and networking among birth defects surveillance programs: an ICBDSR perspective

Birth defects (BD), also known as congenital anomalies, are structural or functional abnormalities present at birth as a result of abnormal prenatal development. Their cause can be broadly categorized as genetic, environmental, or a combination of both. It is estimated that approximately 3-6% of newborn infants worldwide are affected by BD, many of which are associated with serious morbidity, mortality, and lifelong disabilities. The International Clearinghouse for Birth Defects Surveillance and Research (ICBDSR), founded in 1974, promotes worldwide birth defect surveillance, research, and prevention through the ongoing sharing of data, expertise, and training. In this review, we show value and contribution of BD surveillance systems in pursuing these aims. In the time of personalized medicine for many rare and common diseases, there are still massive gaps in our understanding of the causes and mechanisms of many birth defects, especially structural congenital anomalies. The main aim of the Sustainable Development Goals (SDGs), adopted by the United Nations in 2015, is to ensure healthy lives and promote well-being for all children. One specific goal is to end preventable deaths of newborns and children less than 5 years of age by 2030. The SDGs also underscore the need to consider BD as a priority in the global child health agenda. It can be said that counting BD helps BD to count. By sharing data and expertise and joining in surveillance and research, BD surveillance programs can play a major role in increasing our understanding of the causes of BD, and promoting prevention.

Maternal ambient heat exposure during early pregnancy in summer and spring and congenital heart defects - A large US population-based, case-control study

BACKGROUND/OBJECTIVE

Few studies have assessed the effect of ambient heat during the fetal development period on congenital heart defects (CHDs), especially in transitional seasons. We examined and compared the associations between extreme heat and CHD phenotypes in summer and spring, assessed their geographical differences, and compared different heat indicators.

METHODS

We identified 5848 CHD cases and 5742 controls (without major structural defects) from the National Birth Defects Prevention Study, a US multicenter, population-based case-control study. Extreme heat events (EHEs) were defined by using the 95th (EHE95) or 90th (EHE90) percentile of daily maximum temperature and its frequency and duration during postconceptional weeks 3-8. We used a two-stage Bayesian hierarchical model to examine both regional and study-wide associations. Exposure odds ratios (ORs) were calculated using multivariate logistic regression analyses, while controlling for potential confounding factors.

RESULTS

Overall, we observed no significant relationships between maternal EHE exposure and CHDs in most regions during summer. However, we found that 3-11 days of EHE90 during summer and spring was significantly associated with ventricular septal defects (VSDs) study-wide (ORs ranged: 2.17-3.24). EHE95 in spring was significantly associated with conotruncal defects and VSDs in the South (ORs: 1.23-1.78). Most EHE indicators in spring were significantly associated with increased septal defects (both VSDs and atrial septal defects (ASDs)) in the Northeast.

CONCLUSION

While generally null results were found, long duration of unseasonable heat was associated with the increased risks for VSDs and ASDs, mainly in South and Northeast of the US. Further research to confirm our findings is needed.

Germline but not somatic de novo mutations are common in human congenital diaphragmatic hernia

OBJECTIVES

Congenital diaphragmatic hernia (CDH) is a developmental defect of the diaphragm that causes high newborn morbidity and mortality. CDH is considered to be a multifactorial disease, with strong evidence implicating genetic factors. Although recent studies suggest the biological role of deleterious germline de novo variants, the effect of gene variants specific to the diaphragm remains unclear, and few single genes have been definitively implicated in human disease.

METHODS

We performed genome sequencing on 16 individuals with CDH and their unaffected parents, including 10 diaphragmatic samples.

RESULTS

We did not detect damaging somatic mutations in diaphragms, but identified germline heterozygous de novo functional mutations of 14 genes in nine patients. Although the majority of these genes are not known to be associated with CDH, one patient with CDH and cardiac anomalies harbored a frameshift mutation in NR2F2 (aka COUP-TFII), generating a premature truncation of the protein. This patient also carried a missense variant predicted to be damaging in XIRP2 (aka Myomaxin), a transcriptional target of MEF2A. Both NR2F2 and MEF2A map to chromosome 15q26, where recurring de novo deletions and unbalanced translocations have been observed in CDH.

CONCLUSIONS

Somatic variants are not common in CDH. To our knowledge, this is the second case of a germline de novo frameshift mutation in NR2F2 in CDH. Since NR2F2 null mice exhibit a diaphragmatic defect, and XIRP2 is implicated in cardiac development, our data suggest the role of these two variants in the etiology of CDH, and possibly cardiac anomalies.

Risk comparison for prenatal use of analgesics and selected birth defects, National Birth Defects Prevention Study 1997-2011

PURPOSE

To compare the use of nonsteroidal anti-inflammatory drugs (NSAIDs) and/or opioids to the use of acetaminophen without NSAIDs or opioids with respect to associations with birth defects.

