Associations of systolic blood pressure trajectories during pregnancy and risk of adverse perinatal outcomes

This study aimed to explore the association of systolic blood pressure (SBP) trajectories of pregnant women with the risk of adverse outcomes of pregnant women and their fetuses. A register-based cohort of 63,724 pregnant women and their fetuses from January 2013 to December 2017 was investigated. Demographic characteristics, history of disease and family history of disease for pregnant women and perinatal outcomes were recorded, and blood pressure was measured during the whole pregnancy. SBP trajectories were estimated with latent mixture modeling by Proc Traj in SAS using SBP data from the first antenatal care appointment (8-14 weeks), the highest SBP before admission, the admission SBP and the SBP at 2 h postpartum. A censored normal model (CNORM) was considered appropriate, and model fit was assessed using the Bayesian information criterion (BIC). A logistic regression model was used to examine the association between SBP trajectories and the risk of adverse perinatal outcomes. Four distinct SBP trajectory patterns over the pregnancy period were identified and were labeled as low-stable, moderate-stable, high-decreasing and moderate-increasing. Three maternal and three fetal adverse outcomes were selected as the main outcome measures. After adjusting for confounding factors, compared with pregnant women with the low-stable pattern, those with the high-decreasing pattern had a higher risk of developing poor growth outcomes of fetuses, while those with the moderate-increasing pattern had higher risks of developing both adverse maternal and fetal outcomes. Our study results suggest that pregnant women should pay attention to the control of blood pressure throughout pregnancy.