Is there epidemiologic evidence to support vascular disruption as a pathogenesis of gastroschisis?

Prenatal cannabis use disorder and gastroschisis in California, 2007-19

BACKGROUND

Gastroschisis is a congenital anomaly of the abdominal wall with an unknown aetiology. Recent trends in the prevalence of gastroschisis suggest that changing environmental or behavioural factors may contribute. We examined whether prenatal cannabis use disorder was associated with gastroschisis.

METHODS

The Study of Outcomes of Mothers and Infants is a population-based cohort compiled of California birth records that have been linked to Department of Health Care Access and Information hospitalization, emergency department and ambulatory surgery records. We included 2007-19 singleton live births (n = 5 774 656). Cannabis use disorder was measured by diagnosis codes at any visit during pregnancy or at birth. Gastroschisis was measured by diagnosis or surgical repair procedure codes at birth or during the first year of life.

RESULTS

The prevalence of cannabis use disorder was about 1%. The prevalence of gastroschisis was 0.14% and 0.06% among those with and without cannabis use disorder, respectively. There were positive associations between cannabis use disorder and gastroschisis when using a multivariable model [adjusted risk ratio (aRR) = 1.3, 95% confidence interval (CI) 1.0, 1.7) and a matched sample approach (aRR = 1.5, 95% CI 1.1, 2.1). The association varied by maternal age and was largest among people aged >34 years (aRR = 2.5, 95% CI 1.0, 5.8).

CONCLUSIONS

We confirm findings of a positive association between cannabis exposure and gastroschisis and add that it is strongest when maternal age is greater than 34 years. More investigation into whether the association is causal, and why the association varies by maternal age, is encouraged.

Medication use during pregnancy and the risk of gastroschisis: a systematic review and meta-analysis of observational studies

OBJECTIVES

The aetiology of gastroschisis is considered multifactorial. We conducted a systematic review and meta-analysis to assess whether the use of medications during pregnancy, is associated with the risk of gastroschisis in offspring.

METHODS

PubMed, EMBASE, and Scopus were searched from 1st January 1990 to 31st December 2020 to identify observational studies examining the association between medication use during pregnancy and the risk of gastroschisis. The Newcastle-Ottawa Scale was used for the quality assessment of the individual studies. We pooled adjusted measures using a random-effect model to estimate relative risk [RR] and the 95% confidence interval [CI]. I2 statistic for heterogeneity and publication bias was calculated.

RESULTS

Eighteen studies providing data on 751,954 pregnancies were included in the meta-analysis. Pooled RRs showed significant associations between aspirin (RR 1.66, 95% CI 1.16-2.38; I2 = 58.3%), oral contraceptives (RR 1.52, 95% CI 1.21-1.92; I2 = 22.0%), pseudoephedrine and phenylpropanolamine (RR 1.51, 95% CI 1.16-1.97; I2 = 33.2%), ibuprofen (RR 1.42, 95% CI 1.26-1.60; I2 = 0.0%), and gastroschisis. No association was observed between paracetamol and gastroschisis (RR 1.16, 95% CI 0.96-1.41; I2 = 39.4%).

CONCLUSIONS

These results suggest that the exposure in the first trimester of pregnancy to over the counter medications (OTC) such as aspirin, ibuprofen, pseudoephedrine and phenylpropanolamine as well as to oral contraceptives, was associated with an increased risk of gastroschisis. However, these associations are significant only in particular subgroups defined by geographic location, adjustment variables and type of control. Therefore, further research is needed to investigate them as potential risk factors for gastroschisis, to assess their safety in pregnancy and to develop treatment strategies to reduce the risk of gastroschisis in offspring. PROSPERO registration number: CRD42021287529.

Public health priorities for gastroschisis: Summary of a meeting sponsored by the Centers for Disease Control and Prevention and the March of Dimes

BACKGROUND

Gastroschisis has increased worldwide over several decades; however, there are significant gaps in understanding risk factors for development of the defect, particularly those that might be modifiable. Despite advances in survival, little is known about longer-term outcomes for affected individuals.

METHODS

On April 27- and 28, 2023, the National Center on Birth Defects and Developmental Disabilities at the Centers for Disease Control and Prevention (CDC) and March of Dimes sponsored a meeting entitled "Public Health Priorities for Gastroschisis". The meeting goals were to review current knowledge on gastroschisis, discuss research gaps, and identify future priorities for public health surveillance, research, and action related to gastroschisis. Meeting participants encompassed a broad range of expertise and experience, including public health, clinical care of individuals with gastroschisis, affected individuals and families, and representatives from professional organizations and federal agencies.

RESULTS

Several goals were identified for future public health surveillance and research, including focused theory-driven research on risk factors and increased study of longer-term effects of gastroschisis through improved surveillance. Certain public health actions were identified, that which could improve the care of affected individuals, including increased education of providers and enhanced resources for patients and families.

CONCLUSIONS

These efforts may lead to an improved understanding of pathogenesis, risk factors, and outcomes and to improved care throughout the lifespan.

Geotemporospatial and causal inference epidemiological analysis of US survey and overview of cannabis, cannabidiol and cannabinoid genotoxicity in relation to congenital anomalies 2001–2015

Background

Cannabinoids including cannabidiol have recognized genotoxic activities but their significance has not been studied broadly epidemiologically across the teratological spectrum. We examined these issues including contextual space-time relationships and formal causal inferential analysis in USA.

Methods

State congenital anomaly (CA) rate (CAR) data was taken from the annual reports of the National Birth Defects Prevention Network 2001–2005 to 2011–2015. Substance abuse rates were from the National Survey of Drug Use and Health a nationally representative longitudinal survey of the non-institutionalized US population with 74.1% response rate. Drugs examined were cigarettes, monthly and binge alcohol, monthly cannabis and analgesic and cocaine abuse. Early termination of pregnancy for abortion (ETOPFA) rates were taken from the published literature. Cannabinoid concentrations were from Drug Enforcement Agency. Ethnicity and income data were from the US Census Bureau. Inverse probability weighted (IPW) regressions and geotemporospatial regressions conducted for selected CAs.

Results

Data on 18,328,529 births from an aggregated population of 2,377,483,589 for mid-year analyses 2005–2013 comprehending 12,611 CARs for 62 CAs was assembled and ETOPFA-corrected (ETOPFACAR) where appropriate. E-Values for ETOPFACARs by substance trends were elevated for THC (40 CAs), cannabis (35 CAs), tobacco (11 CAs), cannabidiol (8 CAs), monthly alcohol (5 CAs) and binge alcohol (2 CAs) with minimum E-Values descending from 16.55, 1.55x107, 555.10, 7.53x1019, 9.30 and 32.98. Cardiovascular, gastrointestinal, chromosomal, limb reductions, urinary, face and body wall CAs particularly affected. Highest v. lowest substance use quintile CAR prevalence ratios 2.84 (95%C.I. 2.44, 3.31), 4.85 (4.08, 5.77) and 1.92 (1.63, 2.27) and attributable fraction in exposed 0.28 (0.27, 0.28), 0.57 (0.51, 0.62) and 0.47 (0.38, 0.55) for tobacco, cannabis and cannabidiol. Small intestinal stenosis or atresia and obstructive genitourinary defect were studied in detail in lagged IPW pseudo-randomized causal regressions and spatiotemporal models confirmed the causal role of cannabinoids. Spatiotemporal predictive modelling demonstrated strongly sigmoidal non-linear cannabidiol dose-response power-function relationships (P = 2.83x10−60 and 1.61x10−71 respectively).

Conclusions

Data implicate cannabinoids including cannabidiol in a diverse spectrum of heritable CAs. Sigmoidal non-linear dose-response relationships are of grave concern.

These transgenerational genotoxic, epigenotoxic, chromosomal-toxic putatively causal teratogenic effects strongly indicate tight restrictions on community cannabinoid penetration.

