Abstract MP68: Association of Clinical and Subclinical Blood Pressure Elevation During Pregnancy With Maternal Health and Risk of Neonatal Low Birth Weight

Abstract

Introduction: Gestational hypertension is a leading cause of maternal mortality and fetal growth restriction (FGR). However, elevated maternal blood pressure at which trimester contributes to FGR is unknown, and whether gestational prehypertension (a systolic blood pressure [SBP] of 120 - 139 mmHg or a diastolic blood pressure [DBP] of 80 - 89 mmHg) is related with FGR and maternal health is not fully studied. Methods: We analyzed the relation of elevated gestational blood pressure with risk of neonatal low-birth-weight (LBW, birth weight < 2,500 g) and maternal health throughout pregnancy in 21,620 women from a birth cohort in Wuhan, China. Maternal health indicators, including SBP and DBP, were clinically measured during up to 22 antenatal visits. LBW were acquired from medical records. Linear mixed models were used to evaluate the relations of maternal SBP and DBP with LBW. Logistic regressions were used to assess the associations of SBP and DBP in late pregnancy (38.3 weeks) with LBW. Linear regressions were used to evaluate the association of prehypertension/hypertension with indicators of maternal health. Results: Gestational blood pressure increases throughout pregnancy, but a significant elevation of SBP and DBP between 15 and 25 gestational weeks were only observed for women who later delivered LBW newborns. High gestational SBP (≥ 140 mmHg) or DBP (≥ 90 mmHg) was associated with a 220% or 98% higher risk of LBW ( P < 0.03). Notably, preclinical high SBP (120 - 139 mmHg) was also associated with a 40% higher risk of LBW ( P = 0.036). At late pregnancy, elevated gestational SBP and DBP were associated with elevated liver enzymes, blood urea nitrogen, creatinine, and uric acid levels, and decreased activated partial thromboplastin time and prothrombin time. Conclusions: A fast blood pressure elevation in the second trimester may relate with increased risk of LBW. Pregnancy prehypertension was associated with not only LBW risk, but also impaired maternal liver, kidney, and coagulation functions.