BACKGROUND: Early medical management of nausea and vomiting during pregnancy is desirable but less than optimal. The aims of this study were to describe the management of nausea and vomiting during the first prenatal visit and to identify the determinants of 1) addressing the subject of nausea and vomiting during pregnancy with the health practitioner and 2) receiving an antiemetic prescription. METHODS: A prospective study was conducted of 283 women who reported nausea and vomiting during the first trimester of pregnancy. Women were eligible if they were at least 18 years of age and < or = 16 weeks' gestation at the time of their first prenatal visit. Participants completed a questionnaire to determine their maternal characteristics, the presence of nausea and vomiting during pregnancy, and its management. RESULTS: Of the 283 study participants, 79 percent reported that the condition was addressed during their first prenatal visit, 52 percent reported being asked about the intensity and severity of their symptoms, and 22 percent reported being questioned about the extent to which it disrupted their daily tasks. Health practitioners prescribed an antiemetic for 27 percent of women and recommended a nonpharmacological method for 14 percent. Multivariate models showed that the severity of the nausea and vomiting, previous use of an antiemetic, and smoking before pregnancy were significantly associated with an increased likelihood of addressing the subject of nausea and vomiting during pregnancy. Variables associated with an increased likelihood of women receiving an antiemetic prescription included nausea and vomiting severity, excessive salivation, previous antiemetic use, and work status. CONCLUSIONS: Health practitioners can improve their management of nausea and vomiting during pregnancy based on the available guidelines for treatment and they should address important factors such as symptom severity and work status at the first prenatal visit to assess women's need for antiemetic treatment