Objective: To examine differences in intrapartum fetal heart rate (FHR) patterns among cases with various cord abnormalities.
Methods: Vertex singleton cases with nuchal cord (226 cases), velamentous (12 cases), marginal cord insertion (53 cases) or hyper-coiled cord (39 cases) and without them (466) that were delivered at our hospital were examined. The relationship between cord abnormalities and intrapartum FHR patterns were retrospectively investigated. Deceleration patterns were analyzed for the presence of variable, early, late and prolonged decelerations. The frequencies of each FHR pattern per uterine contraction were assessed during 30 uterine contractions at the end of the first stage and throughout the entire second stage of labor.
Results: In the first stage of labor, frequencies of variable decelerations were 34.5+/-23.8% and 27.3+/-25.5% in cases with velamentous insertion and hyper-coiled cord, respectively. These were significantly higher than in controls (11.7+/-17.3%, P<0.0001). In the second stage of labor, however, frequencies of each deceleration were not different among various cord abnormalities.
Conclusion: Fetal heart rate tracing from the first stage of labor is indicated in cases with the prenatal diagnosis of velamentous insertion or hyper-coiling of the cord.