Risk factors for spontaneous preterm delivery before 34 weeks of gestation among Taiwanese women

Objective: To identify the risk factors for spontaneous preterm delivery before 34 weeks of gestation among Taiwanese women. Materials and Methods: This retrospective cohort study involved 36,453 Taiwanese women who delivered between July 1990 and December 2003. Pregnancies complicated by multiple gestation, fetal anomalies, and iatrogenic preterm births due to maternal or fetal indications were excluded. Results: Five hundred and five spontaneous preterm deliveries (1.4%) were identified. Risk factors for early preterm delivery included a prior preterm delivery (odds ratio [OR], 16.5; 95% confidence interval [CI], 11.1-24.6), placental abruption (OR, 13.4; 95% CI, 9.4-19.2), history of fetal demise (OR, 11.8; 95% CI, 7.7-18.0), chorioamnionitis (OR, 10.5; 95% CI, 7.4-14.9), oligohydramnios (OR, 10.1; 95% CI, 6.7-15.3), history of abruption (OR, 7.9; 95% CI, 2.4-26.0), unmarried (OR, 6.2; 95% CI, 2.9-13.2), conception by reproductive technology (OR, 2.7; 95% CI, 1.4-5.5), maternal age less than 20 years (OR, 3.5; 95% CI, 1.8-6.7), maternal age greater than 34 years (OR, 1.6; 95% CI, 1.2-2.1), three or more abortions (OR, 1.6; 95% CI, 1.9-2.3), and premature rupture of membranes (OR, 1.6; 95% CI, 1.3-2.0). Conclusion: Some of the risk factors for early preterm delivery among Taiwanese women were the same as those of other ethnic groups, whereas some of the other risk factors were different.