Evaluation of the Reproducibility and Validity of a Physical Activity Questionnaire for Pregnant Women

Introduction: Physical activity practice has been encouraged by several national and international entities aiming health promotion. However, there is no consensus concerning the influence and optimal intensity of physical activity during pregnancy, probably due to difficulties to measure and classify the level of physical activity by questionnaires. It has not been identified any validation study of physical activity questionnaire on Brazilian pregnant women. The purpose of the present study is to analyze the reliability and concurrent validity of a physical activity questionnaire for pregnant women. Methods: A sample of 68 women in the second trimester of pregnancy has been interviewed by the elaborated questionnaire. Reliability was assessed after approximately a week and in the postpartum. The subjects used a heart rate monitor between the two first interviews (n=38). Results: Reproducibility analyses were adapted with interclass correlation coefficients varying from 0.54 to 0.85. The analysis of categorical variables, with subjective questions of self-perception of physical activity, resulted in wider range of kappa coefficients, with values between 0.29 and 0.76 for application of the questionnaire within one week of interval, and between 0.08 and 0.70 when compared with the postpartum. The validity analyses had a satisfactory result considering the average of differences seen through Bland-Altman graphics comparing questionnaire and the heart rate monitors. However, the dispersion interval was not adequate, since it varied in more than seven hours for light activities and almost eleven hours per day for moderate activities. Analyses of current study seem to assure the reliability of the physical activity questionnaire for pregnant women. However, concerning validation, the comparison with results obtained by heart rate monitors did not show adequate degrees of agreement.