Purpose - to analyze the hormonal function of the fetoplacental complex in pregnant women with normal and low-lying chorion. Materials and methods. 50 pregnant women with a low-lying chorion (main group) and 50 pregnant women with a position of the chorion in the body and fundus of the uterus (control group) were involved in the laboratory examination. All examined women of the main group were divided into 2 subgroups, depending on the period of gestation (25 women at 5-8 weeks of gestation and 25 women at 9-12 weeks of gestation). According to these terms, the control group was also divided (25 women at 5-8 weeks of gestation and 25 women at 9-12 weeks of gestation). During pregnancy in the І trimester of pregnancy, the content of hormones in blood serum was determined: estradiol, chorionic gonadotropin, placental lactogen, progesterone. Results. Conducted research on the level of hormones in the blood serum of pregnant women showed that the concentration of estradiol in the main group was reduced throughout the І trimester of pregnancy. In particular, the content of this hormone was lower compared to the control by 7.2% in 5-8 weeks of gestation (p˃0.05), and by 23.9% - in 9-12 weeks (p<0.05). The content of progesterone in pregnant women with low-lying chorion, on average, was lower compared to the control group by 10.9% in the period of 5-8 weeks of pregnancy (p<0.05) and by 21.0% in the period of 9-12 weeks (p<0.05). It was also established that the level of placental lactogen in the blood serum of pregnant women at 9-12 weeks of gestation in the main group was probably lower compared to the control (p<0.05). Analyzing the content of chorionic gonadotropin, it is noted its significant decrease during the entire early period of gestation in the main group compared to the control, respectively: at 5-8 weeks of gestation - 36990.0±210.0 mg/l and 43270.0±226.0 ml/l (p<0.05); at 9-12 weeks - 37194.0±395.0 mg/l and 54700.55±525.0 ml/l (р<0.05). Conclusions. Pregnant women with low-lying chorion in the early stages of gestation had a much slower increase in hormone levels and lag in quantitative indicators was observed compared to pregnant women in which the chorion was located in the fundus and body of the uterus. This is evidence of hormonal dysfunction of the placenta, and therefore, a marker of the developing of placental dysfunction. A decrease in the levels of hormones of the fetoplacental complex in pregnant women with low placentation is manifested by clinical signs of early placental dysfunction in the form of a threat of termination of pregnancy, partial detachment of the chorion in the early term, spontaneous miscarriage and lead to further progression of placental dysfunction. The research was carried out in accordance with the principles of the Helsinki Declaration. The study protocol was approved by the Local Ethic Committee of Bukovinian State Medical University. The informed consent of the patients was obtained for the conducting the studies. No conflict of interests was declared by the authors.