Diagnosis and outcome of congenital heart disease in fetuses from multiple pregnancies.

OBJECTIVES

(1) To assess the diagnostic accuracy of fetal echocardiography and (2) to evaluate the type and the outcome of congenital heart disease (CHD) detected in fetuses from multiple pregnancies.

SETTING

tertiary referral center for prenatal diagnosis of CHD.

DESIGN

observational study. In the period 1994-2003, 711 fetuses from 330 multiple pregnancies (282 twins, 45 triplets and 3 quadruplets) underwent fetal echocardiography at our unit. CHD were present in 45 of them. Diagnostic accuracy (sensitivity, specificity, positive and negative predictive values) was calculated for fetal echocardiography. For the fetuses with CHD, the following variables were analysed: gestational age at diagnosis, type of CHD, associated anomalies, fetoneonatal outcome. Confirmation of the diagnosis was obtained in 45/48 cases with CHD and in 580/610 without CHD. Mean follow-up time for diseased neonates was 52 months (range 6-127).

RESULTS

In the study population, there were 40 true positives, 5 false negatives, 1 false positive and 632 true negatives, which yields the following figures: sensitivity 88.8% (40/45), specificity 99.8% (632/633), positive predictive value 97.6% (40/41) and negative predictive value 99.2% (632/637). As for the 45 cases with CHD, type of CHD was evenly distributed among left and right heart, conotruncal and septal defects, with 6/7 right heart lesions occurring in recipient fetuses of pregnancies complicated by TTTS. The aneuploidy rate was 7.0% (3/43). As for the outcome, 26 (57.8%) neonates survived and 17 (37.7%) died prior to or after surgery. Very low birthweight accounted for 7 of the 17 perinatal deaths.

CONCLUSIONS

Our data show that the diagnostic performance of fetal echocardiography in multiple gestations is comparable with that obtained in singletons, as far as twin pregnancies are concerned. Data on triplets and quadruplets are too scant to be of statistical relevance. In addition, the importance of prematurity as primary cause of death in this subset of fetuses should be considered when counseling couples with multiple pregnancies and a fetus with CHD.