Prenatal diagnosis and prevalence of critical congenital heart defects: an international retrospective cohort study

Abstract

Objectives: To assess international trends and patterns of prenatal diagnosis of critical congenital heart defects (CCHDs) and their relation to total and live birth CCHD prevalence and mortality.

Setting: Fifteen birth defect surveillance programmes that participate in the International Clearinghouse for Birth Defects Surveillance and Research from 12 countries in Europe, North and South America and Asia.

Participants: Live births, stillbirths and elective terminations of pregnancy for fetal anomaly diagnosed with 1 of 12 selected CCHD, ascertained by the 15 programmes for delivery years 2000 to 2014.

Results: 18 243 CCHD cases were reported among 8 847 081 births. The median total prevalence was 19.1 per 10 000 births but varied threefold between programmes from 10.1 to 31.0 per 10 000. CCHD were prenatally detected for at least 50% of the cases in one-third of the programmes. However, prenatal detection varied from 13% in Slovak Republic to 87% in some areas in France. Prenatal detection was consistently high for hypoplastic left heart syndrome (64% overall) and was lowest for total anomalous pulmonary venous return (28% overall). Surveillance programmes in countries that do not legally permit terminations of pregnancy tended to have higher live birth prevalence of CCHD. Most programmes showed an increasing trend in prenatally diagnosed CCHD cases.

Discussion and conclusions: Prenatal detection already accounts for 50% or more of CCHD detected in many programmes and is increasing. Local policies and access likely account for the wide variability of reported occurrence and prenatal diagnosis. Detection rates are high especially for CCHD that are more easily diagnosed on a standard obstetric four-chamber ultrasound or for fetuses that have extracardiac anomalies. These ongoing trends in prenatal diagnosis, potentially in combination with newborn pulse oximetry, are likely to modify the epidemiology and clinical outcomes of CCHD in the near future.

Keywords: critical congenital heart defects; epidemiology; prenatal diagnosis.

Figure 1

Total prevalence and live birth prevalence (per 10 000 births) with 95% CIs for 12 CCHD types, by programme, International Clearinghouse for Birth Defects Surveillance and Research (ICBDSR) Critical Congenital Heart Defects Prenatal Diagnosis study 2000–2014. ICBDSR programmes, ordered by descending total prevalence, contributed data for different years within this time period (see table 1).Chennai, India programme is not included in prevalence estimates because for this exclusively prenatal programme the denominator data (total births and total live births) are unavailable.

Figure 2

Proportion prenatally diagnosed and proportion of live births among all CCHD cases by programme, International Clearinghouse for Birth Defects Surveillance and Research (ICBDSR) Critical Congenital Heart Defects (CCHD) Prenatal Diagnosis study 2000–2014. ICBDSR Programmes (ordered by descending prenatal diagnosis proportion) contributed data for different years within this time period (see table 1). India-Chennai is not included in the figure because as an exclusively prenatal diagnosis programme, all cases by design were prenatally diagnosed, and information on outcome of pregnancy is missing in the majority of cases.

Figure 3

Proportion of prenatally diagnosed CCHD cases according to clinical presentation and by programme International Clearinghouse for Birth Defects Surveillance and Research (ICBDSR) Critical Congenital Heart Defects (CCHD) Prenatal Diagnosis study 2000–2014. Programmes (ordered by descending prenatal detection proportion) contributed data for different years within this time period (see table 1). India-Chennai is a prenatal diagnosis-only programme. MCA, multiple congenital anomalies.

Figure 4

First month mortality in live birth cases with selected CCHD by programme, International Clearinghouse for Birth Defects Surveillance and Research (ICBDSR) Critical Congenital Heart Defects (CCHD) Prenatal Diagnosis study 2000–2014. ICBDSR programmes (ordered by descending first month mortality) contributed data for different years within this time period (see table 1). India-Chennai and Canada are not included in the graph: pregnancy outcomes in India-Chennai are poorly reported and Canada reported on mortality 1 year after birth, not specified in first week or first month mortality.