Population-Based Surveillance for Birth Defects Potentially Related to Zika Virus Infection - 22 States and Territories, January 2016-June 2017.

Zika virus infection during pregnancy can cause congenital brain and eye abnormalities and is associated with neurodevelopmental abnormalities (1-3). In areas of the United States that experienced local Zika virus transmission, the prevalence of birth defects potentially related to Zika virus infection during pregnancy increased in the second half of 2016 compared with the first half (4). To update the previous report, CDC analyzed population-based surveillance data from 22 states and territories to estimate the prevalence of birth defects potentially related to Zika virus infection, regardless of laboratory evidence of or exposure to Zika virus, among pregnancies completed during January 1, 2016-June 30, 2017. Jurisdictions were categorized as those 1) with widespread local transmission of Zika virus; 2) with limited local transmission of Zika virus; and 3) without local transmission of Zika virus. Among 2,004,630 live births, 3,359 infants and fetuses with birth defects potentially related to Zika virus infection during pregnancy were identified (1.7 per 1,000 live births, 95% confidence interval [CI] = 1.6-1.7). In areas with widespread local Zika virus transmission, the prevalence of birth defects potentially related to Zika virus infection during pregnancy was significantly higher during the quarters comprising July 2016-March 2017 (July-September 2016 = 3.0; October-December 2016 = 4.0; and January-March 2017 = 5.6 per 1,000 live births) compared with the reference period (January-March 2016) (1.3 per 1,000). These findings suggest a fourfold increase (prevalence ratio [PR] = 4.1, 95% CI = 2.1-8.4) in birth defects potentially related to Zika virus in widespread local transmission areas during January-March 2017 compared with that during January-March 2016, with the highest prevalence (7.0 per 1,000 live births) in February 2017. Population-based birth defects surveillance is critical for identifying infants and fetuses with birth defects potentially related to Zika virus regardless of whether Zika virus testing was conducted, especially given the high prevalence of asymptomatic disease. These data can be used to inform follow-up care and services as well as strengthen surveillance.

Baseline Prevalence of Birth Defects Associated with Congenital Zika Virus Infection - Massachusetts, North Carolina, and Atlanta, Georgia, 2013-2014.

Zika virus infection during pregnancy can cause serious brain abnormalities, but the full range of adverse outcomes is unknown (1). To better understand the impact of birth defects resulting from Zika virus infection, the CDC surveillance case definition established in 2016 for birth defects potentially related to Zika virus infection* (2) was retrospectively applied to population-based birth defects surveillance data collected during 2013-2014 in three areas before the introduction of Zika virus (the pre-Zika years) into the World Health Organization's Region of the Americas (Americas) (3). These data, from Massachusetts (2013), North Carolina (2013), and Atlanta, Georgia (2013-2014), included 747 infants and fetuses with one or more of the birth defects meeting the case definition (pre-Zika prevalence = 2.86 per 1,000 live births). Brain abnormalities or microcephaly were the most frequently recorded (1.50 per 1,000), followed by neural tube defects and other early brain malformations† (0.88), eye abnormalities without mention of a brain abnormality (0.31), and other consequences of central nervous system (CNS) dysfunction without mention of brain or eye abnormalities (0.17). During January 15-September 22, 2016, the U.S. Zika Pregnancy Registry (USZPR) reported 26 infants and fetuses with these same defects among 442 completed pregnancies (58.8 per 1,000) born to mothers with laboratory evidence of possible Zika virus infection during pregnancy (2). Although the ascertainment methods differed, this finding was approximately 20 times higher than the proportion of one or more of the same birth defects among pregnancies during the pre-Zika years. These data demonstrate the importance of population-based surveillance for interpreting data about birth defects potentially related to Zika virus infection.

Expanding the Massachusetts Birth Defects Monitoring Program to include additional pregnancy outcomes: Programmatic efforts and impacts on case ascertainment, 2012-2020.

