A Comparison of Perinatal Outcomes according to the Degrees of Birth Weight Discordance in Twin Gestations

Yang, S H; Park, S H; Choi, S M; Seo, Y S; Roh, J R; Jeong, J H

Abstract

OBJECTIVE
The purpose of this study was to determine the effect of discordant fetal growth on subsequent perinatal and neonatal outcome for different degrees of birth weight discordance in twin gestations. Study design: One hundred nineteen sets of twins delivered between 25 and 37 weeks` gestation were studied. They were stratified into four categories according to the percent difference in infant birth weight: < or =10%, 10% to 20%, 20% to 30%, and >30%, which was defined as ([Birth weight of larger twin - Birth weight of smaller twin]/Birth weight of larger twin)x100. The relationship between different birth weight categories and the perinatal and neonatal outcome and the difference in outcome between the large and small infants were evaluated. Multiple logistic regression analysis was used to determine the relationship between the poor perinatal outcome and independent variables.
RESULTS
Twin gestations with >30% birth weight discordance were associated with a higher incidence of small-for-gestational-age (SGA) infants and respiratory distress syndrome of neonates (p<0.001 and p<0.05, respectively). Outcome of the large and small twins showed no significant difference except incidence of SGA infants. Multiple logistic regression analysis revealed that birth weight discordance >30% was not an independent predictor for perinatal outcome.
CONCLUSION
In twin gestations the use of a 30% birth weight difference to define twin discordance seems to be most clinically relevant in identifying those infants at risk for adverse perinatal outcome. However, birth weight discordane is not an independent risk factor for perinatal mortality and morbidity. It suggests that the estimated fetal weight discordance by prenatal ultrasonography is not an indication of preterm delivery.