True knot of the umbilical cord and long-term neurological morbidity of the offspring

Objective
True knot of the umbilical cord is a rare phenomenon with potentially compromised fetal perfusion. We aimed to investigate a possible association between true knot of cord and long-term neurological morbidity of the offspring.

Study Design
A population based cohort analysis was performed, comparing the risk for neurological long-term morbidity of the offspring, based on the presence or absence of true knot of umbilical cord as confirmed upon delivery. Pregnancy and delivery data as well as later neurological related hospital admissions were based on computerized hospital records of the same single regional tertiary center. All singleton infants born between the years 1991-2014 and discharged alive were included in the study. A Kaplan-Meier survival curve was constructed to compare cumulative incidence of neurological morbidity, and a Cox proportional hazards model was used to control for confounders including gestational age, pregnancy complications and maternal factors.

Results
During the study period, 242,342 newborns met the inclusion criteria, 2558 (1.1%) of which were born with a diagnosis of true knot of cord. During the follow up period, total neurological hospitalizations were comparable between the groups (3.7% of the exposed group and 3.1% in the comparison group, p=0.078; Table) as were the cumulative incidences of neurological morbidities over time (log rank p=0.12; Figure). The Cox regression confirmed lack of association between true knot of cord and total neurological related morbidity (adjusted HR=1.153, 95% CI 0.942-1.412, P=0.168) while controlling for diabetes, hypertensive disorders, preterm delivery and maternal age.

Conclusion
Children born following a confirmed diagnosis of true knot of umbilical cord are not at an increased risk for long-term neurological morbidity.