Small for Gestational Age Affects Outcomes on Singletons and Inborn Births in Extremely Preterm Infants: A Japanese Cohort Study

Abstract

Objective This study aimed to compare the short- and long-term outcomes of extremely preterm small for gestational age (SGA) infants and appropriate for gestational age (AGA) infants in Japan. Study Design We retrospectively assessed 434 SGA and 1,716 AGA infants born at 22 to 27 weeks of gestational age (GA) and examined their outcomes on singletons and inborn births between 2003 and 2012. Infants were followed-up for 3 years, and the clinical characteristics and outcomes were compared. Fisher's exact and Student's t-tests were used for independent sample comparison. Logistic regression was used to identify associated factors. Results The prevalence of intraventricular hemorrhage ≥ grade 3 was significantly lower (adjusted odds ratio [aOR]: 0.28; 95% confidence interval [CI]: 0.11 − 0.72), and the prevalence of bronchopulmonary dysplasia at 36 weeks of GA and the need for home oxygen therapy were significantly higher (aOR: 2.20; 95% CI: 1.66 − 2.91 and aOR: 2.46; 95% CI: 1.75–3.47, respectively) in SGA infants than in AGA infants. SGA infants born at 24 to 25 weeks of GA had a significantly higher prevalence of developmental quotient (DQ) < 70 (aOR: 1.73; 95% CI: 1.08 − 2.77). Those born at 26 to 27 weeks of GA showed a significantly higher prevalence of cerebral palsy (CP) and visual impairment (aOR: 2.31; 95% CI: 1.22 − 4.40 and aOR: 2.61; 95% CI: 1.21 − 5.61, respectively). Conclusion In SGA infants, birth at 24 to 25 weeks of GA is an independent risk factor for DQ < 70, and birth at 26 to 27 weeks of GA is an independent risk factor for CP and visual impairment. However, we did not consider nutritional and developmental factors, and a longer follow-up would help assess neurodevelopmental outcomes. Key Points