Effects of delayed cord clamping at different time intervals in late preterm and term neonates: a randomized controlled trial

Abstract

Delayed cord clamping (DCC) at delivery has well-recognized benefits; however, current scientific guidelines lack uniformity in its definition. This parallel-group, three-arm assessor-blinded randomized controlled trial compared the effects of three different timings of DCC at 30, 60, and 120 s on venous hematocrit and serum ferritin levels in late preterm and term neonates not requiring resuscitation. Eligible newborns (n = 204) were randomized to DCC 30 (n = 65), DCC 60 (n = 70), and DCC 120 (n = 69) groups immediately after delivery. The primary outcome variable was venous hematocrit at 24 ± 2 h. Secondary outcome variables were respiratory support, axillary temperature, vital parameters, incidences of polycythemia, neonatal hyperbilirubinemia (NNH), need and duration of phototherapy, and postpartum hemorrhage (PPH). Additionally, serum ferritin levels, the incidence of iron deficiency, exclusive breastfeeding (EBF) rate, and anthropometric parameters were assessed during post-discharge follow-up at 12 ± 2 weeks. Over one-third of the included mothers were anemic. DCC 120 was associated with a significant increase in the mean hematocrit by 2%, incidence of polycythemia, and duration of phototherapy, compared to DCC30 and DCC60; though the incidence of NNH and need for phototherapy was similar. No other serious neonatal or maternal adverse events including PPH were observed. No significant difference was documented in serum ferritin, incidences of iron deficiency, and growth parameters at 3 months even in the presence of a high EBF rate. Conclusion: The standard recommendation of DCC at 30-60 s may be considered a safe and effective intervention in the busy settings of low-middle-income countries with a high prevalence of maternal anemia. Trial registration: Clinical trial registry of India (CTRI/2021/10/037070). What is Known: • The benefits of delayed cord clamping (DCC) makes it an increasingly well-accepted practice in the delivery room. • However, uncertainty continues regarding the optimal timing of clamping; this may be of concern both in the neonate and the mother. What is New: • DCC at 120 s led to higher hematocrit, polycythemia and longer duration of phototherapy, without any difference in serum ferritin, and incidence of iron deficiency. • DCC at 30-60 s may be considered a safe and effective intervention in LMICs.

Keywords: Delayed cord clamping; Hematocrit; Newborn; Postpartum hemorrhage; Time factors; Umbilical cord.