The methodology of the Utah Birth Defect Network: congenital heart defects as an illustration

Pregnancy loss in major fetal congenital heart disease: incidence, risk factors and timing

OBJECTIVE

Fetuses with congenital heart disease (CHD) are at increased risk of pregnancy loss compared with the general population. We aimed to assess the incidence, timing and risk factors of pregnancy loss in cases with major fetal CHD, overall and according to cardiac diagnosis.

METHODS

This was a retrospective, population-level cohort study of fetuses and infants diagnosed with major CHD between 1997 and 2018 identified by the Utah Birth Defect Network (UBDN), excluding cases with termination of pregnancy and minor cardiovascular diagnoses (e.g. isolated aortic/pulmonary pathology and isolated septal defects). The incidence and timing of pregnancy loss were recorded, overall and according to CHD diagnosis, with further stratification based on presence of isolated CHD vs additional fetal diagnosis (genetic diagnosis and/or extracardiac malformation). Adjusted risk of pregnancy loss was calculated and risk factors were assessed using multivariable models for the overall cohort and prenatal diagnosis subgroup.

RESULTS

Of 9351 UBDN cases with a cardiovascular code, 3251 cases with major CHD were identified, resulting in a study cohort of 3120 following exclusion of cases with pregnancy termination (n = 131). There were 2956 (94.7%) live births and 164 (5.3%) cases of pregnancy loss, which occurred at a median gestational age of 27.3 weeks. Of study cases, 1848 (59.2%) had isolated CHD and 1272 (40.8%) had an additional fetal diagnosis, including 736 (57.9%) with a genetic diagnosis and 536 (42.1%) with an extracardiac malformation. The observed incidence of pregnancy loss was highest in the presence of mitral stenosis (< 13.5%), hypoplastic left heart syndrome (HLHS) (10.7%), double-outlet right ventricle with normally related great vessels or not otherwise specified (10.5%) and Ebstein's anomaly (9.9%). The adjusted risk of pregnancy loss was 5.3% (95% CI, 3.7-7.6%) in the overall CHD population and 1.4% (95% CI, 0.9-2.3%) in cases with isolated CHD (adjusted risk ratio, 9.0 (95% CI, 6.0-13.0) and 2.0 (95% CI, 1.0-6.0), respectively, based on the general population risk of 0.6%). On multivariable analysis, variables associated with pregnancy loss in the overall CHD population included female fetal sex (adjusted odds ratio (aOR), 1.6 (95% CI, 1.1-2.3)), Hispanic ethnicity (aOR, 1.6 (95% CI, 1.0-2.5)), hydrops (aOR, 6.7 (95% CI, 4.3-10.5)) and additional fetal diagnosis (aOR, 6.3 (95% CI, 4.1-10)). On multivariable analysis of the prenatal diagnosis subgroup, years of maternal education (aOR, 1.2 (95% CI, 1.0-1.4)), presence of an additional fetal diagnosis (aOR, 2.7 (95% CI, 1.4-5.6)), atrioventricular valve regurgitation ≥ moderate (aOR, 3.6 (95% CI, 1.3-8.8)) and ventricular dysfunction (aOR, 3.8 (95% CI, 1.2-11.1)) were associated with pregnancy loss. Diagnostic groups associated with pregnancy loss were HLHS and variants (aOR, 3.0 (95% CI, 1.7-5.3)), other single ventricles (aOR, 2.4 (95% CI, 1.1-4.9)) and other (aOR, 0.1 (95% CI, 0-0.97)). Time-to-pregnancy-loss analysis demonstrated a steeper survival curve for cases with an additional fetal diagnosis, indicating a higher rate of pregnancy loss compared to cases with isolated CHD (P < 0.0001).

CONCLUSIONS

The risk of pregnancy loss is higher in cases with major fetal CHD compared with the general population and varies according to CHD type and presence of additional fetal diagnoses. Improved understanding of the incidence, risk factors and timing of pregnancy loss in CHD cases should inform patient counseling, antenatal surveillance and delivery planning. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Prenatally diagnosed congenital heart disease: the cost of maternal care

OBJECTIVE

Little is known regarding the effects of a prenatal diagnosis of congenital heart disease (CHD) on the cost of antenatal and delivery care. We sought to compare the maternal costs of care in pregnancies where the fetus or child was diagnosed prenatally vs. postnatally.

