The small-for-gestational-age twin: blessing or curse?

Objective: To compare small-for-gestational-age (SGA) twins to appropriate-for-gestational-age (AGA) twins regarding preterm delivery (PTD).

Study Design: Retrospective review of maternal and neonatal records of live, nonanomalous twins > or = 25 weeks' gestation delivered in 1984-2000 in a tertiary care center. Pregnancies (N = 679) were divided into AGA/ AGA (n = 347), SGA-AGA (n = 191) and SGA/SGA (n = 141) groups using singleton growth curves. The PTD rate was compared and logistic regression analysis was done to study factors that influenced PTD at < or = 34 weeks. p < 0.05 was considered significant.

Results: The PTD rate at < or = 34 weeks was AGA/AGA (38.6%), SGA-AGA (14.7%) and SGA/SGA (1.4%) (p < 0.001). On multiple logistic regression analysis, discordance significantly increased PTD (OR = 5.05, 2.47-10.31, p = 0.001), while smallness for gestational age significantly decreased PTD (OR = 0.095, 0.05-0.17, p < 0.001). The PTD rate increased directly with the increase in the relative overall weight of the twins.

Conclusion: The PTD rate is higher in AGA twins as compared to SGA twins. The PTD rate is directly related to the overall weight of the twins.