BACKGROUND: The etiology of Hyperemesis gravidarum (HG) is unclear. To test the hypothesis of an association between Helicobacter pylori infection and HG, an institution-based case-control study was performed at Aker University Hospital (AUH) during 1994-1999. MATERIAL AND METHOD: From the same source population, 244 incident cases of HG and 244 pregnant women free of the disease (controls) were consecutively identified. RESULTS: H. pylori were noted in 105 cases and 58 control subjects. The presence of H. pylori increased the risk of HG more than two fold (OR = 2.42, 95% CI: 1.64-3.57, P
