Smaller decrease in late second trimester blood pressure is associated with gestational hypertensive disease development.

Objectives: We investigated whether a smaller reduction in 2nd trimester blood pressure (BP) is associated with the development of gestational hypertensive disease.

Study design: We conducted a retrospective cohort study utilizing a clinical database at an urban safety-net hospital. Individuals ages 18-40 with a singleton gestation and 1st trimester prenatal care were included. Those with chronic hypertension were excluded. Systolic BP (SBP), diastolic BP (DBP), & mean arterial pressure (MAP) decrease were calculated. The outcome variable, gestational hypertensive disease (GHDP) included gestational hypertension and preeclampsia with and without severe features.

Results: Of N = 3,355 individuals that met inclusion criteria, 18 % had GHDP. The mean gestational age of 1st trimester and 2nd trimester BP values were 9.8 ± 2.1 and 23.5 ± 2.3 weeks. Those with GHDP compared to those without GHDP had a significantly higher mean 1st trimester SBP (p < 0.01), DBP (p < 0.01), and MAP (p < 0.01). Those with GHDP compared to those without GHDP had a significantly smaller decrease between 1st and 2nd trimester SBP (-1.7 ± 12.3 vs -2.9 ± 11.8, p < 0.001) and MAP (-2.1 ± 8.4 vs -2.7 ± 7.9, p = 0.01). Those with GHDP compared to those without GHDP had a smaller DBP decrease but it was not statistically significant (-2.3 ± 8.7 vs -2.7 ± 8.2, p = 0.19).

Conclusions: Pregnant individuals who experienced a smaller decrease in SBP and MAP were more likely to develop GHDP. A reduced physiologic drop in 2nd trimester BP may suggest underlying vascular dysregulation. Future studies investigating biological mechanisms driving diminished 2nd trimester BP decline, utilizing non-invasive hemodynamic monitoring, are necessary.