Sensitivity of birth certificate reports of birth defects in Atlanta, 1995-2005: effects of maternal, infant, and hospital characteristics

Linked birth cohort files for perinatal health research: California as a model for methodology and implementation

PURPOSE

Rigorous perinatal epidemiologic research depends on population-based parental and neonatal sociodemographic and clinical data. Here we describe the creation of linked birth cohort files, an enriched data source that combines information from vital records with maternal delivery and infant hospital encounter records.

METHODS

Probabilistic linkage techniques were used to link vital records (i.e., birth and fetal death certificates) from the California Department of Public Health with hospital inpatient, ambulatory surgery and emergency department encounter data for mothers and infants from the California Department of Health Care Access and Information.

RESULTS

From 2012 to 2018, 95% of live birth records were successfully linked to maternal and newborn hospital records while 85% of fetal death records were linked to a maternal delivery record. Overall, 93% of postnatal hospital encounters of infants (i.e., <1 year old) were matched to a linked record.

CONCLUSIONS

The linked birth cohort files is a rich resource opening many possibilities for understanding perinatal health outcomes and opportunities for linkage to longitudinal, social determinant, and environmental data. To optimally use this file for research, analysts should evaluate possible shortcomings or biases of the data sources being linked.

Association Between Rates of Down Syndrome Diagnosis in States With vs Without 20-Week Abortion Bans From 2011 to 2018

IMPORTANCE

Many states enacted 20-week abortion bans from 2011 to 2018. Such bans affect individuals who receive diagnoses of fetal anomalies and aneuploidy in the second trimester, preventing pregnant individuals from having the choice of whether or not to continue the pregnancy.

OBJECTIVES

To examine the trends of neonatal Down syndrome rates and assess the association between enactment of 20-week abortion bans and rates of Down syndrome diagnosis.

DESIGN, SETTING, AND PARTICIPANTS

This population-based, historical cohort study used National Vital Statistics System data on 31 157 506 births in the US from 2011 to 2018. Statistical analysis was performed from May 2021 to February 2023.

EXPOSURE

States were categorized as those with or without a 20-week abortion ban enacted during the study period.

MAIN OUTCOMES AND MEASURES

Demographic characteristics between the ban and no-ban states were compared using χ2 tests and 2-sample t tests. Multivariable logistic regression evaluated the adjusted odds of Down syndrome among births in states that enacted 20-week abortion bans after the abortion ban enactment, adjusting for state, year of birth, maternal race and ethnicity, age, educational level, insurance, and number of prenatal visits.

RESULTS

The cohort consisted of 31 157 506 births (mean [SD] maternal age, 28.4 [5.9] years) in the United States, of whom 15 951 neonates (0.05%) received a diagnosis of Down syndrome at birth. A total of 17 states enacted 20-week abortion bans during the study period, and 33 states did not enact bans. In both states with and states without bans, the birth prevalence of neonatal Down syndrome increased over time; in states with bans, rates increased from 48.0 to 58.4 per 100 000 births; in states without bans, rates increased from 47.4 to 53.3 per 100 000 births. In multivariable logistic regression assessing the interaction of time and presence of a 20-week abortion ban, the odds of Down syndrome were higher in states that enacted 20-week abortion bans after enactment of the law compared with the years prior to enactment of the ban (adjusted odds ratio, 1.22; 95% CI, 1.11-1.35).

CONCLUSIONS AND RELEVANCE

In the US from 2011 to 2018, neonatal Down syndrome diagnoses increased more in states that enacted 20-week abortion bans compared with states that did not enact bans. Because these abortion bans were enacted throughout the study period and are known to inhibit choice in patient decision-making, it is possible that the difference in the rates of diagnosis is associated with these policies.

Concordance of neonatal critical condition data between secondary databases: Florida and Texas birth certificate Linkage with medicaid analytic extract

BACKGROUND

Limited information is available about neonates' critical conditions data quality. The study aim was to measure the agreement regarding presence of neonatal critical conditions between Medicaid Analytic eXtract claims data and Birth Certificate (BC) records.

METHODS

Claims data files of neonates born between 1999-2010 and their mothers were linked to birth certificates in the states of Texas and Florida. In claims data, neonatal critical conditions were identified using medical encounter claims records within the first 30 days postpartum, while in birth certificates, the conditions were identified based on predetermined variables. We calculated the prevalence of cases within each data source that were identified by its comparator, in addition to calculating overall agreement and kappa statistics.

RESULTS

The sample included 558,224 and 981,120 neonates in Florida and Texas, respectively. Kappa values show poor agreement (< 20%) for all critical conditions except neonatal intensive care unit (NICU) admission, which showed moderate (> 50%) and substantial (> 60%) agreement in Florida and Texas, respectively. claims data resulted in higher prevalences and capture of a larger proportion of cases than the BC, except for assisted ventilation.

CONCLUSIONS

Claims data and BC showed low agreement on neonatal critical conditions except for NICU admission. Each data source identified cases most of which the comparator failed to capture, with higher prevalences estimated within claims data except for assisted ventilation.

Congenital anomalies associated with oil and gas development and resource extraction: a population-based retrospective cohort study in Texas

BACKGROUND

Oil and gas extraction-related activities produce air and water pollution that contains known and suspected teratogens. To date, health impacts of in utero exposure to these activities is largely unknown.

OBJECTIVE

We investigated associations between in utero exposure to oil and gas extraction activity in Texas, one of the highest producers of oil and gas, and congenital anomalies.

METHODS

We created a population-based birth cohort between 1999 and 2009 with full maternal address at delivery and linked to the statewide congenital anomaly surveillance system (n = 2,234,138 births, 86,315 cases). We examined extraction-related exposures using tertiles of inverse distance-squared weighting within 5 km for drilling site count, gas production, oil production, and produced water. In adjusted logistic regression models, we calculated odds of any congenital anomaly and 10 specific organ sites using two comparison groups: 1) 5 km of future drilling sites that are not yet operating (a priori main models), and 2) 5-10 km of an active well.

RESULTS

Using the temporal comparison group, we find increased odds of any congenital anomaly in the highest tertile exposure group for site count (OR: 1.25; 95% CI: 1.21, 1.30), oil production (OR: 1.08; 95% CI: 1.04, 1.12), gas production (1.20; 95% CI: 1.17, 1.23), and produced water (OR: 1.17; 95% CI: 1.14, 1.20). However, associations did not follow a consistent exposure-response pattern across tertiles. Associations are highly attenuated, but still increased, with the spatial comparison group in the highest tertile exposure group. Cardiac and circulatory defects are strongly and consistently associated with all exposure metrics.

SIGNIFICANCE

Increased odds of congenital anomalies, particularly cardiac and circulatory defects, were associated with exposures related to oil and gas extraction in this large population-based study. Future research is needed to confirm findings, examine specific exposure pathways, and identify potential avenues to reduce exposures among local populations.

IMPACT

About 5% of the U.S. population (~17.6 million people) resides within 1.6 km of an active oil or gas extraction site, yet the influence of this industry on population health is not fully understood. In this analysis, we examined associations between oil and gas extraction-related exposures and congenital anomalies by organ site using birth certificate and congenital anomaly surveillance data in Texas (1999-2009). Increased odds of congenital anomalies, particularly cardiac and circulatory defects, were associated with exposures related to oil and gas extraction in this large population-based study. Future research is needed to confirm these findings.

