A randomized controlled trial comparing dilation and evacuation outcomes with and without oxytocin use
Awarded 2014
Complex Family Planning Fellowship Research
Katherine Whitehouse, DO
University of Hawaii at Manoa

Background: Hemorrhage, the most common complication of dilation and evacuations is estimated to occur in 0.8% to 2.1% of procedures. The rate of hemorrhage increases with gestational age, affecting up to 6.3% of dilation and evacuations performed above 18-weeks gestation. Many practitioners report the use of prophylactic uterotonics, like oxytocin, with dilation and evacuation to minimize blood loss and decrease the risk of hemorrhage. Literature to support this practice is scarce and physiological evidence suggests synthetic oxytocin is unlikely to affect bleeding prior to the third-trimester of pregnancy.
Objectives: To determine whether routine use of intravenous oxytocin will affect the rate at which providers must intervene to control excessive blood loss (yes/no) at the time of dilation and evacuation. Secondary outcomes include measured blood loss, complication rates, procedure length, and postoperative pain and satisfaction.
Methods: This is a randomized, double blind, placebo-controlled trial enrolling participants at two sites, the University of Hawaii and the University of Washington. A total enrollment of 166 subjects is planned. Women undergoing dilation and evacuation at 18- to 24-weeks gestation will be eligible to enroll. Exclusion criteria include uterine anomalies, multiple gestation, use of anticoagulants, chorioamnionitis, bleeding disorders, placenta accreta and preoperative misoprostol use. Subjects will be randomized to receive a bolus of 500-ml of IV fluids with 20-units of oxytocin or 500-ml of IV fluids alone at the time of placenta removal.
The sample size has 80% power (two-side alpha 0.05) to detect a difference of 15% in the need to intervene for bleeding (yes/no). Our primary outcome will be analyzed using a chi-squared test. For secondary outcomes, chi-square test will be used to compare categorical variables and student’s t-tests to compare continuous variables.
Results: Study documents are currently under IRB review. Based on prior studies, we estimate a 20% baseline rate of intervention to control excess blood loss. We hypothesize that if oxytocin had clinically significant effects, it would cause a decrease in intervention rates from 20% to 5%. We hope to provide evidence for or against the practice of the routine use of uterotonics in order to better inform the care of women undergoing dilation and evacuation.

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