BACKGROUND: Birth defects affect 1 in 33 infants in the United States and are a leading cause of infant mortality. Birth defects surveillance is crucial for informing public health action. The Massachusetts Birth Defects Monitoring Program (MBDMP) began collecting other pregnancy losses (OPLs) in 2011, including miscarriages (<20 weeks gestation) or elective terminations (any gestational age), in addition to live births and stillbirths (≥20 weeks gestation). We describe programmatic changes for adding OPLs and their impact on prevalence estimates. METHODS: Using population-based, statewide, data from the MBDMP (2012-2020), we assessed prevalence per 10,000 live births and 95% confidence intervals (CIs) with and without OPLs overall and for specific birth defects by time period, maternal age, and race/ethnicity. RESULTS: Including OPLs required amending a state statute and promulgating regulations, new data sources, and additional data processing, cleaning, and verification. Overall prevalence with OPLs increased from 257.4 (95% CI: 253.5-261.4) to 333.9 (95% CI: 329.4-338.4) per 10,000; increases were observed in all time periods, age, and race/ethnicity groups. After including OPLs, the prevalence increased for neural tube defects [3.2 (2.7-3.6) to 8.3 (7.6-9.0)], and trisomies 13 [0.5 (0.3-0.7) to 4.1 (3.6-4.6)], 18 [1.5 (1.2-1.9) to 8.2 (7.5-8.9)], and 21 [12.3 (11.4-13.2) to 28.9 (27.6-30.2)]. Cardiovascular defects increased slightly, while prevalence of eye/ear, respiratory, and gastrointestinal defects remained similar. CONCLUSIONS: Adding OPLs required substantial programmatic efforts and resulted in more complete case ascertainment, particularly for certain birth defects. More complete case ascertainment will allow for improved research, screening, and resource allocation.

Identifying possible inaccuracy in reported birth head circumference measurements among infants in the US Zika Pregnancy and Infant Registry.

BACKGROUND: The US Zika Pregnancy and Infant Registry (USZPIR) monitors infants born to mothers with confirmed or possible Zika virus infection during pregnancy. The surveillance case definition for Zika-associated birth defects includes microcephaly based on head circumference (HC). METHODS: We assessed birth and follow-up data from infants with birth HC measurements <3rd percentile and birthweight ≥10th percentile to determine possible misclassification of microcephaly. We developed a schema informed by literature review and expert opinion to identify possible HC measurement inaccuracy using HC growth velocity and longitudinal HC measurements between 2 and 12 months of age. Two or more HC measurements were required for assessment. Inaccuracy in birth HC measurement was suspected if growth velocity was >3 cm/month in the first 3 months or HC was consistently >25th percentile during follow-up. RESULTS: Of 6,799 liveborn infants in USZPIR, 351 (5.2%) had Zika-associated birth defects, of which 111 had birth HC measurements <3rd percentile and birthweight ≥10th percentile. Of 84/111 infants with sufficient follow-up, 38/84 (45%) were classified as having possible inaccuracy of birth HC measurement, 19/84 (23%) had HC ≥3rd percentile on follow-up without meeting criteria for possible inaccuracy, and 27/84 (32%) had continued HC <3rd percentile. After excluding possible inaccuracies, the proportion of infants with Zika-associated birth defects including microcephaly decreased from 5.2% to 4.6%. CONCLUSIONS: About one-third of infants in USZPIR with Zika-associated birth defects had only microcephaly, but indications of possible measurement inaccuracy were common. Implementation of this schema in longitudinal studies can reduce misclassification of microcephaly.

Malformations Surveillance: Comparison between Findings at Birth and Age 1 Year.

BACKGROUND: Malformations surveillance programs among newborn infants are used to determine the prevalence of congenital anomalies. A comparison in the same group of infants between the malformations detected at birth and those detected at 1 year of age will identify errors in the surveillance process and, also, the abnormalities more likely not to be detected at birth, but later in the first year of life. METHODS: The malformations identified at birth by Brigham and Women's Hospital (BWH) in the years 2000 and 2005 have been compared with the abnormalities detected in the same infants up to age 1 year by the Massachusetts Birth Defects Monitoring Program. RESULTS: The Massachusetts Birth Defects Monitoring Program identified 557 malformed infants in 2000 and 415 in 2005. Of these, 34 (3.5%) of the malformed infants were missed at birth by BWH Surveillance Program. An additional 22 (2.3%) malformed infants had delayed detection, as they were identified later in the first year. The reasons were the fact that: (1) the Surveillance staff reviewed the physicians' recorded findings only on the first day of life; (2) failure of the examining pediatrician to record the presence of a malformation in her/his notes. The most common abnormalities with delayed detection were mild heart defects, such as atrial septal defects. CONCLUSION: These findings emphasize the importance in a newborn malformations surveillance program of continued follow up in the first days of life, especially in small, premature infants. Birth Defects Research 110:142-147, 2018. © 2017 Wiley Periodicals, Inc.

Accuracy of birth certificate head circumference measurements: Massachusetts, 2012-2013.

