Mild to moderate dyspepsia is commonly associated with nausea and vomiting and complicates about 50% of all pregnancies and it diminishes women’s life quality and social functions during early pregnancy. In most women, these symptoms resolve by fluid and vitamin supplementation as well as dietary modification. About 0.3%-2% of pregnant women suffer from Hyperemesis Gravidarum (HG) characterized by severe and protracted vomiting that often results in dehydration, electrolyte imbalance, ketonemia, ketonuria, and weight loss. Dehydration and acid base disturbances may lead to renal and hepatic injury. Patients who manifest continuous weight loss and electrolyte disturbances may be at risk for growth restriction, fetal anomalies and decreased neonatal birth weight. The onset of gastrointestinal symptoms is always during the first trimester, but HG may persist throughout gestation. The etiology of HG, which still remains unknown, seems to be multifactorial and may be the final result of various unrelated conditions. Indeed, treatment is performed on a symptomatic basis. In particular, psychological causes, gastrointestinal tract dysfunctions, endocrine factors genetic incompatibility, immunological factors and nutritional deficiencies have been considered part of the pathologic mechanism underlying HG.
Significant positive association between HG and H. pylori infection has been demonstrated by several case-control studies, and in a systematic review of previous 14 case-control studies, Golberg et al found higher prevalence of HG in H. pylori-infected pregnant women than uninfected ones. Despite a high seropositive rate in pregnant women with severe gastrointestinal symptoms during early pregnancy, no correlation was found between seropositivity and clinical symptoms or their duration. One of researchers Shirin and colleagues reported an association between H. pylori and mild vomiting during early pregnancy but not with gastrointestinal symptoms later in pregnancy. Studies performed on endoscopic biopsies of gastric mucosa demonstrated that the severity of gastrointestinal symptoms in early pregnancy may be associated with the density of H. pylori in the gastric epithelium. Additionally, two case reports showed that H. pylori eradication treatment reduces the severity of HG.
It has been proposed that a reduction of gastric acid production during early pregnancy as a result of increased accumulation of woman’s body fluid, steroid hormone changes, and immunologic tolerance could lead the activation of latent H. pylori infection, which can exacerbate nausea and vomiting symptoms.