Limits of viability and survival without neurodevelopmental impairment for small-for-gestational-age infants that was born before 34 gestational weeks

Abstract

 The objective of the present study was to elucidate the limits of gestational age and birth weight for viability and survival without neurodevelopmental impairment among small for gestational age infants delivered at preterm period. The retrospective observational study including singleton delivered before 34 weeks’ gestation with the birth weight under 3 ％ tile of local standard between 2010 and 2015 was performed. Outcomes were the prevalence of good short-term prognosis, which was the survival at 28th days after birth, and of good long-term prognosis, which was the survival at three years old without cerebral palsy, mental retardation with the score of Kyoto Scale of Psychological Development under 70, visual disturbance, or acoustic disturbance. Gestational age and birth weight that more than half of infants have good short-term or long-term prognosis were defined as the limit of viability or survival without neurodevelopmental impairment, respectively. Among 61 participants the prevalence of good short-term and long-term prognosis was 92％（56/61）and 71％（39/55）, respectively. The limit of viability was 26 gestational weeks and birthweight ≥400g. The limit of survival without neurodevelopmental impairment was 27 gestational weeks and at birthweight ≥400g. Gestational age and birth weight to predict frequent good short-term prognosis were 26 weeks and 550 g and to predict frequent good long-term prognosis were 27 weeks and 650 g, respectively. These results might be useful for the pregnancy management and patient counseling in cases with FGR.