Impact of maternal body mass index on fetal cardiac remodelling

Maternal obesity and gestational diabetes mellitus (GDM) have been associated with modification in fetal cardiac function which may contribute to their risk to develop cardiovascular disease later in life. There is no account however on the individual role of maternal overweight and GDM on fetal cardiac development. The aim of this study was to evaluate the sphericity index (SI), a variable reflecting the presence of cardiac remodelling, in fetuses of overweight mothers with or without concomitant GDM. This was a prospective cross-sectional study including singleton pregnant women with a body mass index (BMI)≥ 30 kg/m2 at their first pregnancy booking and uncomplicated pregnancies with a BMI < 25 matched for maternal age, parity and gestational age at ultrasound. Criteria of exclusion were the presence of pregestational diabetes or chronic hypertension, conception by in vitro fertilization, development of pre-eclampsia or birthweight < 10 centile. The SI of the left (LVSI) and right ventricles (RVSI) SI were assessed by fetal echocardiography and comparisons among groups performed. The study population included 104 women with a BMI > 30 and 140 control pregnancies. The mean gestational age at the time of fetal echocardiography was 30.2 (interquartile range IQR 28.4- 31.7) GDM was present in 22 (21.1%) of the obese women. When compared to controls obese women showed decreased LVSI (control 1.76, obese no GDM. 1.43, obese GDM 1.39 p = 0.004) and RVSI (control 1.55; obese no GDM 1.40; obese GDM 1.36 p = 0.003). Post hoc analysis demonstrated significant difference in LVSI (p = 0.05) and RVSI (p = 0.04) among women with or without GDM. Cardiac remodelling as expressed by lower LSI and RSI, is present in fetuses of obese mothers also in absence of GDM suggesting a primary role of maternal overweight.