Risk factors and infant outcomes associated with umbilical cord prolapse: a population-based case-control study among births in Washington State.

OBJECTIVE: Our goal was to quantify the magnitude of risk associated with conditions resulting in umbilical cord prolapse and adverse infant outcome after cord prolapse. STUDY DESIGN: This population-based case-control study used birth certificate data from 709 cases and 2407 randomly selected controls. Odds ratios were used as measures of association, with stratification performed to control for confounding. RESULTS: Case infants were more likely to weigh < 2500 mg (odds ratio 4.8, 95% confidence interval 3.7 to 6.2) and to born prematurely (odds ratio 2.9, 95% confidence interval 2.2 to 3.7). Other risk factors were breech presentation (birth weight-adjusted odds ratio 2.5, 95% confidence interval 1.7 to 3.9) and being a second-born twin (odds ratio 5.0, 95% confidence interval 3.3 to 11.7). Subsequent adverse infant outcomes included an increased risk of mortality (relative risk 2.7, 95% confidence interval 1.9 to 4.0), with mortality being less likely to occur among cases delivered by cesarean section (relative risk 0.4, 95% confidence interval 0.2 to 0.6). CONCLUSIONS: This study confirms previously suspected risk factors and supports clinical management of cord prolapse by cesarean section delivery.