Objective: To evaluate in two time intervals the potential impact of prenatal diagnosis on prevalence and spectrum of CHD at birth and in aborted fetuses.
Patients and methods: At the University Hospital of Bari, south-east Italy, in the period between January 1st 1996 and December 31st 1999 a retrospective study was performed of all newborns and termination of pregnancy (TOP) beyond 18 weeks' gestation with postnatally diagnosed CHD. An antenatal fetal ultrasonic evaluation had been always performed between 18-22 weeks' gestation. The prevalence, distribution and detection rate of CHD at birth and in TOP were assessed and compared between two different periods of time (96-97 vs 98-99) to verify an eventual improvement in the prenatal diagnosis due to the learning curve and to new technologies.
Results: Prevalence of severe CHD in livebirths and aborted fetuses showed no significant changes between the two study periods (respectively 4.6@1000 vs 5.4@1000, at birth; 10% vs 11%, in TOP) and the same was observed as for as distribution of CHD. Maternal or fetal risk factors were found in 23% of cases of CHD at birth and in 74% of cases of CHD in aborted fetuses. The antenatal detection rate of CHD did not change between the two study periods in newborns (25% vs 27%, NS) while in aborted fetuses it was higher and showed a significant longitudinal improvement (53% vs 85%, p < 0.05), which was more evident if only selected cases were considered (56% vs 93%, p < 0.03).
Discussion: Our data show that gain in experience in fetal echocardiography has increased the prenatal diagnostic accuracy for congenital cardiac malformations only in selected cases, evaluated by more expert operators. In conclusion the impact of antenatal routine screening for congenital heart disease appears still relatively small.