Global prevalence of congenital anencephaly: a comprehensive systematic review and meta-analysis

Background

Anencephaly is a fatal congenital anomaly characterized by the absence of brain hemispheres and cranial arch. Timely preventive measures can be taken by knowing the exact prevalence of this common neural tube defect; thus, carried out through systematic review and meta-analysis, the present study was conducted to determine the worldwide prevalence, incidence and mortality of anencephaly.

Methods

Cochran’s seven-step instructions were used as the guideline. Having determined the research question and inclusion and exclusion criteria, we studied MagIran, SID, Science Direct, WoS, Web of Science, Medline (PubMed), Scopus, and Google Scholar databases. Moreover, the search strategy in each database included using all possible keyword combinations with the help of “AND” and “OR” operators with no time limit to 2021. The I² test was used to calculate study heterogeneity, and Begg and Mazumdar rank correlation tests were employed to assess the publication bias. Data were analyzed by Comprehensive Meta-Analysis software (Version 2).

Results

In this study, the statements of Preferred Reporting Items for Systematic Reviews and Meta-Analyzes (PRISMA) were used. In the first stage, 1141 articles were found, of which 330 duplicate studies were omitted. 371 articles were deleted based on the inclusion and exclusion criteria by reviewing the title and abstract of the study. 58 articles were removed by reviewing the full text of the article because it was not relevant to the research. 360 studies with a sample size of 207,639,132 people were considered for the meta-analysis. Overall estimate of the prevalence, incidence and attenuation of anencephaly worldwide were 5.1 per ten thousand births (95% confidence interval 4.7–5.5 per ten thousand births), 8.3 per ten thousand births (95% confidence interval 5.5–9.9 per ten thousand births), 5.5 per ten thousand births (95% confidence interval 1.8–15 per ten thousand births) respectively the highest of which according to the subgroup analysis, belonged to the Australian continent with 8.6 per ten thousand births (95% confidence interval 7.7–9.5 per ten thousand births).

Conclusion

The overall prevalence of anencephaly in the world is significant, indicating the urgent need for preventive and treating measures.

Anencephaly is a fatal congenital anomaly characterized by the absence of brain hemispheres and cranial arch. Cochran’s seven-step instructions were used as the guideline. Having determined the research question and inclusion and exclusion criteria, we studied MagIran, SID, Science Direct, WoS, Web of Science, Medline (PubMed), Scopus, and Google Scholar databases. Moreover, the search strategy in each database included using all possible keyword combinations with the help of “AND” and “OR” operators with no time limit to 2021. Out of 1141 initial articles found, and after excluding repetitive ones in various databases and those irrelevant to inclusion criteria, 360 studies with a sample size of 207,639,132 people were considered for the meta-analysis. Overall estimate of the prevalence, incidence and attenuation of anencephaly worldwide were 5.1 per ten thousand births (95% confidence interval 4.7–5.5 per ten thousand births), 8.3 per ten thousand births (95% confidence interval 5.5–9.9 per ten thousand births), 5.5 per ten thousand births (95% confidence interval 1.8–15 per ten thousand births) respectively the highest of which according to the subgroup analysis, belonged to the Australian continent with 8.6 per ten thousand births (95% confidence interval 7.7–9.5 per ten thousand births). The overall prevalence of anencephaly in the world is significant, indicating the urgent need for preventive and treating measures.

Poverty and Risk of Cleft Lip and Palate: An Analysis of United States Birth Data

BACKGROUND

The relationship between poverty and incidence of cleft lip and cleft palate remains unclear. The authors investigated the association between socioeconomic status and cleft lip with or without cleft palate and cleft palate only in the United States after controlling for demographic and environmental risk factors.

METHODS

The U.S. 2016 and 2017 natality data were utilized. Proxies for socioeconomic status included maternal education, use of the Special Supplemental Nutrition Program for Women, Infants, and Children, and payment source for delivery. Multiple logistic regression controlled for household demographics, prenatal care, maternal health, and infant characteristics.

RESULTS

Of 6,251,308 live births included, 2984 (0.05 percent) had cleft lip with or without cleft palate and 1180 (0.02 percent) had cleft palate only. Maternal education of bachelor's degree or higher was protective against, and delayed prenatal care associated with, cleft lip with or without cleft palate (adjusted ORs = 0.73 and 1.14 to 1.23, respectively; p < 0.02). Receiving assistance under the Special Supplemental Nutrition Program for Women, Infants, and Children was associated with cleft palate only (adjusted OR = 1.25; p = 0.003). Male sex, first-trimester tobacco smoking, and maternal gestational diabetes were also associated with cleft lip with or without cleft palate (adjusted ORs = 1.60, 1.01, and 1.19, respectively; p < 0.05). Female sex, prepregnancy tobacco smoking, and maternal infections during pregnancy were associated with cleft palate only (adjusted ORs = 0.74, 1.02, and 1.60, respectively; p < 0.05).

CONCLUSIONS

Increased incidence of orofacial clefts was associated with indicators of lower socioeconomic status, with different indicators associated with different cleft phenotypes. Notably, early prenatal care was protective against the development of cleft lip with or without cleft palate.

CLIINCAL QUESTION/LEVEL OF EVIDENCE

Risk, III.

Association of Gestational Weight Gain With Infant Morbidity and Mortality in the United States

IMPORTANCE

The associations of gestational weight gain (GWG) with infant morbidity and mortality are unclear, and the existing recommendations for GWG have not been stratified by the severity of obesity.

OBJECTIVES

To identify optimal GWG ranges associated with reduced risks of infant morbidity and mortality across maternal body mass index (BMI) categories.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study used US nationwide, linked birth and infant death data between 2011 and 2015 to assess the associations of GWG in 2.0-kg groups with infant morbidity and mortality and identified optimal GWG ranges associated with reduced risks of both outcomes, using multivariable logistic regression models. Statistical analysis was performed from February 11 to October 14, 2021.

EXPOSURE

Gestational weight gain equivalent to 40 weeks.

MAIN OUTCOMES AND MEASURES

The 2 main outcomes were (1) significant morbidity of the newborn infant, defined as any presence of assisted ventilation, admission to the neonatal intensive care unit, surfactant therapy, antibiotic therapy, or seizures; and (2) infant mortality younger than 1 year of age (<1 hour, 1-23 hours, 1-6 days, 7-27 days, or 28-365 days after birth).

RESULTS

In this study of 15 759 945 mother-infant dyads, the mean (SD) age of the women was 28.1 (5.9) years. Women gained a mean (SD) of 14.1 (7.3) kg during pregnancy, and the mean (SD) GWG decreased with BMI categories (underweight, 15.7 [6.4] kg; normal weight, 15.4 [6.2] kg; overweight, 14.2 [7.4] kg; obesity class 1, 12.2 [8.0] kg; obesity class 2, 10.3 [8.4] kg; obesity class 3, 8.2 [9.2] kg; P < .001). A total of 8.8% of the newborns experienced significant morbidity, with the lowest prevalence among infants delivered by women in the normal weight BMI class (8.0%) and the highest among infants delivered by women with class 3 obesity (12.4%); 0.34% of infants died within 1 year of birth, with the lowest prevalence among infants delivered by women in the normal weight BMI class (0.28%) and the highest among infants delivered by women with class 3 obesity (0.58%). Optimal GWG ranges were 12.0 to less than 24.0 kg for underweight and normal weight women, 10.0 to less than 20.0 kg for overweight women, 8.0 to less than 16.0 kg for women with class 1 obesity, 6.0 to less than 16.0 kg for class 2 obesity, and 6.0 to less than 10.0 kg for class 3 obesity. The lower bounds of the optimal GWG ranges appeared to be higher than the existing recommendations for overweight women (10.0 vs 7.0 kg) and for those with class 1 (8.0 vs 5.0 kg), class 2 (6.0 vs 5.0 kg), and class 3 (6.0 vs 5.0 kg) obesity.

