Factors related to fetal demise in cases with congenital heart defects

Congenital heart defects are the most common congenital anomaly. Despite the increasing survival of these children, there is still an increased incidence of fetal demise, frequently attributed to cardiac failure. Considering that abnormal placental development has been described in congenital heart disease, our hypothesis is that placental insufficiency may contribute to fetal death in congenital heart disease.

This study aimed to assess cases with fetal congenital heart disease and intrauterine demise, and analyze factors that are related to the demise.

All congenital heart disease cases diagnosed prenatally during the period January 2002 to January 2021 were selected from the regional prospective congenital heart disease registry, PRECOR. Multiple pregnancies and pregnancies with fetal trisomy 13 or 18, triploidy, and Turner's syndrome were excluded from the analysis, because fetal demise is attributed to the chromosomal abnormality in these cases. Cases were categorized into 4 groups based on the possible cause of fetal death as follows: cardiac failure, additional (genetic) diagnosis, placental insufficiency, and a group in which no cause was found. A separate analysis was performed for isolated congenital heart disease cases.

Of the 4806 cases in the PRECOR registry, 112 had fetal demise, of which 43 were excluded from the analysis (13 multiple pregnancies, 30 genetic). Of these, 47.8% were most likely related to cardiac failure, 42.0% to another (genetic) diagnosis, and 10.1% to placental insufficiency. No cases were allocated to the group with an unknown cause. Only 47.8% of the cases had isolated congenital heart disease, and in this group 21.2% was most likely related to placental insufficiency.

This study shows that in addition to cardiac failure and other (genetic) diagnoses, placental factors play an important role in fetal demise in congenital heart disease, especially in cases of isolated heart defects. Therefore, these findings support the importance of regular ultrasonographic assessment of fetal growth and placental function in fetal congenital heart disease.