METHODS

Costs of maternal care were determined for pregnancies in which the fetus or child was diagnosed with CHD between 1997 and 2012 in the state of Utah. Cases of CHD were identified via a statewide birth defect surveillance program which included data on the timing of diagnosis, maternal demographic and clinical data, and linked to statewide inpatient maternal hospital discharge records. Antenatal testing costs were determined using Medicaid fee estimates and total facility costs were determined for all hospitalizations including delivery. The association of timing of diagnosis of CHD with costs was analyzed using univariable and multivariable models.

RESULTS

Of 2128 pregnancies included in the study, 36% had a fetus prenatally diagnosed with CHD. The prenatal diagnosis group was more likely to have a termination or stillbirth and were younger at delivery (gestational age 37.3 vs 38.0 weeks, p < .001). Labor induction and cesarean delivery rates were similar between groups. Antenatal testing and delivery hospitalization costs were higher in the prenatal diagnosis group: $5819 vs $4041 (p < .001) and $10,509 vs $7802 (p < .001), respectively. Patients in the prenatal diagnosis group had longer lengths of hospital stays (3.5 vs 2.4 d, p > .001). After controlling for significant differences between the groups, including lesion severity, the prenatal diagnosis remained directly associated with antenatal testing costs (+$1472), maternal hospitalization costs (+$2713), and maternal hospital length of stay (+1.0 d).

CONCLUSION

A prenatal diagnosis of fetal CHD was associated with increased prenatal costs, hospitalization costs, and hospital length of stay for affected pregnant patients.

Maternal diabetes-related malformations in Utah: A population study of birth prevalence 2001-2016

Maternal pregestational diabetes mellitus is associated with an increased risk for congenital malformations of about 2-4 times the background risk. Notably, the types and patterns of congenital malformations associated with maternal diabetes are nonrandom, with a well-established increased risk for specific classes of malformations, especially of the heart, central nervous system, and skeleton. While the increased risk in clinical and epidemiological studies is well documented in the literature, a precise estimate of overall birth prevalence of these specific congenital malformations among women with maternal pregestational diabetes, is lacking. The purpose of this study was to determine total prevalence of structural malformations associated with maternal pregestational diabetes mellitus in a population-based study. We identified infants with specific birth defects whose mother had pregestational diabetes mellitus in the Utah Birth Defect Network (UBDN), an active birth defects surveillance program that registers the occurrence of selected structural defects in the state of Utah. We defined specific maternal diabetes-related malformations based on epidemiologic and clinical studies in the literature. Of the 825,138 recorded Utah births between 2001 and 2016, a total of 91 cases were identified as likely having diabetic embryopathy within UBDN data. The prevalence of diabetes-related congenital malformation cases was calculated per year; the overall prevalence of diabetes-related malformations 2001-2016 was 1.1 per 10,000 births in Utah (95% CI, 0.9-1.3). Knowledge of the overall prevalence of diabetes-related malformations is important in predicting the number of cases that are potentially prevented with the implementation of programs to foster preconceptional management of maternal pregestational diabetes.

Early Childhood Inpatient Costs of Critical Congenital Heart Disease

OBJECTIVE

To assess longitudinal estimates of inpatient costs through early childhood in patients with critical congenital heart defects (CCHDs), for whom reliable estimates are scarce, using a population-based cohort of clinically validated CCHD cases.

STUDY DESIGN

Longitudinal retrospective cohort of infants with CCHDs live born from 1997 to 2012 in Utah. Cases identified from birth defect registry data were linked to inpatient discharge abstracts and vital records to track inpatient days and costs through age 10 years. Costs were adjusted for inflation and discounted by 3% per year to generate present value estimates. Multivariable models identified infant and maternal factors potentially associated with higher resource utilization and were used to calculate adjusted costs by defect type.

