Deferred cord clamping (DCC) at 1 min versus 3 min in preterm neonates - an open label randomized, controlled trial

Deferred cord clamping (DCC) is the recommended method of placental transfusion for newborns who are vigorous at birth irrespective of gestational age. But there is lack of uniformity regarding the timing of DCC. The purpose of this study was to determine the effect of DCC for 3 min as compared to DCC for 1 min on clinically relevant hematological and hemodynamic parameters in preterm neonates. The primary outcome evaluated was venous hematocrit (Hct) at 48 (± 4) hrs of postnatal age. The important secondary outcomes assessed were mean blood pressure during the transitional period, venous Hct and ferritin levels at 6 weeks of age and significant neonatal morbidities. Three hundred and four (304) neonates of 30- 36 ^6/7 weeks gestation were assigned in a 1:1 ratio to either DCC for 1 min (n = 152) or DCC for 3 min (n = 152) in this stratified randomized controlled trial. For statistical analysis, the unpaired Student t and Chi square or Fisher's exact test were employed. The DCC for 3 min group had a higher mean Hct at 48 h than the DCC for 1 min group, 43.18 (5.292) vs. 41.02 (4.420), p < 0.001. Additionally, the DCC for 3 min group had a significantly higher mean blood pressure in the transitional phase and mean Hct at 12 h and 6 weeks (p < .0001). In the subgroup analysis (stratified by gestational age of 30-33⁺⁶ weeks, 34-36⁺⁶ weeks), similar differences were noted. There were no significant differences between the groups in terms of need for phototherapy, symptomatic polycythemia or other important neonatal morbidities.

Delaying the clamping of cord for 3 min improves blood pressure and results in higher venous hematocrit in the initial transitional phase and beyond. DCC for 3 min may be a feasible and useful placental transfusion technique in the preterm population. Larger multicentric studies are required to confirm its efficacy and safety.

CTRI/2024/10/075751; registration date October 23, 2024.

• DCC is universally recommended for vigorous neonates at birth but no consensus exist for its duration. • Studies on the effective duration of DCC are scarce in the preterm population.

• Delaying clamping of cord for 3 min is an effective placental transfusion strategy in preterm neonates of 30- 36 6/7 weeks gestation • DCC for 3 min can be an important strategy especially in developing countries where baseline prevalence of anemia is high.