The purpose of this study is to determine the effect of the incentive spirometer on asthma during pregnancy.

This study will provide an evidence basis for obstetricians and physical therapist for women's health about the effect of spirometry on asthma during pregnancy.

Inclusion Criteria:

The patients will have the following criteria:

1. Their age will range from 30 to40years old.
2. Body mass index (BMI) will range from 25-29.9 kg/m2.
3. All patients will be clinically and medically stable.

Exclusion Criteria:

Patients will be excluded from the study if they have the following:

1. Diabetes mellitus.
2. Severe hypertension.
3. Neurological and neuromuscular disorders.
4. Blindness.
5. Developed moderate and severe degree of pleural effusion.
6. Cardiovascular instability.
7. Chronic chest disease.