RESULTS

The final statewide cohort included 1439 CCHD cases among 803 509 livebirths (1.8/1000). The average cost per affected child through age 10 years was $136 682 with a median of $74 924 because of a small number of extremely high cost children; costs were highest for pulmonary atresia with ventricular septal defect and hypoplastic left heart syndrome. Inpatient costs increased by 1.6% per year during the study period. A single birth year cohort (~50 000 births/year) had estimated expenditures of $11 902 899 through age 10 years. Extrapolating to the US population, inpatient costs for a single birth year cohort through age 10 years were ~$1 billion.

CONCLUSIONS

Inpatient costs for CCHDs throughout childhood are high and rising. These revised estimates will contribute to comparative effectiveness research aimed at improving the value of care on a patient and population level.

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.

Epidemiology and Prognosis of Congenital Diaphragmatic Hernia: A Population-Based Cohort Study in Utah

BACKGROUND

Congenital diaphragmatic hernia (CDH) is a relatively frequent and severe malformation. Population-based data on clinical presentation and associated mortality are scarce. We examined a state-wide cohort of infants with a clinically validated diagnosis of CDH to assess their clinical profile, sociodemographic patterns, and infant mortality.

METHODS

We identified CDH cases from Utah's statewide population-based surveillance program among the cohort of all pregnancy outcomes (live births, stillbirths, and pregnancy terminations) delivered from 1999 to 2011. Clinical geneticists reviewed all cases and classified them based on etiology (known, unknown), and whether they were isolated, multiple (additional unrelated major malformations or unique minor malformation), or syndromic (genetic, chromosomal).

RESULTS

CDH occurred in 1 in 3156 births (227/718,990, or 3.17 per 10,000), with no time trend during the 13 years (p = 0.85). CDH was much more common in males (male to female ratio, 1.72:1; p < 0.01). Clinically, 64% of the cases were isolated, 23% were multiples, and 13% were syndromic. Most cases were live born (90%), with fewer stillbirths (7%) and pregnancy terminations (3%). Overall infant mortality was 32.5%, and varied considerably by underlying etiology (isolated 21%; multiple 44%; syndromic 82%). Prognosis was related to specific clinical findings within each etiologic group (e.g., prematurity, low Apgar score, and intrathoracic liver).

CONCLUSION

This information on specific clinical and etiologic factors associated with prognosis can help clinicians and parents in the complex discussions about care planning and management that often occur in a crisis situation, following the diagnosis of CDH, whether prior or after delivery. Birth Defects Research 109:1451-1459, 2017.© 2017 Wiley Periodicals, Inc.

Etiology and clinical presentation of birth defects: population based study

Objective To assess causation and clinical presentation of major birth defects.Design Population based case cohort.Setting Cases of birth defects in children born 2005-09 to resident women, ascertained through Utah's population based surveillance system. All records underwent clinical re-review.Participants 5504 cases among 270 878 births (prevalence 2.03%), excluding mild isolated conditions (such as muscular ventricular septal defects, distal hypospadias).Main outcome measures The primary outcomes were the proportion of birth defects with a known etiology (chromosomal, genetic, human teratogen, twinning) or unknown etiology, by morphology (isolated, multiple, minors only), and by pathogenesis (sequence, developmental field defect, or known pattern of birth defects).Results Definite cause was assigned in 20.2% (n=1114) of cases: chromosomal or genetic conditions accounted for 94.4% (n=1052), teratogens for 4.1% (n=46, mostly poorly controlled pregestational diabetes), and twinning for 1.4% (n=16, conjoined or acardiac). The 79.8% (n=4390) remaining were classified as unknown etiology; of these 88.2% (n=3874) were isolated birth defects. Family history (similarly affected first degree relative) was documented in 4.8% (n=266). In this cohort, 92.1% (5067/5504) were live born infants (isolated and non-isolated birth defects): 75.3% (4147/5504) were classified as having an isolated birth defect (unknown or known etiology).Conclusions These findings underscore the gaps in our knowledge regarding the causes of birth defects. For the causes that are known, such as smoking or diabetes, assigning causation in individual cases remains challenging. Nevertheless, the ongoing impact of these exposures on fetal development highlights the urgency and benefits of population based preventive interventions. For the causes that are still unknown, better strategies are needed. These can include greater integration of the key elements of etiology, morphology, and pathogenesis into epidemiologic studies; greater collaboration between researchers (such as developmental biologists), clinicians (such as medical geneticists), and epidemiologists; and better ways to objectively measure fetal exposures (beyond maternal self reports) and closer (prenatally) to the critical period of organogenesis.

