Effect of parity on maternal and neonatal outcomes in twin gestations

Objective: To compare maternal and neonatal outcomes of twin gestations in nulliparous and multiparous women.

Design: Retrospective analysis of maternal and neonatal records.

Setting: American University of Beirut Medical Center, a referral university-affiliated hospital.

Population: Pregnant women who delivered twin gestations beyond 24 weeks from 1990 to 2004.

Methods: The data collected were analyzed using Student's paired t-test or χ(2) test. Logistic regression analysis was used to study the effect of multiple variables on preterm delivery.

Main outcome measure: Preterm birth rate.

Results: Nulliparas (n=333) were more likely to be younger (28.1±5.4 vs. 30.0±5.2 years; p<0.001) and the pregnancy a product of assisted reproductive technology (23.1 vs. 4.5%; p<0.001) compared with multiparas (n=508). They were at significantly increased risk of preterm delivery (54.4 vs. 45.1%; p=0.009) at lower gestational age (35.6±3.2 vs. 36.2±3.0 weeks; p=0.004). They had longer first and second stages of labor and a higher cesarean delivery rate (61.3 vs. 44.9%; p<0.001). Except for a higher intensive care nursery admission rate and longer nursery stay for twins of nulliparas, all neonatal morbidities were comparable. On multiple logistic regression analysis, multiparity (relative risk 0.70, 95% confidence interval 0.51-0.97) and growth restriction (relative risk 0.16, 95% confidence interval 0.12-0.22) were protective, while discordance (relative risk 2.24, 95% confidence interval 1.40-3.60) was a predictor of preterm delivery.

Conclusions: Nulliparous women with twin gestations are at significantly higher risk for preterm delivery and cesarean delivery compared with multiparous women. Although this was not translated into higher perinatal mortality, these women should be monitored closely and counseled regarding these risks and their attendant morbidity.