1387-P: Risk of Perinatal Complications across Gestational Blood Pressure Levels in Women with and without Gestational Diabetes (GDM)

Hypertensive disorders in pregnancy and GDM are among the leading causes of maternal and perinatal morbidity. In 2017, the American College of Cardiology/American Heart Association released a new guideline for hypertension: systolic/diastolic blood pressure (SBP/DBP) ≥130/80 vs. previous 140/90 mmHg. However, these new cut-points have not been applied to pregnant women due to the lack of evidence on its impact on perinatal outcomes. We examined in women with and without GDM whether the risk of perinatal complications increased across SBP/DBP levels: normal (<120/80 mmHg, untreated), elevated (120-129/<80, untreated), stage 1 gestational hypertension (GH, 130-139/80-89, untreated), and stage 2 GH (≥140/90, treated or untreated). The study was conducted in 2017-2018 among 6458 women with GDM and 50885 without GDM, who were Kaiser Permanente Northern California members without pre-existing hypertension. Logistic regression examined associations of BP categories with perinatal outcomes, adjusting for sociodemographic, medical, and lifestyle covariates. The prevalences were higher in women with vs. without GDM: elevated BP 21.3% vs. 20.0%, stage 1 GH 18.6 % vs. 16.1%, and stage 2 GH 3.6% vs. 2.6% (all P <0.05). Associations with risk of large-for-gestational age were more pronounced among women with vs. without GDM, with adjusted odds ratios (OR) for elevated BP of 1.54 (95% CI 1.28-1.84) vs. 1.22 (1.13-1.31) and for stage 1 GH of 1.35 (1.11-1.64) vs. 1.21 (1.11-1.31) (P for interaction <0.01). Associations with preterm birth and small-for-gestational age were present only for stage 2 GH among women without GDM: OR 1.56 (1.26-1.91) and 1.59 (1.34-1.88), respectively (P for interaction=0.02 and 0.08, respectively). Although GH was more common in women with GDM, its associations with perinatal complications varied by GDM status. Also, our findings suggest the new guideline may identify women with subclinical high BP in pregnancy at risk of perinatal complications.