Analysis of multiple births in Japan. II. Weight at birth of triplets and quadruplets.

Abstract

Birth weight of 124 sets of triplets and 7 sets of quadruplets was analysed in relation to survival states, sex and birth order. Mean birth weight was higher in live, births than in stillbirths in both triplet and quadruplet individuals. Males had higher mean birth weight than females among live born triplets and among live and still born quadruplets. Mean birth weight was larger in unlike-sexed than in like-sexed triplets, suggesting a lower mean birth weight in monozygotic than in dizygotic or trizygotic triplets. Mean birth weight was decreased in the order of twin, triplet and quadruplet individuals.