Prevalence rates study of selected isolated non-Mendelian congenital anomalies in the Hutterite population of Alberta, 1980-2016.

A study of the prevalence rates for selected isolated non-Mendelian congenital anomalies in the Hutterite Brethren of Alberta, Canada was undertaken to further examine longitudinal data in this isolated community that was last reported in 1985 (Lowry et al., 1985), although there are numerous publications on recessive disorders (Boycott et al., 2008; Triggs-Raine et al., 2016). Cases were ascertained from the Alberta Congenital Anomaly Surveillance System for the years 1997-2016. Since our initial results showed some surprising findings in the Hutterite Brethren, such as zero cases of spina bifida, cleft lip and palate, gastroschisis, and omphalocele, and a significant excess of cases with hypospadias, we extended the study to prior years (1980-1996) for selected anomalies. For the extended study period (1980-2016), there was a significant increased prevalence of hypospadias, tetralogy of Fallot and tricuspid atresia in the Hutterite population, and although not statistically significant, zero cases of cleft lip with cleft palate, gastroschisis and omphalocele were confirmed. Further research is needed to determine the precise effects of rural environmental exposures, lifestyle factors, and genetic associations for selected multifactorial congenital anomalies.

Compliments to Dr. Zernotti et al. in describing rates of congenital aural atresia in ethnic groups - A complementary elaboration / Felicitaciones al Dr. Zernotti et al. por su descripción de las tasas de atresia aural congénita en grupos étnicos - elaboración complementaria

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Replica on prevalence of congenital aural atresia in Argentina / Réplica sobre prevalencia de atresia aural congénita en Argentina

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Infant Mortality Attributable to Birth Defects - United States, 2003-2017.

Birth defects are a leading cause of infant mortality in the United States, accounting for 20.6% of infant deaths in 2017 (1). Rates of infant mortality attributable to birth defects (IMBD) have generally declined since the 1970s (1-3). U.S. linked birth/infant death data from 2003-2017 were used to assess trends in IMBD. Overall, rates declined 10% during 2003-2017, but decreases varied by maternal and infant characteristics. During 2003-2017, IMBD rates decreased 4% for infants of Hispanic mothers, 11% for infants of non-Hispanic black (black) mothers, and 12% for infants of non-Hispanic white (white) mothers. In 2017, these rates were highest among infants of black mothers (13.3 per 10,000 live births) and were lowest among infants of white mothers (9.9). During 2003-2017, IMBD rates for infants who were born extremely preterm (20-27 completed gestational weeks), full term (39-40 weeks), and late term/postterm (41-44 weeks) declined 20%-29%; rates for moderate (32-33 weeks) and late preterm (34-36 weeks) infants increased 17%. Continued tracking of IMBD rates can help identify areas where efforts to reduce IMBD are needed, such as among infants born to black and Hispanic mothers and those born moderate and late preterm (32-36 weeks).

Population-based birth defects data in the United States, 2012-2016: A focus on abdominal wall defects.

BACKGROUND/OBJECTIVES: In this report, the National Birth Defects Prevention Network (NBDPN) examines and compares gastroschisis and omphalocele for a recent 5-year birth cohort using data from 30 population-based birth defect surveillance programs in the United States. METHODS: As a special call for data for the 2019 NBDPN Annual Report, state programs reported expanded data on gastroschisis and omphalocele for birth years 2012-2016. We estimated the overall prevalence (per 10,000 live births) and 95% confidence intervals (CI) for each defect as well as by maternal race/ethnicity, maternal age, infant sex, and case ascertainment methodology utilized by the program (active vs. passive). We also compared distribution of cases by maternal and infant factors and presence/absence of other birth defects. RESULTS: The overall prevalence estimates (per 10,000 live births) were 4.3 (95% CI: 4.1-4.4) for gastroschisis and 2.1 (95% CI: 2.0-2.2) for omphalocele. Gastroschisis was more frequent among young mothers (<25 years) and omphalocele more common among older mothers (>40 years). Mothers of infants with gastroschisis were more likely to be underweight/normal weight prior to pregnancy and mothers of infants with omphalocele more likely to be overweight/obese. Omphalocele was twice as likely as gastroschisis to co-occur with other birth defects. CONCLUSIONS: This report highlights important differences between gastroschisis and omphalocele. These differences indicate the importance of distinguishing between these defects in epidemiologic assessments. The report also provides additional data on co-occurrence of gastroschisis and omphalocele with other birth defects. This information can provide a basis for future research to better understand these defects.

