An investigation of the optimal inter-pregnancy interval following pregnancy with a fetus with congenital heart disease

INTRODUCTION: Congenital heart defects (CHD) are one of the most commonly diagnosed congenital malformations in fetuses and newborns. The aim of the study was to determine whether inter-pregnancy interval (IPI), maternal age or number of pregnancies had any influence on the recurrence of congenital heart disease in subsequent pregnancies. MATERIAL AND METHODS: We found in our database 144 women with subsequent pregnancies after CHD in a previous pregnancy. Each woman was selected according to the eligibility and exclusion criteria. Medical history as well as obstetrics history were recorded. Comparisons of groups with and without a recurrence of CHD were performed. We calculated hazard ratios for recurrence of CHD. We also performed analysis of the impact of confounding variables: maternal age and parity. Missing data were excluded from the analysis. Smoking habits as well as socio-demographic characteristics were not evaluated in this study. RESULTS: A higher risk of recurrence of CHD correlated with a shorter IPI, with a median of 11 months compared with 24 months for the group of healthy fetuses in subsequent pregnancy. The results were statistically significant. Parity was proven to be an important confounder of the study. Multivariable analysis including parity and maternal age did not affect the confidence intervals of hazard ratios for IPI. CONCLUSIONS: The optimal IPI to reduce the risk of recurrence of CHD is 24 months. Shorter intervals are related to a higher risk of recurrence of CHD in the next pregnancy and are independent on the age of the woman and parity.