The contents of β-subunit of chorionic gonadotropin (β-CG), estriol, progesterone, dehydroepiandrosterone (DEAS), placental lactogen and cortisol were studied in 164 women of child-bearing age at the 7-9th weeks of pregnancy. The first group (control) consisted of 30 women with physiologic course of pregnancy. The second group (comparison) had 32 patients with the threat of premature delivery of non-infectious etiology. The third group included 36 patients with influenza virus А(Н3N2) (anti-virus antibody titers were 1:4-1:16); the fourth group had 34 women with influenza virus А(Н3N2) (antibody titers were 1:8-1:32); in the fifth group there were 32 patients with influenza virus А(Н3N2) (antibody titers were 1:32-1:128) and the threat of premature delivery in the period of reconvalescence. The patients of the fifth group had the decrease of the level of β-CG till 40.5±2.0 mМЕ/ml, of estriol till 3.4±0.21 nmole/l, of progesterone till 35.1±3.13 nmole/l, of DEAS till 7.3±0.68 nmole/l, of placental lactogen till 12.1±1.0 nmole/l, as well as the increase of cortisol till 738.7±22.08 nmole/l in comparison with 73.0±2.0 mМЕ/ml (р<0.001), 5.9±0.33 nmole/l (р<0.001), 70.6±4.14 nmole/l (р<0.001); 7.3±0.68 nmole/l (р<0.001), 12.1±1.0 nmole/l (р<0.001) and 567.8±24.02 nmole/l (р<0.001) in the first group, respectively. The differences of hormonal status in the fifth and third group consisted of the drop of concentration of β-CG by 22.8% (р<0.001), of estriol by 26.1% (р<0.01), of progesterone by 32.1% (р<0.001) and placental lactogen by 32.4% (р<0.001). At the same time there were no significant changes in the concentration of DEAS and there were registered higher indicators of cortisol, i.e. the increase by 11.5% (р<0.05), which suggested the significance of the growth of antivirus antibody titers in the suppression of synthesis of hormones in ovaries and in syncytiotrophoblast as a result of direct and indirect negative influence of influenza infection.