This research with a quantitative approach, descriptive, cross-sectional and analytical, was carried out with the objective of classifying the level of sedentary lifestyle of a group of pregnant women and associating it with their body mass index, for which the Pérez Sedentarism test was applied. - Rojas- García (modification of the Manero test). The sample consisted of 22 pregnant women. 32% of the total sample studied was active and 18.2% very active; with severe sedentary lifestyle, 27.3%; moderate, 9.1% and mild sedentary lifestyle, 13.6%. In other words, 50% were classified as active and very active; and the other half showed some level of sedentary lifestyle. The BMI was normal in 68% of the sample and overweight in the remaining 32%; the whole group of 18.2% very active, with normal BMI. The statistical test does not significantly associate the level of sedentary lifestyle with the BMI; However, it classifies as a risk factor for overweight, severe sedentary lifestyle; and as a protective factor, the level of assets.