The menstrual cycle and nausea or vomiting after wisdom teeth extraction.

We have investigated 195 pre-menopausal women undergoing third molar extractions, in a prospective study, to assess the influence of the day of the menstrual cycle on the incidence of postoperative nausea or vomiting. In the 95 patients taking the oral contraceptive pill the incidence of postoperative nausea or vomiting was higher on days 9 to 15 of the menstrual cycle (P < 0.05) than on days one to eight and days 16 to the end of cycle. In the 100 patients who were not taking the oral contraceptive pill the incidence of postoperative nausea or vomiting was not higher on days 9 to 15. The strongest predictor for postoperative nausea or vomiting in our study was a previous episode of postoperative nausea or vomiting (P < 0.005). Patients with a tendency to motion sickness did not have a higher incidence of postoperative nausea or vomiting.