specific share and predictive importance in the formation of impediment to the development of the fetus.The clinical retrospective study was carried out with occasion-control, traditional design. By random selection method, in the main group of 92 mothers were merged, whose pregnancy ended with the birth of a newborn with cervical development. The syndrome of fetal development of the fetus has been observed based on the non-conformity of the fetal data with the gestation period (after the 18th week of pregnancy with 10 percurrent indicators).The frequency and possible combinations of risk factors were analyzed during the material processing process. In the majority of cases of fetal development, the simultaneous existence of several factors of risk has been identified. Statistically significant risk factors have been defined as predictorative significance.The risk factors for high predictor significance have been identified: low levels of life (84%), endocrine pathology (82%), ischemic heart disease (85%), 85% of cases of cervical inflammation (85%), cervicitis (81%), chronic inflammation of ovaries (82%), endocrinologic pathology (82%), 86%) and the risk of pregnancy (80%). The predominant importance of preemaciation (92%) and minority (89%) was particularly high.In the study process, the mother's social-hygienic and medical-biological characteristics were studied. The risk factors, statistically significant, prioritized and high premedical significance have been identified, which can be detected at the preliminary stage. Timely identification and development of individual measures of management is important to minimize the exposure quality, to reduce the negative impact on pregnancy and the fetus.

Purpose The aim of the present study was to evaluate the determinants of gas exchange in smoking and nonsmoking teenagers during an incremental exercise test. Materials and Methods One hundred and fifty healthy Bulgarian school children in the age span 15 -17 years took part in the study. All participants completed anthropometric measurementsstanding height, weight and BMI and a questionnaire about smoking habits. The studied group performed an incremental exercise test on a treadmill following a modified Balke protocol. Results Near 90% of participating teenagers completed the exercise test to the end. Boys showed significantly higher values of oxygen consumption on different levels of the test and maximal oxygen consumption -VO 2 peak mL.min-1 = 2287 ±337 vs. 1702±278; p<0.001. In the studied population, smokers had slightly lower values without a significant difference -VO 2 peak mL.min-1 = 1777±288 vs. 1851±417; NS. VO 2 increases with age and correlated best with weight (R=0.83) and height (R=0.65) but less with BMI (R=0.59). Ventilatory equivalents for O 2 and CO 2 (V E /VO 2 , V E /VCO 2 ) decline with age. Girls in comparison with the boys had greater fatigue perception (Borg scale) during the incremental test.Conclusions The anthropometric parameters were the best determinants of physical capacity in teenagers. Smokers showed slightly lower but not significant values for VO 2 peak. Boys had significantly higher values for VO 2 peak compared with girls.