National population-based estimates for major birth defects, 2010-2014.

BACKGROUND: Using the National Birth Defects Prevention Network (NBDPN) annual data report, U.S. national prevalence estimates for major birth defects are developed based on birth cohort 2010-2014. METHODS: Data from 39 U.S. population-based birth defects surveillance programs (16 active case-finding, 10 passive case-finding with case confirmation, and 13 passive without case confirmation) were used to calculate pooled prevalence estimates for major defects by case-finding approach. Fourteen active case-finding programs including at least live birth and stillbirth pregnancy outcomes monitoring approximately one million births annually were used to develop national prevalence estimates, adjusted for maternal race/ethnicity (for all conditions examined) and maternal age (trisomies and gastroschisis). These calculations used a similar methodology to the previous estimates to examine changes over time. RESULTS: The adjusted national birth prevalence estimates per 10,000 live births ranged from 0.62 for interrupted aortic arch to 16.87 for clubfoot, and 19.93 for the 12 critical congenital heart defects combined. While the birth prevalence of most birth defects studied remained relatively stable over 15 years, an increasing prevalence was observed for gastroschisis and Down syndrome. Additionally, the prevalence for atrioventricular septal defect, tetralogy of Fallot, omphalocele, and trisomy 18 increased in this period compared to the previous periods. Active case-finding programs generally had higher prevalence rates for most defects examined, most notably for anencephaly, anophthalmia/microphthalmia, trisomy 13, and trisomy 18. CONCLUSION: National estimates of birth defects prevalence provide data for monitoring trends and understanding the impact of these conditions. Increasing prevalence rates observed for selected conditions warrant further examination.

Impact of state tobacco control policies on birth defects.

While research has demonstrated the effects of tobacco control policies on birth outcomes, there is little known about their impact on birth defects. Using 2005-2015 natality data on 26,334,854 singletons from 47 US states and District of Columbia linked to state-level cigarette taxes and smoke-free restaurant legislation, we examined the impact of tobacco control policies on birth defects by maternal race/ethnicity and education. We found that among white women with less than a high school degree, every $1.00 increase in cigarette taxes reduced prenatal smoking by 3.48 percentage points and reduced the risk of their infant having any birth defect by 0.0023 percentage points. Tax increases also reduced the risk of cyanotic heart defects, cleft palate, gastroschisis, and limb reduction. We found no evidence for associations between the enactment of smoke-free legislation, prenatal smoking and birth defects. Our findings suggest that state cigarette taxes are a population-level intervention that can help reduce prenatal smoking and the risk of birth defects.

The prevalence of birth defects among non-Hispanic Asian/Pacific Islanders and American Indians/Alaska Natives in Texas, 1999-2015.

BACKGROUND: There is considerable variability in the prevalence of birth defects among racial/ethnic groups. This study estimated birth defect prevalence among the less studied non-Hispanic (NH) Asian/Pacific Islander (PI) and American Indian/Alaska Native (AI/AN) populations in Texas relative to NH Whites. METHODS: Data were obtained from the Texas Birth Defect Registry from 1999 to 2015 for deliveries to Texas-resident women who were NH White, NH Asian/PI, or AI/AN. This covers a live birth population of 2.6 million. Prevalence ratios and 95% confidence intervals (95% CIs) were calculated for NH Asian/PIs and AI/ANs (relative to NH Whites) for 44 birth defects using Poisson regression adjusting for maternal age. RESULTS: After adjustment there were 33 statistically significant prevalence ratios (aPRs). Among NH Asian/PIs, 23 defects had a lower aPR (0.38-0.86) and three defects had a higher aPR (1.19-2.50). AI/ANs had one defect with a significantly lower aPR (0.64) and six with a higher aPR (1.36-4.63). CONCLUSIONS: Non-Hispanic Asian/PIs generally have a lower prevalence ratio for many birth defects while AI/ANs have a higher prevalence ratio compared to NH Whites. These findings update the limited literature on this topic and warrant additional research to identify the true associations across a range of birth defects among these understudied racial/ethnic groups.

Selected acculturation factors and birth defects in the National Birth Defects Prevention Study, 1997-2011.

