Public Health Practice of Population-Based Birth Defects Surveillance Programs in the United States

Louis AM, Agopian AJ. Scientific impact of the National Birth Defects Prevention Network multistate collaborative publications

BACKGROUND

Given the lack of a national, population-based birth defects surveillance program in the United States, the National Birth Defects Prevention Network (NBDPN) has facilitated important studies on surveillance, research, and prevention of major birth defects. We sought to summarize NBDPN peer-reviewed publications and their impact.

METHODS

We obtained and reviewed a curated list of 49 NBDPN multistate collaborative publications during 2000-2022, as of December 31, 2022. Each publication was reviewed and classified by type (e.g., risk factor association analysis). Key characteristics of study populations and analytic approaches used, along with publication impact (e.g., number of citations), were tabulated.

RESULTS

NBDPN publications focused on prevalence estimates (N = 17), surveillance methods (N = 11), risk factor associations (N = 10), mortality and other outcomes among affected individuals (N = 6), and descriptive epidemiology of various birth defects (N = 5). The most cited publications were those that reported on prevalence estimates for a spectrum of defects and those that assessed changes in neural tube defects (NTD) prevalence following mandatory folic acid fortification in the United States.

CONCLUSIONS

Results from multistate NBDPN publications have provided critical information not available through other sources, including US prevalence estimates of major birth defects, folic acid fortification and NTD prevention, and improved understanding of defect trends and surveillance efforts. Until a national birth defects surveillance program is established in the United States, NBDPN collaborative publications remain an important resource for investigating birth defects and informing decisions related to health services planning of secondary disabilities prevention and care.

Prevalence and descriptive epidemiology of Turner syndrome in the United States, 2000-2017: A report from the National Birth Defects Prevention Network

The lack of United States population-based data on Turner syndrome limits assessments of prevalence and associated characteristics for this sex chromosome abnormality. Therefore, we collated 2000-2017 data from seven birth defects surveillance programs within the National Birth Defects Prevention Network. We estimated the prevalence of karyotype-confirmed Turner syndrome diagnosed within the first year of life. We also calculated the proportion of cases with commonly ascertained birth defects, assessed associations with maternal and infant characteristics using prevalence ratios (PR) with 95% confidence intervals (CI), and estimated survival probability. The prevalence of Turner syndrome of any pregnancy outcome was 3.2 per 10,000 female live births (95% CI = 3.0-3.3, program range: 1.0-10.4), and 1.9 for live birth and stillbirth (≥20 weeks gestation) cases (95% CI = 1.8-2.1, program range: 0.2-3.9). Prevalence was lowest among cases born to non-Hispanic Black women compared to non-Hispanic White women (PR = 0.5, 95% CI = 0.4-0.6). Coarctation of the aorta was the most common defect (11.6% of cases), and across the cohort, individuals without hypoplastic left heart had a five-year survival probability of 94.6%. The findings from this population-based study may inform surveillance practices, prenatal counseling, and diagnosis. We also identified racial and ethnic disparities in prevalence, an observation that warrants further investigation.

The Differences of Population Birth Defects in Epidemiology Analysis between the Rural and Urban Areas of Hunan Province in China, 2014-2018

Objectives

To compare the differences of epidemiology analysis in population birth defects (BDs) between the rural and urban areas of Hunan Province in China.

Methods

The data of population-based BDs in Liuyang county (rural) and Shifeng district (urban) in Hunan Province for 2014-2018 were analyzed. BD prevalence rates, percentage change, and annual percentage change (APC) by sex and age were calculated to evaluate time trends. Risk factors associated with BDs were assessed using simple and multiple logistic regression analyses.

Results

The BD prevalence rate per 10,000 perinatal infants (PIs) was 220.54 (95% CI: 211.26-230.13) in Liuyang and 181.14 (95% CI: 161.18-202.87) in Shifeng. Significant decreasing trends in BD prevalence rates were noted in the female PIs (APC = -9.31, P = 0.044) and the total BD prevalence rate in Shifeng (APC = -14.14, P = 0.039). Risk factors for BDs were as follows: rural area, male PIs, PIs with gestational age < 37 weeks, PIs with birth weight < 2500 g, and migrant pregnancies.

Conclusions

We should focus on rural areas, reduce the prevalence of premature and low birth weight infants, and provide maternal healthcare services for migrant pregnancies for BD prevention from the perspective of population-based BD surveillance.

Evaluation of a health information exchange system for microcephaly case-finding - New York City, 2013-2015

Background

Birth defects surveillance in the United States is conducted principally by review of routine but lagged reporting to statewide congenital malformations registries of diagnoses by hospitals or other health care providers, a process that is not designed to rapidly detect changes in prevalence. Health information exchange (HIE) systems are well suited for rapid surveillance, but information is limited about their effectiveness at detecting birth defects. We evaluated HIE data to detect microcephaly diagnosed at birth during January 1, 2013–December 31, 2015 before known introduction of Zika virus in North America.