The medical and surgical management of gastroschisis

Gastroschisis (GS) is a full-thickness abdominal wall defect in which fetal intestine herniates alongside the umbilical cord into the intrauterine cavity, resulting in an intestinal injury of variable severity. An increased prevalence of gastroschisis has been observed across several continents and is a focus of epidemiologic study. Prenatal diagnosis of GS is common and allows for delivery planning and treatment in neonatal intensive care units (NICUs) by collaborative interdisciplinary teams (neonatology, neonatal nursing and pediatric surgery). Postnatal treatment focuses on closure of the defect, optimized nutrition, complication avoidance and a timely transition to enteral feeding. Babies born with complex GS are more vulnerable to complications, have longer and more resource intensive hospital stays and benefit from standardized care pathways provided by teams with expertise in managing infants with intestinal failure. This article will review the current state of knowledge related to the medical and surgical management and outcomes of gastroschisis with a special focus on the role of the neonatologist in supporting integrated team-based care.

Regional variation in gastroschisis: a nationwide database review of demographics and outcomes

BACKGROUND

Gastroschisis is an index neonatal malformation with an increasing incidence from earlier decades. The aim of this study was to investigate regional variations in patient demographics, outcomes, and costs in gastroschisis.

MATERIALS AND METHODS

The 2016 kid's inpatient database (KID) obtained from the Healthcare Cost and Utilization Project (HCUP) was used to obtain gastroschisis birth, demographic, and outcome data across four U.S. geographical regions: Northeast, Midwest, South, and West. Categorical variables were analyzed with Pearson's Chi-squared test. Odds ratios (OR) with 95% confidence intervals (CI) were reported for variables with significance (p < 0.05). Appropriate logistic regressions were used for comparing categorical, cardinal, and continuous data.

RESULTS

2043 gastroschisis cases were obtained from the 2016 KID database with a weighted incidence of 5.1 per 10,000 live births. Incidence of gastroschisis across regions was similar when controlling for a number of hospitals reporting to KID. Prematurity was common, with 59% (1204) of neonates with gastroschisis born at less than 37 weeks. 52% (N = 1067) of gastroschisis infants were male. 46% (955) were White, 9% (178) African American, 22% (450) Hispanic, and 8% (155) other. The overall mortality of gastroschisis in this database was 3.6% (75). The average length of stay was 39 days and average cost of treatment was $357,436. Though without significant differences in mortality, there were significant differences in demographics, costs, and lengths of stay between regions.

CONCLUSIONS

There has been a significant increase in gastroschisis incidence over the last three decades. This significant increase appears to be related to an increase in socioeconomic inequality and an alteration in the population demographics in the United States. Further study of regional variations will facilitate the development of best practice guidelines that benefit all.

The spectrum of brain malformations and disruptions in twins

Twins have an increased risk for congenital malformations and disruptions, including defects in brain morphogenesis. We analyzed data on brain imaging, zygosity, sex, and fetal demise in 56 proband twins and 7 less affected co-twins with abnormal brain imaging and compared them to population-based data and to a literature series. We separated our series into malformations of cortical development (MCD, N = 39), cerebellar malformations without MCD (N = 13), and brain disruptions (N = 11). The MCD group included 37/39 (95%) with polymicrogyria (PMG), 8/39 (21%) with pia-ependymal clefts (schizencephaly), and 15/39 (38%) with periventricular nodular heterotopia (PNH) including 2 with PNH but not PMG. Cerebellar malformations were found in 19 individuals including 13 with a cerebellar malformation only and another 6 with cerebellar malformation and MCD. The pattern varied from diffuse cerebellar hypoplasia to classic Dandy-Walker malformation. Brain disruptions were seen in 11 individuals with hydranencephaly, porencephaly, or white matter loss without cysts. Our series included an expected statistically significant excess of monozygotic (MZ) twin pairs (22/41 MZ, 54%) compared to population data (482/1448 MZ, 33.3%; p = .0110), and an unexpected statistically significant excess of dizygotic (DZ) twins (19/41, 46%) compared to the literature cohort (1/46 DZ, 2%; p < .0001. Recurrent association with twin-twin transfusion syndrome, intrauterine growth retardation, and other prenatal factors support disruption of vascular perfusion as the most likely unifying cause.

Lifestyle and sociodemographic risk factors for gastroschisis: a systematic review and meta-analysis

BACKGROUND

Gastroschisis is strongly associated with young maternal age. This association suggests the need for further investigations on non-genetic risk factors. Identifying these risk factors is a public health priority in order to develop prevention strategies aimed at reducing the prevalence and health consequences in offspring.

OBJECTIVE

To systematically assess and quantitatively synthesise the available epidemiological studies to evaluate the association between non-genetic risk factors and gastroschisis.

METHODS

Literature from PubMed, EMBASE and Scopus was searched for the period 1990-2018. Epidemiological studies reporting risk estimates between lifestyle and sociodemographic risk factors and gastroschisis were included. Two pairs of reviewers independently extracted information on study characteristics following Preferred Reporting Items for Systematic Reviews and Meta-Analyses and MOOSE (Meta-analysis Of Oservational Studies in Epidemiology) guidelines. Relative risk (RR) estimates were calculated across the studies and meta-analysis was performed using random-effects model.

RESULTS

We identified 58 studies. Meta-analyses were conducted on 29 studies. Maternal smoking (RR 1.56, 95% CI 1.40 to 1.74), illicit drug use (RR 2.14, 95% CI 1.48 to 3.07) and alcohol consumption (RR 1.40, 95% CI 1.13 to 1.70) were associated with an increased risk of gastroschisis. A decreased risk among black mothers compared with non-Hispanic white mothers (RR 0.49, 95% CI 0.38 to 0.63) was found. For Hispanic mothers no association was observed.

CONCLUSIONS

Exposure to smoking, illicit drugs and alcohol during pregnancy is associated with an increased risk of gastroschisis. A significantly decreased risk for black mothers was observed. Further epidemiological studies to assess the potential role of other environmental factors are strongly recommended.

PROSPERO REGISTRATION NUMBER

CRD42018104284.

Major birth defects in the Brazilian side of the triple border: a population-based cross-sectional study

Background

Major birth defects increase the risk of fetal death and pediatric hospitalization, which also impact on healthcare costs. Sociodemographic factors can drastically affect reproductive health and be used to discriminate the exposure to hidden risk factors. Foz do Iguassu is a Brazilian city located in the triple-border region of Brazil / Paraguay / Argentina with high rates of birth defects. However no study aimed to verify factors associated with this incidence or preventive care is reported. The current work investigated the prevalence of major birth defects and its association with maternal sociodemographic factors in Foz do Iguassu.

Methods

In this population-based cross-sectional study we used data of all live births occurred in Foz do Iguassu from 2012 to 2017. The associated sociodemographic variables such as maternal age, maternal education, maternal race, country of residence, maternal parity and onset of prenatal care were analyzed. Each major birth defect was described according to absolute and relative frequencies, Kruskal-Wallis and logistic regression models were used to evaluate variables associated with selected birth defects.

Results

The most prevalent major birth defects were Cleft Lip and/or Palate (9.5/10,000), gastroschisis (6.93/10,000), spina bifida (5.53/10,000), hydrocephalus (5.53/10,000), hypospadias (4.55/10,000), Down syndrome (4.23/10,000), anencephaly (2.93/10,000), anorectal atresia / stenosis (1.95/10,000), undetermined sex (1.95/10,000), esophageal atresia / stenosis with or without fistula (1.63/10,000) and limb reduction defects (1.30/10,000). Maternal age was associated with gastroschisis and Down syndrome. Only maternal education up to 7 years was statistically associated with major birth defects considering all other sociodemographic variables.

Conclusion

Cleft Lip and/or Palate and Gastroschisis prevalence were higher than those found in the literature. This findings may suggest a distinct epidemiological behavior regarding major birth defects in the region. The work opens new perspectives for birth defects risk factors in the triple-border.

