Objective: The aim of our study was to investigate whether the discrepancies in results between various studies of umbilical vein administration of oxytocin for retained placenta may be related to differences in the infusion techniques used.
Study design: An in vitro, descriptive study was performed. Contrast medium was injected into the umbilical vessels of 25 freshly delivered placentas and sequential x-ray films were taken.
Results: Capillary filling was inconsistent after injection of 20 ml of solution into the umbilical vein without or with "milking" of the cord (1/5 and 2/5, respectively). These are the techniques most commonly used in reported controlled clinical studies. Injection via an infant mucus aspiration catheter introduced along the umbilical vein to 5 cm from the placental insertion demonstrated a cotyledonary pattern in three of five cases after 20 ml and in all 5 after 30 ml.
Conclusion: The latter method (use of increased infusion volumes) is recommended in future studies to determine the effectiveness of umbilical vein administration of oxytocin for retained placenta.