Introduction:
The recent data has shown that regular physical activity during pregnancy and before pregnancy has a positive effect on the physical and psychological condition of the future mother, fetal development, parturition, and functioning during postpartum period^1–6. What is more, physical activity started in pregnancy may have impact on a lifelong change to a health-promoting lifestyle. Research has also proved that prenatal physical activity of mothers has a long-term effect on the health of the children, including a reduction in the risk of obesity in later life^7,8.

Material and Methods:
A cross-sectional study is conducted within a group of healthy women in second trimester of singleton pregnancy and in the postpartum period. The study design included a questionnaire for characterizing sociodemographic, medical history (including pre-pregnancy BMI and weight gain) and International Physical Activity Questionnaire (IPAQ). All statistical analysis will be performed on dedicated software.

Results:
The study revealed that women who reported being physically active before and during pregnancy were more likely to have full-term birth and had a lower incidence of very premature and extremely premature births. Women who exercised during pregnancy more often gave birth to children with a normal body weight and were less likely to have children with low, very low or extremely low body weight.

Conclusions:
Our findings indicate that promoting physical activity and weight management remains a priority in public health policy, and women of childbearing age should be encouraged to adopt or maintain an active and healthy lifestyle during pregnancy in order to avoid sedentary - and obesity-associated risks affecting birth and newborns' health.