Background: Pre-pregnancy obesity and inadequate maternal weight gain during pregnancy can lead to adverse effects in the newborn but also to metabolic, cardiovascular and even neurological diseases in older ages of the offspring. Heart activity can be used as a proxy for the activity of the autonomic nervous system (ANS). The aim of this study is to evaluate the effect of pre-pregnancy weight, maternal weight gain and maternal metabolism on the ANS of the fetus in healthy pregnancies.
Methods: A total of 184 fetal magnetoencephalographic datasets from healthy pregnant women (gestational age ranging from 27-38 weeks) were included. Fetal heart activity was recorded via fetal magnetoencephalography and fetal heart rate (HR) and heart rate variability (HRV) were determined. Participants were either assigned one BMI group: underweight (BMI < 18.5), normal weight (BMI 18.5 - 24.9), overweight (BMI 25.0 - 29.9) and obese (≥ 30.0) or: low, normal and high weight gain. Fetal HR and HRV were compared between the groups. The effects of maternal weight, weight gain and insulin sensitivity on fetal HR and HRV were tested through partial correlation and mediation analysis, adjusting for gestational age, gender and parity.
Results: Fetuses of pre-pregnancy obese mothers have higher HR compared to fetuses of normal weight mothers. Fetal HR was found to negatively correlate with maternal weight gain and birth weight. There was a causal effect of fetal HR on the relationship between maternal weight gain and birth weight. As for fetal HRV, standard deviation normal to normal interval (SDNN) and low frequency component (LF) were lower for mothers with high weight gain compared to normal weight gain. Lower maternal insulin sensitivity was associated with a higher fetal HR as well as a lower HRV (a negative correlation with LF/HF). Fetal LF/HF and pre-pregnancy BMI, independently mediated the effect of maternal insulin sensitivity on fetal HR.
Conclusions: Higher pre-pregnancy BMI, excessive weight gain and decreased insulin sensitivity in healthy pregnancies results in increased fetal heart activity. Also, the effect of maternal weight gain on birth weight seems to be mediated through fetal heart rate. This indicates that the fetal ANS is sensitive to alterations of maternal weight, changes in maternal weight and maternal metabolism. These findings support the concept of fetal programming and add knowledge about the important influence of intrauterine environment on the developing cardiac ANS and the possible programming of obesity.
Biography: Haliza is an academic researcher and PhD candidate at the Eberhard-Karls-Universität Tübingen, with a specialization in Neuroscience. Over the past four years, her research has been focused on the development of fetal autonomic nervous system related to maternal weight, weight gain and metabolism in healthy pregnancies. She has a B.Eng. degree in Electrical Engineering from University of Malaya, M.Eng. in Electrical and Telecommunications from University of Technology Malaysia and M.Sc. in Biomedical Engineering from Universität zu Lübeck. Previously, she worked as a quality assurance engineer and assistant lecturer in Malaysia. Her current interest includes advanced methods in signal processing, statistical modelling and data analytics.