Association of 24‐Hour Ambulatory Blood Pressure During Pregnancy in Adolescents and Young Adults With Measures of Fetal Autonomic Nervous System Development

The autonomic nervous system regulates physiological processes, including cardiovascular functions. Changes in maternal systolic and diastolic blood pressure (SBP; DBP), as well as fetal heart rate and heart rate variability, can serve as indicators of possible risk for adverse perinatal and developmental outcomes. This study examined the association between maternal blood pressure during pregnancy and fetal autonomic nervous system heart rate indices. This was a secondary analysis of a pregnant adolescent and young adult cohort with data collected between 2009 and 2012. Ambulatory SBP and DBP measurements were recorded for 24-hours, three times across the second and third trimesters of pregnancy. Fetal heart rate indices were obtained from a standardized paradigm at 36-38 weeks gestational age. Associations of maternal ambulatory blood pressure trajectories with fetal heart rate indices were evaluated while controlling for body mass index (BMI) using linear mixed model regression. Higher maternal nighttime SBP and DBP trajectories, when controlling for pre-pregnancy BMI, were associated with greater fetal heart rate variability during rest. The associations did not survive Bonferroni correction. Nighttime blood pressure trajectories may affect the development of the fetal autonomic system, and additional research in diverse, adult samples is needed.