Birthweight Percentiles for Twins Based on Sex and Chorionicity in the South of China

Birthweight percentile chart for different gestational age was served as an essential tool in the appropriate evaluation of neonates. Such percentile chart for twins based on different chrionicity were less reported. The aim of this study was to construct up-to-data sex specific twin neonates birth weight references by gestational ages based on different chorionicity in South of China. We retrospectively analysis 3431 twins birthweight born between 25 weeks and 40 weeks gestational age based on sex and chrionicity between 2015 to 2020 in local hospital. The smoothed birthweight percentile curves were conducted through the method, Generalized Additive Models for Location Scale and Shape (GAMLSS) .The mean birth weight of monochorionic twins were significantly lower than that of dichorionic twins , and the gestational week of delivery were earlier. The calculated 50th percentile birthweight values of twin boys were higher than those for girls based on the same chorionicity, except male monochorionic twins who were born before 31 weeks gestational age. Neonates birthweight percentile chart based on sex and chrionicity provide a tool for assessing the well being of twin infants. Use twin growth charts based on chrionicity is likely to prevent the over-diagnosis of SGA in normal growth twins.