Summary The purpose of the research: analysis of the course of pregnancy and labor in patients qualified for the prenatal diagnostic tests program in Opole Region. Material and methods: 2513 pregnant women participated in the program. There were 1763 (70.1%) patients above 35 years of age, out of whom 515 women (20.5%) were qualified for amniocentesis and 394 of them (15.6%) decided to undergo the test. Within the group of patients who underwent amniocentesis, 39 karyotypes (9.8%) were found. Analysis of the number of amniocenteses carried out and the number of detected fetal defects showed that initially the number of invasive tests was rising. However, since 2007, i.e. since the introduction of biochemical diagnostic tests based on Kryptor technology, a significant decrease of amniocenteses tests has been observed, while the rate of detected chromosome aberrations in fetuses has not changed. The course of pregnancy and labor in patients above 35 years of age, who gave birth to children in Gynecology and Obstetrics Hospital in Opole, has also been analyzed. The investigated group comprised 106 patients who underwent amniocentesis, and 138 patients who did not consent to having the invasive test. Apart from a small difference in average birth weight, the analysis of infant condition and their biophysical parameters after the labor has not shown any significant differences. In both groups gestational diabetes was the most frequent disease, and statistically it was diagnosed more often in patients who had not undergone amniocentesis. No statistically significant differences in the frequency of occurrence of other pregnancy complications have been found. Conclusions: 1. Amniocentesis carried out due to genetic indications between 15th and 20th week of pregnancy may be considered to be a procedure which is safe both for a mother and a fetus. 2. Amniocentesis does not affect the course of pregnancy or the mode of delivery in any significant way. 3. Proper genetics counseling service based on biochemical research enables to decrease the number of amniocenteses tests, while the rate of detected chromosome defects in fetuses remains unchanged.