The significance of birth weight discordance in twins.

The author found, among 329 twin pairs, 50 (15.2%) cases of weight discordancy reaching or exceeding 22%. Among the 50 twin pairs, there were 65 boys and 35 girls, a sex ratio of 185.7. This degree of weight discordancy appears to be unrelated to maternal age, parity and gestational length. Growth retardation of one or both fetuses was significantly more frequent (80%) among weight-discordant than among concordant one (11.1%). There were more perinatal deaths between discordant than concordant twins. Among the twins who were born with evidence of growth discordancy, there was slightly increased incidence of abnormal presentation, delivery by cesarean section, and low Apgar score as compared to the concordants.