A Cochrane review [Abstract] 1 included 40 studies with a total of 4 884 infants. The delay in cord clamping was 30 to 180 seconds (mostly between 30 to 60 seconds). There were less babies who died before discharge in delayed cord clamping group compared with early cord clamping group (table T1).There was no or little difference in severe intraventricular haemorrhage or in chronic lung disease.
| Outcome | Relative effect(95% CI) | Risk with control - early cord clamping | Risk with intervention - delayed cord clamping (95% CI) | №of participants(studies) |
|---|---|---|---|---|
| Death of baby (up to discharge) | RR 0.73(0.54 to 0.98) | 74/1000 | 54/1000 (40 to 72) | 2680(20) |
| Severe intraventricular haemorrhage | RR 0.94(0.63 to 1.39) | 48/1000 | 45/1000 (30 to 66) | 2058(10) |
| Intraventricular haemorrhage | RR 0.83(0.70 to 0.99) | 187 per 1000 | 155 per 1000(131 to 185) | 2333(15) |
| Chronic lung disease - oxygen supplement at 36 weeks (corrected for gestation) | RR 1.04(0.94 to 1.14) | 494 per 1000 | 514 per 1000(464 to 563) | 1644(6) |
Another systematic review and meta-analysis 2 included 18 RCTs (2834 infants). Mostly the delayd of clamping was 60 seconds or more. Delayed clamping reduced hospital mortality (RR 0.68; 95% CI 0.52 to 0.90; risk difference, -0.03; 95% CI -0.05 to -0.01; P = .005; number needed to benefit, 33; 95%). Subgroup analyses showed no differences between randomized groups in Apgar scores, intubation for resuscitation, admission temperature, mechanical ventilation, intraventricular hemorrhage, brain injury, chronic lung disease, patent ductus arteriosus, necrotizing enterocolitis, late-onset sepsis, or retinopathy of prematurity. Delayed clamping increased peak hematocrit by 2.73 percentage points (95% CI 1.94 to 3.52; P < .00001) and reduced the proportion of infants having blood transfusion by 10% (95% CI 6 to 13%; P < .00001). Potential harms of delayed clamping included polycythemia and hyperbilirubinemia.
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