Fish consumption prior to pregnancy and pregnancy outcomes in the National Birth Defects Prevention Study, 1997-2011.

OBJECTIVE: To evaluate the relationships between maternal fish consumption and pregnancy outcomes in a large, population-based sample of women in the USA. DESIGN: We collected average fish consumption prior to pregnancy using a modified version of the semi-quantitative Willett FFQ. We estimated adjusted OR (aOR) and 95 % CI for associations between different levels of fish consumption and preterm birth (<37 weeks), early preterm birth (<32 and <35 weeks) and small-for-gestational-age infants (SGA; <10th percentile). SETTING: The National Birth Defects Prevention Study (NBDPS). SUBJECTS: Control mother-infant pairs with estimated delivery dates between 1997 and 2011 (n 10 919). RESULTS: No significant associations were observed between fish consumption and preterm birth or early preterm birth (aOR = 0·7-1·0 and 0·7-0·9, respectively). The odds of having an SGA infant were elevated (aOR = 2·1; 95 % CI 1·2, 3·4) among women with daily fish consumption compared with women consuming fish less than once per month. No associations were observed between other levels of fish consumption and SGA (aOR = 0·8-1·0). CONCLUSIONS: High intake of fish was associated with twofold higher odds of having an SGA infant, while moderate fish consumption prior to pregnancy was not associated with preterm or SGA. Our study, like many other studies in this area, lacked information regarding preparation methods and the specific types of fish consumed. Future studies should incorporate information on nutrient and contaminant contents, preparation methods and biomarkers to assess these relationships.

Do foreign- and U.S.-born mothers across racial/ethnic groups have a similar risk profile for selected sociodemographic and periconceptional factors?

BACKGROUND: We examined differences in selected pregnancy-related risk factors, including maternal sociodemographic characteristics, health-related conditions, and periconceptional behavioral factors, among foreign-born versus U.S.-born control mothers across race/ethnic groups. METHODS: We used data from the National Birth Defects Prevention Study, and calculated odds ratios (ORs) and 95% confidence intervals (CIs) of the risk factors, for foreign-born Hispanic, non-Hispanic white, non-Hispanic black, and Asian/Pacific Islander (API) mothers, compared to their U.S.-born counterparts. RESULTS: Across all race/ethnic groups, foreign-born mothers were older and had lower odds of obesity compared to their U.S.-born counterparts. With the exception of foreign-born black mothers, foreign-born mothers from other race/ethnic groups had significantly lower odds of binge drinking during the periconceptional period. Compared to U.S.-born, foreign-born Hispanic mothers had twice the odds of gestational diabetes (OR = 2.23; 95% CI = 1.36-3.66). Certain health behaviors were less prevalent in foreign-born black mothers (e.g., folic acid use; OR = 0.54; 95% CI = 0.31-0.96) and foreign-born API mothers (e.g., cigarette smoking; OR = 0.10; 95% CI = 0.02-0.48). CONCLUSIONS: Significant differences in pregnancy related risk factors during the periconceptional period and throughout pregnancy were observed between maternal nativity groups and across race/ethnicity. Prevention efforts for both prepregnancy and after conception should be designed and delivered according to maternal nativity for each racial/ethnic group.

Importance of including all pregnancy outcomes to reduce bias in epidemiologic studies of neural tube defects--Texas, 1999 to 2005.

BACKGROUND: Neural tube defects (NTDs) often result in fetal death or elective termination; therefore, not all cases are captured in typical hospital-based surveillance. We examined sociodemographic differences among pregnancy outcomes to assess sources of bias in NTD surveillance and research. METHODS: We used 1999 to 2005 Texas Birth Defects Registry data, a population-based active surveillance system, and calculated crude and adjusted prevalence ratios (aPRs). We then assessed the association of anencephaly and spina bifida with the selected characteristics, stratified by pregnancy outcomes (fetal death, elective termination, or live birth). RESULTS: Data were available for 1852 NTD cases (anencephaly, 677; spina bifida, 954; and encephalocele, 221), resulting in 1211 live births, 236 fetal deaths, and 405 elective terminations. For both anencephaly and spina bifida, a significant excess of Hispanic mothers was observed among live-birth cases (aPRs=1.2-2.4), but not among mothers experiencing other pregnancy outcomes. Mothers of anencephaly cases resulting in a non-live birth were more likely to be adolescents (aPRs=2.4-2.7 for ages<20 years old vs. ages 25-29 years old), but this pattern was not observed for live-birth cases. A trend of increasing anencephaly risk with increasing parity was demonstrated only among fetal-death cases. For spina bifida, mothers of fetal-death (but not live-birth) cases were less likely to live along the Texas-Mexico border (aPR=0.30). CONCLUSIONS: Demographic differences across NTD pregnancy outcomes exist and are a potential source of bias. Inclusion of all pregnancy outcomes in NTD surveillance is vital in NTD monitoring and research.

