Oxytocin and Hypotension During Dilation and Evacuation Procedures at 18-24 Weeks Gestation

Oxytocin is a neurohormone that is routinely administered to patients during dilation and evacuation procedures (D&E) to control bleeding despite minimal evidence in support of this common practice. In this study, the authors sought to evaluate patients with hypotension after receiving oxytocin during D&E procedures. The secondary data from a double-blind, randomized, placebo-controlled trial involving 112 patients who underwent a D&E at 18-24 weeks gestation and prophylactically received an intravenous bolus of either 30 units of oxytocin in 500 mL of normal saline or 500 mL of saline alone at the start of the procedure were analyzed. Anesthesia providers measured blood pressure before, at the time of, and after study medication administration in 5-minute increments until the end of the procedure. No differences in demographic characteristics or mean blood pressure between the 2 groups were observed. The proportion of hypotensive patients was not statistically different at 5 minutes following fluid bolus (oxytocin 25% versus placebo 13%, P=.09). The proportion of hypotensive patients was similar by 10 minutes (oxytocin 20% versus placebo 16%, P=.62). A sample size of 112 provided the ability to detect a 23% difference in the proportion of patients who experienced hypotension (2-sided 95% CI, power of 80%). These findings suggest that oxytocin may have a transient hypotensive effect.