Medication Use and Pain Management in Pregnancy: A Critical Review

BACKGROUND

Pain during pregnancy is common, and its management is complex. Certain analgesics may increase the risk for adverse fetal and pregnancy outcomes, while poorly managed pain can result in adverse maternal outcomes such as depression and hypertension. Guidelines to assist clinicians in assessing risks and benefits of exposure to analgesics for the mother and unborn infant are lacking, necessitating evidence-based recommendations for managing pain in pregnancy.

METHODS

A comprehensive literature search was conducted to assess pregnancy safety data for pharmacological and nonpharmacological pain management methods. Relevant clinical trials and observational studies were identified using multiple medical databases, and included studies were evaluated for quality and possible biases.

RESULTS

Paracetamol and nonsteroidal anti-inflammatory drugs (NSAIDs) are appropriate for mild to moderate pain, but NSAIDs should be avoided in the third trimester due to established risks. Short courses of weaker opioids are generally safe in pregnancy, although neonatal abstinence syndrome must be monitored following third trimester exposure. Limited safety data for pregabalin and gabapentin indicate that these are unlikely to be major teratogens, and tricyclic antidepressants and serotonin-norepinephrine reuptake inhibitors have limited but overall reassuring safety data. Many of the included studies were limited by methodological issues.

CONCLUSIONS

Findings from this review can guide clinicians in their decision to prescribe analgesics for pregnant women. Treatment should be tailored to the lowest therapeutic dose and shortest possible duration, and management should involve a discussion of risks and benefits and monitoring for response. Further research is required to better understand the safety profile of various analgesics in pregnancy.

Influence of periconception smoking behavior on birth defect risk

BACKGROUND

Smoking is one of the most important modifiable risk factors for adverse maternal and neonatal outcomes. Smoking during pregnancy has been associated with fetal growth restriction, adverse pregnancy outcomes, and chronic adult diseases. Existing research has evaluated the risk of smoking on congenital defects. However, no studies have evaluated how periconception smoking affects birth defects.

OBJECTIVE

The purpose of this study was to assess the association of maternal smoking and the timing of periconception exposure with congenital birth defects.

STUDY DESIGN

This study was a population-based retrospective cohort of live births in Ohio from 2006-2015 with the use of data from birth certificates. Rates of cardiovascular, musculoskeletal, gastrointestinal, and neural tube birth defects were compared between a referent group of women who did not smoke and a group of women who smoked (1) during the preconception period of 3 months before conception only and not in the first trimester and (2) in the preconception period plus throughout the first trimester of pregnancy. Multivariate logistic regression was used to quantify the relationship between periconception smoking and the rate of birth defects after adjustment for maternal race, age, pregestational diabetes mellitus, and socioeconomic factors.

RESULTS

Of the 1,436,036 live births in the study period, 75% of mothers did not smoke during the preconception period or during pregnancy. There were 334,156 women (23.3%) who smoked during pregnancy; 6.0% of the population smoked preconception only, and 17.3% of the population smoked both during the preconception period and through the first trimester. Smoking during the preconception period only, even without first trimester exposure, was associated with a 40% increased risk of gastroschisis. Smoking that was limited to preconception only was not associated with any other individual birth defects. However, smoking through the first trimester was associated with a statistically significant increased risk of several defects that included gastroschisis and limb reduction and a composite outcome of any defect, even after adjustment for coexisting factors.

CONCLUSION

Smoking during the period of fetal organogenesis (during the first trimester of pregnancy) is associated with increased risk of some birth defects. In this study, we provide novel data that smoking during the few months before conception, even with cessation in the first trimester, may also pose a risk for fetal malformation such as gastroschisis. These findings highlight the importance of preconception women's public health education efforts and warrant further investigation.

The development of the dorsal mesentery in human embryos and fetuses

The vertebrate intestine has a continuous dorsal mesentery between pharynx and anus that facilitates intestinal mobility. Based on width and fate the dorsal mesentery can be subdivided into that of the caudal foregut, midgut, and hindgut. The dorsal mesentery of stomach and duodenum is wide and topographically complex due to strong and asymmetric growth of the stomach. The associated formation of the lesser sac partitions the dorsal mesentery into the right-sided "caval fold" that serves as conduit for the inferior caval vein and the left-sided mesogastrium. The thin dorsal mesentery of the midgut originates between the base of the superior and inferior mesenteric arteries, and follows the transient increase in intestinal growth that results in small-intestinal looping, intestinal herniation and, subsequently, return. The following fixation of a large portion of the abdominal dorsal mesentery to the dorsal peritoneal wall by adhesion and fusion is only seen in primates and is often incomplete. Adhesion and fusion of mesothelial surfaces in the lesser pelvis results in the formation of the "mesorectum". Whether Toldt's and Denonvilliers' "fasciae of fusion" identify the location of the original mesothelial surfaces or, alternatively, represent the effects of postnatal wear and tear due to intestinal motility and intra-abdominal pressure changes, remains to be shown. "Malrotations" are characterized by growth defects of the intestinal loops with an ischemic origin and a narrow mesenteric root due to insufficient adhesion and fusion.

Understanding gastroschisis and its clinical management: where are we?

Gastroschisis is the commonest developmental defect of the anterior abdominal wall in both developed and developing countries. The past 30 years have seen transformational improvements in outcome due to advances in neonatal intensive care and enhanced integration between the disciplines of maternal fetal medicine, neonatology and pediatric surgery. A review of gastroschisis, which emphasizes its epidemiology, multidisciplinary care strategies and contemporary outcomes is timely. Areas covered: This review discusses the current state of knowledge related to prevalence and causation, and postulated embryopathologic mechanisms contributing to the development of gastroschisis. Using relevant, current literature with an emphasis on high level evidence where it exists, we review modern techniques of prenatal diagnosis, pre and postnatal risk stratification, preferred timing and method of delivery, options for abdominal wall closure, nutritional management, and short and long term clinical and neurodevelopmental follow-up. Expert commentary: This section explores controversies in contemporary management which contribute to practice and cost variation and discusses the benefits of novel nutritional therapies and care standardization that target unnecessary practice variation and improve overall cost-effectiveness of gastroschisis care. The commentary concludes with a review of fertile areas of gastroschisis research, which represent opportunities for knowledge synthesis and further outcome improvement.

Gastroschisis in Europe - A Case-malformed-Control Study of Medication and Maternal Illness during Pregnancy as Risk Factors

BACKGROUND

Gastroschisis, a congenital anomaly of the abdomen, is associated with young maternal age and has increased in prevalence in many countries. Maternal illness and medication exposure are among environmental risk factors implicated in its aetiology.

METHODS

A population-based case-malformed control study was conducted using data from 18 European congenital anomaly registries, with information on first trimester medication use, covering 8 million births 1995-2012. 1577 gastroschisis cases (of which 4% stillbirths, 11% terminations of pregnancy) were compared to 153 357 non-chromosomal/monogenic controls. Literature review identified previous associations concerning maternal illness and medication exposure to be tested as signals. Logistic regression adjusted for maternal age group, registry, and time period was used to evaluate associations.

RESULTS

Comparing gastroschisis to other congenital anomalies, the data supported signals concerning maternal depression (aOR 2.52, 95% CI 1.45, 4.39), antidepressant use (aOR 2.03, 95% CI 1.22, 3.38), postnatal depression/psychosis following a previous pregnancy (aOR 8.32, 95% CI 2.56, 27.01), sexually transmitted infections (aOR 2.85, 95% CI 1.13, 7.24), topical antivirals (aOR 5.31, 95% CI 1.63, 17.33), and continuation of oral contraceptives in early pregnancy (aOR 2.17, 95% CI 1.13, 4.18). Exploratory analyses suggested associations with a wider range of maternal infections and medications, including tonsillitis and the expectorant bromhexine.

CONCLUSIONS

While it is difficult to disentangle the effects of the medication and underlying indication, our results add to the evidence base on preventable risk factors for gastroschisis. These risk factors may contribute to the higher risk among young mothers, and geographical and temporal variation in prevalence.

