Demographic and obstetric factors influencing pregnancy outcome in twin gestations.

Objective: Our purpose was to identify the influence of parity and previous preterm delivery on pregnancy outcome in twin gestations.

Study Design: A retrospective comparative analysis of women with twin gestations completing an outpatient preterm labor surveillance program between April 1995 and February 2000 was performed. Included were those enrolled at <24 weeks' gestation. Parity, maternal age, prepregnancy body mass index (BMI), cerclage, tocolytic use, and pregnancy outcome were identified. Data were divided into nulliparas, multiparas without previous preterm delivery, and those with previous preterm delivery. Analysis of variance and the Pearson chi2 test were used for statistical analysis.

Results: Data were analyzed for 1268 twin pregnancies. The mean gestational age at delivery for the multiparous women without a history of previous preterm delivery (35.3 +/- 2.7 weeks) was significantly greater than the mean gestational age at delivery for nulliparous (34.4 +/- 3.2 weeks) and multiparous women with a previous preterm delivery (34.0 +/- 3.1 weeks), P <.001. The greater gestational age at delivery in the multiparous women without a previous preterm delivery was associated with a significantly shorter newborn hospital stay and a lower need for mechanical ventilation use compared with the other groups (all P values < or =.001).

Conclusion: In twin gestations, multiparous women without history of previous preterm delivery have a significantly greater gestational age at delivery, a lower incidence of cerclage, and a reduced neonatal hospital stay than do nulliparous women or those with a history of a previous preterm delivery.