Background: Diagnosing hypertensive disorders in pregnancy utilizes systolic blood pressure (BP) of >140 mmHg and/or diastolic of >90 mmHg. However, since 2017, the American College of Cardiology and the American Heart Association (ACC/AHA) have been endorsing lower BP thresholds for diagnosing hypertension. Objectives: This study determines if antenatal lower threshold BP elevations under elevated BP and Stage 1 hypertension from ACC/AHA show an increased risk of gestational hypertension, preeclampsia, and adverse perinatal outcomes. Materials and Methods: This retrospective cohort study included service patients with prenatal consultations and deliveries at a private tertiary-level hospital from February 2016 to 2020. Antenatal BP measurements, categorized into “normal,” “elevated BP,” and “Stage 1 hypertension” under ACC/AHA classifications, had crude and adjusted relative risks (aRRs) and 95% confidence intervals (CIs) estimated to determine their associations with hypertensive disorders of pregnancy. Results: Stage 1 hypertension was twice more likely to develop gestational hypertension (aRR: 2.314, 95% CI: 1.08–4.98) and thrice more likely to develop preeclampsia (aRR: 3.673, 95% CI: 2.30–5.86), whether without (aRR: 3.520, 95% CI: 1.33–9.29) or with severe features (aRR: 3.717, 95% CI: 2.16–6.41). There was a slightly increased risk for adverse perinatal outcomes from Stage 1 hypertension, as well as all outcomes from elevated BP, but was not statistically significant. Majority of BP elevations were during the third trimester. Conclusion Lower threshold Stage 1 hypertension showed an increased risk of developing hypertensive disorders of pregnancy, with a three-fold increased risk for preeclampsia. There may be advantages in its application for diagnosing preeclampsia or having increased monitoring for these patients.
Gestational hypertension