Costs, mortality, and hospital usage in relation to prenatal diagnosis in d-transposition of the great arteries

BACKGROUND

The impact of prenatal diagnosis of d-transposition of the great arteries (dTGA) on health-care usage is largely unknown. We evaluated a population-based cohort to assess costs, mortality and inpatient encounters by whether dTGA was prenatally diagnosed or not.

METHODS

The dTGA cases (born 1997-2011) identified at the Utah Birth Defect Network, which includes data on timing of diagnosis, were linked to statewide inpatient discharge data. We excluded preterm cases or cases with additional major heart defects. We evaluated hospitalizations and costs for infants (first year of life) and mothers (10 months before birth) using multivariable models adjusted for demographic and clinical risk factors.

RESULTS

Of 119 cases, 14 (12%) were prenatally diagnosed. Birth weight, surgical complexity and extracardiac defects/syndromes were similar between groups. Of 7 deaths (6%), two occurred pre-intervention in postnatally diagnosed infants. Prenatal diagnosis was associated with more in-hospital days (estimate 13 additional days, p = 0.03) and higher mean costs for mothers ($4,141 vs $12,148) and infants (90,419 vs $49,576). Prenatal diagnosis independently predicted higher adjusted costs for the overall cohort ($22,570, p = 0.045). After excluding deaths, total costs were no longer significantly different.

CONCLUSION

Mothers of prenatally diagnosed infants with dTGA had higher inpatient costs compared with those postnatally diagnosed. Costs trended higher for their infants, although were not significantly different. Linkage of population-based surveillance systems and outcome databases can be a powerful tool to further explore the complex relationship of prenatal diagnosis to costs and outcomes in other types of congenital heart diseases. Birth Defects Research 109:262-270, 2017. © 2017 Wiley Periodicals, Inc.

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.

Validation of congenital anomaly coding in Canada's administrative databases compared with a congenital anomaly registry

BACKGROUND

Congenital anomaly (CA) surveillance provides epidemiologic data that are necessary for health planning. Approaches to CA surveillance vary; however, an increasing number of jurisdictions rely on administrative health databases for case ascertainment. This study aimed to assess the validity of CA coding in three administrative databases compared with a CA registry.

METHODS

A cohort of 5862 live and stillborn infants from Calgary Alberta Canada was created through linking 12 clinical and administrative databases. Diagnostic codes for all health care contacts (hospitalizations, emergency room visits, out-patient physician visits) in the first 3 months of life were examined for relevant International Classification of Disease codes. Sensitivity, positive predictive values, and kappa coefficients were calculated, and data from the Alberta Congenital Anomalies Surveillance System was used as the reference standard.

RESULTS

The ability of administrative data to accurately ascertain CAs varied by data source and the specificity of the diagnosis. Consistently, hospitalization data out-performed other administrative data sources in terms of sensitivity, positive predictive values, and kappa. Kappa scores for CAs easily visible at birth ranged from moderate (0.62 for emergency room visits and 0.65 for out-patient physician claims) to good (0.83 for hospitalization data) depending on the data source.

CONCLUSION

The validity of CA coding in administrative databases compared with a CA registry varies by database used and by CA studied. This has important implications for national surveillance efforts. Condition-specific validity should be assessed locally before use of these data sources for research or planning purposes.

Association of twinning and maternal age with major structural birth defects in Utah, 1999 to 2008

BACKGROUND

Twinning is a risk factor for birth defects. Using population-based data from the Utah Birth Defect Network and the Utah Department of Health Vital Records, we investigated whether twinning increases the risk of major structural birth defects in live-born opposite-sex (OS) and same-sex (SS) twins as proxies for monozygotic and dizygotic twins, respectively. We also assessed whether maternal age modified the association between twinning and birth defects.

METHODS

All resident live-born singleton (n = 492,143) and twin (n = 13,596) infants issued a Utah birth certificate and delivered from 1999 through 2008 were included. Unadjusted and adjusted odds ratios (aORs) with 95% confidence intervals were calculated for each birth defect using unconditional logistic regression.

