(550) Mean arterial pressure and neonatal outcomes in pregnancies complicated by mild chronic hypertension

To examine the relationship between mean arterial pressure (MAP) during pregnancy and neonatal outcomes in women with chronic hypertension (cHTN).


Study Design: A secondary analysis of the Chronic Hypertension and Pregnancy (CHAP) Trial, an open-label, multicenter, randomized treatment trial of cHTN in pregnancy, was conducted. Patients in the active treatment group (Active) were given antihypertensive medication to maintain a blood pressure (BP) of < 140/90mmHg; patients in the standard treatment group (Control) were withheld antihypertensive treatment unless BP reached ≥160mmHg systolic or ≥105mmHg diastolic. Logistic regression assessed associations between average and highest MAP on neonatal outcomes. Odds ratios of primary neonatal composite outcome [bronchopulmonary dysplasia (BPD), retinopathy of prematurity (ROP), necrotizing enterocolitis (NEC), or intraventricular hemorrhage (IVH) 3 or 4] and individual secondary outcomes [neonatal intensive care unit admission (NICU), low birth weight (LBW) < 2500g, and small for gestational age (SGA)] were calculated.

Results: A total of 2,284 patients were included: 1155 Active and 1129 Control. Average MAP was lower in Active compared to Control (95.9±7.3 vs 98.6±7.8, p< 0.0001). Average MAP≥107 (i.e.,BP >140/90) occurred less commonly in Active vs Control (7% vs 13%, p< 0.0001). Results were consistent when analyses were repeated using highest MAP (Table 1). Adjusted models controlling for randomization group demonstrated that average MAP was positively associated with each neonatal outcome examined except NEC, specifically: neonatal composite [aOR 1.24 (95% CI 1.09–1.16)], NICU admission [aOR 1.07 (1.06–1.08)], LBW [(aOR 1.12 (1.11–1.14)], SGA < 5th% [aOR 1.03 (1.01–1.06)] and SGA < 10th% [aOR 1.02 (1.01–1.04)]. Models using highest MAP demonstrated consistent associations except IVH 3/4.

Conclusion:

Treatment of chronic hypertension in pregnancy to < 140/90mmHg resulted in lower MAP, and MAP was positively associated with most adverse neonatal outcomes. The long-term effect of MAP on childhood outcomes is important to consider in future CHAP analyses.