The odds of respiratory distress syndrome (RDS), bronchopulmonary dysplasia (BPD) and severe BPD are higher among VLBW infants born before 30 weeks of gestation to mothers with pregnancy-induced hypertension (PIH), according to a new study published online April 13, 2023 in Scientific Reports, a Nature journal.¹

A total of 4990 infants born before 30 weeks of gestation and mean birth weight 970 g, were selected for this study to analyse the impact of maternal PIH, whether gestational hypertension, pre-eclampsia or eclampsia, on mortality and morbidity in very low birth weight (VLBW) infants. Maternal PIH was defined as “newly diagnosed hypertension in a pregnant woman after 20 weeks of gestation, with systolic blood pressure ≥ 140 mm Hg and/or diastolic blood pressure ≥ 90 mm Hg”. Out of these, 855 (17.1%) infants were born to women with PIH, while the remaining 4135 (82.9%) infants were born to women without PIH. Data for the study was sourced from neonatal intensive care units (NICUs) who were a part of the Korean Neonatal Network (KNN) registry. Infants of mothers with chronic hypertension and infants with major congenital anomalies were not included in the study.

Analysis of data revealed that mothers with PIH tended to be older (34.1 years) compared to those without PIH (33.3 years). They also had higher use of antenatal steroids (52.7% vs 45.6%, respectively), higher rates of cesarean births (96.6% vs 67.2%, respectively). The infants born to mothers with PIH had lower birth weight (850 g vs 996 g, respectively); they were also more likely to be small for gestational age (28.7 % vs 4.8%, respectively).

Infants born to mothers with PIH have a significantly higher incidence of ARDS, bronchopulmonary dysplasia and severe bronchopulmonary dysplasia. After adjusting for confounding variables, the risk of ARDS was increased almost 2-folds among infants born to mothers with PIH with an odds ratio of 1.98. The ORs for bronchopulmonary dysplasia and severe bronchopulmonary dysplasia were 1.45 and 1.41 respectively. The differences between the two groups with regard to severe intraventricular hemorrhage, periventricular leukomalacia, retinopathy of prematurity, or death during NICU stay were statistically nonsignificant.

This study has shown the higher incidence of neonatal respiratory morbidities like respiratory distress syndrome and bronchopulmonary dysplasia among infants born preterm as singletons to mothers with PIH. It highlights the need for close monitoring and care of such infants.

Reference

1. Kim HR, et al. Outcomes of singleton preterm very low birth weight infants born to mothers with pregnancy-induced hypertension. Sci Rep. 2023 Apr 13;13(1):6100. doi: 10.1038/s41598-023-33206-y.