P2C314: Effect of Maternal Hypertensive Disorders of Pregnancy on Mortality & Selected Morbidities in Premature Infants ≤34 Weeks

Background: Hypertensive Disorders of Pregnancy (HDP) are a group of disorders that include both pre-existing and pregnancy-induced hypertension. It is the most common group of disorders of pregnancy, with the prevalence in hospitalized pregnant patients increasing from 13.3% in 2017 to 15.9% in 2019 [1]. One of the more common and harmful forms of HDP is preeclampsia, which is associated with significant maternal and fetal morbidity [2-5]. In a large meta-analysis, infants born to mothers with HDP were found to have a significantly increased risk of stillbirth and neonatal death as compared to mothers without HDP [6]. In this study, we aim to describe the outcomes of premature infants born to mothers with HDP and compare them to those born to mothers without HDP.

Methods: This is a single-center retrospective cohort study. We identified 197 neonates born to mothers with HDP at a gestational age at or less than 34 weeks between 2015 and 2020. These neonates were then matched at a 1:2 ratio by gestational age to 394 randomly selected neonates born to mothers without HDP across the same time interval. Qualitative and quantitative data for both the infant and mother was collected, including characteristics and management of the pregnancy and delivery, resuscitation efforts, prematurity complications, and labs. Categorical data was analyzed using chi-squared tests. Continuous data was analyzed using unpaired t-tests and Mann-Whitney U tests to compare mean and median values, respectively.

Results: There were 197 newborns in the HDP group and 394 in the control (Table 1). No significant difference was found in birth weight, and survival to discharge. Despite both groups having comparable rates of respiratory distress syndrome (RDS) and bronchopulmonary dysplasia (BPD), intubation rates were significantly lower (p < 0.01) in the HDP group. While there were significantly less antibiotic usage (p < 0.01) and shorter duration of antibiotic use (p < 0.01) in the HDP group, there was no difference in diagnosed sepsis rates (Figure 1).

Conclusion: Birth weight outcomes between groups are notable, as preeclampsia is a known cause of fetal growth restriction. The lack of difference in birth weight between groups suggests that the drop off in growth occurs beyond 34 weeks gestation. While there was no statistical difference in RDS, the significant difference in intubation rate suggests that RDS was less severe in infants born to HDP mothers as compared to the control group. Similarly, the decrease in antibiotic usage and duration in HDP group suggests that providers are less likely to attribute clinical findings to sepsis in these patients and would therefore be less inclined to treat with antibiotics due to a lower index of suspicion for sepsis in this population.