Methods

Data from an HIE system were queried for microcephaly diagnostic codes on day of birth or during the first two days after birth at three Bronx hospitals for births to New York City resident mothers. Suspected cases identified by HIE data were compared with microcephaly cases that had been identified through direct inquiry of hospital records and confirmed by chart abstraction in a previous study of the same cohort.

Results

Of 16,910 live births, 43 suspected microcephaly cases were identified through an HIE system compared to 67 confirmed cases that had been identified as part of the prior study. A total of 39 confirmed cases were found by both studies (sensitivity = 58.21%, 95% CI: 45.52–70.15%; positive predictive value = 90.70%, 95% CI: 77.86–97.41%; negative predictive value = 99.83%, 95% CI: 99.76–99.89% for HIE data).

Conclusion

Despite limitations, HIE systems could be used for rapid newborn microcephaly surveillance, especially in the many jurisdictions where more labor-intensive approaches are not feasible. Future work is needed to improve electronic medical record documentation quality to improve sensitivity and reduce misclassification.

Relationship of databases of live births and infant deaths for analysis of congenital malformations

Abstract Objectives: to describe the prevalence of congenital malformations in live births in Recife, based on the relationship of birth and infant death data. Methods: a cross-sectional study with data from the Live Birth Information System (Sinasc) and Mortality (MIS) of residents in Recife-PE between 2013 and 2015. The deterministic linkage of deaths and live births (LB) with malformation and the prevalence rate were calculated. Results: 545 (95.1%) deaths and live births were matched. According to the Sinasc, the prevalence of congenital malformations was 10.4 per 1,000 LB. After the linkage, the rate was 12.4. Malformations of the musculoskeletal system (42.1%) among live births were high-lighted, as well as malformations of the circulatory system (35.3%) found in infant deaths. Conclusions: linkage increased the prevalence of congenital malformations in the studied cohort. This demonstrates the potential of this strategy for the monitoring of congenital malformations, which can be used to monitor infant death.

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

BACKGROUND

Using the National Birth Defects Prevention Network (NBDPN) annual data report, U.S. national prevalence estimates for major birth defects are developed based on birth cohort 2010-2014.

METHODS

Data from 39 U.S. population-based birth defects surveillance programs (16 active case-finding, 10 passive case-finding with case confirmation, and 13 passive without case confirmation) were used to calculate pooled prevalence estimates for major defects by case-finding approach. Fourteen active case-finding programs including at least live birth and stillbirth pregnancy outcomes monitoring approximately one million births annually were used to develop national prevalence estimates, adjusted for maternal race/ethnicity (for all conditions examined) and maternal age (trisomies and gastroschisis). These calculations used a similar methodology to the previous estimates to examine changes over time.

RESULTS

The adjusted national birth prevalence estimates per 10,000 live births ranged from 0.62 for interrupted aortic arch to 16.87 for clubfoot, and 19.93 for the 12 critical congenital heart defects combined. While the birth prevalence of most birth defects studied remained relatively stable over 15 years, an increasing prevalence was observed for gastroschisis and Down syndrome. Additionally, the prevalence for atrioventricular septal defect, tetralogy of Fallot, omphalocele, and trisomy 18 increased in this period compared to the previous periods. Active case-finding programs generally had higher prevalence rates for most defects examined, most notably for anencephaly, anophthalmia/microphthalmia, trisomy 13, and trisomy 18.

CONCLUSION

National estimates of birth defects prevalence provide data for monitoring trends and understanding the impact of these conditions. Increasing prevalence rates observed for selected conditions warrant further examination.

Status of population-based birth defects surveillance programs before and after the Zika public health response in the United States

BACKGROUND

The 2016 Zika public health response in the United States highlighted the need for birth defect surveillance (BDS) programs to collect population-based data on birth defects potentially related to Zika as rapidly as possible through enhanced case ascertainment and reporting. The National Birth Defects Prevention Network (NBDPN) assessed BDS program activities in the United States before and after the Zika response.

METHODS

The NBDPN surveyed 54 BDS programs regarding activities before and after the Zika response, lessons learned, and programmatic needs. Follow-up emails were sent and phone calls were held for programs with incomplete or no response to the online survey. Survey data were cleaned and tallied, and responses to open-ended questions were placed into best-fit categories.

RESULTS

A 100% response rate was achieved. Of the 54 programs surveyed, 42 reported participation in the Zika public health response that included BDS activities. Programs faced challenges in expanding their surveillance effort given the response requirements but reported mitigating factors such as establishing and enhancing partnerships and program experience with surveillance and clinical activities. Beyond funding, reported program needs included training, surveillance tools/resources, and availability of clinical experts.

