Advanced maternal age, short interpregnancy interval, and perinatal outcome

OBJECTIVE: The purpose of this study was to evaluate whether the association between short interpregnancy intervals and perinatal outcome varies with maternal age. STUDY DESIGN: We performed a retrospective cohort study among 263,142 Dutch women with second deliveries that occurred between 2000 and 2007. Outcome variables were preterm delivery (<37 weeks of gestation), low birthweight in term deliveries (<2500 g) and small-for-gestational age (<10th percentile for gestational age on the basis of sex-and parity-specific Dutch standards). RESULTS: Short interpregnancy intervals (<6 months) was associated positively with preterm delivery and low birthweight, but not with being small for gestational age. The association of short interpregnancy interval with the risk of preterm delivery was weaker among older than younger women. There was no clear interaction between short interpregnancy interval and maternal age in relation to low birthweight or small for gestational age. CONCLUSION: The results of this study indicate that the association of short interpregnancy interval with preterm delivery attenuates with increasing maternal age.