Fetal heart screening in low‐risk pregnancies

Abstract

The aim of this study was to assess whether a screening program for fetal cardiac malformations is justified in a low‐risk population, and which factors influence its accuracy. The fetal heart was evaluated in 7024 pregnant women at 20–22 weeks, and evaluation was repeated at a more advanced gestational age in 9% of cases. Cardiological follow‐up was continued postnatally until 2 years of age. The overall prevalence of cardiac anomaly was 0.93% The incidences of major and minor defects were 0.44% and 0.48%, respectively. There were 23 true positives (0.33%). in 20 cases, the diagnosis was made in the second trimester, and 13 women (6.5%) chose termination of pregnancy. Seventeen of the 20 cases identified in the second trimester were serious malformations. There were 42 false negatives (0.60%). Of these, 12 had signs of cardiac dysfunction at birth or within the 1st month of life, and three of them died as a result of their cardiac anomaly. There were eight false positives (0.11%), all of a minor type. Six abnormal karyotypes, out of a total of 21 performed in the true‐positive group (28.5%) were found. In addition five of 42 newborns in the false‐negative group had trisomy 21. The overall sensitivity was 35.4% and 61.3% for major defects. The accuracy in two distinct periods was estimated because the level of experience of the operators was different: sensitivity was 45.2% in period 1 (1986–88) (77.8% for major defects) and 26.5% in period 2 (1989–92) (52.9% for major defects). We conclude that a fetal heart screening program in the obstetrics population is justified. It defines a high‐risk group for karyotyping, allows planning of delivery in a tertiary center or the choice of terminating the pregnancy for the parents and appears to have a positive cost‐benefit ratio. A crucial factor is the level of training and experience of the operators, who need specific teaching support. Copyright © 1995 International Society of Ultrasound in Obstetrics and Gynecology Copyright © 1995 International Society of Ultrasound in Obstetrics and Gynecology