Background: The third stage of labour is from birth of the baby until delivery of the placenta. Clamping the umbilical cord is one component of active management of the third stage. Deferring cord clamping allows blood flow between the baby and the placenta to continue; net transfer to the baby is called placental transfusion. If the cord is clamped immediately placental transfusion is restricted. Gravity is one of several factors that may influence the volume and duration of placental transfusion at both vaginal and caesarean births. Hence raising or lowering the baby whilst the cord is intact may influence placental transfusion, which in turn may affect outcome for the baby and the woman.
Objectives: To compare the effects of alternative positions for the baby between birth and cord clamping on outcome for the baby, outcome for the mother and on use of health service resources.
Search strategy: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (July 2010).
Selection criteria: Randomised trials comparing alternative positions for the baby at vaginal and caesarean birth, before clamping of the umbilical cord.
Data collection and analysis: We independently assessed trial eligibility and quality. When necessary, we contacted study authors for additional information.
Main results: Thirty-seven studies (7559 mother-infant pairs) were excluded: 33 (7296) because they did not compare alternative positions for the baby before clamping the umbilical cord and four (263) due to quasi-random allocation. No studies met the inclusion criteria. One additional trial is ongoing.
Authors' conclusions: No randomised trials have assessed the influence of gravity on placental transfusion. Large, well-designed randomised trials are needed to assess whether gravity influences placental transfusion at vaginal and caesarean births and, if so, whether this affects short-term and long-term outcome for the baby and for the mother.