Epidemiology of nausea and vomiting of pregnancy: prevalence, severity, determinants, and the importance of race/ethnicity

Background: Studies that contributed to the epidemiology of nausea and vomiting of pregnancy have reported conflicting findings, and often failed to account for all possible co-variables necessary to evaluate the multidimensional associations. The objectives of this study were to: 1) Estimate the prevalence and the severity of nausea and vomiting of pregnancy during the 1(st) and the 2(nd) trimester of pregnancy, and 2) Identify determinants of presence and severity of nausea and vomiting of pregnancy during the 1(st) and 2(nd) trimesters separately, with a special emphasis on the impact of race/ethnicity. Methods: A prospective study including pregnant women attending the Centre Hospitalier Universitaire (CHU) Sainte-Justine or Rene-Laennec clinics for their prenatal care was conducted from 2004 to 2006. Women were eligible if they were >= 18 years of age, and <= 16 weeks of gestation. Women were asked to fill out a 1(st) trimester self-administered questionnaire and were interviewed over the telephone during their 2(nd) trimester of pregnancy. Presence of nausea and vomiting of pregnancy was based on the reporting of pregnant women (yes/no); severity of symptoms was measured by the validated modified-PUQE index. Results: Of the 367 women included in the study, 81.2% were Caucasians, 10.1% Blacks, 4.6% Hispanics, and 4.1% Asians. Multivariate analyses showed that race/ethnicity was significantly associated with a decreased likelihood of reporting nausea and vomiting of pregnancy (Asians vs. Caucasians OR: 0.13; 95%CI 0.02-0.73; and Blacks vs. Caucasians OR: 0.29; 95%CI 0.09-0.99). Conclusion: Our study showed that race/ethnicity was associated with the reporting of nausea and vomiting of pregnancy in the 1(st) trimester of pregnancy.