Teen maternal age and very preterm birth of twins

Background: As teen singleton pregnancy is associated with higher risks of adverse birth outcome, and twin pregnancy, regardless of maternal age, may result in poor outcome, teens pregnant with twins may represent a particularly vulnerable group. However, little has been documented regarding teen twin pregnancy outcome. Objective: To characterize the risk of very preterm birth among teens having twins. Design: Cross-sectional analysis of the US 1995-2000 Matched Multiple Birth Data Set. Methods: We calculated the risk of very preterm birth (< 33 weeks' gestation) for teen and young adult mothers of twins (< 16 years, 1718 years, 19-20 years), compared to 21-24 year olds, stratified by race/ethnicity. Adjusted odds ratios were estimated controlling for marital status and entry into prenatal care. Results: Odds of very preterm birth decreased significantly with increasing age. Odds ratios ranged from 2.07 (1.73,2.48) to 1.20 (1.11,1.29) according to maternal age for White teen mothers, from 1.76 (1.48,2.09) to 1.13 (1.03,1.24) for Black teen mothers, and from 2.19 (1.77,2.72) to 1.15 (1.02,1.31) for Hispanic teen mothers. Odds of very preterm birth among teen mothers of twins were about the same as those for teen mothers of singletons. Conclusions: Teens having twins have higher odds of very preterm birth than young adult mothers. However, the association between age and preterm birth was similar among teen mothers having twins as for those having singletons.