Nausea and vomiting of pregnancy.

Nausea and vomiting are common experiences in pregnancy, affecting 70% to 80% of all pregnant women. Various metabolic and neuromuscular factors have been implicated in the pathogenesis of nausea and vomiting of pregnancy (NVP) and hyperemesis gravidarum (HG), an entity distinct from NVP. However, their exact cause is unknown. Consequently, treatment of NVP and HG can be difficult, as neither the optimal targets for treatment nor the full effects of potential treatments on the developing fetus are known. This article reviews the epidemiology, pathology, diagnosis, outcomes, and treatment of NVP and HG.