Interventions for nausea and vomiting in early pregnancy.

BACKGROUND: Nausea and vomiting are the most common symptoms experienced in early pregnancy, with nausea affecting between 70 and 85% of women. About half of pregnant women experience vomiting.

OBJECTIVES: The objective of this review was to assess the effects of different methods of treating nausea and vomiting in early pregnancy.

SEARCH STRATEGY: We searched the Cochrane Pregnancy and Childbirth Group trials register and the Cochrane Controlled Trials Register. Date of last search: October 2001.

SELECTION CRITERIA: Randomised trials of any treatment for nausea and/or vomiting in early pregnancy.

DATA COLLECTION AND ANALYSIS: Trial quality was assessed and data were extracted independently by two reviewers.

MAIN RESULTS: Twenty-three trials were included. These trials were of variable quality. Nausea treatments were different anti-histamine medications, vitamin B6 (pyridoxine), the combination tablet Debendox (Bendectin) and P6 acupressure. For hyperemesis gravidarum five trials were identified testing treatments with oral ginger root extract, oral corticosteroids or injected adrenocorticotropic hormone (ACTH) and intravenous diazepam. Based on 13 trials, there was an overall reduction in nausea from anti-emetic medication (odds ratio 0.17, 95% confidence interval 0.13 to 0.21).

REVIEWER'S CONCLUSIONS: Anti-emetic medication appears to reduce the frequency of nausea in early pregnancy. There is some evidence of adverse effects, but there is very little information on effects on fetal outcomes from randomised controlled trials. Of newer treatments, pyridoxine (vitamin B6) appears to be more effective in reducing the severity of nausea. The results from trials of P6 acupressure are equivocal. No trials of treatments for hyperemesis gravidarum show any evidence of benefit. Evidence from observational studies suggests no evidence of teratogenicity from any of these treatments.