RESULTS

Birth defects were slightly more likely to occur in SS (aOR = 1.94; 95% confidence interval, 1.70-2.21) than OS (aOR = 1.55; 95% confidence interval, 1.27-1.90) twins. The aORs stratified by maternal age did not show a trend for any twin type when calculated for all birth defects combined. However, trends were observed for coarctation, pyloric stenosis, and shaft or penoscrotal hypospadias in OS twins; microcephaly, anotia/microtia, conotruncal defects, membranous ventricular septal defects, pyloric stenosis, all hypospadias, and craniosynostosis in SS twins; and tetralogy of Fallot, right ventricular outflow tract obstructions, renal agenesis/hypoplasia, and craniosynostosis in all twins.

CONCLUSION

All twin types have an increased risk for birth defects compared with singletons. SS twins have the highest risk, presumably due to the influence of monozygotic twins. The risk for birth defects in twins was not significantly modified by the mother's age.

Barriers to prenatal detection of congenital heart disease: a population-based study

OBJECTIVE

To evaluate the extent and determinants of missed prenatal detection of congenital heart disease (CHD) in a population-based setting.

METHODS

This was a retrospective cohort study of cases with CHD, excluding minor defects, identified between 1997 and 2007 by a statewide surveillance program. We examined a comprehensive list of potential risk factors for which data were available in the surveillance database from abstracted medical charts. We analyzed the association of fetal, maternal and encounter factors with 1) whether a prenatal ultrasound was performed and 2) prenatal detection of CHD.

RESULTS

CHD was detected prenatally in only 39% of 1474 cases, with no improvement in detection rate over the 10-year period. Among the 97% (n = 1431) of mothers who underwent one or more ultrasound examinations, 35% were interpreted as abnormal; fetal echocardiography was performed in 27% of the entire cohort. Maternal and encounter factors increasing the adjusted odds of prenatal detection included: family history of CHD (OR, 4.3 (95% CI, 1.9-9.9)), presence of extracardiac defects (OR, 2.7 (95% CI, 1.9-3.9)) and ultrasound location i.e. high risk clinic vs clinic (OR, 2.1 (95% CI, 1.3-3.1)). Defects that would be expected to have an abnormal outflow-tract view were missed more often (64%) than were those that would be expected to have an abnormal four-chamber view (42%).

CONCLUSION

The majority of CHD cases over the 10-year study period were missed prenatally and detection rates did not increase materially during that time. The failure to detect CHD prenatally was related to encounter characteristics, specifically involving screening ultrasound examinations, which may be targeted for improvement.

Prevalence of esophageal atresia among 18 international birth defects surveillance programs

BACKGROUND

The prevalence of esophageal atresia (EA) has been shown to vary across different geographical settings. Investigation of geographical differences may provide an insight into the underlying etiology of EA.

METHODS

The study population comprised infants diagnosed with EA during 1998 to 2007 from 18 of the 46 birth defects surveillance programs, members of the International Clearinghouse for Birth Defects Surveillance and Research. Total prevalence per 10,000 births for EA was defined as the total number of cases in live births, stillbirths, and elective termination of pregnancy for fetal anomaly (ETOPFA) divided by the total number of all births in the population.

RESULTS

Among the participating programs, a total of 2943 cases of EA were diagnosed with an average prevalence of 2.44 (95% confidence interval [CI], 2.35-2.53) per 10,000 births, ranging between 1.77 and 3.68 per 10,000 births. Of all infants diagnosed with EA, 2761 (93.8%) were live births, 82 (2.8%) stillbirths, 89 (3.0%) ETOPFA, and 11 (0.4%) had unknown outcomes. The majority of cases (2020, 68.6%), had a reported EA with fistula, 749 (25.5%) were without fistula, and 174 (5.9%) were registered with an unspecified code.

CONCLUSIONS

On average, EA affected 1 in 4099 births (95% CI, 1 in 3954-4251 births) with prevalence varying across different geographical settings, but relatively consistent over time and comparable between surveillance programs. Findings suggest that differences in the prevalence observed among programs are likely to be attributable to variability in population ethnic compositions or issues in reporting or registration procedures of EA, rather than a real risk occurrence difference. Birth Defects Research (Part A), 2012.