CONCLUSIONS AND RELEVANCE

This study analyzed the associations of GWG with infant morbidity and mortality across BMI categories and found that inadequate GWG was associated with increased risks of adverse infant outcomes even for women with obesity. The results suggested that weight maintenance or weight loss should not be used as routine guidelines.

Risk of non-syndromic orofacial clefts by maternal rural-urban residence and race/ethnicity: A population-based case-control study in Washington State 1989-2014

BACKGROUND

Orofacial clefts (OFC) have multifactorial aetiology. Established risk factors explain a small proportion of cases.

OBJECTIVES

To evaluate OFC risk by maternal rural residence and race/ethnicity, and test whether these associations changed after US-mandated folic acid fortification.

METHODS

This population-based case-control study included all non-syndromic OFC cases among Washington State singleton livebirths between 1989-2014 and birth year-matched controls. Data sources included birth certificates and hospital records. Logistic regression estimated odds ratios (OR) and 95% confidence intervals (CI) for OFC by maternal rural-urban residence (adjusted for maternal race/ethnicity) and by maternal race/ethnicity. We evaluated additive and multiplicative effect measure modification by time of folic acid fortification (before vs. after). Probabilistic quantitative bias analysis accounted for potential differential case ascertainment for infants born to Black mothers.

RESULTS

The overall non-syndromic OFC birth prevalence was 1.0 per 1000 livebirths (n = 2136 cases). Among controls (n = 25 826), 76% of mothers were urban residents and 72% were of White race/ethnicity. OFC risk was slightly higher for infants born to rural than to urban mothers, adjusting for race/ethnicity (OR 1.12, 95% CI 1.01, 1.25). The association was similar before and after US-mandated folic acid fortification. Compared with infants born to White mothers, OFC risk was higher for American Indian mothers (OR 1.73, 95% CI 1.35, 2.23) and lower for Black (OR 0.62, 95% CI 0.48, 0.81), Hispanic (OR 0.75, 95% CI 0.64, 0.87), and Asian/Pacific Islander (API) mothers (OR 0.87, 95% CI 0.74, 1.02). Bias analysis suggests the observed difference for Black mothers may be explained by selection bias. Post-fortification, the association of OFC with maternal API race/ethnicity decreased and with maternal Black race/ethnicity increased relative to maternal White race/ethnicity.

CONCLUSIONS

Infants born to rural mothers and to American Indian mothers in Washington State during 1989-2014 were at higher OFC risk before and after US-mandated folic acid fortification.

The risk of birth defects with conception by ART

STUDY QUESTION

What is the association between ART conception and treatment parameters and the risk of birth defects?

SUMMARY ANSWER

Compared to naturally conceived singleton infants, the risk of a major nonchromosomal defect among ART singletons conceived with autologous oocytes and fresh embryos without use of ICSI was increased by 18%, with increases of 42% and 30% for use of ICSI with and without male factor diagnosis, respectively.

WHAT IS KNOWN ALREADY

Prior studies have indicated that infertility and ART are associated with an increased risk of birth defects but have been limited by small sample size and inadequate statistical power, failure to differentiate results by plurality, differences in birth defect definitions and methods of ascertainment, lack of information on ART treatment parameters or study periods spanning decades resulting in a substantial historical bias as ART techniques have improved.

STUDY DESIGN, SIZE, DURATION

This was a population-based cohort study linking ART cycles reported to the Society for Assisted Reproductive Technology Clinic Outcome Reporting System (SART CORS) from 1 January 2004 to 31 December 2015 that resulted in live births from 1 September 2004 to 31 December 2016 in Massachusetts and North Carolina and from 1 September 2004 to 31 December 2015 for Texas and New York: these were large and ethnically diverse States, with birth defect registries utilizing the same case definitions and data collected, and with high numbers of ART births annually. A 10:1 sample of non-ART births were chosen within the same time period as the ART birth. Naturally conceived ART siblings were identified through the mother's information. Non-ART children were classified as being born to women who conceived with ovulation induction (OI)/IUI when there was an indication of infertility treatment on the birth certificate, but the woman did not link to the SART CORS; all others were classified as being naturally conceived.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The study population included 135 051 ART children (78 362 singletons and 56 689 twins), 23 647 naturally conceived ART siblings (22 301 singletons and 1346 twins) and 9396 children born to women treated with OI/IUI (6597 singletons and 2799 twins) and 1 067 922 naturally conceived children (1 037 757 singletons and 30 165 twins). All study children were linked to their respective State birth defect registries to identify major defects diagnosed within the first year of life. We classified children with major defects as either chromosomal (i.e. presence of a chromosomal defect with or without any other major defect) or nonchromosomal (i.e. presence of a major defect but having no chromosomal defect), or all major defects (chromosomal and nonchromosomal). Logistic regression models were used to generate adjusted odds ratios (AORs) and 95% CI to evaluate the risk of birth defects due to conception with ART (using autologous oocytes and fresh embryos), and with and without the use of ICSI in the absence or presence of male factor infertility, with naturally conceived children as the reference. Analyses within the ART group were stratified by combinations of oocyte source (autologous, donor) and embryo state (fresh, thawed), with births from autologous oocytes and fresh embryos as the reference. Analyses limited to fresh embryos were stratified by oocyte source (autologous, donor) and the use of ICSI. Triplets and higher-order multiples were excluded.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 21 998 singleton children (1.9%) and 3037 twin children (3.3%) had a major birth defect. Compared to naturally conceived children, ART singletons (conceived from autologous oocytes, fresh embryos without the use of ICSI) had increased risks of a major nonchromosomal birth defect (AOR 1.18, 95% 1.05, 1.32), cardiovascular defects (AOR 1.20, 95% CI 1.03, 1.40), and any birth defect (AOR 1.18, 95% CI 1.09, 1.27). Compared to naturally conceived children, ART singletons conceived (from autologous oocytes, fresh embryos) with the use of ICSI, the risks were increased for a major nonchromosomal birth defect (AOR 1.30, 95% CI 1.16, 1.45 without male factor diagnosis; AOR 1.42, 95% CI 1.28, 1.57 with male factor diagnosis); blastogenesis defects (AOR 1.49, 95% CI 1.08, 2.05 without male factor; AOR 1.56, 95% CI 1.17, 2.08 with male factor); cardiovascular defects (AOR 1.28, 95% CI 1.10,1.48 without male factor; AOR 1.45, 95% CI 1.27, 1.66 with male factor); in addition, the risk for musculoskeletal defects was increased (AOR 1.34, 95% CI 1.01, 1.78 without male factor) and the risk for genitourinary defects in male infants was increased (AOR 1.33, 95% CI 1.08, 1.65 with male factor). Comparisons within ART singleton births conceived from autologous oocytes and fresh embryos indicated that the use of ICSI was associated with increased risks of a major nonchromosomal birth defect (AOR 1.18, 95% CI 1.03, 1.35), blastogenesis defects (AOR 1.65, 95% CI 1.08, 2.51), gastrointestinal defects (AOR 2.21, 95% CI 1.28, 3.82) and any defect (AOR 1.11, 95% CI 1.01, 1.22). Compared to naturally conceived children, ART singleton siblings had increased risks of musculoskeletal defects (AOR 1.32, 95% CI 1.04, 1.67) and any defect (AOR 1.15, 95% CI 1.08, 1.23). ART twins (conceived with autologous oocytes, fresh embryos, without ICSI) were at increased risk of chromosomal defects (AOR 1.89, 95% CI 1.10, 3.24) and ART twin siblings were at increased risk of any defect (AOR 1.26, 95% CI 1.01, 1.57). The 18% increased risk of a major nonchromosomal birth defect in singleton infants conceived with ART without ICSI (∼36% of ART births), the 30% increased risk with ICSI without male factor (∼33% of ART births), and the 42% increased risk with ICSI and male factor (∼31% of ART births) translates into an estimated excess of 386 major birth defects among the 68 908 singleton children born by ART in 2017.

