Anatomical, physiological and biochemical adaptations that occur during pregnancy are profound. Changes in respiratory physiology are a part of the same process. In the present study of 70 selected women, 50 pregnant and nonpregnant control, it was found that out of seven parameters studied five showed changes. There were changes in respiratory frequency, tidal volume, vital capacity, inspiratory capacity and expiratory reserve volume. Maximum voluntary ventilation and timed vital capacity did not change. RF, VT, VC and IC rose significantly while ERV had a significant fall. These changes may be affecting ante-intranatal behaviour of pregnant women and their pregnancy outcome.