Umbilical cord coiling index is defined in terms of the number of 360-degree spiral course of umbilical vessels. This can be described in two main ways:
- the number of coils per one centimetre of length of cord.
- Normocoiled: one coil for a length of five centimetres.
- Hypercoiled: more than one coil per five centimetres.
- Hypocoiled: fewer than one coil per five centimetres.
- the total number of coils divided by the total length of the cord in centimetres.
- Normocoiled: 10th–90th percentile
- Hypercoiled: >90th percentile
- Hypocoiled: <10th percentile
Significance
This index plays an important role in predicting the pregnancy outcome and risk of low birth weight 2.
Hypocoiling can be associated with hypertensive disorders, placental abruption, preterm labour, oligohydramnios, and abnormal fetal heart rate.
Hypercoiling can be associated with maternal diabetes, polyhydramnios, caesarean delivery, congenital anomalies, and neonatal respiratory distress.