Birth weight for gestational age among Flemish twin population

Objective: The aim of this study was to develop birth weight references for twins. Mean birth weights of individual twins are lower than those of singletons, hence singleton birth weight curves may not be suitable to assess twin birth weights. Study design: Twin birth weight curves were developed according to gestational age, gender, parity and mode of conception. The curves are based on population-based data of 40,494 twins born in Flanders, Belgium between 1987 and 2007. Results: A different growth potential was found comparing the birth weights of twins and singletons. Twins deviate from the singleton curve from 30 weeks gestational age on. Conclusion: Our study underlines that singleton birth weight curves differ from twin birth weight curves. We developed specific twin birth weight curves can be used in clinical practice in order to follow growth patterns of twins in utero.