LIMITATIONS, REASONS FOR CAUTION

In the SART CORS database, it was not possible to differentiate method of embryo freezing (slow freezing vs vitrification), and data on ICSI was only available in the fresh embryo ART group. In the OI/IUI group, it was not possible to differentiate type of non-ART treatment utilized, and in both the ART and OI/IUI groups, data were unavailable on duration of infertility.

WIDER IMPLICATIONS OF THE FINDINGS

The use of ART is associated with increased risks of a major nonchromosomal birth defect, cardiovascular defect and any defect in singleton children, and chromosomal defects in twins; the use of ICSI further increases this risk, the most with male factor infertility. These findings support the judicious use of ICSI only when medically indicated. The relative contribution of ART treatment parameters versus the biology of the subfertile couple to this increased risk remains unclear and warrants further study.

STUDY FUNDING/COMPETING INTEREST(S)

This project was supported by grant R01 HD084377 from the National Institute of Child Health and Human Development. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institute of Child Health and Human Development, or the National Institutes of Health, nor any of the State Departments of Health which contributed data. E.W. is a contract vendor for SART; all other authors report no conflicts.

TRIAL REGISTRATION NUMBER

N/A.

The Prevalence of Nonsyndromic Oral Clefts in Twins Compared to Singletons: The Association With Birth Weight

PURPOSE

To examine the prevalence of nonsyndromic oral clefts in twins compared to singletons in the United States and to evaluate the association between birth weight and nonsyndromic oral clefts.

DESIGN

A large population-based cross-sectional study was performed using the data from the US National Center for Health Statistics database in 2017.

PARTICIPANTS

Our sample consisted of 128 310 twins and 3 723 273 singletons.

METHODS

The variables collected were sociodemographic variables, environmental predictors, and clinical measures. Descriptive analysis, bivariate, and multivariate logistic regression were performed.

MAIN OUTCOME MEASURE

The main outcome variable in our study is nonsyndromic oral clefts.

RESULTS

The prevalence of nonsyndromic oral clefts was 5.22 per 10 000 in twins and 5.12 per 10 000 in singletons. Results show no significant risk of nonsyndromic oral clefts in twins compared to singletons (P = .92). There was a significant relationship between birth weight and infant diagnosed with nonsyndromic oral clefts (P = .01). Unadjusted odds ratio for birth weight was 2.52 (95% CI: 2.25-2.82). Adjusted odds for potential confounders such as mother's age, race, mother's education, gender of the infant, APGAR 5-minute score, gestational age, prenatal smoking, number of prenatal care visits, and mother's body mass index were resulted in similar but with a slightly lower odds of 2.11 (95% CI: 1.78-2.50).

CONCLUSION

Compared to singletons, twins did not have higher risk of nonsyndromic oral clefts. Infants with low birth weight were more prone to have nonsyndromic oral clefts.

Validity of diagnosis and procedure codes for identifying neural tube defects in infants

PURPOSE

The use of validated criteria to identify birth defects in electronic healthcare databases can avoid the cost and time-intensive efforts required to conduct chart reviews to confirm outcomes. This study evaluated the validity of various case-finding methodologies to identify neural tube defects (NTDs) in infants using an electronic healthcare database.

METHODS

This analysis used data generated from a study whose primary aim was to evaluate the association between first-trimester maternal prescription opioid use and NTDs. The study was conducted within the Medication Exposure in Pregnancy Risk Evaluation Program. A broad approach was used to identify potential NTDs including diagnosis and procedure codes from inpatient and outpatient settings, death certificates and birth defect flags in birth certificates. Potential NTD cases were chart abstracted and confirmed by clinical experts. Positive predictive values (PPVs) and 95% confidence intervals (95% CI) are reported.

RESULTS

The cohort included 113 168 singleton live-born infants: 55 960 infants with opioid exposure in pregnancy and 57 208 infants unexposed in pregnancy. Seventy-three potential NTD cases were available for the validation analysis. The overall PPV was 41% using all diagnosis and procedure codes plus birth certificates. Restricting approaches to codes recorded in the infants' medical record or to birth certificate flags increased the PPVs (72% and 80%, respectively) but missed a substantial proportion of confirmed NTDs.

CONCLUSIONS

Codes in electronic healthcare data did not accurately identify confirmed NTDs. These results indicate that chart review with adjudication of outcomes is important when conducting observational studies of NTDs using electronic healthcare data.

Prenatal exposure to nitrate in drinking water and the risk of congenital anomalies

BACKGROUND

Nitrate is a common water contaminant that has been associated with birth defects, although the evidence is limited. The purpose of this study was to examine whether maternal consumption of nitrate through drinking water is associated with an increased risk of congenital anomalies.

METHODS

The study included a total of 348,250 singletons births from the state of Missouri between January 1, 2004 and December 31, 2008. Individual-level birth defect data and maternal and child characteristics were obtained from the Missouri birth defects registry and state vital statistics records. Outcomes were linked with county-specific monthly estimates of the nitrate concentration in finished water, based on data collected for compliance with the Safe Drinking Water Standard. Poisson models were fit to examine the association between nitrate exposure and birth defects. Average nitrate exposure during the first trimester and over 12 months prior to birth were modeled as continuous variables. Sensitivity analyses included restriction of the sample to counties with <20% and <10% private well usage to reduce exposure misclassification as well as limiting the analyses to residents of rural counties only to account for potential confounding by urbanicity.

RESULTS

Estimated water concentrations of nitrate were generally low and below the Environmental Protection Agency's maximum contaminant level of 10 mg/L. Nitrate exposure was associated with a significantly increased risk of limb deficiencies (RR for 1 mg/L (RR1) = 1.26, 95% CI = 1.05, 1.51) in models without well restriction. Nitrate was also weakly associated with an increased risk of congenital heart defects (RR1 = 1.13, 95%CI = 0.93, 1.51) and neural tube defects (RR1 = 1.18, 95%CI = 0.93, 1.51) in models with well restriction (<10%).

CONCLUSION

The positive associations found between nitrate exposure via drinking water and congenital abnormalities are largely consistent with some previous epidemiologic studies. The results of this study should be interpreted with caution given limitations in our ability to estimate exposures and the lack information on some risk factors for congenital abnormalities. Our findings may have serious policy implications given that exposure levels in our study were well below current EPA standards for nitrate in drinking water.

The association between natural gas well activity and specific congenital anomalies in Oklahoma, 1997-2009

BACKGROUND

Natural gas drilling may pose multiple health risks, including congenital anomalies, through air pollutant emissions and contaminated water. Two recent studies have evaluated the relationship between natural gas activity and congenital anomalies, with both observing a positive relationship.

OBJECTIVES

We aimed to evaluate whether residence near natural gas wells is associated with critical congenital heart defects (CCHD), neural tube defects (NTD), and oral clefts in Oklahoma, the third highest natural gas producing state in the US.

