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 < 0.001). This association was much stronger in Africans as compared to non-Africans (OR = 5.26, 95% CI: 1.04-26.57 vs. OR = 1.67, 95% CI: 1.07-2.61) after controlling for the confounding effect of maternal age. A gradient effect of exposure to H. pylori, determined by presence of specific IgG antibody in serum, and increased frequency of HG was present in Africans (test for linear trend P = 0.05) and non-Africans (test for linear trend P = 0.004).
Conclusion: These results indicate that H. pylori increase the risk of HG with a dose-response pattern and stronger in Africans.