Hypoxic Ischemic Encephalopathy and Maternal Adverse Outcomes

There is a paucity of publications on the composite maternal adverse outcomes (CMAO) among deliveries complicated with versus without neonatal hypoxic ischemic encephalopathy (HIE).

To compare the CMAO among deliveries complicated with versus without HIE.

This is a secondary analysis of data from Assessment of Perinatal Excellence (APEX), an observational study (from March 2008 to Feb 2011) conducted across 25 hospitals by the Eunice Kennedy Shriver National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network. The inclusion criteria for our analysis were non-anomalous live born singletons, who were at least 35 weeks, who did not have scheduled cesarean delivery, and had information on whether the newborn had or did not have HIE. CMAO included any of the following: postpartum endometritis, obstetrical anal sphincter injury, blood transfusion, admission to intensive care unit (ICU), hysterectomy, or maternal death during hospitalization. Sensitivity analysis included CMAO among low- versus high-risk pregnancies. A low-risk pregnancy was defined as delivery at ≥ 37.0 weeks, without maternal comorbidity. Unadjusted and adjusted risk ratios (aRR) with 95% confidence intervals (CI) were estimated using Poisson regression with robust error variance, adjusting for variables significant in univariate analysis.

Among the 118,422 cohorts in the APEX database, 93,031 (78.6%) met the inclusion criteria, and among them, 871 (0.9%) had HIE. The overall rate of CMAO was 4.8% (4,442/93,031). CMAO occurred in 8.7% of deliveries complicated by HIE compared with 4.8% of those without HIE (aRR 1.54 95%CI 1.24, 1.91). The components of CMAO that differed significantly between the two groups included postpartum endometritis, blood transfusion and admission to ICU. In this cohort, 80,942 pregnancies (87.1%) were classified as low-risk, and 691 of the 871 cases of hypoxic-ischemic encephalopathy (79.3%) occurred in this group. In low-risk pregnancies, CMAO occurred in 7.8% of deliveries complicated by HIE versus 4.5% of those without HIE ((aRR 1.51; 95% CI 1.17, 1.96). Similarly, among high-risk pregnancies, CMAO occurred in 12.2% versus 6.2%, respectively (aRR 1.93; 95% CI 1.30,2.88).

The composite maternal adverse outcome occurred in ∼1 out of 10 deliveries complicated by hypoxic ischemic encephalopathy, and it was 1.5-fold higher rate than deliveries without HIE. These findings suggest that neonatal HIE and maternal morbidity frequently coexist, including among pregnancies otherwise classified as low risk.