BACKGROUND: Acculturation has been examined with respect to various pregnancy adverse outcomes, including birth defects. Given the mixed and limited findings on the association between nativity and birth defects, we sought to further explore parental nativity and years lived in the U.S. across a range of defects. METHODS: Data from the National Birth Defects Prevention Study were used for this analysis. Infants with one of 46 major isolated birth defects (30 noncardiac/16 cardiac conditions) and infants without birth defects (controls) born during 1997-2011 were included. We examined parental nativity (foreign-born mothers, fathers, and both parents combined compared to a referent of both U.S.-born parents) and the number of years lived in the U.S. (≤5/6+ years). Descriptive statistics and logistic regression analyses were performed to estimate crude/adjusted odds ratios and 95% confidence intervals. RESULTS: Compared to U.S.-born mothers, foreign-born mothers tended to be older (25+ years), of Hispanic or Other race/ethnicity and were less likely to have reported drinking, smoking, illicit drug use, or having taken folic acid. In the adjusted analysis, seven findings among both parents reporting a foreign-birth were significant, including an increased association with spina bifida, anotia/microtia, and diaphragmatic hernia (aORs range: 1.3-1.7), and a reduced association with craniosynostosis and gastroschisis (aORs = 0.7). A generally protective effect was observed among foreign-born subjects living in the U.S. ≤5 years. CONCLUSIONS: We found that nativity was associated with some selected isolated defects, although the direction of effect varied by phenotype and by a number of years residing in the U.S.

Prevalence of selected birth defects by maternal nativity status, United States, 1999-2007.

OBJECTIVES: We investigated differences in prevalence of major birth defects by maternal nativity within racial/ethnic groups for 27 major birth defects. METHODS: Data from 11 population-based birth defects surveillance systems in the United States including almost 13 million live births (approximately a third of U.S. births) during 1999-2007 were pooled. We calculated prevalence estimates for each birth defect for five racial/ethnic groups. Using Poisson regression, crude and adjusted prevalence ratios (aPRs) were also calculated using births to US-born mothers as the referent group in each racial/ethnic group. RESULTS: Approximately 20% of case mothers and 26% of all mothers were foreign-born. Elevated aPRs for infants with foreign-born mothers were found for spina bifida and trisomy 13, 18, and 21, while lower prevalence patterns were found for pyloric stenosis, gastroschisis, and hypospadias. CONCLUSIONS: This study demonstrates that birth defects prevalence varies by nativity within race/ethnic groups, with elevated prevalence ratios for some specific conditions and lower prevalence for others. More detailed analyses focusing on a broader range of maternal behaviors and characteristics are required to fully understand the implications of our findings.

Prevalence of Congenital Anomalies in the Japan Environment and Children's Study.

BACKGROUND: The aims of the present report were to estimate the prevalence of congenital anomalies (CAs) among infants in Japan using data from the Japan Environment and Children's Study (JECS) and to evaluate the validity of CA classification within JECS. METHODS: Data on CAs were collected at delivery and at age 1 month from the medical records of 101,825 infants at 15 regional centers. The analyses focused on 61 CAs, selected on the basis of reported associations with environmental exposure. Prevalence per 10,000 pregnancies (including miscarriages, stillbirths, and live births) was stratified according to four reporting patterns (at delivery, at age 1 month, at either, and at both). To evaluate the accuracy of observed CA prevalence, the medical records of 179 cases from a single JECS regional center underwent independent, retrospective re-evaluation. RESULTS: The prevalence of major CAs in four reporting patterns (at delivery, at age 1 month, at either, and at both) was 2.4, 2.6, 3.5, and 1.4 for myelomeningocele/spina bifida; 4.3, 4.2, 5.3, and 3.2 for cleft palate; 18.1, 17.4, 19.5, and 15.1 for cleft lip with or without cleft palate; 73.4, 100.3, 120.8, and 52.8 for congenital heart disease; and 10.5, 14.1, 15.0, and 9.6 for Down's syndrome, respectively. In the subsample re-evaluation, CA diagnoses were confirmed for 92.7%, 93.3%, 90.5%, and 97.8% of cases in the four reporting patterns (at delivery, at age 1 month, at either, and at both), respectively. CONCLUSIONS: The present report generated reliable data concerning the prevalence of major CAs in JECS.

Epidemiology of birth defects based on surveillance data from 2011-2015 in Guangxi, China: comparison across five major ethnic groups.

