Risk factors and outcomes associated with nuchal cord. A population-based study.

OBJECTIVE: To assess risk factors and outcomes associated with nuchal cord at birth. STUDY DESIGN: A population-based, case-control study was conducted using linked birth and hospitalization records. Three thousand newborns were randomly selected from all singleton births with nuchal cord as noted on the birth record (n=5,426) in King County, Washington, 1992-1993. For comparison, 3,000 controls were randomly selected from the 46,952 unaffected singletons births. RESULTS: An increased risk of nuchal cord was associated with induction of labor (odds ratio [OR] adjusted for maternal age and parity 2.0, 95% confidence interval [CI] 1.7-2.3), African American infant race (OR 1.3, 95% CI 1.0-1.6), primi-parity (OR 1.2, 95% CI 1.0-1.5) and male sex (OR 1.2, 95% CI 1.0-1.3). After exclusion of selected obstetric complications, the risk of nuchal cord associated with induction of labor increased (OR 2.4, 95% CI 2.0-3.0). Nuchal cord was associated with increased risks of fetal distress (OR 2.7, 95% CI 2.1-3.4), meconium staining (OR 2.1, 95% CI 1.7-2.6), five-minute Apgar score < 7 (OR 1.6, 95% CI 1.1-2.4) and assisted ventilation < 30 minutes (OR 1.9, 95% CI 1.4-2.6). Although hospital charges for newborns with nuchal cord were slightly greater than for those without (P =.02), hospital lengths of stay did not differ significantly. CONCLUSION: Induction of labor was identified as an independent risk factor for nuchal cord. Certain adverse perinatal outcomes are increased in neonates with nuchal cord. However, neonates with nuchal cord do not have significantly longer neonatal hospital stays, and thus the adverse effects of nuchal cord may be transient.