Inclusion Criteria:  Criteria: Inclusion Criteria:  For pregnant women:  course of pregnancy allowing participation in physical activities adapted to pregnant women consent of the obstetric care provider to participate in the study tests and exercise classes; taking part in all diagnostic and control tests to assess selected biological, functional and psychological parameters at each trimester of pregnancy, during the puerperium and one year after childbirth; participant's consent to use data from the medical documentation on the course of childbirth and the assessment of the new-born, as well as the results of preventive examinations in children aged one, two, four and six, routinely performed according to the Polish pediatric care system; availability to participate in classes three times a week until the day of delivery; declaration of participation in postpartum classes at least once a week and self-completion of the exercise program according to written instructions prepared by the exercise specialist; women can participate in the exercise programs regardless of their level of fitness or exercise capacity, as well as the level of motor skills (based on the diagnostic exercise tests, the exercise program will be tailored to the individual needs and capabilities of a woman).  For nonpregnant women:  nulliparous; lack of diagnosed infertility and other disorders of the reproductive system; taking part in all diagnostic and control tests to assess selected biological, functional and psychological parameters at indicated time points: before and after each of the 8-week exercise program during the first 8 months of the study and once every 3 months during the following twelve months of the study declaration of availability to participate in exercise classes three times a week for the first 8 months of the program (attendance at least 80% is required); declaration of participation in classes at least once a week and self-completion of the exercise program to the required 150 minutes of physical activity per week, according to the written guidelines prepared by the instructor, for the next 12 months of the program; women can participate in the exercise program regardless of their level of fitness or exercise capacity, as well as the level of motor skills (based on the diagnostic exercise tests, the exercise program will be tailored to the individual needs and capabilities of a woman).  Exclusion Criteria for Pregnant and Nonpregnant Women:  contraindications to increased physical effort or to any of the diagnostic or control tests; allergies to materials used during diagnostic and control tests (e.g. nickel present in steel plates of vaginal electrodes, disinfectants); other conditions that, according to the researchers, will threaten the health or safety of the participants or will significantly affect the quality of the collected data.