High Prevalence of Severe Nausea and Vomiting of Pregnancy and Hyperemesis Gravidarum Among Relatives of Affected Individuals

Abstract

The most common cause of hospitalization in the first half of pregnancy is hyperemesis gravidarum (HG), or severe nausea and vomiting of pregnancy (NVP). The reported estimates of the incidence of NVP/HG range from 0.3% to 10.8% with a mean of about 0.5%. Several lines of evidence suggest that ethnic origin and possibly genetic predisposition play a role in the development of NVP/HG. Most prior studies of HG were small population-based or case series that provided no information on family history. The present study was a self-reported survey assessing the incidence of severe NVP/HG among relatives of affected individuals. The participants were 1224 women who had experienced HG during one or more pregnancies and had completed an online survey evaluating family history administered by the Hyperemesis Education and Research (HER) Foundation. Most study subjects were nonHispanic white (88%) and nearly all resided in the United States (78%) or other English-speaking countries. No control group was recruited. Of the 1224 participants, 28% (348) reported that their mother had severe NVP or HG while pregnant with them. Among 9% (109/1224), there was a strong family history of HG: two or more affected relatives including sister(s), mother, grandmother, daughters, aunt(s), and cousin(s). The prevalence of HG among sisters of participants was 19% (19/721). Severe disease requiring total parenteral nutrition or a nasogastric feeding tube occurred in 25% (49/198) of the affected sisters. All three sets of identical twins reported in the survey had HG. These findings provide strong but preliminary evidence for a significant role of maternal genetic susceptibility in the development of severe nausea and vomiting of pregnancy.