232. Adaptation of blood pressure during normotensive pregnancies and pregnancies complicated by hypertension – A systematic review and meta-analysis

Abstract

Introduction Data on blood pressure (BP) adaptation in pregnancy show conflicting results on the occurrence of a mid-pregnancy BP drop. These inconsistent findings may contribute to delayed recognition of maladaptation in women at risk for a hypertensive complicated pregnancy. Objective To meta-analytically describe the pattern of BP adaptation in singleton normotensive pregnancies and hypertensive pregnancies. Methods We performeda systematic review and meta-analysis using PubMed and Embase. Studies included, needed to report a reference non-pregnant measurement. Mean differences between pregnant and reference measurements were calculated for systolic BP (SBP) and diastolic BP (DBP) in predefined gestational intervals using a random-effects model. Results In total, 110 studies were included (23079 BP readings). In normotensive pregnancy, both SBP and DBP started to decrease early in pregnancy, reaching their maximum reduction of −3.3% (−3.7 mmHg, (95% CI, −5.1 to −2.3)) and −5.6% (−3.9 mmHg, (95% CI, −4.8 to −3.0)) respectively in the late second trimester. In the third trimester, SBP and DBP gradually increased to reference values. In hypertensive complicated pregnancies, SBP did not decrease, while DBP initially decreased with −7.2% (−5.8 mmHg, (95% CI, −8.3 to −3.4)) in the early second trimester. From the second half of pregnancy onwards, BP increased to values higher than reference. SBP and DBP increased with 35% (38.2 mmHg, (95% CI, 27.3–49.2)) and 37% (26.1 mmHg, (95% CI, 18.4–33.8)) respectively in the hypertensive group, statistically significantly higher than normotensive pregnancies (p Discussion This is the first meta-analysis on BP adaptation during pregnancy. In normotensive pregnancy, both SBP and DBP initially decrease, reaching their nadir in the late second trimester showing a clinically moderate, but statistically significant mid-pregnancy drop. Hypertensive complicated pregnancies lack a SBP decrease in early pregnancy which might reflect impaired vascular compliance in these women.