Rhodes Index of Nausea and Vomiting - Form 2 in pregnant women - A confirmatory factor analysis

Background: of Nausea and Vomiting-Form 2 (INV2) in practice and research, empirical analyses have not been consistently performed to verify the a pri ori factors that guided the subclass construction of the symptoms. Objectives: To examine the dimensional structure of Rhodes INV in a sample of pregnant women. Method: Data were collected from 152 pregnant women who were experiencing s ome degree of nausea and vomiting during early pregnancy and analyzed using structural equation modeling techniques. Five competing measurement struct ures were tested and compared. The structure (model) that provided the clos est fit to the data was selected and relationships (factor loadings) betwee n the constructs and indicators were established. Results: The model fitting the data the closest was a three-factor structur e measuring nausea, vomiting, and retching as three separate, but correlate d dimensions. The factor loadings were high (0.73-0.96) and significant (p < .001). The model treating nausea and vomiting as a one-factor concept as well as the model including two factors named symptom occurrence and sympto m distress did not fit the data. Conclusion: Rhodes INV2 is a valid measurement tool if subscales are formed to reflect the multidimensional structure of nausea and vomiting in pregna ncy.