METHODS

We conducted a retrospective cohort study among singleton births in Oklahoma (n = 476,600) to evaluate natural gas activity and congenital anomalies. We calculated an inverse distance-squared weighted (IDW) score based on the number of actively producing wells within a two-mile radius of the maternal residence during the month of delivery. We used modified Poisson regression with robust error variance to estimate prevalence proportion ratios (PPR) and 95% confidence intervals (CI) for the association between tertiles of natural gas activity (compared to no wells) and CCHD, NTD, and oral clefts adjusted for maternal education.

RESULTS

We observed an increased, though imprecise, prevalence of NTDs among children with natural gas activity compared to children with no wells (2nd tertile PPR: 1.34, 95% CI: 0.93, 1.93; 3rd tertile PPR: 1.20, 95% CI: 0.82, 1.75). We observed no association with CCHD or oral clefts overall. Specific CCHDs of common truncus, transposition of the great arteries, pulmonary valve atresia and stenosis, tricuspid valve atresia and stenosis, interrupted aortic arch, and total anomalous pulmonary venous connection were increased among those living in areas with natural gas activity compared to those living in areas without activity, though not statistically significant.

DISCUSSION

Our results were similar to previous studies for NTDs and specific CCHDs. Future directions include evaluating the association between specific phases of the drilling process and congenital anomalies to better refine the relevant exposure period.

Zika virus infection estimates, Mexico

Objective

To assess the magnitude of the Mexican epidemic of Zika virus infection and the associated risk of microcephaly.

Methods

From the reported number of laboratory-confirmed symptomatic infections among pregnant women and the relevant birth rate, we estimated the number of symptomatic cases of infection that occurred in Mexico between 25 November 2015, when the first confirmed Mexican case was reported, and 20 August 2016. We used data from the birth certificates to compare mean monthly incidences of congenital microcephaly before (1 January 2010–30 November 2015) and after (1 December 2015–30 September 2017) the introduction of Zika virus, stratifying the data according to whether the mother’s place of residence was at an altitude of at least 2200 m above sea level. We used Poisson interrupted time series, statistical modelling and graphical analyses.

Findings

Our estimated number of symptomatic cases of infection that may have occurred in the general population of Mexico between 25 November 2015 and 20 August 2016, 60 172, was 7.3-fold higher than the corresponding number of reported cases. The monthly numbers of microcephaly cases per 100 000 live births were significantly higher after the introduction of the virus than before (incidence rate ratio, IRR: 2.9; 95% confidence interval, CI: 2.3 to 3.6), especially among the babies of women living at altitudes below 2200 m (IRR: 3.4; 95% CI: 2.9 to 3.9).

Conclusion

The Mexican epidemic appears to be much larger than indicated by estimates based solely on counts of laboratory-confirmed cases, and to be associated with significantly increased risk of microcephaly.

Parental Age and Risk of Infant Leukaemia: A Pooled Analysis

BACKGROUND

Infant leukaemia (IL) is extremely rare with fewer than 150 cases occurring each year in the United States. Little is known about its causes. However, recent evidence supports a role of de novo mutations in IL aetiology. Parental age has been associated with several adverse outcomes in offspring, including childhood cancers. Given the role of older parental age in de novo mutations in offspring, we carried out an analysis of parental age and IL.

METHODS

We evaluated the relationship between parental age and IL in a case-control study using registry data from New York, Minnesota, California, Texas, and Washington. Records from 402 cases [219 acute lymphoblastic leukaemia (ALL), 131 acute myeloid leukaemia (AML), and 52 other] and 45 392 controls born during 1981-2004 were analysed. Odds ratios (OR) and 95% confidence intervals (CI) were calculated by logistic regression. Estimates were adjusted for infant sex, birth year category, maternal race, state, and mutually adjusted for paternal or maternal age, respectively.

RESULTS

Infants with mothers' age ≥40 years had an increased risk of developing AML (OR 4.80, 95% CI 1.80, 12.76). In contrast, paternal age <20 was associated with increased risk of ALL (OR 3.69, 95% CI 1.62, 8.41).

CONCLUSION

This study demonstrates increased risk of infant ALL in relation to young paternal age. Given record linkage, there is little concern with recall or selection bias, although data are lacking on MLL gene status and other potentially important variables. Parent of origin effects, de novo mutations, and/or carcinogenic exposures may be involved in IL aetiology.

A quality assessment of reporting sources for microcephaly in Utah, 2003 to 2013

BACKGROUND

Obtaining accurate microcephaly prevalence is important given the recent association between microcephaly and Zika virus. Assessing the quality of data sources can guide surveillance programs as they focus their data collection efforts. The Utah Birth Defect Network (UBDN) has monitored microcephaly by data sources since 2003. The objective of this study was to examine the impact of reporting sources for microcephaly surveillance.

METHODS

All reported cases of microcephaly among Utah mothers from 2003 to 2013 were clinically reviewed and confirmed. The UBDN database was linked to state vital records and hospital discharge data for analysis. Reporting sources were analyzed for positive predictive value and sensitivity.

RESULTS

Of the 477 reported cases of microcephaly, 251 (52.6%) were confirmed as true cases. The UBDN identified 94 additional cases that were reported to the surveillance system as another birth defect, but were ultimately determined to be true microcephaly cases. The prevalence for microcephaly based on the UBDN medical record abstraction and clinical review was 8.2 per 10,000 live births. Data sources varied in the number and accuracy of reporting, but a case was more likely to be a true case if identified from multiple sources than from a single source.

CONCLUSION

While some reporting sources are more likely to identify possible and true microcephaly cases, maintaining a multiple source methodology allows for more complete case ascertainment. Surveillance programs should conduct periodic assessments of data sources to ensure their systems are capturing all possible birth defects cases. Birth Defects Research (Part A) 106:983-988, 2016. © 2016 Wiley Periodicals, Inc.

The prevalence of selected major birth defects in the United States

Although collectively they are fairly common, birth defects receive limited attention as a group of outcomes either clinically or from a public health perspective. This article provides an overview of the prevalence, trends and selected socio-demographic risk factors for several major birth defects, including neural tube defects, cranio-facial anomalies, congenital heart defects, trisomies 13, 18, and 21, and gastroschisis and omphalocele. Attention should focus on strengthening existing registries, creating birth defects surveillance programs in states that do not have them, and standardizing registry methods so that broadly national data to monitor these trends are available.

The role of maternal age in twin pregnancy outcomes

BACKGROUND

There are limited data on how maternal age is related to twin pregnancy outcomes.

OBJECTIVE

The purpose of this study was to assess the relationship between maternal age and risk for preterm birth, fetal death, and neonatal death in the setting of twin pregnancy.

STUDY DESIGN

This population-based study of US birth, fetal death, and period-linked birth-infant death files from 2007-2013 evaluated neonatal outcomes for twin pregnancies. Maternal age was categorized as 15-17, 18-24, 25-29, 30-34, 35-39, and ≥40 years of age. Twin live births and fetal death delivered at 20-42 weeks were included. Primary outcomes included preterm birth (<34 weeks and <37 weeks), fetal death, and neonatal death at <28 days of life. Analyses of preterm birth at <34 and <37 weeks were adjusted for demographic and medical factors, with maternal age modeled with the use of restricted spline transformations.

