Correlates of human umblical cord length and significance of its distribution into the chorionic plate in Zambian infants at the University Teaching Hospital, Lusaka

Abstract

There are few documented studies of human umbilical cord length and its insertion into the chorionic plate. However abnormal umbilical cord length (either excessive or shortened) is a known risk factor for adverse perinatal outcome. Long cords have been associated with cord prolapse, entanglement, torsion and thrombosis whereas short cords are associated with rupture of the cord, failure of the fetus to descend in labour and also associated with some congenital fetal anomalies and malpresentation.Umbilical cord may have central, eccentric, marginal or velamentous insertion into the chorionic plate of the placenta. Central and eccentric insertions account for more than 90% of insertions and have no clinical importance. Peripheral insertions (marginal and velamentous) have been associated with vessel rupture, fetal growth restriction, stillbirth, neonatal death or malformed infants.This was a prospective study at UTH in 1997, of 916 Zambian infants, to study the average length of the umbilical cord of infants 28 weeks of gestation age or more, and the prevalence of distribution of umbilical cord insertion into the chorionic plate. Length and insertion were, in addition, correlated with maternal and fetal factors.The mean, median and mode of umbilical cord length were 50.7, 50.0 and 50.0 cms respectively and were consistent with studies from elsewhere. The range was from 21.0 to 110.0 cm. Almost 75% of umbilical cord lengths in the series were between 40 and 60 cm. There was a tendency for cord length to increase towards term though, in view of the wide variation in lengths, this was not statistically significant. There was a weak positive correlation between cord length and birthweight (r=0.24) and also placental weight (r=.22). There was no difference in cord length by gender or by presentation when considered alone. However male infants delivered by vertex had a longer mean cord length than female infants delivered by breech (51.0 cm vs 46.6 cm, p=0.01). No obvious adverse fetal or perinatal outcome due to a fetus having an excessively long or short umbilical cord was found in this study, though stillborn infants had slightly shorter cords.Central insertion of the umbilical cord was found in 47.5 % of the cases while eccentric, marginal and velamentous insertions accounted for 50.5, 2.0 and 0 % respectively. There was no significant association between various insertions and infant birthweight and placental weight, and neither was the fate of the infant fetus adversely affected. This study helps in establishing a baseline for cord length and insertions and will assist as a baseline for further studies on umbilical cord length and placenta.