Blood pressure during pregnancy, neonatal size and altered body composition: the Healthy Start study

The objective of this study is to estimate associations between changes in maternal arterial pressure during normotensive pregnancies and offspring birth weight and body composition at birth.

Prospective study of 762 pregnant normotensive Colorado women, recruited from outpatient obstetrics clinics. Repeated arterial pressure measurements during pregnancy were averaged within the second and third trimesters, respectively. Multivariable regression models estimated associations between second to third trimester changes in arterial pressure and small-for-gestational-age birth weight, fat mass, fat-free mass and percent body fat.

A greater second to third trimester increase in maternal arterial pressure was associated with greater odds of small-for-gestational-age birth weight. Greater increases in maternal diastolic blood pressure were associated with reductions in offspring percent body fat (-1.1% in highest vs lowest quartile of increase, 95% confidence interval: -1.9%, -0.3%).

Mid-to-late pregnancy increases in maternal arterial pressure, which do not meet clinical thresholds for hypertension are associated with neonatal body size and composition.