Maternal hypertensive disorders in pregnancy and risk of hypoxic-ischemia encephalopathy

Hypoxic-ischemic encephalopathy (HIE) is one of the most serious birth complications for neonates. Few studies reported the relationship between maternal blood pressure disorders and risk of neonatal HIE.

This study was conducted to examine whether maternal hypertensive disorders in pregnancy increase the risk of HIE.

The analyses were performed using data from a large population-based cohort study aiming to prevent neural tube defects by supplementation with folic acid. The subjects comprised 183,981 women with singleton live births delivered at gestational ages of 32-42 weeks, who registered in two southern provinces in China. Blood pressure was measured by trained health care workers at each prenatal visit. Diagnosis information on HIE was recorded at the time of delivery.

Totally 19,298 women (10.49%) were diagnosed with maternal hypertensive disorders in pregnancy and 255 infants (1.4 per 1000) with HIE, respectively. Compared with the normotensive group, a great increment in the risk of HIE was observed in women with hypertensive disorders (adjusted RR = 2.40, 95% confidence interval [CI]: 1.79-3.22) after adjusting for maternal confounding factors. A greater association was presented among preterm (32-36 weeks) infants with an adjusted RR of 5.45 (95% CI: 2.79, 10.65) compared to a RR of 2.09 (95% CI: 1.49, 2.92) among full-term (37-42 weeks) infants (p for heterogeneity < .05). Further stratification analyses showed that no matter with or without small for gestational age (SGA), maternal hypertensive disorders were associated with the increased risk for HIE. Sensitivity analyses excluding infants with low or high birth weight did not appreciably change the findings.

Our present study demonstrated a positive association of maternal hypertensive disorders in pregnancy with the risk of neonatal HIE.