Abstract: Background: Pregnancy has many effects on the functions of women body systems.It is known that the respiratory rate of pregnant women increases as early as the first trimester. The aim of this study is to investigate the effects of pregnancy (2nd and 3rd trimesters) on lung function parameters (FVC, FEV1 and PEFR) and respiratory muscles power parameters (MIP and MEP) in Sudanese women from Khartoum state.