Excessively long umbilical cord: a preventive factor of miserable outcomes of pregnancies with true umbilical cord knots

Abstract

Objective: We examined the clinical significance of pregnancies with true umbilical cord knots related to umbilical cord length.Methods: The material reviewed consisted of the total population of Japanese women who gave birth to singleton babies at 34–41 weeks’ gestation at Japanese Red Cross Katsushika Maternity Hospital between 2002 and 2017.Results: During the study period, there were 32,315 Japanese women who gave birth to singleton babies at 34–41 weeks’ gestation. Of these, true umbilical cord knots were recognized in 209 cases (0.6%). In addition, excessively long umbilical cords were recognized in 98 of the 209 cases (46.9%). On multivariate analysis, true umbilical cord knots were associated with intrauterine fetal demise (adjusted OR 5.65, 95% confidence interval [CI] 1.9–17, p = .02) and excessively long umbilical cord (adjusted OR 8.26, 95% CI 6.0–11, p < .01). The incidence of intrauterine fetal demise in cases with the excessively long umbilical cord (0%) was significantly lower than that without excessively long umbilical cord (4.2%, p = .04), and it was not different measurably from that without true umbilical cord knots (0.3%, p = 1.00).Conclusions: Excessively long umbilical cords may contribute to the decreased risk of intrauterine fetal demise in singleton pregnancies delivered at ≥34 weeks’ gestation.