Epidemiology, Risk Factors, and Pathogenesis of NVEP
Nausea and vomiting during pregnancy is known to be more common in younger primigravid women, as well as in Western countries and urban areas.[2] Risk factors for its development include history of estrogen-based medication causing nausea and motion or migraine causing nausea. Multiple gestation pregnancies,[3] women who did not take multivitamins before conception,[4] those with acid reflux,[5] and those with a hydatidiform mole[6] also are known be at increased risk. There seems to be a genetic component to developing hyperemesis gravidarum; several studies demonstrate that daughters of women who experienced the condition are at increased risks.[7,8] It is interesting that alcohol consumption and cigarette smoking have both been demonstrated to be protective.[9] The exact pathogenesis of NVEP remains unclear; however, hormonal changes including elevated serum human chorionic gonadotropin have been implicated,[2] as have psychological factors and stress response.[10] Delayed or dysrhythmic gastric motility also has been postulated as a likely cause of NVEP.[2]