Maternal smoking during pregnancy and birth defects in children: a systematic review with meta-analysis

This systematic review aimed to investigate the association between maternal smoking during pregnancy and birth defects in children. We performed an electronic search of observational studies in the databases ovid MEDLINE (1950 to April 2010), LILACS and SciELO. We included 188 studies with a total of 13,564,914 participants (192,655 cases). Significant positive associations were found between maternal smoking and birth defects in the following body systems: cardiovascular (OR: 1.11; 95%CI: 1.03-1.19), digestive (OR: 1.18; 95%CI: 1.07-1.30), musculoskeletal (OR: 1.27; 95%CI: 1.16-1.39) and face and neck (OR: 1.28; 95%CI: 1.19-1.37). The strength of association between maternal smoking and birth defects measured by the OR (95%CI) is significantly related to the amount of cigarettes smoked daily (χ2 = 12.1; df = 2; p = 0.002). In conclusion, maternal smoking during pregnancy is associated with congenital malformations in children and this association is dose-dependent.

Delayed vasculogenesis and impaired angiogenesis due to altered Ang-2 and VE-cadherin levels in the chick embryo model following exposure to cadmium

PURPOSE

Cadmium (Cd) causes chick embryo malformation and abnormal extra-embryonic vasculature. This study investigates the effect of Cd on vasculogenesis, quantifies extra-embryonic vascular development following exposure to cadmium acetate (CdAc).

METHODS

After 48 or 60 h incubation, chicks were explanted and treated with 50 µl of 50 µM CdAc or equimolar sodium acetate. Embryos were again incubated then re-examined 4, 8, 24 and 48 h later. Gross morphological and histological manifestations were noted. Vasculogenesis was assessed by the development of omphalomesenteric vessels from blood islands. Sinus terminalis (ST), area vasculosa (AV), vessel density and embryo crown-rump length (CRL) were measured. Ang-2 and VE-cadherin mRNA expression was analysed by RT-PCR.

RESULTS

Vasculogenesis was delayed on gross and histological examination. ST length, AV area, vessel density and CRL were significantly reduced in the Cd group. Ang-2 was increased 4 h after exposure to Cd, whereas VE-cadherin was reduced.

CONCLUSION

Cd exposure inhibits normal development of extra-embryonic vasculature in line with growth retardation of the chick embryo in association with altered expression of Ang-2 and VE-cadherin.

Maternal exposures in the National Birth Defects Prevention Study: Time trends of selected exposures

BACKGROUND

Our objective was to describe time trends in selected pregnancy exposures in the National Birth Defects Prevention Study (NBDPS).

METHODS

We analyzed data from the NBDPS, a multi-site case-control study of major birth defects, for mothers of live-born infants without birth defects (controls), with an expected date of delivery (EDD) from 1998 to 2011. Mothers from the 10 participating centers across the United States were interviewed by phone between 6 weeks and 2 years after the EDD. We focused on maternal race/ethnicity and five maternal risk factors: obesity, use of folic acid-containing multivitamins, opioid analgesics, selective serotonin reuptake inhibitors, and loratadine because of their prevalence of use and some reports of associations with major birth defects. Prevalence time trends were examined using the Kendall's τβ test statistic.

RESULTS

The exposure trend analysis included 11,724 control mothers with EDDs from 1998 to 2011. We observed a significant increase in obesity prevalence among control mothers, as well as use of selective serotonin reuptake inhibitors and loratadine. We also observed an increase in periconceptional use of folic acid-containing multivitamins. Some of the time trends varied by race/ethnicity. No remarkable trend in the overall use of opioid analgesics was observed. The racial/ethnic distribution of mothers changed slightly during the study period.

CONCLUSION

Long-term, population-based case-control studies continue to be an effective way to assess exposure-birth defects associations and provide guidance to health care providers. However, investigators examining rare outcomes covering many years of data collection need to be cognizant of time trends in exposures.

Prevalence and risk factors for gastroschisis in a public hospital from west México

Mexico is recognized as a country with a high prevalence of gastroschisis, although the cause of this remains unclear. We define the prevalence and potential risk factors for gastroschisis in a public hospital from west México. A case-control study was conducted among 270 newborns, including 90 patients with nonsyndromic gastroschisis (cases) and 180 infants without birth defects (controls), born all during the period 2009 to 2013 at the Hospital Civil de Guadalajara "Dr. Juan I. Menchaca" (Guadalajara, Mexico), from a total of 51,145 live births. Potential maternal risk factors for gastroschisis were compared using multivariate logistic regression analysis to evaluate the deviance explained by different variables of interest. The overall prevalence of gastroschisis in live births was 17.6 per 10,000 births (95% confidence interval [CI] 14.0-21.2), whereas in offspring of women ≤ 19 years old was 29.9 per 10,000 births (95% CI 21.9-38.0). Mothers ≤ 19 years (adjusted odds ratio [aOR] 2.8: 95% CI 1.5-5.1), anemia during pregnancy (aOR 10.7; 95% CI 2.0-56.9), first-trimester exposure to hormonal contraceptives (aOR 3.7; 95% CI 1.0-13.0), and first-trimester alcohol consumption (aOR 3.4; 95% CI 1.6-7.3), were associated with gastroschisis. Contrarily, adjusted OR for pre-pregnancy body mass index ≥ 25 kg/m(2) has protective odds (aOR 0.2; 95% CI 0.1-0.5). Our results suggest an increased risk for gastroschisis among mothers under the age of 20, with anemia during pregnancy, and those who used hormonal contraceptives or consumed alcohol during early pregnancy, whereas, pre-pregnancy overweight has a protective OR, and they are discussed as clues in its pathogenesis.

Challenges in Studying Modifiable Risk Factors for Birth Defects

Conducting research to identify modifiable risk factors for birth defects is difficult for a variety of reasons. While some challenges are familiar to researchers across many disciplines, the confluence of issues affecting birth defects research may not be well understood by those outside of the field. This article describes several methodological challenges to the study of birth defects and ways these challenges might be addressed: (1) ascertainment, definition and classification of birth defects; (2) exposure assessment on modifiable risk factors; (3) analytical challenges related to small numbers and multiple statistical tests; (4) the role of genetics, including the collection of specimens and analysis of genetic data; and (5) challenges in translating research and demonstrating public health impact. Understanding these issues is important for researchers planning studies, reviewers evaluating the scientific merit of results from these studies, and consumers of the research, including fellow researchers, policy makers, health care providers, and families.

Maternal genitourinary infections and the risk of gastroschisis

Genitourinary infections (GUIs) have been associated with increased risk of gastroschisis in 2 studies. Using data collected in the Slone Epidemiology Center Birth Defects Study, we examined the association between GUI and gastroschisis. From 1998 to 2010, mothers of 249 gastroschisis cases and 7,104 controls were interviewed within 6 months of delivery about pregnancy events, including vaginal infections, genital herpes, urinary tract infections (UTIs), and other sexually transmitted diseases (STDs). Women were considered exposed if they reported at least 1 instance of a GUI in the first trimester. Logistic regression models were used to calculate odds ratios and 95% confidence intervals. Women who reported having any GUI had an adjusted odds ratio of 1.8 (95% confidence interval (CI): 1.3, 2.4). The highest risk was seen among women who reported a UTI only (adjusted odds ratio = 2.3, 95% CI: 1.5, 3.5), while the odds ratio for an STD only was slightly elevated (adjusted odds ratio = 1.2, 95% CI: 1.0, 1.5). Among women under 25 years of age, the odds ratio for UTI only was 2.6 (95% CI: 1.7, 4.0), and among older women it was 1.8 (95% CI: 0.6, 5.9). When we considered the joint association of UTIs and young maternal age, a synergistic effect was observed. The results of this study add further evidence that UTIs may increase the risk of gastroschisis.