RESULTS

A total of 955,882 twin live births from 2007-2013 were included in the analysis. Preterm birth rates at <34 and <37 weeks gestation were highest for women 15-17 years of age, decreased across subsequent maternal age categories, nadired for women 35-39 years old, and then increased slightly for women ≥40 years old. Risk for fetal death generally decreased across maternal age categories. Risk for fetal death was 39.9 per 1000 live births for women 15-17 years old, 24.2 for women 18-24 years old, 17.8 for women 25-29 years old, 16.4 for women 30-34 years old, 17.2 for women 35-39 years old, and 15.8 for women ≥40 years old. Risk for neonatal death at <28 days was highest for neonates born to women 15-17 years old (10.0 per 1,000 live births), decreased to 7.3 for women 18-24 years old and 5.5 for women 25-29 years old and ranged from 4.3-4.6 for all subsequent maternal age categories. In adjusted models, risk for preterm birth at <34-<37 weeks gestation was not elevated for women in their mid-to-late 30s; however, risk was elevated for women <20 years old and increased progressively with age for women in their 40s.

CONCLUSION

Although twin pregnancy is associated with increased risk for most adverse perinatal outcomes, this analysis did not find advanced maternal age to be an additional risk factor for fetal death and infant death. Preterm birth risk was relatively low for women in their late 30s. Risks for adverse outcomes were higher among younger women; further research is indicated to improve outcomes for this demographic group. It may be reasonable to counsel women in their 30s that their age is not a major additional risk factor for adverse obstetric outcomes in the setting of twin pregnancy.

Identifying birth defects in automated data sources in the Vaccine Safety Datalink

PURPOSE

The Vaccine Safety Datalink (VSD), a collaboration between the Centers for Disease Control and Prevention and several large healthcare organizations, aims to monitor safety of vaccines administered in the USA. We present definitions and prevalence estimates for major structural birth defects to be used in studies of maternal vaccine safety.

METHODS

In this observational study, we created and refined algorithms for identifying major structural birth defects from electronic healthcare data, conducted formal chart reviews for severe cardiac defects, and conducted limited chart validation for other defects. We estimated prevalence for selected defects by VSD site and birth year and compared these estimates to those in a US and European surveillance system.

RESULTS

We developed algorithms to enumerate >50 major structural birth defects from standardized administrative and healthcare data based on utilization patterns and expert opinion, applying criteria for number, timing, and setting of diagnoses. Our birth cohort included 497 894 infants across seven sites. The period prevalence for all selected major birth defects in the VSD from 2004 to 2013 was 1.7 per 100 live births. Cardiac defects were most common (65.4 per 10 000 live births), with one-fourth classified as severe, requiring emergent intervention. For most major structural birth defects, prevalence estimates were stable over time and across sites and similar to those reported in other population-based surveillance systems.

CONCLUSIONS

Our algorithms can efficiently identify many major structural birth defects in large healthcare datasets and can be used in studies evaluating the safety of vaccines administered to pregnant women. Copyright © 2017 John Wiley & Sons, Ltd.

Evaluation of the Sensitivity and Accuracy of Birth Defects Indicators on the 2003 Revision of the U.S. Birth Certificate: Has Data Quality Improved?

BACKGROUND

The 2003 revision of the U.S. Birth Certificate was restricted to birth defects readily identifiable at birth. Despite being the lone source of birth defects cases in some studies, we lack population-based information on the quality of birth defects data from the most recent revision of the birth certificate.

METHODS

We linked birth certificate data to confirmed cases from the Florida Birth Defects Registry (FBDR) to assess the sensitivity and positive predictive value (PPV) of birth defects indicators on the birth certificate. Descriptive statistics and log-binomial regression were used to examine variation in data quality measures by defect type and other characteristics. We also evaluated the contribution of birth certificates as a case ascertainment source for the FBDR.

RESULTS

Sensitivity of the birth certificate was poor (19.1%) with variation across defects ranging from 55% for anencephaly and 54% for gastroschisis, to <10% for other defects. PPV was better (87.1%) and ranged from >93% for orofacial clefts and gastroschisis to <55% for anencephaly and limb reduction defects. We also observed variation in data quality across maternal, infant, and hospital characteristics. Of cases identified by the birth certificate and not any other FBDR data source, 54.9% were false-positive diagnoses.

CONCLUSIONS

Efforts to restrict the 2003 revision of the birth certificate to defects identifiable at birth have not improved the likelihood that birth certificates will identify infants born with those defects. We do not recommend the use of birth certificates as a source of birth defects data without case verification strategies.

Gastroschisis: epidemiology and mode of delivery, 2005-2013

BACKGROUND

Gastroschisis is a severe congenital anomaly the etiology of which is unknown. Research evidence supports attempted vaginal delivery for pregnancies complicated by gastroschisis in the absence of obstetric indications for cesarean delivery.

OBJECTIVE

The objectives of the study evaluating pregnancies complicated by gastroschisis were to determine the proportion of women undergoing planned cesarean vs attempted vaginal delivery and to provide up-to-date epidemiology on the risk factors associated with this anomaly.

STUDY DESIGN

This population-based study of US natality records from 2005 through 2013 evaluated pregnancies complicated by gastroschisis. Women were classified based on whether they attempted vaginal delivery or underwent a planned cesarean (n = 24,836,777). Obstetrical, medical, and demographic characteristics were evaluated. Multivariable log-linear regression models were developed to determine the factors associated with the mode of delivery. Factors associated with the occurrence of the anomaly were also evaluated in log-linear models.

RESULTS

Of 5985 pregnancies with gastroschisis, 63.5% (n = 3800) attempted vaginal delivery and 36.5% (n = 2185) underwent a planned cesarean delivery. The rate of attempted vaginal delivery increased from 59.7% in 2005 to 68.8% in 2013. Earlier gestational age and Hispanic ethnicity were associated with lower rates of attempted vaginal delivery. Factors associated with the occurrence of gastroschisis included young age, smoking, high educational attainment, and being married. Protective factors included chronic hypertension, black race, and obesity. The incidence of gastroschisis was 3.1 per 10,000 pregnancies and did not increase during the study period.

CONCLUSION

Attempted vaginal delivery is becoming increasingly prevalent for women with a pregnancy complicated by gastroschisis. Recommendations from the research literature findings may be diffusing into clinical practice. A significant proportion of women with this anomaly still deliver by planned cesarean, suggesting further reduction of surgical delivery for this anomaly is possible.

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.

Comparison of birth certificates and hospital-based birth data on pregnancy complications in Los Angeles and Orange County, California

Background

The incidence of both gestational diabetes mellitus and preeclampsia is on the rise; however, these pregnancy complications may not be systematically reported. This study aimed to examine differences in reporting of preeclampsia and gestational diabetes between hospital records and birth certificate data, and to determine if such differences vary by maternal socioeconomic status indicators.

Methods

We obtained over 70,000 birth records from 2001 to 2006 from the perinatal research database of the Memorial Care system, a network of four hospitals in Los Angeles and Orange Counties, California. Memorial birth records were matched to corresponding state birth certificate records and analyzed to determine differential rates of reporting of preeclampsia and diabetes. Additionally, the influence of maternal socioeconomic factors on the reported incidence of such adverse pregnancy outcomes was analyzed. Socioeconomic factors of interest included maternal education levels, race, and type of health insurance (private or public).

Results

It was found that the birth certificate data significantly underreported the incidence of both preeclampsia (1.38 % vs. 3.13 %) and diabetes (1.97 % vs. 5.56 %) when compared to Memorial data. For both outcomes of interest, the degree of underreporting was significantly higher among women with lower education levels, among Hispanic women compared to Non-Hispanic White women, and among women with public health insurance.

