Morbidity and mortality in neonates with Down Syndrome based on gestational age

Greater than 50% of neonates with Down Syndrome (DS) have perinatal complications that require admission to the neonatal intensive care unit (NICU) at birth. Previous studies have shown increased morbidity and mortality rates in neonates without DS delivered prior to 39 weeks of completed gestation.

To determine if an association exists between gestational age at delivery and adverse outcomes in neonates with DS.

Neonates with DS admitted to a large, tertiary care center NICU from 2010 to 2020 were evaluated. Gestational age (GA) was stratified into 4 groups: <34 (preterm), 34-36 (late-preterm), 37-38 (early-term) and ≥39 (term + post-term) completed weeks. Fisher's exact tests were used to evaluate morbidity and mortality rates between groups.

Of the 314 neonates with DS, 10% (N = 31) were <34 weeks, 22% (N = 68) 34-36 weeks, 40% (N = 127) 37-38 weeks, and 28% (N = 88) ≥39 completed weeks at birth. Baseline characteristics were similar between groups. GA at birth <34 weeks was associated with a higher in-hospital mortality rate when compared to those born 37-38 (19% vs. 0%, P < 0.001) and ≥39 (19% vs. 3%, P = 0.01). Neonates with DS born <34 weeks had a higher likelihood of oxygen requirement at time of discharge compared to 34-36, 37-38, and ≥39 groups (P = 0.01; P < 0.001; P < 0.001 respectively). Neonates with DS < 34 weeks were more likely to develop necrotizing enterocolitis (P = 0.02) and require nitric oxide (P = 0.014) compared to neonates with DS ≥ 39. We observed no differences in the need for surgical interventions between groups aside from the rate of gastrostomy/jejunostomy tube placement between 34-36 weeks and 37-38 weeks GA.

Neonates with DS born preterm (<34 weeks) represent a highly vulnerable subgroup. Multidisciplinary strategies are needed to address their higher rates of morbidity and mortality.