Maternal residential atrazine exposure and gastroschisis by maternal age

Previous literature has suggested a link between maternal exposure to atrazine (the most commonly used herbicide in the US) and risk for gastroschisis (a birth defect that involves incomplete closure of the abdominal wall). Our objective was to evaluate the relationship between maternal atrazine exposure and gastroschisis risk by maternal age. We analyzed data for 1,161 cases with isolated gastroschisis and 8,390 controls delivered in Texas from 1999 through 2008. We estimated atrazine exposure based on maternal county of residence and data from the United States Geological Survey. Logistic regression was conducted among all subjects, and separately among offspring of women <25 and ≥25 years. Risk for gastroschisis in offspring was significantly increased for women ≥25 years with high levels of residential atrazine exposure compared to low (adjusted odds ratio: 1.97, 95 % confidence interval 1.19-3.26). This association was not observed among women <25 years. Our results provide additional insight into the suspected relationship of gastroschisis with atrazine. This relationship appears to be different in older versus younger mothers, providing further evidence that the etiology of gastroschisis may vary based on maternal age.

Anomalies associated with gastroschisis and omphalocele: analysis of 2825 cases from the Texas Birth Defects Registry

BACKGROUND/PURPOSE

The increasing prevalence of abdominal wall defects prompted analysis of anomalies associated with gastroschisis and omphalocele in the Texas Birth Defects Registry (TDBR).

METHODS

Cases of gastroschisis (ICD9 code 756.71), omphalocele (756.70), and/or unspecified anomalies of the abdominal wall (756.79) were obtained from the TDBR after IRB approval and analyzed using Microsoft Access© and Excel© databases.

RESULTS

Analysis began with 2825 cases including 1831 of gastroschisis, 814 of omphalocele, and 180 of unspecified abdominal wall defects plus 9680 associated anomalies that were classified according to system. The overall prevalence of abdominal wall defects among 3,806,299 Texas births from 1999 to 2008 was 7.4 per 10,000 with 4.8 per 10,000 for gastroschisis and 2.1 for omphalocele. After excluding ambiguous cases (8.5% possibly misclassified), anomaly spectra were similar for the two AWD with musculoskeletal (limb contractures or defects), cardiovascular, gastrointestinal, urogenital, and central nervous system defects being most common. Of 1831 cases with gastroschisis, 594 (32%) had associated anomalies compared to 654 (80%) of 814 omphalocele cases.

CONCLUSIONS

Gastroschisis as well as omphalocele has significant associated anomalies that are important to appreciate during pre- and postnatal management.

Maternal smoking, xenobiotic metabolizing enzyme gene variants, and gastroschisis risk

Maternal smoking during pregnancy is one proposed risk factor for gastroschisis, but reported associations have been modest, suggesting that differences in genetic susceptibility might play a role. We included 108 non-Hispanic white and 62 Hispanic families who had infants with gastroschisis, and 1,147 non-Hispanic white and 337 Hispanic families who had liveborn infants with no major structural birth defects (controls) in these analyses. DNA was extracted from buccal cells collected from infants and mothers, and information on periconceptional smoking history was obtained from maternal interviews, as part of the National Birth Defects Prevention Study. We analyzed five polymorphisms in three genes that code for enzymes involved in metabolism of some cigarette smoke constituents (CYP1A1, CYP1A2, and NAT2). Logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) independently for maternal smoking and maternal and infant gene variants, and to assess joint associations of maternal smoking and maternal or infant gene variants with gastroschisis. In analyses adjusted for maternal age at delivery and stratified by maternal race-ethnicity, we identified three suggestive associations among 30 potential associations with sufficient numbers to calculate ORs: CYP1A1*2A for non-Hispanic white mothers who smoked periconceptionally (aOR = 0.38, 95% CI 0.15-0.98), and NAT2*6 for Hispanic non-smoking mothers (aOR = 2.17, 95% CI 1.12-4.19) and their infants (aOR = 2.11, 95% CI 1.00-4.48). This analysis does not support the occurrence of effect modification between periconceptional maternal smoking and most of the xenobiotic metabolizing enzyme gene variants assessed.

A vascular and thrombotic model of gastroschisis

A binary vascular/thrombotic pathogenesis for gastroschisis, a form of congenital bowel herniation, is proposed, where normal right umbilical vein involution creates a possible site for thrombosis adjacent to the umbilical ring. If thrombosis occurs, it weakens the area, explaining overwhelmingly right-sided lesions. The model arises from the existence of two groups of risk factors with different maternal age associations. Older mothers show a greater association with vascular factors (although this may actually represent a lack of any significant maternal age effect), consistent with associations of gastroschisis with congenital heart lesions and with amyoplasia. Alternatively, other predispositions, and especially decreased maternal age, the greatest known risk factor, associate with factors raising maternal estrogen, with evidence that estrogen in turn acts here as a predisposition to thrombosis. Absorption of thrombotic by-products from the amniotic fluid can explain the unusual amniocyte inclusions that are common with gastroschisis, while a role for estrogens suggests a connection between rising gastroschisis prevalence and increasing environmental contamination with estrogen disruptors. This model explains a variety of structural and epidemiological findings, and suggests that stratification of data based on binary effects may clarify associated risks and mechanisms. The model also shows that what is often referred to as vascular disruption may actually reflect alternative or additional factors instead, including thrombosis as a primary mechanism.

The role of maternal stress in early pregnancy in the aetiology of gastroschisis: an incident case control study

Objective

The incidence of gastroschisis, a congenital anomaly where the infant abdominal wall is defective and intestines protrude from the abdominal cavity, is increasing in many countries. The role of maternal stress in some adverse birth outcomes is now well established. We tested the hypothesis that major stressful life events in the first trimester are risk factors for gastroschisis, and social support protective, in a case-control study in the United Kingdom.

Methods

Gastroschisis cases and three controls per case (matched for maternal age) were identified at routine 18-20 week fetal anomaly ultrasound scan, in 2007-2010. Face to face questionnaire interviews were carried out during the antenatal period (median 24 weeks gestation) asking about serious stressful events and social support in the first trimester. Data were analysed using conditional logistic regression.

Results

Two or more stressful life events in the first trimester (adjusted OR 4.9; 95% CI 1.2-19.4), and moving address in the first trimester (aOR 4.9; 95% CI 1.7-13.9) were strongly associated with risk of gastroschisis, independent of behavioural risk factors including smoking, alcohol, and poor diet. Perceived availability of social support was not associated with reduced risk of gastroschisis (aOR 0.8; 95% CI 0.2-3.1).

Conclusions

Stressful maternal life events in the first trimester of pregnancy including change of address were strongly associated with a substantial increase in the risk of gastroschisis, independent of stress related high risk behaviours such as smoking, alcohol consumption and poor diet. This suggests that stress pathways are involved in the aetiology of gastroschisis.

Prevalence and correlates of gastroschisis in 15 states, 1995 to 2005

OBJECTIVE

To identify trends in the prevalence and epidemiologic correlates of gastroschisis using a large population-based sample with cases identified by the National Birth Defects Prevention Network over the course of an 11-year period.

METHODS

This study examined 4,713 cases of gastroschisis occurring in 15 states during 1995-2005, using public use natality data sets for denominators. Multivariable Poisson regression was used to identify statistically significant risk factors, and Joinpoint regression analyses were conducted to assess temporal trends in gastroschisis prevalence by maternal age and race and ethnicity.

RESULTS

Results show an increasing temporal trend for gastroschisis (from 2.32 per 10,000 to 4.42 per 10,000 live births). Increasing prevalence of gastroschisis has occurred primarily among younger mothers (11.45 per 10,000 live births among mothers younger than age 20 years compared with 5.35 per 10,000 among women aged 20 to 24 years). In the multivariable analysis, using non-Hispanic whites as the referent group, non-Hispanic black women had the lowest risk of having a gastroschisis-affected pregnancy (prevalence ratio 0.42, 95% confidence interval [CI] 0.37-0.48), followed by Hispanics (prevalence ratio 0.86, 95% CI 0.81-0.92). Gastroschisis prevalence did not differ by newborn sex.