BACKGROUND: The causes of birth defects (BDs) are complex and include genetic and environmental factors and/or their interactions. More research is needed to describe the epidemiology of BDs within specific regions of China. This study focused on differences in the prevalence of BDs based on ethnicity in a large city in Guangxi Province, China. METHODS: Surveillance data of infants born in 114 registered hospitals in Liuzhou between 2011 and 2015 were analyzed to determine the epidemiology of BDs across five major ethnic groups. We calculated the prevalence of BDs and relative risk of BDs by ethnicity. RESULTS: There were 260,722 perinatal infants of which 6581 had BDs, with the average prevalence of 25.24 per 1000 perinatal infants (PIs). Prevalence data showed an obvious uptrend over the past 5 years. Han had the highest prevalence of total BDs (28.98‰), followed by Zhuang (25.19‰), Yao (18.50‰), Miao (15.78‰) and Dong (14.24‰). Relative to the Han; Zhuang, Miao, Yao, and Dong had a lower risk of musculoskeletal and urogenital malformations; Miao and Yao had a lower risk of cardiovascular malformation; and Dong had a lower risk of cardiovascular and craniofacial malformation. Several maternal risk factors were found to be associated with BDs (e.g., maternal and gestational age, number of antenatal care visits). CONCLUSION: This study provided a comprehensive description of ethnic differences in the risk of BDs in Liuzhou City, China. Observed ethnic differences in the risk of BDs may be related to genetic susceptibilities, environment, cultural customs, or to potential combinations of these factors.

Birth defect survival for Hispanic subgroups.

BACKGROUND: Previous studies demonstrate that infant and childhood mortality differ among children with birth defects by maternal race/ethnicity, but limited mortality information is published for Hispanic ethnic subgroups. METHODS: We performed a retrospective cohort study using data for children with birth defects born to Hispanic mothers during 1999-2007 from 12 population-based state birth defects surveillance programs. Deaths were ascertained through multiple sources. Survival probabilities were estimated by the Kaplan-Meier method. Cox proportional hazards regression was used to examine the effect of clinical and demographic factors on mortality risk. RESULTS: Among 28,497 Hispanic infants and children with major birth defects, 1-year survival was highest for infants born to Cuban mothers at 94.6% (95% confidence intervals [CI] 92.7-96.0) and the lowest for Mexicans at 90.2% (95% CI 89.7-90.6; p < .0001). For children aged up to 8 years, survival remained highest for Cuban Americans at 94.1% (95% CI 91.8-95.7) and lowest for Mexican Americans at 89.2% (95% CI 88.7-89.7; p = .0002). In the multivariable analysis using non-Hispanic White as the reference group, only infants and children born to Mexican mothers were noted to have a higher risk of mortality for cardiovascular defects. CONCLUSIONS: This analysis provides a better understanding of survival and mortality for Hispanic infants and children with selected birth defects. The differences found in survival, particularly the highest survival rates for Cuban American children and lowest for Mexican American children with birth defects, underscores the importance of assessing Hispanic ethnic subgroups, as differences among subgroups appear to exist.

Proposal of a Classification System for the Assessment and Treatment of Prominent Ear Deformity.

BACKGROUND: Prominent ear is the most common external ear deformity. To comprehensively treat prominent ear deformity, adequate comprehension of its pathophysiology is crucial. In this article, we analyze cases of prominent ear and suggest a simple classification system and treatment algorithm according to pathophysiology. METHODS: We retrospectively reviewed a total of 205 Northeast Asian patients' clinical data who underwent an operation for prominent ear deformity. Follow-up assessments were conducted 3, 6, and 12 months after surgery. Prominent ear deformities were classified by diagnostic checkpoints. Class I (simple prominent ear) includes prominent ear that developed with the absence of the antihelix without conchal hypertrophy. Class II (mixed-type prominent ear) is defined as having not only a flat antihelix, but also conchal excess. Class III (conchal-type prominent ear) has an enlarged conchal bowl with a well-developed antihelix. RESULTS: Among the three types of prominent ear, class I was most frequent (162 patients, 81.6%). Class II was observed in 28 patients (13.6%) and class III in 10 patients (4.8%). We used the scaphomastoid suture method for correction of antihelical effacement, the anterior approach conchal resection for correction of conchal hypertrophy, and Bauer's squid incision for lobule prominence. The complication rate was 9.2% including early hematoma, hypersensitivity, and suture extrusion. Unfavorable results occurred in 4% including partial recurrence, overcorrection, and undercorrection. CONCLUSIONS: To reduce unfavorable results and avoid recurrence, we propose the use of a classification and treatment algorithm in preoperative evaluation of prominent ear. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Racial disparity in infant mortality.