Use of oral contraceptives in pregnancy and major structural birth defects in offspring.

BACKGROUND: Oral contraceptives (OCs) are the most commonly used reversible contraceptive method among US women. Although the majority of previous studies have reported no association between OC use during pregnancy and birth defects, some studies have reported increased occurrence of neural tube defects, limb reduction defects, and urinary tract anomalies. METHODS: We assessed OC use among mothers who participated in the multisite, case-control, National Birth Defects Prevention Study. Mothers of 9986 infants with 32 types of birth defects and 4000 infants without birth defects were included. RESULTS: Maternal OC use during the first 3 months of pregnancy was associated with an increased odds ratio for 2 of 32 birth defects: hypoplastic left heart syndrome (adjusted odds ratio = 2.3 [95% confidence interval = 1.3-4.3) and gastroschisis (1.8 [1.3-2.7]). CONCLUSION: Previous reports of associations between OC use and specific types of anomalies were not corroborated. Given that associations were assessed for 32 types of birth defects, our findings of 2 increased associations between OC use and gastroschisis and hypoplastic left heart syndrome should be interpreted as hypotheses until they can be evaluated further. Overall, our findings are consistent with the majority of previous studies that found women who use OCs during early pregnancy have no increased risk for most types of major congenital malformations.

Anencephaly and spina bifida among Hispanics: maternal, sociodemographic, and acculturation factors in the National Birth Defects Prevention Study.

BACKGROUND: We used data from the multisite National Birth Defects Prevention Study for expected delivery dates from October 1997 through 2003, to determine whether the increased risk in anencephaly and spina bifida (neural tube defects (NTDs)) in Hispanics was explained by selected sociodemographic, acculturation, and other maternal characteristics. METHODS: For each type of defect, we examined the association with selected maternal characteristics stratified by race/ethnicity and the association with Hispanic parents' acculturation level, relative to non-Hispanic whites. We used logistic regression and calculated crude odds ratios (ORs) and their 95% confidence intervals (CIs). RESULTS: Hispanic mothers who reported the highest level of income were 80% less likely to deliver babies with spina bifida. In addition, highly educated Hispanic and white mothers had 76 and 35% lower risk, respectively. Other factors showing differing effects for spina bifida in Hispanics included maternal age, parity, and gestational diabetes. For spina bifida there was no significant elevated risk for U.S.-born Hispanics, relative to whites, but for anencephaly, corresponding ORs ranged from 1.9 to 2.3. The highest risk for spina bifida was observed for recent Hispanic immigrant parents from Mexico or Central America residing in the United States <5 years (OR = 3.28, 95% CI = 1.46-7.37). CONCLUSIONS: Less acculturated Hispanic parents seemed to be at highest risk of NTDs. For anencephaly, U.S.-born and English-speaking Hispanic parents were also at increased risk. Finally, from an etiologic standpoint, spina bifida and anencephaly appeared to be etiologically heterogeneous from these analyses.

Birth defects and military service since 1990.

The National Birth Defects Prevention Study (NBDPS) is an ongoing, multicenter, case-control study of over 30 major birth defects, and is one of the largest studies of the causes of birth defects to date. Data from it were examined to determine if maternal or paternal military service since 1990 as reported during the interview was associated with birth defects among offspring. Logistic regression was used to produce odds ratios (ORs) adjusted for major confounders. Overall, the results indicated no statistically significant association between parental military service since 1990 and increased risk of birth defects.

The prevalence and predictors of anencephaly and spina bifida in Texas.