CONCLUSIONS

Our findings demonstrate that the prevalence of gastroschisis has been increasing since 1995 among 15 states in the United States, and that higher rates of gastroschisis are associated with non-Hispanic white maternal race and ethnicity, and maternal age younger than 25 years (particularly younger than 20 years of age).

LEVEL OF EVIDENCE

III.

A case-control study of maternal bathing habits and risk for birth defects in offspring

BACKGROUND

Nearly all women shower or take baths during early pregnancy; however, bathing habits (i.e., shower and bath length and frequency) may be related to the risk of maternal hyperthermia and exposure to water disinfection byproducts, both of which are suspected to increase risk for multiple types of birth defects. Thus, we assessed the relationships between bathing habits during pregnancy and the risk for several nonsyndromic birth defects in offspring.

METHODS

Data for cases with one of 13 types of birth defects and controls from the National Birth Defects Prevention Study delivered during 2000-2007 were evaluated. Logistic regression analyses were conducted separately for each type of birth defect.

RESULTS

There were few associations between shower frequency or bath frequency or length and risk for birth defects in offspring. The risk for gastroschisis in offspring was increased among women who reported showers lasting ≥15 compared to <15 minutes (adjusted odds ratio: 1.43, 95% confidence interval: 1.18-1.72). In addition, we observed modest increases in the risk for spina bifida, cleft lip with or without cleft palate, and limb reduction defects in offspring of women who showered ≥15 compared to <15 minutes. The results of comparisons among more specific categories of shower length (i.e., <15 minutes versus 15-19, 20-29, and ≥ 30 minutes) were similar.

CONCLUSIONS

Our findings suggest that shower length may be associated with gastroschisis, but the modest associations with other birth defects were not supported by analyses of bath length or bath or shower frequency. Given that showering for ≥15 minutes during pregnancy is very common, further evaluation of the relationship between maternal showering habits and birth defects in offspring is worthwhile.

Swimming pool use and birth defect risk

OBJECTIVE

Swimming during pregnancy is recommended. However, the use of swimming pools is also associated with infection by water-borne pathogens and exposure to water disinfection byproducts, which are 2 mechanisms that are suspected to increase risk for birth defects. Thus, we evaluated the relationship between maternal swimming pool use during early pregnancy and risk for select birth defects in offspring.

STUDY DESIGN

Data were evaluated for nonsyndromic cases with 1 of 16 types of birth defects (n = 191-1829) and controls (n = 6826) from the National Birth Defects Prevention Study delivered during 2000-2006. Logistic regression analyses were conducted separately for each birth defect type. Separate analyses were conducted to assess any pool use (yes vs no) and frequent use (5 or more occasions in 1 month) during the month before pregnancy through the third month of pregnancy.

RESULTS

There was no significant positive association between any or frequent pool use and any of the types of birth defects, even after adjustment for several potential confounders (maternal race/ethnicity, age at delivery, education, body mass index, folic acid use, nulliparity, smoking, annual household income, surveillance center, and season of conception). Frequent pool use was significantly negatively associated with spina bifida (adjusted odds ratio, 0.68; 95% confidence interval, 0.47-0.99). Among offspring of women 20 years old or older, pool use was associated with gastroschisis (adjusted odds ratio, 1.3; 95% confidence interval, 1.0-1.8), although not significantly so.

CONCLUSION

We observed little evidence suggesting teratogenic effects of swimming pool use. Because swimming is a common and suggested form of exercise during pregnancy, these results are reassuring.

Maternal periconceptional occupational exposure to pesticides and selected musculoskeletal birth defects

This population-based U.S. study investigated the association between major musculoskeletal malformations and periconceptional maternal occupational pesticide exposure for a wide range of occupations. We conducted a multi-site case-control analysis using data from the National Birth Defects Prevention Study among employed women with due dates from October 1, 1997 through December 31, 2002. Cases included 871 live-born, stillborn, or electively terminated fetuses with isolated craniosynostosis, gastroschisis, diaphragmatic hernia, or transverse limb deficiencies. Controls included 2857 live-born infants without major malformations. Using self-reported maternal occupational information, an industrial hygienist used a job-exposure matrix and expert opinion to evaluate the potential for exposure to insecticides, herbicides or fungicides for each job held during one month pre-conception through three months post-conception. Exposures analyzed included any exposure (yes/no) to pesticides, to insecticides only, to both insecticides and herbicides (I+H) and to insecticides, herbicides and fungicides (I+H+F). We used logistic regression to evaluate the association between exposures and defects, controlling for infant and maternal risk factors. Occupational exposure to I+H+F was associated with gastroschisis among infants of women aged 20 years or older (adjusted odds ratio [aOR]=1.88; 95% confidence interval [CI]: 1.16-3.05), but not for women under age 20 (aOR=0.48; 95% CI: 0.20-1.16). We found no significant associations for the other defects. Additional research is needed to validate these findings in a separate population.

Association between maternal age and birth defects of unknown etiology: United States, 1997-2007

BACKGROUND

Birth defects affect 3% of babies born, and are one of the leading causes of infant mortality. Both younger and older maternal age may pose increased risks for certain birth defects. This study assessed the relationship between maternal age at the estimated delivery date and the risk for birth defects.

METHODS

Data were obtained from the National Birth Defects Prevention Study, a population-based case-control study including mothers across 10 states. Maternal age was stratified into six categories: <20, 20 to 24, 25 to 29, 30 to 34, 35 to 39, and ≥40 years, and also analyzed as a continuous variable. Logistic regression models adjusted formaternal race/ethnicity, education, body mass index (BMI), folic acid use, smoking, gravidity, and parental age difference were used to estimate adjusted odds ratios (aORs) and 95% confidence intervals (CIs).

RESULTS

For maternal age <20 years, associations with total anomalous pulmonary venous return (aOR, 2.3; 95% CI, 1.3-4.0), amniotic band sequence (aOR, 2.4; 95% CI, 1.5-3.8), and gastroschisis (aOR, 6.1; 95% CI, 4.8-8.0) were observed. For the ≥40 year age group, associations with several cardiac defects, esophageal atresia (aOR, 2.9; 95% CI, 1.7-4.9), hypospadias (aOR, 2.0; 95% CI, 1.4-3.0), and craniosynostosis (aOR, 1.6; 95% CI, 1.1-2.4) were observed. Results using maternal age as a continuous variable were consistent with those that used categorized maternal age.

CONCLUSION

Elucidating risk factors specific to women ateither extreme of maternal age may offer prevention opportunities. All women should be made aware of prevention opportunities, such as folic acid supplementation, to reduce the occurrence of birth defects.

Short interpregnancy interval and gastroschisis risk in the National Birth Defects Prevention Study

BACKGROUND

The micronutrient depletion hypothesis proposes that consecutive pregnancies spaced too closely may leave insufficient time for maternal micronutrient replenishment. Short interpregnancy intervals (IPI) have been associated with an increased risk for several adverse pregnancy outcomes, but an association with gastroschisis risk has not been previously explored.

METHODS

Within a population-based, case-control study, we evaluated the association between IPI length and gastroschisis risk using multivariable logistic regression models to estimate gastroschisis odds ratios for IPI <12 months and 12 to 17 months relative to those 18 to 23 months. We further evaluated the association between IPI and gastroschisis risk stratified by maternal age, periconceptional multivitamin use, preceding pregnancy outcome, study center region, and season of conception to explore whether observed associations were compatible with the hypothesis of maternal micronutrient depletion.

RESULTS

For women with IPI <12 months, the adjusted odds ratio (aOR) was 1.7 (95% confidence interval [CI]: 1.1-2.5). The magnitude of the observed effect did not differ among strata of maternal age or periconceptional multivitamin use. However, the association was more pronounced after a miscarriage or termination (aOR: 2.5; 95% CI: 1.1-5.6) and among women who resided in northern study areas (aOR: 2.8; 95% CI: 1.3-5.9). The higher risk observed with short IPI among women in northern study areas was attenuated for spring/summer conceptions.

