Changes in blood pressure during healthy pregnancy: a longitudinal cohort study

To study longitudinally changes in blood pressure (BP) and heart rate (HR) during healthy pregnancies and to evaluate the influence of parity, pregestational overweight, and excessive weight gain.

A prospective longitudinal cohort study of 57 healthy white women with singleton pregnancies. BP and HR were measured repeatedly at gestational age 14-16 weeks, 22-24 weeks, 30-32 weeks, 36 weeks, and 6 months postpartum using both an oscillometric measurement device (Dinamap) and finger arterial pressure (Finometer PRO).

SBP, DBP, and mean arterial pressure (MAP) reached a statistically significant trough at gestational age 22-24 weeks using both measurement devices. When compared with the nonpregnant measurement, SBP at gestational age 22-24 weeks was 6.2 mmHg [95% confidence interval (95% CI) 1.3-11.2] lower measured by Finometer and 7.2 mmHg (95% CI 4.2-10.1) lower measured by Dinamap. DBP and MAP were 8.9 mmHg (95% CI 4.6-13.2) and 9.8 mmHg (95% CI 5.3-14.2) lower measured by Finometer. Measured by Dinamap, DBP and MAP were 4.5 mmHg (95% CI 1.7-7.3) and 5.4 mmHg (95% CI 2.8-7.9) lower at gestational age 22-24 weeks when compared with the nonpregnant state. SBP was significantly higher in women with pregestational BMI at least 25 kg/m with both measurement devices (both P < 0.05). There were no differences in SBP, DBP, or MAP depending on parity or excessive weight gain.

BP measured repeatedly by two different noninvasive devices during pregnancy and postpartum showed a statistically significant drop in mid-pregnancy, followed by a progressive increase until term.