Outcomes of singleton small for gestational age preterm infants exposed to maternal hypertension: a retrospective cohort study.

Background: Hypertensive disorders of pregnancy (HDP) are a major cause of small for gestational age (SGA). Preterm SGA infants have higher rates of adverse outcomes than appropriate for gestational age infants. However, the outcomes are not well established in the setting of HDP.

Methods: Retrospective population-based study using the Canadian Neonatal Network database from January 1, 2010 to December 31, 2016 of SGA infants <33 weeks gestation. Using multivariable models, we determined the adjusted odds ratios (AORs) with 95% confidence intervals (CI) for mortality, bronchopulmonary dysplasia (BPD), severe intraventricular hemorrhage (IVH), severe retinopathy of prematurity, necrotizing enterocolitis, late-onset sepsis, and patent ductus arteriosus (PDA) in infants of HDP mothers and compared them to infants of non-HDP mothers.

Results: Of the 2081 eligible SGA infants, 1317 (63%) were born to HDP mothers and had lower odds of mortality (AOR 0.57, 95% CI 0.39-0.83) and BPD (AOR 0.69, 95% CI 0.53-0.90). Sub-group analysis demonstrated decreased mortality in 26-28 and 29-32 weeks gestation groups, decreased BPD in 29-32 weeks gestation group, and decreased PDA in <26 weeks gestation group.

Conclusion: Preterm SGA infants of HDP mothers have lower odds of mortality and BPD compared to infants of non-HDP mothers.