Introduction: The dynamic cyclical changes in the levels of various hormones during different phases of menstrual cycle are known to affect functioning of the respiratory system. Studies suggest that progesterone and estrogen levels strengthen the respiratory musculature and increase the relaxation of bronchial smooth muscles. This variation has been cited as the cause of change in lung functions during various phases of menstrual cycle.

Aim: To find out the effect on pulmonary functions during different phase of menstrual cycle.

MethodologyPatients who fulfil inclusion criteria were selected .The 30 female   subjects of age between 18 – 25 years were included. Girls were divided into two groups: Group 1(BMI = 18–22 kg/m²) [according to Asian scale], Group 2 (BMI = 23–26.9 kg/m²).Data of all the subjects were acquiring in the following two phases of menstrual cycle: Menstrual phase & Secretary Phase. These days were calculated from LMP dates. Subjects were asked to report two times on the 2^nd or 3^rd and between 20^th–22^nd days of menstrual cycle.

Result:  All parameters of pulmonary function were insignificant except PEFR of secretary phase.

Conclusion: There is no change in pulmonary function due to higher BMI in overweight   compare to normal.