In the United States, African-American infants have significantly higher mortality than white infants. Previous work has identified associations between individual socioeconomic factors and select community-level factors. In this review, the authors look beyond traditional risk factors for infant mortality and examine the social context of race in this country, in an effort to understand African-American women's long-standing birth outcome disadvantage. In the process, recent insights are highlighted concerning neighborhood-level factors such as crime, segregation, built environment, and institutional racism, other likely causes for the poor outcomes of African-American infants in this country compared with infants in most other industrialized nations.

Counselling pregnant women at the crossroads of Europe and Asia: effect of Teratology Information Service in Turkey.

Background Previous studies from western countries demonstrated the effectiveness of Teratology Information Service (TIS) counselling in reducing the teratogenic risk perception of pregnant women. Objective To assess whether TIS counselling would be effective in reducing the teratogenic risk perception of the Turkish pregnant women. Setting A TIS (Terafar) operating in a university hospital in Turkey. Methods A cross-sectional survey study. Pregnant women with non-teratogenic medication exposures were asked to assign scores on visual analogue scales (VAS) in response to the questions aiming to measure their teratogenic risk perception. The mean score before and after counselling were compared and the associations with maternal socio-demographic characteristics were analysed using SPSS (Version 20.0). Main outcome measures The differences in the mean scores of the perception regarding the baseline risk of pregnancy, own teratogenic risk and the likelihood of termination of pregnancy before and after counselling and their possible associations with maternal socio-demographic characteristics. Results 102 pregnant women participated in the study. The counselling significantly reduced the mean own teratogenic risk perception score and the mean score for the likelihood of termination of pregnancy whereas the mean baseline risk perception score was not significantly changed. Pregnancy week <8 and the exposed number of active ingredients <3 were significantly associated with the difference in the mean score for the likelihood of termination of pregnancy. Conclusions TIS counselling lowers the teratogenic risk perception of Turkish pregnant women and increases their likelihood to continue the pregnancy as it does in the western countries.

Association Between Infant Mortality Attributable to Birth Defects and Payment Source for Delivery - United States, 2011-2013.

Birth defects are a leading cause of infant mortality in the United States (1), accounting for approximately 20% of infant deaths. The rate of infant mortality attributable to birth defects (IMBD) in the United States in 2014 was 11.9 per 10,000 live births (1). Rates of IMBD differ by race/ethnicity (2), age group at death (2), and gestational age at birth (3). Insurance type is associated with survival among infants with congenital heart defects (CHD) (4). In 2003, a checkbox indicating principal payment source for delivery was added to the U.S. standard birth certificate (5). To assess IMBD by payment source for delivery, CDC analyzed linked U.S. birth/infant death data for 2011-2013 from states that adopted the 2003 revision of the birth certificate. The results indicated that IMBD rates for preterm (<37 weeks of gestation) and term (≥37 weeks) infants whose deliveries were covered by Medicaid were higher during the neonatal (<28 days) and postneonatal (≥28 days to <1 year) periods compared with infants whose deliveries were covered by private insurance. Similar differences in postneonatal mortality were observed for the three most common categories of birth defects listed as a cause of death: central nervous system (CNS) defects, CHD, and chromosomal abnormalities. Strategies to ensure quality of care and access to care might reduce the difference between deliveries covered by Medicaid and those covered by private insurance.

Assessing the Impact of Different Race-Bridging Algorithms on the Reported Rate of Birth Defects.

INTRODUCTION: In Florida prior to 2004, the birth certificate only allowed parents to identify themselves as 1 race. The birth certificate was subsequently revised in 2004, allowing parents to identify with more than 1 race. This inconsistency in data collection methods can greatly impact the results of race-specific time trend analyses. Race-bridging techniques have been developed to reassign multiple race responses to single race categories. This investigation aimed to compare race-specific birth defect rates calculated in 2 ways: (1) the current method: treating those selecting multiple race categories as though they selected Other race, and (2) the bridged method: attempting to classify those selecting multiple categories into the category they would have selected if they could only pick 1 race. METHODS: Data from the Florida Office of Vital Statistics and the Florida Birth Defects Registry were used to examine rates of selected birth defects by race among births to non-Hispanic mothers from 2005 to 2014. Rates of selected birth defects were calculated and compared for the following race groups: white, black, American Indian/Alaska Native (AIAN), and Asian/Pacific Islander (API) using the following 6 bridging methods: (1) no bridging method, (2) largest group, whole allocation, (3) smallest group, whole allocation, (4) largest group other than white, (5) equal fractions, fractional allocation, and (6) reported fractions, fractional allocation. RESULTS: The differences in birth defect rates comparing the current method to the recalculated bridged-race population depends on the bridging method used. Using largest group, whole-allocation, the total population of white, black, and API races increased, whereas the total number of AIAN remained unaffected. Using the smallest group or largest group other than white, whole-allocation, the total population of black, API, and AIAN increased, resulting in decreased birth defect rates. Lastly, using equal fractions or reported fractions, fractional allocation we found an increase in the live birth count for each race and a corresponding decrease in birth defect rates. DISCUSSION: Race-bridging techniques may be useful when reviewing race-specific rates over time, or to account for the lack of comparability of race/ethnic classification in birth defect studies, particularly national studies combining data from different states. However, determining the best race-bridging technique warrants further investigation on larger populations and on other health outcomes.

