Comparison of Hematocrit and Microbilirubin Levels at 48 Hours after Cesarean Delivery in Term Infants:Delayed Cord Clamping for 30 Seconds versus Delayed Cord Clamping for 30 Seconds Combined with Umbilical Cord Milking

Abstract

The rate of cesarean delivery in Thailand has been steadily increasing to over 40% of all births, leading to a higher risk of neonatal anemia associated with early cord clamping. Delayed cord clamping (DCC) and umbilical cord milking (UCM) enhance neonatal red blood cell volume and iron stores. However, evidence on DCC combined with UCM among term infants delivered by cesarean section remains limited. The objective of this study was to compare hematocrit (Hct) and microbilirubin levels at 48 hours after birth between term infants undergoing DCC for 30 seconds (n=79) and DCC for 30 seconds combined with UCM (n=70). It was conducted at Sansai Hospital, Chiang Mai, Thailand, from October 2022 to March 2023. Additional analysis used optimal 1:1 propensity score matching without replacement, with a caliper of 0.2 standard deviations of the logit propensity score, resulting in 67 matched pairs. All propensity score covariates achieved an absolute standardized mean difference (SMD) below 0.10 after matching. It was found that the mean Hct was slightly higher in the DCC + UCM group than in the DCC group (51.27±4.99% vs. 50.87±5.27%, mean difference=0.40 percentage points, 95%CI: -1.44 to 2.25, p>0.05, Cohen’s dz = 0.05), without statistical significance. Mean microbilirubin levels were similar (9.36±1.94 vs. 9.47±1.96 mg/dL; mean difference-0.12 mg/dL, 95%CI: -0.90 to 0.67, p> 0.05). Neonatal intensive care unit admission (4.5% vs. 1.5%, p>0.05) and phototherapy (4.5% vs. 6.0%, p<0.05) also did not differ significantly. In conclusion, DCC for 30 seconds combined with UCM was not associated with statistically significant differences in neonatal hematocrit or microbilirubin levels. A randomized controlled trial is recommended to confirm the efficacy and safety of this combined intervention.