Conclusion

The Memorial Care database is a more reliable source of information than birth certificate data for analyzing the incidence of preeclampsia and diabetes among women in Los Angeles and Orange Counties, especially for subpopulations of lower socioeconomic status.

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.

Maternal residential exposure to agricultural pesticides and birth defects in a 2003 to 2005 North Carolina birth cohort

BACKGROUND

Birth defects are responsible for a large proportion of disability and infant mortality. Exposure to a variety of pesticides have been linked to increased risk of birth defects.

METHODS

We conducted a case-control study to estimate the associations between a residence-based metric of agricultural pesticide exposure and birth defects. We linked singleton live birth records for 2003 to 2005 from the North Carolina (NC) State Center for Health Statistics to data from the NC Birth Defects Monitoring Program. Included women had residence at delivery inside NC and infants with gestational ages from 20 to 44 weeks (n = 304,906). Pesticide exposure was assigned using a previously constructed metric, estimating total chemical exposure (pounds of active ingredient) based on crops within 500 meters of maternal residence, specific dates of pregnancy, and chemical application dates based on the planting/harvesting dates of each crop. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals for four categories of exposure (<10(th) , 10-50(th) , 50-90(th) , and >90(th) percentiles) compared with unexposed. Models were adjusted for maternal race, age at delivery, education, marital status, and smoking status.

RESULTS

We observed elevated ORs for congenital heart defects and certain structural defects affecting the gastrointestinal, genitourinary and musculoskeletal systems (e.g., OR [95% confidence interval] [highest exposure vs. unexposed] for tracheal esophageal fistula/esophageal atresia = 1.98 [0.69, 5.66], and OR for atrial septal defects: 1.70 [1.34, 2.14]).

CONCLUSION

Our results provide some evidence of associations between residential exposure to agricultural pesticides and several birth defects phenotypes. Birth Defects Research (Part A) 106:240-249, 2016. © 2016 Wiley Periodicals, Inc.

Estimates of the live births, natural losses, and elective terminations with Down syndrome in the United States

The present and future live birth prevalence of Down syndrome (DS) is of practical importance for planning services and prioritizing research to support people living with the condition. Live birth prevalence is influenced by changes in prenatal screening technologies and policies. To predict the future impact of these changes, a model for estimating the live births of people with DS is required. In this study, we combine diverse and robust datasets with validated estimation techniques to describe the non-selective and live birth prevalence of DS in the United States from 1900-2010. Additionally, for the period 1974-2010, we estimate the impact of DS-related elective pregnancy terminations (following a prenatal diagnosis of DS) on the live births with DS. The live birth prevalence for DS in the most recent years (2006-2010) was estimated at 12.6 per 10,000 (95% CI 12.4-12.8), with around 5,300 births annually. During this period, an estimated 3,100 DS-related elective pregnancy terminations were performed in the U.S. annually. As of 2007, the estimated rates at which live births with DS were reduced as a consequence of DS-related elective pregnancy terminations were 30% (95% CI: 27.3-31.9) for the U.S. as a whole. Our results and our model provide data on the impact of elective pregnancy terminations on live births with DS and may provide a baseline from which future trends for live births with DS can be estimated.

Development and implementation of the first national data quality standards for population-based birth defects surveillance programs in the United States

Background

Population-based birth defects surveillance is a core public health activity in the United States (U.S.); however, the lack of national data quality standards has limited the use of birth defects surveillance data across state programs. Development of national standards will facilitate data aggregation and utilization across birth defects surveillance programs in the U.S.

Methods

Based on national standards for other U.S. public health surveillance programs, existing National Birth Defects Prevention Network (NBDPN) guidelines for conducting birth defects surveillance, and information from birth defects surveillance programs regarding their current data quality practices, we developed 11 data quality measures that focused on data completeness (n = 5 measures), timeliness (n = 2), and accuracy (n = 4). For each measure, we established tri-level performance criteria (1 = rudimentary, 2 = essential, 3 = optimal). In January 2014, we sent birth defects surveillance programs in each state, District of Columbia, Puerto Rico, Centers for Disease Control and Prevention (CDC), and the U.S. Department of Defense Birth and Infant Health Registry an invitation to complete a self-administered NBDPN Standards Data Quality Assessment Tool. The completed forms were electronically submitted to the CDC for analyses.

Results

Of 47 eligible population-based surveillance programs, 45 submitted a completed assessment tool. Two of the 45 programs did not meet minimum inclusion criteria and were excluded; thus, the final analysis included information from 43 programs. Average scores for four of the five completeness performance measures were above level 2. Conversely, the average scores for both timeliness measures and three of the four accuracy measures were below level 2. Surveillance programs using an active case-finding approach scored higher than programs using passive case-finding approaches for the completeness and accuracy measures, whereas their average scores were lower for timeliness measures.

Conclusions

This initial, nation-wide assessment of data quality across U.S. population-based birth defects surveillance programs highlights areas for improvement. Using this information to identify strengths and weaknesses, the birth defects surveillance community, working through the NBDPN, can enhance and implement a consistent set of standards that can promote uniformity and enable surveillance programs to work towards improving the potential of these programs.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-015-2223-2) contains supplementary material, which is available to authorized users.

Racial/ethnic differences in survival of United States children with birth defects: a population-based study

OBJECTIVES

To examine racial/ethnic-specific survival of children with major birth defects in the US.

STUDY DESIGN

We pooled data on live births delivered during 1999-2007 with any of 21 birth defects from 12 population-based birth defects surveillance programs. We used the Kaplan-Meier method to calculate cumulative survival probabilities and Cox proportional hazards models to estimate mortality risk.

RESULTS

For most birth defects, there were small-to-moderate differences in neonatal (<28 days) survival among racial/ethnic groups. However, compared with children born to non-Hispanic white mothers, postneonatal infant (28 days to <1 year) mortality risk was significantly greater among children born to non-Hispanic black mothers for 13 of 21 defects (hazard ratios [HRs] 1.3-2.8) and among children born to Hispanic mothers for 10 of 21 defects (HRs 1.3-1.7). Compared with children born to non-Hispanic white mothers, a significantly increased childhood (≤ 8 years) mortality risk was found among children born to Asian/Pacific Islander mothers for encephalocele (HR 2.6), tetralogy of Fallot, and atrioventricular septal defect (HRs 1.6-1.8) and among children born to American Indian/Alaska Native mothers for encephalocele (HR 2.8), whereas a significantly decreased childhood mortality risk was found among children born to Asian/Pacific Islander mothers for cleft lip with or without cleft palate (HR 0.6).

CONCLUSION

Children with birth defects born to non-Hispanic black and Hispanic mothers carry a greater risk of mortality well into childhood, especially children with congenital heart defect. Understanding survival differences among racial/ethnic groups provides important information for policy development and service planning.

Assessment of congenital anomalies in infants born to pregnant women enrolled in clinical trials

In 2011 and 2012, the Division of Microbiology and Infectious Diseases at the National Institute of Allergy and Infectious Diseases, National Institutes of Health, held a series of meetings to provide guidance to investigators regarding study design of clinical trials of vaccines and antimicrobial medications that enroll pregnant women. Assessment of congenital anomalies among infants born to women enrolled in these trials was recognized as a challenging issue, and a workgroup with expertise in epidemiology, pediatrics, genetics, dysmorphology, clinical trials, and infectious diseases was formed to address this issue. The workgroup considered 3 approaches for congenital anomalies assessment that have been developed for use in other studies: (1) maternal report combined with medical records review, (2) standardized photographic assessment and physical examination by a health professional who has received specific training in congenital anomalies, and (3) standardized physical examination by a trained dysmorphologist (combined with maternal interview and medical records review). The strengths and limitations of these approaches were discussed with regard to their use in clinical trials. None of the approaches was deemed appropriate for use in all clinical trials. Instead, the workgroup acknowledged that decisions regarding the optimal method of assessment of congenital anomalies will likely vary depending on the clinical trial, its setting, and the agent under study; in some cases, a combination of approaches may be appropriate. The workgroup recognized the need for more research on approaches to the assessment of congenital anomalies to better guide investigators in optimal design of clinical trials that enroll pregnant women.

