Oxytocin uterotonic agents are routinely administered during the third stage of labor, however, the administration route is varying, intravenously or intramuscularly. We aimed to compare the effect of different regimens of postpartum oxytocin administration on hemoglobin (Hb) and hematocrit (Hct) decline.
A randomized, 3-arm study of women who delivered vaginally at term in a single tertiary medical center was conducted. Immediately following the delivery of the fetus women randomly received one of 3 oxytocin regimens: 1) intramuscular 10units (IM group); 2) intravenous 10units in 100 ml 0.9%NaCl solution over 10-15 min (IV group); or 3) combined IV + IM regimens (IV + IM group). Primary outcome was defined as the level of Hb decline between prepartum and postpartum measurements.
Overall, 210 women (70 in each group) were randomized, with 171 included in the final analysis (IM group-61, IV group-57, IV + IM group-53). There was no significant difference between the groups regarding maternal age, pre-pregnancy body-mass-index (BMI), parity, operative vaginal deliveries rate, the rate of episiotomy or perineal tears or neonatal birthweight. Mean prepartum Hb and Hct level were 12.3 ± 1.1 g/dl and 36.9 ± 2.7%, respectively, with no significant difference between the groups. Mean postpartum HB and Hct decline was 1.3 ± 0.8 g/dl and 3.7 ± 2.3%, respectively, with no difference between the groups. In multivariable analysis after adjusting for parity, pre-pregnancy BMI, labor induction, episiotomy or perineal tears and neonatal birthweight, oxytocin regimen was not associated with any difference in hematological measurements.
Postpartum Hb and Hct decline was usually minor following vaginal deliveries, and was not affected by postpartum oxytocin regimen.

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