Variables related to nausea and vomiting during pregnancy.

Seventy to 90 percent of all pregnant women experience nausea, and 50 percent have at least one episode of vomiting or retching. A continuous measure was used to quantify symptoms of nausea with or without vomiting or retching during pregnancy in 126 women. Relationships between symptoms and selected variables were evaluated. Nausea with or without vomiting or retching was associated with maternal age, occupation, parity, cigarette smoking, infant gender, and the personality trait of independence. Significant associations were entered into multiple regression equations. Fourteen percent of the variation in symptoms overall, 25.1 percent of the variation in nausea symptoms, and 16.6 percent of the variation in vomiting or retching symptoms were explained by a combination of these selected independent variables. Although this study found associations, independent variables contributed little to predicting or explaining the presence and severity of nausea and vomiting during pregnancy. More sensitive measures and evaluation are required to understand and treat this perplexing phenomenon.