Are residents of mountain-top mining counties more likely to have infants with birth defects? The West Virginia experience

BACKGROUND

Pooled 1996 to 2003 birth certificate data for four central states in Appalachia indicated higher rates of infants with birth defects born to residents of counties with mountain-top mining (MTM) than born to residents of non-mining-counties (Ahern 2011). However, those analyses did not consider sources of uncertainty such as unbalanced distributions or quality of data. Quality issues have been a continuing problem with birth certificate analyses. We used 1990 to 2009 live birth certificate data for West Virginia to reassess this hypothesis.

METHODS

Forty-four hospitals contributed 98% of the MTM-county births and 95% of the non-mining-county births, of which six had more than 1000 births from both MTM and nonmining counties. Adjusted and stratified prevalence rate ratios (PRRs) were computed both by using Poisson regression and Mantel-Haenszel analysis.

RESULTS

Unbalanced distribution of hospital births was observed by mining groups. The prevalence rate of infants with reported birth defects, higher in MTM-counties (0.021) than in non-mining-counties (0.015), yielded a significant crude PRR (cPRR = 1.43; 95% confidence interval [CI] = 1.36-1.52) but a nonsignificant hospital-adjusted PRR (adjPRR = 1.08; 95% CI = 0.97-1.20; p = 0.16) for the 44 hospitals. So did the six hospital data analysis ([cPRR = 2.39; 95% CI = 2.15-2.65] and [adjPRR = 1.01; 95% CI, 0.89-1.14; p = 0.87]).

CONCLUSION

No increased risk of birth defects was observed for births from MTM-counties after adjustment for, or stratification by, hospital of birth. These results have consistently demonstrated that the reported association between birth defect rates and MTM coal mining was a consequence of data heterogeneity. The data do not demonstrate evidence of a "Mountain-top Mining" effect on the prevalence of infants with reported birth defects in WV.

Adjusting for multiple-misclassified variables in a study using birth certificates

PURPOSE

Birth certificates are a convenient source of population data for epidemiologic studies. It is well documented, however, that birth certificate data can be highly inaccurate. Nonetheless, studies based on birth certificates are routinely analyzed without accounting for sources of data errors. We focused on the association between maternal cigarette smoking and cleft lip and palate based on birth certificate data.

METHODS

We adjusted odds ratio estimates simultaneously for exposure and outcome misclassification. We also calculated odds ratios adjusted for exposure misclassification only and outcome misclassification only.

RESULTS

Adjustment for both maternal smoking during pregnancy and clefting resulted in adjusted odds ratios that ranged from less than 1.0 to much greater than the unadjusted estimate of 1.16, with most adjusted estimates outside of the 95% confidence limits (1.01, 1.33).

CONCLUSIONS

Because of the potentially large impact of birth certificate classification errors, we suggest that inferences from these or similar records employ quantitative methods for incorporating uncertainties caused by data errors.

The influence of misclassification bias on the reported rates of congenital anomalies on the birth certificates for West Virginia--a consequence of an open-ended query

BACKGROUND

Passive surveillance for congenital anomalies using birth certificates are generally considered to have biased reporting, though the sources of those biases are not well-known nor controlled for. We have analyzed the congenital anomaly reporting data for 418,385 live births in West Virginia (1990-2009) from the 1989 US standard birth certificate and have newly identified a particular source of bias.

METHODS

Congenital anomaly prevalence rates per 100 live births have been determined for both specified birth defects and for other congenital anomalies by county, by hospital, and by year. Extreme outliers were identified by z score. Text strings for "other congenital anomaly" reports recorded for 1998-2009 were assessed for information on congenital anomalies.

RESULTS

While rates for specified birth defects reported in checked-box format showed little variation, rates for "other congenital anomaly" collected in open-ended format showed much variation. Nearly half of the "other congenital anomaly" reports were for neonatal conditions rather than for major structural congenital anomalies. This misclassification alone had elevated the state-wide congenital anomaly reporting rate from 1.1 to 1.8% of live births. Geographic clustering and a temporal bulge in congenital anomaly reports disappeared after misclassified data were removed.

CONCLUSIONS

Data collected in checked-box format on specified birth defects showed consistent patterns over time and space, while data collected in open-ended format on "other congenital anomalies" showed an epidemiological pattern reflecting neonatal conditions rather than birth defects. The 2003 US standard birth certificate wisely limits data collection to specified birth defects using the checked-box format.

A comparison of two surveillance strategies for selected birth defects in Florida

OBJECTIVE

We linked data from two independent birth defects surveillance systems with different case-finding methods in an overlapping geographic area to assess Florida's suveillance of birth defects (e.g., neural tube defects, orofacial clefts, gastroschisis/omphalocele, and chromosomal defects), focusing on sensitivity and completeness of ascertainment measures.

METHODS

Live-born infants identified from each system born during 2003-2006 in a nine-county catchment area with specific birth defects were linked to birth certificates. Using the enhanced surveillance system as a gold standard, we calculated the sensitivity of the Florida Birth Defects Registry (FBDR) for identifying infants. Next, we used capture-recapture models to estimate the completeness of case ascertainment and the prevalence of each birth defect in the catchment area. We used multivariable logistic regression models with backward elimination to estimate adjusted odds ratios and 95% confidence intervals for factors significantly associated with the FBDR's failure to capture infants ultimately identified by enhanced surveillance.

RESULTS

The FBDR's sensitivity was 89.3%, and the overall completeness of ascertainment was estimated as 86.6%. Defect-specific sensitivity and completeness of ascertainment varied significantly by defect. The combined defect-specific sensitivity for all malformations under study was 86.6%; completeness of ascertainment ranged from 45.6% for anencephaly to 88.6% for Down syndrome, 87.9% for spina bifida without anencephaly, and 87.0% for orofacial clefts.

CONCLUSIONS

For the defects under study, the FBDR captured nearly nine of every 10 infants born with selected birth defects. However, the FBDR's ability to identify specific defects was both more limited and defect dependent with widely varying defect-specific sensitivities.

Quality and integration of public health information systems: A systematic review focused on immunization and vital records systems

OBJECTIVES

Public health professionals rely on quantitative data for the daily practice of public health as well as organizational decision making and planning. However, several factors work against effective data sharing among public health agencies in the US. This review characterizes the reported barriers and enablers of effective use of public health IS from an informatics perspective.

METHODS

A systematic review of the English language literature for 2005 to 2011 followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) format. The review focused on immunization information systems (IIS) and vital records information systems (VRIS). Systems were described according to the structural aspects of IS integration and data quality.

RESULTS

Articles describing IIS documented issues pertaining to the distribution of the system, the autonomy of the data providers, the heterogeneous nature of information sharing as well as the quality of the data. Articles describing VRIS were focused much more heavily on data quality, particularly whether or not the data were free from errors.

CONCLUSIONS

For state and local practitioners to effectively utilize data, public health IS will have to overcome the challenges posed by a large number of autonomous data providers utilizing a variety of technologies.