Texas shares a 1255-mile border with Mexico and encompasses a variety of ecosystems, industries and other potential environmental exposures. The Texas Birth Defects Registry is an active surveillance system which covers all pregnancy outcomes (livebirths, fetal deaths and elective pregnancy terminations). This study describes the occurrence and the predictors of neural tube defects (anencephaly and spina bifida) in Texas between 1999 and 2003. Birth prevalence, crude and adjusted prevalence ratios and 95% confidence intervals were calculated using Poisson regression, for each defect, by fetal/infant sex, delivery year and maternal sociodemographic characteristics. Among approximately 1.8 million livebirths, a total of 1157 neural tube defects cases were ascertained by the Registry, resulting in an overall prevalence of 6.33 cases per 10 000 livebirths. The prevalences of anencephaly and spina bifida were 2.81 and 3.52 per 10 000 livebirths respectively. Prevalences of both defects were highest in Hispanics, among mothers living along the border with Mexico, among women of higher parity and among mothers who were 40+ years of age. In addition, the prevalence of each defect was higher among women with no record of prenatal care and among women with less than 7 years of education. Hispanic ethnicity was an important predictor for anencephaly, along with sex, maternal age, parity and border residence. However, only border residence and delivery year were significant predictors for spina bifida.

Alcohol consumption by women before and during pregnancy.

OBJECTIVES: To determine the prevalence, patterns, and predictors of alcohol consumption prior to and during various intervals of pregnancy in the U.S. METHODS: Alcohol-related, pregnancy-related, and demographic data were derived from computer-assisted telephone interviews with 4,088 randomly selected control mothers from the National Birth Defects Prevention Study who delivered live born infants without birth defects during 1997-2002. Alcohol consumption rates and crude and adjusted odds ratios (OR) were calculated. RESULTS: 30.3% of all women reported drinking alcohol at some time during pregnancy, of which 8.3% reported binge drinking (4+ drinks on one occasion). Drinking rates declined considerably after the first month of pregnancy, during which 22.5% of women reported drinking, although 2.7% of women reported drinking during all trimesters of pregnancy and 7.9% reported drinking during the 3rd trimester. Pre-pregnancy binge drinking was a strong predictor of both drinking during pregnancy (adjusted OR = 8.52, 95% CI = 6.67-10.88) and binge drinking during pregnancy (adjusted OR = 36.02, 95% CI = 24.63-52.69). Other characteristics associated with both any drinking and binge drinking during pregnancy were non-Hispanic white race/ethnicity, cigarette smoking during pregnancy, and having an unintended pregnancy. CONCLUSIONS: Our study revealed that drinking during pregnancy is fairly common, three times the levels reported in surveys that ask only about drinking during the month before the survey. Women who binge drink before pregnancy are at particular risk for drinking after becoming pregnant. Sexually active women of childbearing ages who drink alcohol should be advised to use reliable methods to prevent pregnancy, plan their pregnancies, and stop drinking before becoming pregnant.

Awareness and attitudes regarding prenatal testing among Texas women of childbearing age.

Despite increased visibility and availability of prenatal testing procedures, very little is known about the attitudes among the populace toward these procedures. Using a computer assisted telephone interview of pregnant and non-pregnant women of childbearing age we analyze awareness and attitudes regarding prenatal tests among a diverse group of women of childbearing age in Texas. We also examine maternal characteristics associated with awareness and the willingness to undergo these procedures. While 89% were aware that such tests are available, younger, black and less educated women were less likely to know about prenatal tests for birth defects. Seventy-two percent of respondents said they would want their baby tested while Hispanic and black women were significantly more likely to express an interest than non-Hispanic whites. This study demonstrates the variability of knowledge and beliefs and confirms the importance of taking time to understand an individual's personal beliefs, knowledge and attitudes about prenatal diagnosis.

Folic acid supplementation among diabetic, overweight, or obese women of childbearing age.

OBJECTIVE: To examine whether obese, overweight, or diabetic women were equally likely to supplement with folic acid as normal-weight or nondiabetic women. DESIGN: Texas Behavioral Risk Factor Surveillance System was used to compare folic acid supplementation rates among obese, overweight, or diabetic women to those of normal-weight or nondiabetic women. PARTICIPANTS: Responses from nonpregnant Texas women of ages 18 to 44 were analyzed. MAIN OUTCOME MEASURES: Odds ratios were calculated for association between diabetes, body mass index, and folic acid supplementation. RESULTS: Of 6,835 participants, 35% reported daily folic acid supplementation. Obese women were less likely to supplement, even after adjustment for other factors. CONCLUSIONS: All women of childbearing age, but especially those who are obese or diabetic, should be encouraged to take folic acid daily to reduce the risk of neural tube defects.

