The effects of the menstrual cycle on the incidence of emesis and efficacy of ondansetron.

Postoperative nausea and vomiting after general anesthesia remains a complex and perturbing phenomenon associated with several factors. In women, the phase of the menstrual cycle as a factor in postoperative nausea and emesis is controversial. This retrospective study was performed to assess the effects of the menstrual cycle and efficacy of the antiemetic ondansetron on postoperative emesis.