CONCLUSIONS

Existing BDS programs with experience implementing active case-finding and case verification were able to adapt their surveillance efforts rapidly to collect and report data necessary for the Zika response. Program sustainability for BDS remains challenging; thus, continued support, training, and resource development are important to ensure that the infrastructure built during the Zika response is available for the next public health response.

Population-based pregnancy and birth defects surveillance in the era of Zika virus

BACKGROUND

Zika virus is a newly recognized human teratogen; monitoring its impact on the birth prevalence of microcephaly and other adverse pregnancy outcomes will continue to be an urgent need in the United States and worldwide.

METHODS

When the Centers for Disease Control and Prevention (CDC) activated the Emergency Operations Center for the Zika virus outbreak response in January of 2016, public health leadership recognized that a joint, coordinated effort was required between activities focused on the effects of the infection among pregnant women and those focused on birth defects in fetuses and infants. Before the introduction of Zika virus in the Americas, population-based birth defects surveillance occurred independently of pregnancy surveillance activities.

RESULTS

The coordination of pregnancy surveillance and birth defects surveillance implemented through the CDC Zika virus response represents a paradigm shift.

CONCLUSION

Coordination of these surveillance systems provides an opportunity to capture information from both a prospective and retrospective approach. This relatively modest investment in the public health infrastructure can continue to protect pregnant women and their infants during the ongoing response to Zika virus and in the next emergent threat to maternal and child health. Birth Defects Research 109:372-378, 2017. © 2017 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.

Noninvasive prenatal screening for fetal common sex chromosome aneuploidies from maternal blood

Objective

To explore the feasibility of high-throughput massively parallel genomic DNA sequencing technology for the noninvasive prenatal detection of fetal sex chromosome aneuploidies (SCAs).

Methods

The study enrolled pregnant women who were prepared to undergo noninvasive prenatal testing (NIPT) in the second trimester. Cell-free fetal DNA (cffDNA) was extracted from the mother’s peripheral venous blood and a high-throughput sequencing procedure was undertaken. Patients identified as having pregnancies associated with SCAs were offered prenatal fetal chromosomal karyotyping.

Results

The study enrolled 10 275 pregnant women who were prepared to undergo NIPT. Of these, 57 pregnant women (0.55%) showed fetal SCA, including 27 with Turner syndrome (45,X), eight with Triple X syndrome (47,XXX), 12 with Klinefelter syndrome (47,XXY) and three with 47,XYY. Thirty-three pregnant women agreed to undergo fetal karyotyping and 18 had results consistent with NIPT, while 15 patients received a normal karyotype result. The overall positive predictive value of NIPT for detecting SCAs was 54.54% (18/33) and for detecting Turner syndrome (45,X) was 29.41% (5/17).

Conclusion

NIPT can be used to identify fetal SCAs by analysing cffDNA using massively parallel genomic sequencing, although the accuracy needs to be improved particularly for Turner syndrome (45,X).

Testing the Feasibility of a Passive and Active Case Ascertainment System for Multiple Rare Conditions Simultaneously: The Experience in Three US States

Background

Owing to their low prevalence, single rare conditions are difficult to monitor through current state passive and active case ascertainment systems. However, such monitoring is important because, as a group, rare conditions have great impact on the health of affected individuals and the well-being of their caregivers. A viable approach could be to conduct passive and active case ascertainment of several rare conditions simultaneously. This is a report about the feasibility of such an approach.

Objective

To test the feasibility of a case ascertainment system with passive and active components aimed at monitoring 3 rare conditions simultaneously in 3 states of the United States (Colorado, Kansas, and South Carolina). The 3 conditions are spina bifida, muscular dystrophy, and fragile X syndrome.

Methods

Teams from each state evaluated the possibility of using current or modified versions of their local passive and active case ascertainment systems and datasets to monitor the 3 conditions. Together, these teams established the case definitions and selected the variables and the abstraction tools for the active case ascertainment approach. After testing the ability of their local passive and active case ascertainment system to capture all 3 conditions, the next steps were to report the number of cases detected actively and passively for each condition, to list the local barriers against the combined passive and active case ascertainment system, and to describe the experiences in trying to overcome these barriers.

Results

During the test period, the team from South Carolina was able to collect data on all 3 conditions simultaneously for all ages. The Colorado team was also able to collect data on all 3 conditions but, because of age restrictions in its passive and active case ascertainment system, it was able to report few cases of fragile X syndrome. The team from Kansas was able to collect data only on spina bifida. For all states, the implementation of an active component of the ascertainment system was problematic. The passive component appears viable with minor modifications.

Conclusions

Despite evident barriers, the joint passive and active case ascertainment of rare disorders using modified existing surveillance systems and datasets seems feasible, especially for systems that rely on passive case ascertainment.

