Factors Influencing Umbilical Cord Separation Time in Term and Preterm Newborns: A Prospective Cohort Study from a Tertiary Center in Turkey

Objective Umbilical cord separation time (UCST) may be influenced by neonatal, perinatal, maternal, and environmental factors. This study aimed to determine UCST in term and preterm newborns and to identify factors associated with its variation. Study Design In this prospective cohort study, 970 newborns delivered between March 2021 and March 2022 at a tertiary maternity and children’s hospital were enrolled. Demographic and perinatal data, maternal health history, and umbilical cord characteristics were recorded. Cord separation and related findings were assessed by parental interviews on postnatal days 7 and 14. Results Of the 970 neonates, 51.7% were male, 17.1% were preterm. Mean UCST was 8.5 ± 3.1 days (median: 8, range: 3-21). In univariable analyses, UCST was significantly longer in preterm infants (p=0.028), after cesarean delivery (C/S) (p<0.001), and was shorter in summer than in autumn (p=0.004). After revision of birth-weight categories in the categorical analysis, the association between birth-weight groups and UCST was no longer statistically significant (χ2=6.43, p=0.377). In multivariable linear regression performed in 902 newborns with complete data, higher lactate (β=-0.210, 95% CI: -0.413 to -0.006, p=0.043) and hemoglobin (β=-0.166, 95% CI: -0.255 to -0.076, p<0.001) levels were independently associated with shorter UCST, whereas C/S (β=1.171, 95% CI: 0.740 to 1.601, p<0.001) and summer birth (β=-0.473, 95% CI: -0.893 to -0.053, p=0.027) remained independently associated with UCST. The explanatory power of the model was limited (R2=0.094). Conclusion UCST was associated with several perinatal and environmental factors, although the observed effects were generally modest. In multivariable analysis, lactate, hemoglobin, delivery mode, and summer birth remained independently associated with UCST. Further multicenter studies are needed to clarify the mechanisms and clinical implications of these associations.