Parental needs among children with birth defects: defining a parent-to-parent support network

The objective of this study was to explore how a parent-to-parent support network could impact parents of a child with a structural birth defect by specifically looking at parents' continued needs, aspects influencing their participation in support networks, and their recommendations. Structural birth defects occur in approximately 3 % of all infants, representing a significant public health issue. For many reasons, parents are uniquely qualified to provide support to each other. Data were collected retrospectively through a qualitative approach of focus groups or one-on-one interviews. Thirty one parents of infants registered in the Utah Birth Defect Network participated in the study. Three themes emerged, "current sources and inconsistencies in parent-to-parent-support," "aspects that influence participation in parent-to-parent network," and "recommendations for a parent-to-parent program." Health care providers need to be aware of the services and inform parents about these options. A statewide parent-to-parent network integrated into all hospitals would be a valuable resource to facilitate sharing of issues related to caring for an infant or child with a birth defect.

Congenital heart disease in a Chinese hospital: pre- and postnatal detection, incidence, clinical characteristics and outcomes

BACKGROUND

The pre- and postnatal detection rate, incidence, clinical characteristics and outcomes of congenital heart disease (CHD) have been studied in developed countries for many years, but rarely have large-scale studies been reported in Chinese populations. The aim of the present study was to investigate the pre- and postnatal detection rates, incidence, clinical characteristics and outcomes of CHD in a Chinese hospital in order to improve the future screening and treatment of CHD.

METHODS

Fetuses without risk factors for CHD were screened using basic cardiac ultrasound examination (BCUE). Fetuses with suspected cardiac malformation revealed by BCUE and fetuses with risk factors were screened using extended cardiac ultrasound examination. Outcomes recorded from fetal, neonatal and postmortem records over 4 years (2006-2009) included: therapeutic termination of pregnancy, spontaneous abortions or stillbirths, deaths at birth or in the neonatal period (before 28 days of age), and rate of birth and clinical characteristics of newborns.

RESULTS

A total of 34,071 fetuses were screened for CHD during a period of 4 years, of which 173 fetuses were screened for CHD using BCUE and 301 fetuses were screened using extended cardiac ultrasound examination. The incidence of fetal CHD increased from 1.1% in 2006 to 2.4% in 2009 (P < 0.05), yielding an overall incidence of 1.5% (523/34,071). Of the fetuses with CHD, 48.2% (252/523) died before 28 days of age (including intra-uterine death and termination of pregnancy), 51.8% (271/523) lived more than 28 days and the incidence of live newborns with CHD was 0.80% (271/34071).

CONCLUSIONS

The prevalence of CHD was quite common in this Chinese hospital. Detailed profiles of CHD suggest that, while training programs in obstetric screening at this hospital were beneficial, prenatal intervention, treatment and care of fetal CHD were inefficient and should be strengthened in China.

How valid are the rates of Down syndrome internationally? Findings from the International Clearinghouse for Birth Defects Surveillance and Research

Rates of Down syndrome (DS) show considerable international variation, but a systematic assessment of this variation is lacking. The goal of this study was to develop and test a method to assess the validity of DS rates in surveillance programs, as an indicator of quality of ascertainment. The proposed method compares the observed number of cases with DS (livebirths plus elective pregnancy terminations, adjusted for spontaneous fetal losses that would have occurred if the pregnancy had been allowed to continue) in each single year of maternal age, with the expected number of cases based on the best-published data on rates by year of maternal age. To test this method we used data from birth years 2000 to 2005 from 32 surveillance programs of the International Clearinghouse for Birth Defects Surveillance and Research. We computed the adjusted observed versus expected ratio (aOE) of DS birth prevalence among women 25-44 years old. The aOE ratio was close to unity in 13 programs (the 95% confidence interval included 1), above 1 in 2 programs and below 1 in 18 programs (P < 0.05). These findings suggest that DS rates internationally can be evaluated simply and systematically, and underscores how adjusting for spontaneous fetal loss is crucial and feasible. The aOE ratio can help better interpret and compare the reported rates, measure the degree of under- or over-registration, and promote quality improvement in surveillance programs that will ultimately provide better data for research, service planning, and public health programs.

