Pathophysiology

Although the exact cause is not yet to be known, multiple theories suggest the etiology. Higher levels of hCG (that peaks late in 1st trimester and early in second trimester) have been implicated in many patients with Hyperemesis gravidarum. Higher levels of Estrogen (that peaks in the first trimester) have been suggested to be the cause of this condition. As a result of gastrointestinal changes in pregnancy, lower esophageal sphincter undergoes relaxation which brings about GERD symptoms hence exaggerating emetic symptoms.