Hypercoiling of the umbilical cord in uncomplicated singleton pregnancies

The umbilical coiling index (UCI) is a measure of the number of coils in the umbilical cord in relation to its length. Hypercoiled cords with a UCI of >0.3 coils/cm have been associated with adverse fetal and neonatal outcomes.

The primary aim is to determine the accuracy of UCI measured on second trimester ultrasound in predicting UCI at birth. The secondary outcome is to investigate the association between hypercoiling of the umbilical cord on prenatal ultrasound and adverse maternal, fetal and neonatal outcomes.

This was a prospective cohort study of uncomplicated singleton pregnancies. Seventy two patients were included in the study. UCI was measured in the second trimester ultrasound, and compared to UCI measured postnatally. Outcomes of patients with hypercoiled cords on ultrasound were compared to outcomes of patients with normocoiled cords.

Our results failed to show a strong correlation between the UCI determined with ultrasound, and the UCI determined with examination of the umbilical cord after delivery. We also did not demonstrate that measurement of the UCI on second trimester ultrasound is able to predict adverse maternal, fetal or neonatal outcomes.

This study suggests that measurement of the umbilical coiling index should not be part of routine second trimester sonography in patients with uncomplicated singleton pregnancies, with no other medical or surgical comorbidities.