The World Health Organization recommends infants should be exclusively breastfed for the first six months of life. Various factors can affect the maintenance of lactation. Increased physical activity and stress are thought to negatively affect breastfeeding success. The aim of this case study was to examine the effect of high serum creatine-kinase (CK) values and the success of breastfeeding after sports competition. It is assumed that continuous aerobic exercise is a stress for the body that can have a negative impact on lactation and extended breastfeeding. Methods. The level of acute muscle damage (AC) was measured before and after the competition in order to confirm continuous exposure to aerobic exercise. Results. After the competition, elevated serum creatine-kinase levels were noted. Prolactin and TSH values remained within optimal values. Conclusion. Several months of preparation for the competition had an impact on increasing acute muscle damage (AC) after the competition. No negative effect of continuous aerobic exercise on breastfeeding success was observed in this case study.

Pregnancy is a physiological condition during which a series of morphological and anatomical
changes occur. Adaptation to new changes in the body depends on the psychological and
physical condition of the patient. One of the many factors that affect the quality of life is physical
exercise. Proper exercise prevents certain chronic diseases, reduces pregnancy discomfort, gives
a feeling of satisfaction and influences a positive outcome of the pregnancy. The aim of this
study was to examine the validity of the preliminary version of the questionnaire, and therefore
examine the impact of exercise on the quality of life during pregnancy. The questionnaire
involved pregnant women (N=33). All of whom were in their third trimester of pregnancy. The
participants voluntarily filled out an anonymous questionnaire. The questionnaire included
information about: social and marital status, education, frequency of maternity problems, the
type of exercise, as well as the level of training load during pregnancy. High reliability and
validity of the survey (0,873) was determined by Cronbach alpha coefficient. Pregnant women
(48%) commonly practiced low intensity yoga, up to three times a week. Most of the women
(45%) believe that the exercise has a positive impact on their health. A difference of statistical
significance was observed between the type of exercise and heart burn (r=0.349; p=0.046), as
well as between the type of exercise and body weight (r=0.357; p=0.041). The results of this
pilot study show a lower incidence of common maternity symptoms in pregnant women who
exercised during pregnancy.