CONCLUSION

Short IPI was associated with an increased risk for gastroschisis, particularly among women whose preceding pregnancy resulted in a miscarriage or termination and among those who resided in northern study areas with winter/fall conception.

The role of maternal nutrition in the aetiology of gastroschisis: an incident case-control study

BACKGROUND

Gastroschisis, a congenital anomaly involving a defect in the fetal abdominal wall, has increased in prevalence in many countries, but the aetiology is uncertain. We tested the hypothesis that high maternal alcohol consumption and poor diet in the first trimester are risk factors in a case-control study in the UK (1 July 2007 to 28 February 2010).

METHODS

Gastroschisis cases and three controls per case (matched for maternal age) were identified at 18- to 20-week routine anomaly screening ultrasound scan (USS). Interviews were carried out during the antenatal period (median 24 weeks' gestation) using a piloted questionnaire. Conditional logistic regression was used to describe the associations between exposure variables and gastroschisis, adjusted for known confounding variables.

RESULTS

The response rate was 73% for cases (n = 91) and 70% for controls (n = 217). High consumption of fruits and vegetables during the first trimester (aOR 0.2; 95% CI 0.04-0.6), taking folic acid for at least 6 weeks during the first trimester (aOR 0.3; 95% CI 0.1-0.7) and increasing body fat percentage of total maternal body weight (aOR 0.9; 95% CI 0.8-0.9 per 1% increase) were independently associated with reduced risk. Cigarette smoking (aOR 2.7; 95% CI 1.1-6.8) was an independent risk factor.

CONCLUSION

We report for the first time that higher intake of fruits and vegetables during the first trimester, longer duration of folic acid supplementation and higher body fat percentage are associated with reduced risk of fetal gastroschisis, independent of cigarette smoking. The increased risk of cigarette smoking is greatest in older women and in high socio-economic groups.

Maternal occupational exposure to polycyclic aromatic hydrocarbons: effects on gastroschisis among offspring in the National Birth Defects Prevention Study

BACKGROUND

Exposure to polycyclic aromatic hydrocarbons (PAHs) occurs in many occupational settings. There is evidence in animal models that maternal exposure to PAHs during pregnancy is associated with gastroschisis in offspring; however, to our knowledge, no human studies examining this association have been conducted.

OBJECTIVE

Our goal was to conduct a case-control study assessing the association between estimated maternal occupational exposure to PAHs and gastroschisis in offspring.

METHODS

Data from gastroschisis cases and control infants were obtained from the population-based National Birth Defects Prevention Study for the period 1997-2002. Exposure to PAHs was assigned by industrial hygienist consensus, based on self-reported maternal occupational histories from 1 month before conception through the third month of pregnancy. Logistic regression was used to determine the association between estimated occupational PAH exposure and gastroschisis among children whose mothers were employed for at least 1 month during the month before conception through the third month of pregnancy.

RESULTS

The prevalence of estimated occupational PAH exposure was 9.0% in case mothers (27 of 299) and 3.6% in control mothers (107 of 2,993). Logistic regression analyses indicated a significant association between occupational PAHs and gastroschisis among mothers ≥ 20 years of age [odds ratio (OR) = 2.53; 95% confidence interval (CI): 1.27, 5.04] after adjusting for maternal body mass index, education, gestational diabetes, and smoking. This association was not seen in mothers < 20 years (OR = 1.14; 95% CI: 0.55, 2.33), which is notable because although young maternal age is the strongest known risk factor for gastroschisis, most cases are born to mothers ≥ 20 years.

CONCLUSION

Our findings indicate an association between occupational exposure to PAHs among mothers who are ≥ 20 years and gastroschisis. These results contribute to a body of evidence that PAHs may be teratogenic.

Nonsteroidal antiinflammatory drug use among women and the risk of birth defects

OBJECTIVE

We examined whether the use of nonsteroidal antiinflammatory drugs (NSAIDs) in early pregnancy was associated with a range of structural birth defects.

STUDY DESIGN

Data were from the National Birth Defects Prevention Study, a multisite population-based, case-control study of risk factors for birth defects.

RESULTS

Among women in the National Birth Defects Prevention Study, 22.6% reported the use of NSAIDs in the first trimester of pregnancy, most commonly ibuprofen, aspirin, and naproxen. Of the 29 defect groups that were examined, most were not associated with NSAID use. Small-to-moderate increased risks of some oral cleft groups, some neural tube defect groups, anophthalmia/microphthalmia, pulmonary valve stenosis, amniotic bands/limb body wall defects, and transverse limb deficiencies were associated with ibuprofen, aspirin, and naproxen exposure.

CONCLUSION

The use of NSAIDs in early pregnancy does not appear to be a major risk factor for birth defects, although there were a few moderate associations between NSAIDs and specific birth defects.

Umbilical artery pulsatility index and fetal abdominal circumference in isolated gastroschisis

OBJECTIVES

To investigate changes in abdominal circumference (AC) and umbilical artery pulsatility index (UA-PI) with gestation in fetuses with isolated gastroschisis, and to determine whether a relationship exists between UA-PI and fetal AC.

METHODS

Data from 58 pregnancies with isolated gastroschisis diagnosed at between 24 and 36 weeks' gestation were included in the study. Z-scores were calculated with respect to expected UA-PI values in normal pregnancies after log-transformation. AC-Z-scores were calculated with respect to expected size in normal pregnancies according to a standard chart. Functional linear discriminant analysis (FLDA) was applied to generate 50(th), 5(th) and 95(th) percentile curves for changes in both AC and UA-PI with gestational age in fetuses with gastroschisis. These curves were compared with the standard curves, as were the means. UA-PI was also plotted against AC. For this relationship, a robust Spearman correlation coefficient was obtained with FLDA.

RESULTS

In fetuses with gastroschisis, there was a highly significant negative correlation between UA-PI and AC, normalized for gestation using Z-scores (median correlation coefficient, - 0.289; median P = 0.000023). Moreover, compared with standard curves AC was lower and UA-PI higher in the gestational-age range studied. Both the AC and UA-PI curves showed a significantly different rate of change with gestation compared with the normal ranges. The mean values for fetuses with gastroschisis compared with the standard AC and UA-PI range curves were significantly different for AC throughout gestation, and for UA-PI from 32 weeks' gestation.

CONCLUSIONS

In fetal gastroschisis, it is well known that AC tends to be smaller, though UA-PI has not been reported to be abnormal in any consistent way. There is a clear relationship between the fetus's AC for gestation and UA-PI, which is not the case for normally grown fetuses. The data suggest that the growth restriction seen in gastroschisis may be explained by hypoxia, and not simply by the classical explanation of extra-abdominal displacement of the abdominal viscera.

Exposure to non-steroidal anti-inflammatory drugs during pregnancy and the risk of selected birth defects: a prospective cohort study

Background

Since use of non-steroidal anti-inflammatory drugs (NSAIDs) during pregnancy is common, small increases in the risk of birth defects may have significant implications for public health. Results of human studies on the teratogenic risks of NSAIDs are inconsistent. Therefore, we evaluated the risk of selected birth defects after prenatal exposure to prescribed and over-the-counter NSAIDs.

Methods and Findings

We used data on 69,929 women enrolled in the Norwegian Mother and Child Cohort Study between 1999 and 2006. Data on NSAID exposure were available from a self-administered questionnaire completed around gestational week 17. Information on pregnancy outcome was obtained from the Medical Birth Registry of Norway. Only birth defects suspected to be associated with NSAID exposure based upon proposed teratogenic mechanisms and previous studies were included in the multivariable logistic regression analyses. A total of 3,023 women used NSAIDs in gestational weeks 0–12 and 64,074 women did not report NSAID use in early pregnancy. No associations were observed between overall exposure to NSAIDs during pregnancy and the selected birth defects separately or as a group (adjusted odds ratio 0.7, 95% confidence interval 0.4–1.1). Associations between maternal use of specific types of NSAIDs and the selected birth defects were not found either, although an increased risk was seen for septal defects and exposure to multiple NSAIDs based on small numbers (2 exposed cases; crude odds ratio 3.9, 95% confidence interval 0.9–15.7).