Validation of birth outcomes from the Society for Assisted Reproductive Technology Clinic Outcome Reporting System (SART CORS): population-based analysis from the Massachusetts Outcome Study of Assisted Reproductive Technology (MOSART).

OBJECTIVE: To assess the validity of outcome data reported to the Society for Assisted Reproductive Technology Clinic Outcome Reporting System (SART CORS) compared with data from vital records and the birth defects registry in Massachusetts. DESIGN: Longitudinal cohort. SETTING: Not applicable. PARTICIPANT(S): A total of 342,035 live births and fetal deaths from Massachusetts mothers giving birth in the state from July 1, 2004, to December 31, 2008; 9,092 births and fetal deaths were from mothers who had conceived with the use of assisted reproductive technology (ART) and whose cycle data had been reported to the SART CORS. INTERVENTION(S): Not applicable. MAIN OUTCOME MEASURE(S): Percentage agreement between maternal race and ethnicity, delivery outcome (live birth or fetal death), plurality (singleton, twin, or triplet+), delivery date, and singleton birth weight reported in the SART CORS versus vital records; sensitivity and specificity for birth defects among singletons as reported in the SART CORS versus the Massachusetts Birth Defects Monitoring Program (BDMP). RESULT(S): There was >95% agreement between the SART CORS and vital records for fields of maternal race/ethnicity, live birth/fetal death, and plurality; birth outcome date was within 1 day with 94.9% agreement and birth weight was within 100 g with 89.6% agreement. In contrast, sensitivity for report of any birth defect was 38.6%, with a range of 18.4%-50.0%, for specific birth defect categories. CONCLUSION(S): Although most SART CORS outcome fields are accurately reported, birth defect variables showed poor sensitivity compared with the gold standard data from the BDMP. We suggest that reporting of birth defects be discontinued.

Abdominal Wall Defects among Mexican American Infants: The Effect of Maternal Nativity.

BACKGROUND: US-born Mexican American women have greater rates of preterm birth and consequent overall infant mortality than their Mexico-born peers. However, the relation of Mexican American women's nativity to rates of congenital anomalies is poorly understood. Hispanic ethnicity and young maternal age are well-known risk factors for gastroschisis. OBJECTIVE: To determine the extent to which nativity of Mexican American women is associated with abdominal wall defects. METHODS: Stratified and multivariable logistic regression analyses were performed on the 2003-2004 National Center for Health Statistics linked live birth-infant death cohort. Only Mexican American infants were studied. Maternal variables examined included nativity, age, education, marital status, parity, and prenatal care usage. RESULTS: Infants with US-born Mexican American mothers (n=451,272) had an abdominal wall defect rate of 3.9/10,000 compared with 2.0/10,000 for those with Mexico-born mothers (n=786,878), RR=1.9 (1.5-2.4). Though a greater percentage of US-born (compared wtih Mexico-born) Mexican American mothers were teens, the nativity disparity was actually widest among women in their 20s. The adjusted (controlling for maternal age, education, marital status, parity, and prenatal care) odds ratio of abdominal wall defects among infants of US-born (compared with Mexico-born) Mexican American mothers was 1.6 (1.2-2.0). CONCLUSIONS: US-born Mexican American women have nearly a two-fold greater rate of delivering an infant with an abdominal wall defect than their Mexico-born counterparts. This phenomenon is only partially explained by traditional risk factors and highlights a detrimental impact of lifelong residence in the United States, or something closely related to it, on the pregnancy outcome of Mexican American women.