Anthropometry of twins

Abstract

Twins are smaller than singletons at birth, due to both shorter gestational age and intrauterine growth restriction. Additionally, an intrapair discordance in birth weight is quite frequent. In twins, as in singletons, body weight and body composition vary with gestational age. However, in each pair of twins, a difference in birth weight, although correlated with, is not proportional to differences in body composition components. When compared to singletons, normally grown twins show similar body composition components. In contrast, growth-restricted twins have lower lean mass and possibly lower fat mass and bone mineral content when compared to singletons matched for gestational age. During the first 2 years of life, twins show a catch-up growth but do not reach the body size of singletons. Between 2 and 9 years of age, height in twins is only marginally lower than singletons, whereas weight gain is considerably less. Monozygotic twins are both lighter and shorter than dizygotic twins. Birth weight, parental height, zygosity, and gender are the determinants of somatic growth of twins in the first 9 years of life. In adulthood, twins seem to have a slightly lower weight than singletons. With regard to body composition, there is a persisting correlation between birth weight and body composition components.