Survival outcomes of very low birth weight infants with trisomy 18

Trisomy 18 (T18) is one of the most commonly diagnosed aneuploidies leading to poor survival outcome. However, little is known about the dual risk of T18 and very low birth weight (VLBW, weighing <1500 g at birth). We aimed to investigate the survival and clinical features of VLBW infants with T18. In this observational cohort study, infants with T18 admitted to the neonatal intensive care unit in Kyushu University Hospital from 2000 to 2019 were eligible. Among 30 infants with T18 who were enrolled as study participants, 11 (37%) were born with VLBW. VLBW infants had lower gestational age (34.4 vs. 39.4 weeks, p < 0.01) and a higher incidence of esophageal atresia (64% vs. 11%, p < 0.01) than non-VLBW infants. The proportions of patients who underwent any surgery (55% vs. 5%, p < 0.01) and positive pressure ventilation (82% vs. 32%, p = 0.02) were higher in VLBW than non-VLBW infants. One-year overall survival rate (45% vs. 26%, p = 0.32 by log-rank test) did not differ between the two groups. In conclusion, being born at VLBW may not be fatal for infants with T18 undergoing active interventions.