A case control population-based study investigating smoking as a risk factor for gastroschisis in Utah, 1997-2005

BACKGROUND

Smoking in pregnancy increases the risk for many different adverse pregnancy outcomes, including birth defects. Gastroschisis, a birth defect most commonly associated with young maternal age has been associated with smoking, but findings are inconsistent. We assessed whether smoking increases the risk for gastroschisis using population-based data from Utah.

METHODS

Gastroschisis cases (n = 189) were identified from the Utah Birth Defect Network and all live births without birth defects (n = 423,499) occurring in Utah from January 1, 1997 through December 31, 2005 served as controls. Exposure data were derived from birth certificates and fetal death certificates and, for terminated pregnancies, the Utah Birth Defect Network.

RESULTS

Women who smoked during the first trimester of pregnancy had an increased risk of gastroschisis (OR 1.6; 95% CI: 1.1, 2.3) after adjusting for maternal age and preconception BMI. Discordance between birth certificate data and data from structured interviews increased exposure prevalence from 16.9 to 22.2% for case mothers and 7.4 to 13.2% for control mothers. Accounting for this misclassification, the crude OR decreased by 24%, 1.9 (1.3, 2.7).

CONCLUSIONS

Though first trimester cigarette smoking was reported on birth certificates by more mothers of gastroschisis cases than controls, adjustment for confounders (maternal age and preconception BMI) and smoking misclassification suggests the association is weak. Despite a decrease in smoking prevalence among all women of childbearing years in Utah between 1997 and 2005, the prevalence of gastroschisis has not followed a similar trend.

Frequency of holoprosencephaly in the International Clearinghouse Birth Defects Surveillance Systems: searching for population variations

BACKGROUND

Holoprosencephaly (HPE) is a developmental field defect of the brain that results in incomplete separation of the cerebral hemispheres that includes less severe phenotypes, such as arhinencephaly and single median maxillary central incisor. Information on the epidemiology of HPE is limited, both because few population-based studies have been reported, and because small studies must observe a greater number of years in order to accumulate sufficient numbers of births for a reliable estimate.

METHODS

We collected data from 2000 through 2004 from 24 of the 46 Birth Defects Registry Members of the International Clearinghouse for Birth Defects Surveillance and Research. This study is based on more than 7 million births in various areas from North and South America, Europe, and Australia.

RESULTS

A total of 963 HPE cases were registered, yielding an overall prevalence of 1.31 per 10,000 births. Because the estimate was heterogeneous, possible causes of variations among populations were analyzed: random variation, under-reporting and over-reporting bias, variation in proportion of termination of pregnancies among all registered cases and real differences among populations.

CONCLUSIONS

The data do not suggest large differences in total prevalence of HPE among the studied populations that would be useful to generate etiological hypotheses.

Positive predictive value of computerized records for major congenital malformations

PURPOSE

To assess the positive predictive value of computerized records in a linked database of vital records and infant claims, with medical record confirmation to detect congenital malformations in a Medicaid population.

METHODS

Study subjects were selected from cases identified for three studies of congenital malformations in the Tennessee Medicaid (TennCare) population including 173 827 (studies 1 and 2) and 519 465 (study 3) mother/infant pairs. Possible malformations were identified from computerized databases of birth certificates linked with maternal and infant claims. Medical records were reviewed for all possible congenital malformations and positive predictive values were calculated for each data source and for each malformation.

RESULTS

Among 1430 potential congenital malformations identified from either birth certificates or inpatient claims, 67.7% were confirmed by medical record review. The positive predictive value varied considerably depending on the data source and the organ system. For example, cardiac defects had a very low positive predictive value when identified from birth certificates, and somewhat higher positive predictive value when identified from inpatient claims. Orofacial defects had 90.9% positive predictive value from birth certificates and inpatient claims. Requiring evidence of a diagnostic or therapeutic procedure increased the positive predictive value to >90% for specific defects, but substantially reduced the number of included cases.

CONCLUSIONS

Depending on the defect, computerized claims data linked to vital records offer opportunities for identifying birth defects in populations of vulnerable persons. However, for many defects, medical record confirmation is likely to be required to provide valid identification of malformation occurrence.