National estimates and race/ethnic-specific variation of selected birth defects in the United States, 1999-2001.

BACKGROUND: In the United States, birth defects affect approximately 3% of all births, are a leading cause of infant mortality, and contribute substantially to childhood morbidity. METHODS: Population-based data from the National Birth Defects Prevention Network were combined to estimate the prevalence of 21 selected defects for 1999-2001, stratified by surveillance system type. National prevalence was estimated for each defect by pooling data from 11 states with active case-finding, and adjusting for the racial/ethnic distribution of US live births. We also assessed racial/ethnic variation of the selected birth defects. RESULTS: National birth defect prevalence estimates ranged from 0.82 per 10,000 live births for truncus arteriosus to 13.65 per 10,000 live births for Down syndrome. Compared with infants of non-Hispanic (NH) white mothers, infants of NH black mothers had a significantly higher birth prevalence of tetralogy of Fallot, lower limb reduction defects, and trisomy 18, and a significantly lower birth prevalence of cleft palate, cleft lip with or without cleft palate, esophageal atresia/tracheoesophageal fistula, gastroschisis, and Down syndrome. Infants of Hispanic mothers, compared with infants of NH white mothers, had a significantly higher birth prevalence of anencephalus, spina bifida, encephalocele, gastroschisis, and Down syndrome, and a significantly lower birth prevalence of tetralogy of Fallot, hypoplastic left heart syndrome, cleft palate without cleft lip, and esophageal atresia/tracheoesophageal fistula. CONCLUSIONS: This study can be used to evaluate individual state surveillance data, and to help plan for public health care and educational needs. It also provides valuable data on racial/ethnic patterns of selected major birth defects.

Residential mobility patterns and exposure misclassification in epidemiologic studies of birth defects.

Many studies of environmental exposures and birth defects use mothers' addresses at delivery as a proxy for the exposure. The validity of these studies is questionable because birth defects generally occur within 8 weeks of conception and the mother's address at delivery may differ from her address early in pregnancy. In order to assess the extent of this bias, we examined the pattern of maternal residential mobility over the span of 3 months prior to conception through delivery, and associated maternal socio-demographic characteristics. We linked Texas subjects from a national case-control study of birth defects with their corresponding records from the Texas Birth Defects Registry and the Texas live birth certificates. Logistic regression analyses were conducted to assess maternal socio-demographic factors related to mobility during pregnancy. Overall, 33% of case and 31% of control mothers changed residence between conception and delivery. The pattern of mobility was similar for both case and control mothers for each pregnancy period. Multivariate analyses indicated that for case mothers, older age (OR=0.39, 95% CI=0.21-0.70), higher household income (OR=0.35, 95% CI=0.18-0.68), Hispanic ethnicity (OR=0.64, 95% CI=0.44-0.92), and higher parity (OR=0.59, 95% CI=0.38-0.94) were indicators of lower mobility during pregnancy. For control mothers, the same pattern of association was present, however, only older age was significantly associated with low rates of mobility. Studies of birth defects using maternal address at delivery as a proxy for maternal environmental exposures during pregnancy may be subject to considerable nondifferential exposure misclassification due to maternal mobility during pregnancy.

Medical records vs. interview responses: a comparative analysis of selected variables for linked birth defect cases.

BACKGROUND: Data pertaining to birth defects are subject to certain limitations depending on the collection method. This study compares the agreement of data from medical records and maternal interviews. METHODS: The medical records and maternal interviews were linked for 1017 deliveries. Prevalence, concordance and kappa coefficients were calculated for maternal gestational and non-gestational diabetes, insulin use, seizures/epilepsy, Hispanic ethnicity, and infant/fetus sex. RESULTS: The prevalence of non-gestational diabetes was 4.3% in the medical records and 3.4% in the maternal interviews, with 98.1% agreement. The prevalence of gestational diabetes was 7.9% in medical records and 9.2% in maternal interviews, with 94.3% agreement. Similar prevalences and high levels of agreement were observed between the two systems for infant/fetus sex and mother's Hispanic ethnicity. Although high concordance was observed for seizures/epilepsy, kappa value was moderate. CONCLUSIONS: The availability of two distinct sources of data provides an exceptional opportunity to compare and validate both data sources. We found that the data for certain variables from maternal interviews strongly agreed with information from medical records. However, the extent of that agreement depended on the type of variable measured. Our results suggest that for some variables such as demographic variables, researchers can use either of the two data sources.