Effect of gravity on volume of placental transfusion: a multicentre, randomised, non-inferiority trial

Background: Delayed cord clamping allows for the passage of blood from the placenta to the baby and reduces the risk of iron deficiency in infancy. To hold the infant for more than 1 min at the level of the vagina (as is presently recommended), on the assumption that gravity affects the volume of placental transfusion, is cumbersome, might result in low compliance, and interferes with immediate contact of the infant with the mother. We aimed to assess whether gravity affects the volume of placental transfusion

Methods: We did a multicentre non-inferiority trial at three university-affiliated hospitals in Argentina. We obtained informed consent from healthy mothers with normal term pregnancies admitted early in labour. Vigorous babies born vaginally were randomly assigned in a 1:1 ratio by computer-generated blocks and sequentially numbered sealed opaque envelopes to be held for 2 min before clamping the umbilical cord, at the level of the vagina (introitus group) or on the mother's abdomen or chest (abdomen group). Newborn babies were weighed immediately after birth and after cord clamping. The primary outcome was the difference in weight (as a proxy of placental transfusion volume). The prespecified non-inferiority margin was 18 g (20%). We used t test and χ(2) test for group comparison, and used a multivariable linear regression analysis to control for covariables. This trial is registered with ClinicalTrials.gov, number NCT01497353.

Findings: Between Aug 1, 2011, and Aug 31, 2012, we allocated 274 newborn babies to the introitus group and 272 to the abdomen group. 77 newborn babies in the introitus group and 78 in the abdomen group were ineligible after randomisation (eg, caesarean section, forceps delivery, short umbilical cord or nuchal cord). Mean weight change was 56 g (SD 47, 95% CI 50-63) for 197 babies in the introitus group compared with 53 g (45, 46-59) for 194 babies in the abdomen group, supporting non-inferiority of the two approaches (difference 3 g, 95% CI -5.8 to 12.8; p=0.45). We did not note any serious adverse events during the study.

Interpretation: Position of the newborn baby before cord clamping does not seem to affect volume of placental transfusion. Mothers could safely be allowed to hold their baby on their abdomen or chest. This change in practice might increase obstetric compliance with the procedure, enhance maternal-infant bonding, and decrease iron deficiency in infancy.

Funding: Foundation for Maternal and Child Health (FUNDASAMIN).