Hyperemesis gravidarum: pathogenesis and the use of antiemetic agents.

INTRODUCTION: Nausea and vomiting in pregnancy remains the most common cause of hospitalization in the first half of pregnancy. Although the exact cause is largely unknown, an interaction of genetic, biological and psychological factors is plausible. An endocrine trigger for hyperemesis has been linked with both ovarian and placental hormones, but this association requires further clarification. The use of type-3 serotonin receptor antagonists is increasing but as yet there are no convincing data to demonstrate their superiority over the other antiemetics. AREAS COVERED: A computerized search was conducted using PubMed, Embase, Cinahl, Lilacs, ISI Web of Science, the Cochrane Central Register of Controlled Trials (all from inception or 1960 to October 2010), and Research Registries of ongoing trials. The key words used were nausea, vomiting, emesis, hyperemesis gravidarum, morning sickness, pregnancy, pregnancy complications, treatment, efficacy, effectiveness, antiemetics, safety and teratogenesis. EXPERT OPINION: The precise mechanism underlying hyperemesis gravidarum remains unclear, but appears to be multifactorial. As yet there is no evidence that any antiemetic class is superior to another with respect to effectiveness.