SummaryHealthy fetal development requires substantial maternal physiological adaptations during pregnancy. Therefore, the autonomic nervous system (ANS) undergoes profound changes as gestation advances, reflecting the increasing demands on the maternal cardiovascular system. Heart rate variability (HRV) parameters indicate a finely tuned regulatory balance instrumental for controlling these complex physiological requirements. However, this tight regulation may reduce the mother’s physiological flexibility in responding to external stressors and increases an individual’s vulnerability to environmental influences. This study aims to investigate the association between environmental heat exposure and the dynamic regulation of the maternal autonomic nervous system (ANS) during pregnancy. Furthermore, we aim to examine the joint effect of environmental heat, air pollution, and traffic noise. We will assess these associations across short-term vs. long-term exposure and within the individual trimesters of pregnancy, as sensitivity of the ANS to environmental stress may change with prolonged exposure or advancing gestation. Autonomic modulation in pregnant participants will also be compared with that of non-pregnant female controls to identify pregnancy-specific responses to environmental heat exposure and environmental co-exposures. This research project utilizes data from pregnant NAKO participants and a comparison group of non-pregnant female controls, both with available 24-hour ECG recordings (SOMNOwatch) or resting ECG data. This data provides detailed insight into Cardiac Autonomic Modulation measured by heart rate and HRV. We will link these physiological measurements with precise estimates of air temperature, relative humidity, air pollution, and road traffic noise at the participants' residential addresses. The results of this project will provide a deeper understanding of environmental heat exposure and its association with maternal autonomic modulation and physiological strain. Furthermore, the study will provide insights into the joint effects of environmental risk factors relevant to the health of pregnant women in Germany. This forms the scientific foundation to develop targeted warning systems that protect specifically pregnant women during critical heat periods or times of high air pollution and traffic noise and thereby to improve public health recommendations for risk minimization.

Keywords climate-change-vulnerability environmental-exposome heart-rate-variability heat-stress pregnancy-health

InstitutionsMartin-Luther-Universität Halle-Wittenberg