Assessing the Practices of Population-Based Birth Defects Surveillance Programs Using the CDC Strategic Framework, 2012

OBJECTIVE

We assessed the practices of U.S. population-based birth defects surveillance programs in addressing current and emergent public health needs.

METHODS

Using the CDC Strategic Framework considerations for public health surveillance (i.e., lexicon and standards, legal authority, technological advances, workforce, and analytic capacity), during 2012 and 2013, we conducted a survey of all U.S. operational birth defects programs (n=43) soliciting information on legal authorities, case definition and clinical information collected, types of data sources, and workforce staffing. In addition, we conducted semi-structured interviews with nine program directors to further understand how programs are addressing current and emergent needs.

RESULTS

Three-quarters of birth defects surveillance programs used national guidelines for case definition. Most birth defects surveillance programs (86%) had a legislative mandate to conduct surveillance, and many relied on a range of prenatal, postnatal, public health, and pediatric data sources for case ascertainment. Programs reported that the transition from paper to electronic formats was altering the information collected, offering an opportunity for remote access to improve timeliness for case review and verification. Programs also reported the growth of pooled, multistate data collaborations as a positive development. Needs identified included ongoing workforce development to improve information technology and analytic skills, more emphasis on data utility and birth defects-specific standards for health information exchange, and support to develop channels for sharing ideas on data interpretation and dissemination.

CONCLUSION

The CDC Strategic Framework provided a useful tool to determine the birth defects surveillance areas with positive developments, such as multi-state collaborative epidemiologic studies, and areas for improvement, such as preparation for health information exchanges and workforce database and analytic skills. Our findings may inform strategic deliberations for enhancing the effectiveness of birth defects surveillance programs.

Global Birth Prevalence of Spina Bifida by Folic Acid Fortification Status: A Systematic Review and Meta-Analysis

BACKGROUND

Birth defects remain a significant source of worldwide morbidity and mortality. Strong scientific evidence shows that folic acid fortification of a region's food supply leads to a decrease in spina bifida (a birth defect of the spine). Still, many countries around the world have yet to approve mandatory fortification through government legislation.

OBJECTIVES

We sought to perform a systematic review and meta-analysis of period prevalence of spina bifida by folic acid fortification status, geographic region, and study population.

SEARCH METHODS

An expert research librarian used terms related to neural tube defects and epidemiology from primary research from 1985 to 2010 to search in EMBASE and MEDLINE. We searched the reference lists of included articles and key review articles identified by experts.

SELECTION CRITERIA

Inclusion criteria included studies in English or French reporting on prevalence published between January 1985 and December 2010 that (1) were primary research, (2) were population-based, and (3) reported a point or period prevalence estimate of spina bifida (i.e., prevalence estimate with confidence intervals or case numerator and population denominator). Two independent reviewers screened titles and abstracts for eligible articles, then 2 authors screened full texts in duplicate for final inclusion. Disagreements were resolved through consensus or a third party.

DATA COLLECTION AND ANALYSIS

We followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses, or PRISMA, abstracting data related to case ascertainment, study population, folic acid fortification status, geographic region, and prevalence estimate independently and in duplicate. We extracted overall data and any subgroups reported by age, gender, time period, or type of spina bifida. We classified each period prevalence estimate as "mandatory" or "voluntary" folic acid fortification according to each country's folic acid fortification status at the time data were collected (as determined by a well-recognized fortification monitoring body, Food Fortification Initiative). We determined study quality on the basis of sample representativeness, standardization of data collection and birth defect assessment, and statistical analyses. We analyzed study-level period prevalence estimates by using a random effects model (α level of < 0.05) for all meta-analyses. We stratified pooled period prevalence estimates by birth population, fortification status, and continent.

RESULTS

Of 4078 studies identified, we included 179 studies in the systematic review and 123 in a meta-analysis. In studies of live births (LBs) alone, period prevalences of spina bifida were (1) lower in geographical regions with mandatory (33.86 per 100,000 LBs) versus voluntary (48.35 per 100,000 LBs) folic acid fortification, and (2) lower in studies of LBs, stillbirths, and terminations of pregnancy in regions with mandatory (35.22 per 100,000 LBs) versus voluntary (52.29 per 100,000 LBs) fortification. In LBs, stillbirths, and terminations of pregnancy studies, the lowest pooled prevalence estimate was in North America (38.70 per 100,000). Case ascertainment, surveillance methods, and reporting varied across these population-based studies.

CONCLUSIONS

Mandatory legislation enforcing folic acid fortification of the food supply lags behind the evidence, particularly in Asian and European countries. This extensive literature review shows that spina bifida is significantly more common in world regions without government legislation regulating full-coverage folic acid fortification of the food supply (i.e., Asia, Europe) and that mandatory folic acid fortification resulted in a lower prevalence of spina bifida regardless of the type of birth cohort. African data were scarce, but needed, as many African nations are beginning to adopt folic acid legislation.