Approximately 70 percent of women who are pregnant have nausea and vomiting. These symptoms may have a significant impact on the mother, her family, and others, such as coworkers. Although several pharmacologic agents can reduce symptoms, most women are reluctant to take medications during the first trimester of pregnancy, when nausea and vomiting are most severe.Acupuncture is thought to be beneficial in reducing the symptoms of nausea and vomiting by stimulating the median nerve at P6, the Neiguan acupuncture point; however, clinical trials have produced contradictory results. Rosen and colleagues studied the efficacy of noninvasive electrical stimulation (acustimulation) of the median nerve at the P6 point to relieve symptoms of nausea and vomiting during pregnancy.

The researchers recruited 230 women who were having nausea and vomiting for at least three days between six and 12 weeks of gestation. Women were excluded if they had other conditions that could cause nausea, had cardiac pacemakers, or had been treated with acupuncture previously. On admission to the study, the patients completed a standardized questionnaire to document the severity and impact of their symptoms. Baseline assessments of height, weight, blood pressure, urinary specific gravity, and ketonuria were obtained. The patients were assigned randomly to receive an active or a sham electrical stimulator and were told that they might be able to feel the electric impulses. Patients could increase the intensity of the device to control symptoms if necessary.

Patients were asked to complete the symptom questionnaire in the morning and evening on the first seven days of the study and on days 9, 11, 13, 17, and 21. Patients also recorded the amount of time they wore the device, the location of the device, intensity settings, the use of medications during the study, and perceived side effects.

There were no statistically significant differences in women in the treatment group (95 patients) compared with women in the control group (92 patients). Three patients from each group withdrew from the study, but only one patient withdrew because of a problem with the device. The change in symptom index in patients who received treatment was significantly better than the change in the control group. In addition, 77 percent of treated patients gained weight during the study compared with only 54 percent of patients in the control group. Three episodes of dehydration were reported in patients receiving acustimulation (2.6 percent) compared with 12 episodes among patients in the control group (10.6 percent). The groups did not differ in the use of additional medication during the study period. Among women in the acustimulation group, 72 percent did not use additional medication, compared with 75 percent of women in the control group.

The authors conclude that nerve stimulation at the P6 Neiguan point reduces symptoms of nausea and vomiting during early pregnancy and is associated with measurable improvement in well-being and weight gain.