Blood pressure trajectories during pregnancy, labor, and postpartum period: a multicenter study in Japan

Fig. 1. Flow diagram of the study population selection and matching procedure. Flow diagram illustrating the selection of the study population and matching procedures. Of the 20,293 pregnant women who delivered at term and had valid blood pressure measurements, pregnancies were sequentially excluded based on the gestational age criteria, multiple gestations, stillbirth or major fetal anomalies, missing maternal background data, preexisting medical conditions affecting blood pressure regulation, and obstetric complications. The final analytical cohort comprised 14,240 low-risk, normotensive women with singleton term deliveries. Non-pregnant women younger than 45 years with blood pressure data from routine health checkups were screened as a reference population, and eligible low-risk, normotensive pregnant women were matched 1:1 with non-pregnant women (n = 54,905) based on age, height, pre-pregnancy weight, smoking status, and drinking status. *Items are not mutually exclusive

Fig. 2. Model-estimated blood pressure trajectories during pregnancy and estimated pre-pregnancy blood pressure. Modeled outpatient blood pressure trajectories during pregnancy and estimated pre-pregnancy blood pressure in low-risk normotensive women. A Red and blue solid lines represent the model-estimated mean systolic and diastolic blood pressures, respectively, derived from linear mixed-effects models incorporating restricted cubic splines (df = 3). Shaded areas indicate 95% confidence intervals. Gestational age (in weeks) was used as the time variable. The estimated pre-pregnancy blood pressure values are shown as dots and were derived from non-pregnant women matched for age, height, pre-pregnancy weight, smoking status, and drinking status (red and blue dots represent systolic and diastolic blood pressure, respectively). B The model-estimated blood pressure trajectories of the nulliparous (red line) and multiparous (blue line) women are shown

Fig. 3. Blood pressure changes during labor. A Changes in blood pressure during labor in women who underwent vaginal delivery (n = 11,836). Red and blue lines indicate the mean systolic and diastolic blood pressures, respectively, with error bars representing 95% confidence intervals. Blood pressure was evaluated at the final outpatient visit, at hospital admission, during the first stage of labor, at peak intrapartum levels, immediately after delivery, and in the early postpartum period (1 and 2 h after delivery). B Changes in blood pressure during labor in nulliparous (red line) and multiparous (blue line) women

Fig. 4. Model-estimated postpartum blood pressure trajectories. A Modeled postpartum blood pressure trajectories in low-risk, normotensive women. Red and blue lines indicate the model-estimated mean systolic and diastolic blood pressures, respectively, derived from linear mixed-effects models incorporating restricted cubic splines (df = 3). Shaded areas indicate 95% confidence intervals. B Postpartum blood pressure trajectories in nulliparous (red line) and multiparous (blue line) women. C Postpartum blood pressure trajectories stratified by the mode of delivery (red line, cesarean section; blue line, vaginal delivery)