METHODS

We used data from the National Birth Defects Prevention Study (1997-2011). Exposure was self-reported maternal analgesic use from the month before through the third month of pregnancy (periconceptional). Adjusted odds ratios (aORs) were calculated to examine associations with 16 birth defects.

RESULTS

Compared to acetaminophen, mothers reporting NSAIDs were significantly more likely to have offspring with gastroschisis, hypospadias, cleft palate, cleft lip with cleft palate, cleft lip without cleft palate, anencephaly, spina bifida, hypoplastic left heart syndrome, pulmonary valve stenosis, and tetralogy of Fallot (aOR range, 1.2-1.6). Opioids were associated with tetralogy of Fallot, perimembranous ventricular septal defect, and ventricular septal defect with atrial septal defect (aOR range, 1.8-2.3), whereas use of both opioids and NSAIDs was associated with gastroschisis, cleft palate, spina bifida, hypoplastic left heart syndrome, and pulmonary valve stenosis (aOR range, 2.0-2.9).

CONCLUSIONS

Compared to periconceptional use of acetaminophen, selected birth defects occurred more frequently among infants of women using NSAIDs and/or opioids. However, we could not definitely determine whether these risks relate to the drugs or to indications for treatment.

Epidemiology and Prognosis of Congenital Diaphragmatic Hernia: A Population-Based Cohort Study in Utah

BACKGROUND

Congenital diaphragmatic hernia (CDH) is a relatively frequent and severe malformation. Population-based data on clinical presentation and associated mortality are scarce. We examined a state-wide cohort of infants with a clinically validated diagnosis of CDH to assess their clinical profile, sociodemographic patterns, and infant mortality.

METHODS

We identified CDH cases from Utah's statewide population-based surveillance program among the cohort of all pregnancy outcomes (live births, stillbirths, and pregnancy terminations) delivered from 1999 to 2011. Clinical geneticists reviewed all cases and classified them based on etiology (known, unknown), and whether they were isolated, multiple (additional unrelated major malformations or unique minor malformation), or syndromic (genetic, chromosomal).

RESULTS

CDH occurred in 1 in 3156 births (227/718,990, or 3.17 per 10,000), with no time trend during the 13 years (p = 0.85). CDH was much more common in males (male to female ratio, 1.72:1; p < 0.01). Clinically, 64% of the cases were isolated, 23% were multiples, and 13% were syndromic. Most cases were live born (90%), with fewer stillbirths (7%) and pregnancy terminations (3%). Overall infant mortality was 32.5%, and varied considerably by underlying etiology (isolated 21%; multiple 44%; syndromic 82%). Prognosis was related to specific clinical findings within each etiologic group (e.g., prematurity, low Apgar score, and intrathoracic liver).

CONCLUSION

This information on specific clinical and etiologic factors associated with prognosis can help clinicians and parents in the complex discussions about care planning and management that often occur in a crisis situation, following the diagnosis of CDH, whether prior or after delivery. Birth Defects Research 109:1451-1459, 2017.© 2017 Wiley Periodicals, Inc.

Understanding the Natural Progression of Spina Bifida: Prospective Study

BACKGROUND

Spina bifida (SB) is monitored through birth defects surveillance across the United States and in most developed countries. Although much is known about the management of SB and its many comorbid conditions in affected individuals, there are few systematic, longitudinal studies on population-based cohorts of children or adults. The natural history of SB across the life course of persons with this condition is not well documented. Earlier identification of comorbidities and secondary conditions could allow for earlier intervention that might enhance the developmental trajectory for children with SB.

OBJECTIVE

The purpose of this project was to assess the development, health, and condition progression by prospectively studying children who were born with SB in Arizona and Utah. In addition, the methodology used to collect the data would be evaluated and revised as appropriate.

METHODS

Parents of children with SB aged 3-6 years were eligible to participate in the study, in English or Spanish. The actual recruitment process was closely documented. Data on medical history were collected from medical records; family functioning, child behaviors, self-care, mobility and functioning, and health and well-being from parent reports; and neuropsychological data from testing of the child.

RESULTS

In total, 152 individuals with SB were identified as eligible and their parents were contacted by site personnel for enrollment in the study. Of those, 45 (29.6%) declined to participate and 6 (3.9%) consented but did not follow through. Among 101 parents willing to participate, 81 (80.2%) completed the full protocol and 20 (19.8%) completed the partial protocol. Utah enrolled 72.3% (73/101) of participants, predominately non-Hispanic (60/73, 82%) and male (47/73, 64%). Arizona enrolled 56% (28/50) of participants they had permission to contact, predominately Hispanic (18/28, 64%) and male (16/28, 57%).

CONCLUSIONS

We observed variance by site for recruitment, due to differences in identification and ascertainment of eligible cases and the required institutional review board processes. Restriction in recruitment and the proportion of minorities likely impacted participation rates in Arizona more than Utah.