Medical treatment of early-onset mild gestational hypertension reduces total peripheral vascular resistance and influences maternal and fetal complications

Abstract

Objective: Complications in early-onset mild gestational hypertension (GH) are better predicted by total peripheral vascular resistance (TPVR) > 1350 dyne than by blood pressure. We therefore aimed to assess the possible reduction of severe complications by lowering TPVR with nitric oxide (NO) donors, oral fluids and standard antihypertensive therapy in women with early-onset mild GH.

Methods: A group of 400 patients with early-onset (20-27 weeks' gestation) mild GH (systolic and diastolic blood pressure < 170/110 mmHg) and TPVR > 1350 dyne were enrolled in a prospective non-randomized trial with sequential allocation: 100 patients were treated with nifedipine (Group A); 100 with nifedipine and NO donors (Group B); 100 with nifedipine and oral fluids (Group C); and 100 with nifedipine, NO donors and oral fluids (Group D). TPVR was checked 1 month after initiation of therapy, and the number of patients with severe maternal and fetal complications was recorded in each group. The relationship between reduction in TPVR and the frequency of severe complications was assessed.

Results: Severe complications developed in 51% of patients in Group A, 48% in Group B, 53% in Group C and 35% in Group D, the frequency in Group D being significantly lower than that in the other treatment groups (P < 0.05). A reduction in TPVR of < 15% predicted the occurrence of severe complications with sensitivity 95.2% and specificity 88.3%. In Group D a reduction in TPVR of ≥ 15% was more probable (odds ratio (OR) = 2.03; 95% CI, 1.15-3.60; P < 0.015) and severe complications were less probable (OR = 0.52; 95% CI, 0.29-0.91; P < 0.023).

Conclusion: In women with early-onset mild GH, combined treatment with NO donors, oral fluids and nifedipine optimally reduces TPVR and seems to reduce maternal and fetal complications.