Introduction: Compared to females, male sex is associated with higher rates of mortality and morbidity in preterm infants. Hypertensive disorders of pregnancy are associated with placental dysfunction, which affects fetal growth and development. Sex of the fetus plays a significant role in placental development. The effect of fetal sex on outcomes of preterm infants of HDP mothers is not established.
Objective: To compare the sex-based outcomes of preterm infants < 33 weeks gestation born to mothers with HDP and normotensive pregnancies.
Methods: Using the Canadian Neonatal Network Database, we investigated the sex-based outcomes of singleton infants < 33 weeks gestation born to mothers with HDP and normotensive pregnancies admitted to Canadian NICUs between January 2008 and December 2016. Infants with major congenital anomalies and moribund were excluded. Using multivariable models, we determined the sex-based adjusted odds ratios with 95% CI for bronchopulmonary dysplasia (BPD), severe intraventricular hemorrhage (IVH), retinopathy of prematurity (ROP) > stage2, necrotizing enterocolitis (NEC), late-onset sepsis (LOS) and mortality in infants of HDP mothers compared to infants of normotensive mothers.
Results: Of the 27056 infants eligible in the study, there were 15096 males (55%) of which 3009 (20%) were born to HDP mothers. Of the 11960 female infants, 2946 (25%) were born to HDP mothers. Table 1 shows the demographic variables of the infants. Compared to infants of normotensive mothers, both male and female infants of HDP mothers had lower odds of mortality. Female infants of HDP lower odds of severe IVH. LOS was higher in male infants of HDP mothers. There was no difference in BPD, NEC, and ROP between the groups (Tables2 and 3).
Conclusion: Based on infant sex, outcomes of infants born to mothers with HDP is significantly different from infants of normotensive mothers. Our results can be used to counsel parents.