Conclusions

Exposure to NSAIDs during the first 12 weeks of gestation does not seem to be associated with an increased risk of the selected birth defects. However, due to the small numbers of NSAID-exposed infants for the individual birth defect categories, increases in the risks of specific birth defects could not be excluded.

Maternal smoking in pregnancy and birth defects: a systematic review based on 173 687 malformed cases and 11.7 million controls

BACKGROUND

There is uncertainty over whether maternal smoking is associated with birth defects. We conducted the first ever comprehensive systematic review to establish which specific malformations are associated with smoking.

METHODS

Observational studies published 1959–2010 were identified (Medline), and included if they reported the odds ratio (OR) for having a non-chromosomal birth defect among women who smoked during pregnancy compared with non-smokers. ORs adjusted for potential confounders were extracted (e.g. maternal age and alcohol), otherwise unadjusted estimates were used. One hundred and seventy-two articles were used in the meta-analyses: a total of 173 687 malformed cases and 11 674 332 unaffected controls.

RESULTS

Significant positive associations with maternal smoking were found for: cardiovascular/heart defects [OR 1.09, 95% confidence interval (CI) 1.02–1.17]; musculoskeletal defects (OR 1.16, 95% CI 1.05–1.27); limb reduction defects (OR 1.26, 95% CI 1.15–1.39); missing/extra digits (OR 1.18, 95% CI 0.99–1.41); clubfoot (OR 1.28, 95% CI 1.10–1.47); craniosynostosis (OR 1.33, 95% CI 1.03–1.73); facial defects (OR 1.19, 95% CI 1.06–1.35); eye defects (OR 1.25, 95% CI 1.11–1.40); orofacial clefts (OR 1.28, 95% CI 1.20–1.36); gastrointestinal defects (OR 1.27, 95% CI 1.18–1.36); gastroschisis (OR 1.50, 95% CI 1.28–1.76); anal atresia (OR 1.20, 95% CI 1.06–1.36); hernia (OR 1.40, 95% CI 1.23–1.59); and undescended testes (OR 1.13, 95% CI 1.02–1.25). There was a reduced risk for hypospadias (OR 0.90, 95% CI 0.85–0.95) and skin defects (OR 0.82, 0.75–0.89). For all defects combined the OR was 1.01 (0.96–1.07), due to including defects with a reduced risk and those with no association (including chromosomal defects).

CONCLUSIONS

Birth defects that are positively associated with maternal smoking should now be included in public health educational materials to encourage more women to quit before or during pregnancy.

Neonatal abdominal wall defects

Gastroschisis and omphalocele are the two most common congenital abdominal wall defects. Both are frequently detected prenatally due to routine maternal serum screening and fetal ultrasound. Prenatal diagnosis may influence timing, mode and location of delivery. Prognosis for gastroschisis is primarily determined by the degree of bowel injury, whereas prognosis for omphalocele is related to the number and severity of associated anomalies. The surgical management of both conditions consists of closure of the abdominal wall defect, while minimizing the risk of injury to the abdominal viscera either through direct trauma or due to increased intra-abdominal pressure. Options include primary closure or a variety of staged approaches. Long-term outcome is favorable in most cases; however, significant associated anomalies (in the case of omphalocele) or intestinal dysfunction (in the case of gastroschisis) may result in morbidity and mortality.

Maternal caffeine intake and risk of selected birth defects in the National Birth Defects Prevention Study

BACKGROUND

Caffeine intake is common during pregnancy, yet few epidemiologic studies have examined the association between maternal caffeine consumption and birth defects. Using data from the National Birth Defects Prevention Study (NBDPS), we examined the association between maternal caffeine consumption and anotia/microtia, esophageal atresia, small intestinal atresia, craniosynostosis, diaphragmatic hernia, omphalocele, and gastroschisis.

METHODS

The NBDPS is a multi-site population-based case-control study. The present analysis included 3,346 case infants and 6,642 control infants born from October 1997 through December 2005. Maternal telephone interview reports of demographic characteristics and conditions and exposures before and during pregnancy were collected. Odds ratios and 95% confidence intervals, adjusted for relevant covariates, were calculated to estimate the associations between maternal dietary caffeine intake (coffee, tea, soda, and chocolate) and maternal use of caffeine-containing medications and each defect.

RESULTS

We observed small, statistically significant elevations in adjusted odds ratios ranging from 1.3 to 1.8 for total maternal dietary caffeine intake or specific types of caffeinated beverages and anotia/microtia, esophageal atresia, small intestinal atresia, and craniosynostosis; however, dose-response patterns were absent. Periconceptional use of caffeine-containing medications was infrequent and estimates were imprecise.

CONCLUSIONS

We did not find convincing evidence of an association between maternal caffeine intake and the birth defects included in this study. The increasing popularity of caffeine-containing energy drinks and other caffeinated products may result in higher caffeine intake among women of childbearing age. Future studies should consider more detailed evaluation of such products.

Rising prevalence of gastroschisis in Washington State

The aim of this study was to assess gastroschisis prevalence in Washington (WA) State in relation to putative risk factors. Gastroschisis prevalence was calculated from the WA State birth cohort during 1987-2006 using an administrative database with birth certificate data linked with hospital discharge records and the ICD-9 procedure code 54.71, which specifies gastroschisis repair. Poisson regression analysis was used to evaluate time trends while adjusting for risk factors. Birth year was included as a linear term. Maternal age, smoking, race, residence in urban versus rural area, geographic region (eastern versus western Washington), paternal age, and infant gender were included as categorical factors. Prevalence ratios were adjusted for birth year and all of the preceding factors. Two hundred and eighty-two infants with gastroschisis were identified. In the adjusted analysis, the prevalence ratio for gastroschisis was 1.1 per year (95% CI 1.08-1.13), indicating an average 10% increase per birth year. Teen mothers were at a higher risk compared to mothers≥25 yr old (adjusted rate ratio [aRR] 8.02; 95% CI 5.30-12.13), as were teen fathers (aRR 2.35; 95% CI 1.48-3.74) compared to fathers≥25 years old. Maternal smoking was associated with a higher risk compared to those who were nonsmokers (aRR 1.58; 95% CI 1.19-2.09). Black mothers had a lower risk compared with white mothers. There was no association with geographic classification of mother's residence. Gastroschisis prevalence has increased in WA, particularly in teen mothers and in smokers. This is not explained by a rise in teenage pregnancies or maternal smoking. Further investigation of factors specific to teenage lifestyle is warranted.

Gastroschisis: an update

Gastroschisis (GS) continues to increase in frequency, with several studies now reported an incidence of between 4 and 5 per 10,000 live births. The main risk factor would seem to be young maternal age, and it is in this group that the greatest increase has occurred. Whilst various geographical regions confer a higher risk, the impact of several other putative risk factors, including smoking and illicit drug use, may be less important than when first identified in early epidemiological studies. Over 90% of cases of GS will now be diagnosed on antenatal ultrasound, but its value in determining the need for early delivery remains unclear. There would appear no clear evidence for either routine early delivery or elective caesarean section for infants with antenatally diagnosed GS. Delivery at a centre with paediatric surgical facilities reduces the risk of subsequent morbidity and should represent the standard of care. The relative roles of primary closure, staged closure and ward reduction, with or without general anaesthesia, appear less clear with considerable variation between centres in both the use of these techniques and subsequent surgical outcomes. Survival rates continue to improve, with rates well in excess of 90% now routine. The limited long-term developmental data available would suggest that normal or near-normal outcomes may be expected although there remains a need for further studies.