Intrapair birthweight discordance in twins

Background : Birthweight differences in twin pairs influence their perinatal outcome as well as growth and development. Growth-discordant twins have not been well characterized in our local environment.
Objective : To determine the frequency of birthweight discordance in live-born twin pairs and document some factors that may influence it.
Methods : In this cross-sectional study, 104 live-born twin pairs were recruited and their intrapair birthweight differences were determined. Twin pairs whose birthweight difference was 15% or more, using the larger infant as the growth standard, were designated as discordant. The maternal age, parity, and birth order of the heavier twin were noted.
Results : The prevalence of birthweight discordance was 28.8% when a 15% cut-off point was used but dropped to 9.6% when a 25% cut-off point was applied. Grand multiparity was associated with a significantly increased risk of delivery of discordant twins. Same-sex twin pairs accounted for 60% of all cases of birthweight discordance.
Conclusion : Birthweight discordance is common in twin gestations in Benin City, especially among grand multiparous women.