BACKGROUND: Zika virus has recently emerged as a novel cause of microcephaly. CDC has asked states to rapidly ascertain and report cases of Zika-linked birth defects, including microcephaly. Massachusetts added head circumference to its birth certificate (BC) in 2011. The accuracy of head circumference measurements from state vital records data has not been reported. METHODS: We sought to assess the accuracy of Massachusetts BC head circumference measurements by comparing them to measurements for 2,217 infants born during 2012-2013 captured in the Massachusetts Birth Defects Monitoring Program (BDMP) data system. BDMP contains information abstracted directly from infant medical records and served as the true head circumference value (i.e., gold standard) for analysis. We calculated the proportion of head circumference measurements in agreement between the BC and BDMP data. We assigned growth chart head circumference percentile categories to each BC and BDMP measurement, and calculated the sensitivity and specificity of BC-based categories to predict BDMP-based categories. RESULTS: No difference was found in head circumference measurements between the two sources in 77.9% (n = 1,727) of study infants. The sensitivity of BC-based head circumference percentile categories ranged from 85.6% (<3rd percentile) to 92.7% (≥90th percentile) and the specificity ranged from 97.6% (≥90th percentile) to 99.3% (<3rd percentile). CONCLUSIONS: BC head circumference measurements agreed with those abstracted from the medical chart the majority of the time. Head circumference measurements on the BC were more specific than sensitive across all standardized growth chart percentile categories.

Delayed diagnosis of critical congenital heart defects: trends and associated factors.

OBJECTIVE: We aimed to examine trends in timing of diagnosis of critical congenital heart defects (CCHDs) and factors associated with delayed diagnosis (diagnosis after discharge home following delivery). METHODS: We examined a population-based retrospective cohort of CCHD cases among live births identified through the Massachusetts Birth Defects Monitoring Program. Congenital heart defects were considered critical if the infant received corrective surgery, interventional catheterization, palliative care, or died as a result of the defect within 12 months of birth. Timing of initial diagnosis was classified as prenatal, postnatal before discharge home, or delayed. Demographic, perinatal, and mortality information was obtained from the Registry of Vital Records and Statistics. Prevalence ratios (PRs) were used to examine associations with delayed diagnosis. RESULTS: Among 460 467 live births to Massachusetts residents between 2004 and 2009, we identified 916 CCHD cases, of which 126 (13.8%) had delayed diagnosis. Rates of prenatal CCHD diagnosis increased from 44.9% in 2004 to 63.8% in 2009, whereas rates of delayed diagnosis decreased from 17.1% to 10.6% over the same time period. Among cases with delayed diagnosis, the most common defects were coarctation, pulmonary valve stenosis, and tetralogy of Fallot. Delayed diagnosis was associated with delivery outside a tertiary hospital (adjusted PR: 3.6 [95% confidence interval: 2.5-5.2]) and isolated CCHD (adjusted PR: 1.7 [95% confidence interval: 1.1-2.7]). CONCLUSIONS: Despite increasing prenatal diagnosis of CCHDs, delayed diagnosis still occurs in over 10% of cases. Understanding factors associated with delayed diagnosis could help to improve prenatal and postnatal screening efforts, including pulse oximetry testing.

Clinician reviewers in birth defects surveillance programs: survey of the National Birth Defects Prevention Network.

BACKGROUND: Some birth defects surveillance programs utilize a clinician reviewer ("Clinician") to assist the multidisciplinary staff in the process of case review, coding and classification. The untested assumption is that expertise in the evaluation of individuals with birth defects and genetic syndromes in clinical practice, usually clinical genetics, is useful in reviewing medical records. METHODS: We conducted an exploratory survey of the 50 functioning birth defects surveillance programs that participated in the National Birth Defects Prevention Network in 2004. The survey was mailed electronically to program coordinators and included 10 questions with check-off option replies. Open-ended comments were also solicited. RESULTS: Responses were received from 31 of 50 (62%) programs, 21 (68%) which used a Clinician. In addition to the 9 centers that identified themselves as participants in the National Birth Defects Prevention Study (NBDPS), there were 12 non-NBDPS programs using a Clinician, 2 of whom were not clinical geneticists (1 nurse genetic counselor and 1 primary pediatrician). A total of 86% (18/21) of Clinicians were employed part-time or as consultants; 1 was full-time, and 2 were volunteers. In addition to the core activities of classifying defects and reviewing cases to determine if a syndrome was present, over one-half of the Clinicians participated in education of birth defects surveillance programs staff, research, and program development. Most (86%; 18/21) Clinicians had been trained informally for their roles. Only 1 had received a formal performance review. CONCLUSIONS: Aside from the 9 centers in the NBDPS in which the position of Clinician is funded by the Centers for Disease Control and Prevention (CDC), about one-half of the remaining respondent birth defects surveillance programs used a Clinician. Future research is needed to determine why a birth defects surveillance program hires or refrains from using a Clinician, and whether a Clinician accomplishes the desired goals. This survey reveals a lack of formal training for the Clinicians in their roles in the surveillance programs, and a lack of quality monitors, which might be addressed in the future.