[Epidemiology and clinical value of true umbilical cord knots].

OBJECTIVE

To evaluate the epidemiology of true knots of the umbilical cord and their impact on pregnancy outcome.

MATERIALS AND METHODS

22531 singleton deliveries were included in this retrospective study (1976-1994). Newborns with malformations were excluded. The database of the 2nd Department of Obstetrics and Gynaecology, Vienna University Hospital was analyzed.

RESULTS

The incidence of true knots was 1.27% (n = 286). Multiparous women are more likely to give birth to a child with a true knot of the umbilical cord than primiparae (1.52% vs. 1.01%, P < 0.001). Male fetuses are more frequently affected than females (1.49% vs. 1.04%, P = 0.01). Duration of pregnancy, fetal weight, presentation and mode of delivery are not significantly influenced by umbilical knots. Fetal acidosis (pH < 7.10) was more common in the cohort with true knots as compared with the controls (8.33% vs. 4.03%, P < 0.01). Apgar score and transfer rate to a neonatal unit were not influenced. Still-births were more common in the cohort with umbilical knots (1.7% vs. 0.6%, P < 0.05); there was no neonatal death in the cohort with true knots, however.

CONCLUSION

A fetus with a true knot of the umbilical cord is at risk for fetal death. During labour umbilical knots have no adverse effect on pregnancy outcome.