[Association between blood pressure during 12-28 weeks gestation and pre-eclampsia: predictive value of blood pressure trajectories constructed by latent class growth modeling].

To explore the associations between blood pressure trajectories during pregnancy and risk of future pre-eclampsia in a large cohort enrolling pregnant women at gestational age of ~12 weeks from community hospitals in Tianjin. Latent class growth modeling (LCGM) was used to model the blood pressure trajectories. This was a large prospective cohort study. The study enrolled pregnant women of ~12 weeks of gestation in 19 community hospitals in Tianjin from November 1, 2016 to May 30, 2018. We obtained related information during 5 antepartum examinations before gestational week 28, i.e., week 12, week 16, week 20, week 24 and week 28. LCGM was used to model longitudinal systolic (SBP) and diastolic blood pressure (DBP) trajectories. For the association study, the predictors were set as SBP and DBP trajectory membership (built separately), the outcome was defined as the occurrence of preeclampsia after 28 weeks of gestation. A total of 5 809 cases with known pregnant outcomes were documented. After excluding 249 cases per exclusion criteria, 5 560 cases with singleton pregnancy were included for final analysis. There were 128 cases preeclampsia and 106 cases gestational hypertension in this cohort. Univariate logistic regression and multivariate logistic regression showed the higher baseline SBP level and DBP level were related with increased risk of preeclampsia. Four distinctive SBP trajectories and DBP trajectories from 12 weeks to 28 weeks of gestation were identified by LCGM. After controlling for potential confounders (baseline BMI, being primipara or not, white blood cell counts, hemoglobin level, platelet counts and alanine aminotransferase level), the for SBP latent classification trajectory_ 4 was 4.023 (95%: 2.368 to 6.835, <0.001), and the for SBP latent classification trajectory_3 was 1.854 (95%: 1.223 to 2.811, =0.004). Logistic regression showed that: using the DBP latent classification trajectory_1 as the reference group, the for DBP latent classification trajectory_4 was 4.100 (95%: 2.571 to 6.538, <0.001), and 2.632 (95%: 1.570 to 4.414, <0.001) for DBP latent classification trajectory_2. After controlling for potential confounders (baseline BMI, being primipara or not, white blood cell counts, hemoglobin level, platelet counts and alanine aminotransferase level), the for DBP_traj_4 was 2.527 (95%: 1.534 to 4.162, <0.001), and the for DBP_traj_3 was 1.297 (95%: 0.790 to 2.128, =0.303), and 2.238 (95%: 1.328 to 3.772, =0.002) for DBP_traj_2. Therefore, BP trajectories from 12 weeks to 28 weeks identified by LCGM served as novel risk factors that independently associated with the occurrence of preeclampsia. Receiver operating characteristic (ROC) curve analysis showed incremental diagnostic performance by combing baseline blood pressure levels with blood pressure trajectories. By applying LCGM, we for the first time identified distinctive BP trajectories from gestational week 12 to 28, which can independently predict the development of preeclampsia after 28 weeks of gestation.