Mortality and neurological outcomes in extremely and very preterm infants born to mothers with hypertensive disorders of pregnancy

Abstract

To evaluate the impact of maternal hypertensive disorders of pregnancy (HDP) on mortality and neurological outcomes in extremely and very preterm infants using a nationwide neonatal database in Japan. This population-based retrospective study was based on an analysis of data collected by the Neonatal Research Network of Japan from 2003 to 2015 of neonates weighing 1,500 g or less at birth, between 22 and 31 weeks’ gestation. A total of 21,659 infants were randomly divided into two groups, HDP (n = 4,584) and non-HDP (n = 4,584), at a ratio of 1:1 after stratification by four factors including maternal age, parity, weeks of gestation, and year of delivery. Short-term (neonatal period) and medium-term (3 years of age) mortality and neurological outcomes were compared between the two groups by logistic regression analyses. In univariate analysis, HDP was associated with an increased risk for in-hospital death (crude odds ratio [OR], 1.31; 95% confidence interval, 1.04–1.63) and a decreased risk for severe intraventricular haemorrhage (0.68; 0.53–0.87) and periventricular leukomalacia (0.60; 0.48–0.77). In multivariate analysis, HDP was significantly associated with a lower risk for in-hospital death (adjusted OR, 0.61; 0.47–0.80), severe intraventricular haemorrhage (0.47; 0.35–0.63), periventricular leukomalacia (0.59; 0.45–0.78), neonatal seizures (0.40; 0.28–0.57) and cerebral palsy (0.70; 0.52–0.95) at 3 years after adjustment for covariates including birth weight. These results were consistent with those of additional analyses, which excluded cases with histological chorioamnionitis and which divided the infants into two subgroups (22–27 gestational weeks and 28–31 gestational weeks). Maternal HDP was associated with an increased risk for in-hospital death without adjusting for covariates, but it was also associated with a lower risk for mortality and adverse neurological outcomes in extremely and very preterm infants if all covariates except HDP were identical.

Mothers with hypertensive disorders of pregnancy increased risk of periventricular leukomalacia in extremely preterm or extremely low birth weight infants: A propensity score analysis

“…Another study found that the factors such as sex, gestational age, birth weight, multiple births, and antenatal steroids could affect the mortality of EP infants ( 16 ). In our study, after matching these factors, there was no significant difference in survival rate between the two groups, which was consistent with the results of Kono et al ( 7 , 8 ), but inconsistent with the results reported in Japan ( 13 ).…”

“…Over the past years, several studies have reported the effect of HDP on the clinical outcomes of preterm infants, but these conclusions are contradictory, especially in mortality ( 4 – 8 ), bronchopulmonary dysplasia (BPD) ( 4 , 5 , 9 – 12 ), and intraventricular hemorrhage (IVH) ( 4 , 5 , 10 , 13 – 15 ). The inconsistency of these results may be related to different study populations and inconsistent baseline characteristics of the subjects.…”

“…The inconsistency of these results may be related to different study populations and inconsistent baseline characteristics of the subjects. Recently, a retrospective study was performed in Japan, a total of 21,659 extremely or very preterm infants were divided into HDP and non-HDP groups, at a ratio of 1:1 after stratification by four factors including gestational age, maternal age, year of delivery, and parity ( 13 ). The results showed that the mortality and the incidence of severe IVH were lower in the HDP group.…”

Increased Risk for Respiratory Complications in Male Extremely Preterm Infants: A Propensity Score Matching Study

“…IVH is the most common brain injury in EPIs. Antenatal steroid treatment and hypertensive disorders of pregnancy can reduce the incidence of severe IVH in EPIs ( 3 , 5 , 27 , 47 , 48 ). Our results showed that there were no significant differences in the incidence of IVH and severe IVH between the two groups after matching.…”

Neurologic Sequelae Associated with Hypertensive Disorders of Pregnancy

“…Paradoxically, lower mortalities and adverse neurological outcomes such as periventricular leukomalacia, intraventricular hemorrhage and cerebral palsy have been retrospectively reported in specific studies of extremely and very preterm infant populations when associated with HDP, compared with cohorts without HDP [53]. HDP may offer a protective effect for a subset of children who experienced HDP.…”