Objective — study the efficacy and safety of therapy for threatened miscarriage with micronized progesterone (Utrogestan) and dydrogesterone (Duphaston) in the multicenter open prospective comparative non-interventional study in Russia. Material and methods. 114 clinical sites in Russia that provide medical care to pregnant women diagnosed with threatened miscarriage, 1,241 women aged 18—35 with a confirmed threat of spontaneous abortion (scanty bloody discharge from the genital tract, pain in the lower abdomen) with a gestation period from 8 to 22 full weeks participated in the study. Depending on prescribed therapy, patients were distributed into three groups. Patients of the first group (399 subjects) received micronized progesterone (Utrogestan), 200 mg orally thrice a day until resolution of acute symptoms of threatened miscarriage (scarlet discharge from the genital tract, pain in the abdomen) and then micronized progesterone vaginally 200 mg twice a day and 200 mg orally once a day before bed. Patients of the second group (436 subjects) received micronized progesterone (utrogestan) 200 mg vaginally twice a day and 200 mg orally once a day before bed. Patients of the third group (406 subjects) received dydrogesterone (duphaston), 40 mg orally once, then 10 mg every 8 hours until resolution of symptoms. Treatment with Utrogestan and Duphaston was carried out according to registered indications and methods of administration, reflected in the prescribing information for these medicinal products for human use. The period of case follow-up corresponded to the duration of hospital treatment due to threat of spontaneous abortion until discharge (on average 8.5±0.1 days). During the study, data were collected on the severity of patients’ condition dynamically in the course of therapy, the speed of arrest of symptoms of threatened miscarriage (scarlet discharge from the urinary tract, lower abdomen pains), dynamics of psycho-emotional status of women (level of anxiety and depression), the use of additional medicinal products, the presence of adverse events. All performed medical studies and procedures as part of the study were routine, used in everyday medical practice. Statistical analysis was carried out using IBM SPSS Statistics V23.0 (software). The study has identifier in the ClinicalTrials.gov database: NCT03309735. Results. The study groups receiving different therapy for threatened miscarriage dot not differ according to the primary outcome measure, i.e. discharge from the hospital with prolonged pregnancy (p=0.127), as well as according to duration of hospitalization (p=0.577). The speed of arrest of symptoms of threatened miscarriage (drawing pains in the abdomen) was significantly higher in patients of Group 1 and 2 (micronized progesterone) as compared with those of Group 3 (dydrogesterone) (p=0.019). As regards the efficacy of arrest of blood discharge from the genital tract, no statistically significant differences were revealed between the study groups (p=0.392). As regards the psycho-emotional status of women dynamically in the course of therapy, statistically significant differences were revealed between the study groups on the third day of therapy: the levels of anxiety and depression were lower in patients of Group 1 and 2 (micronized progesterone) as compared with those of Group 3 (dydrogesterone) (p=0.001). At the time of discharge from the hospital, the average level of anxiety and depression returned normal in all study groups. Conclusion. The presented results of the study demonstrate the comparable efficacy and safety of therapy for threatening miscarriage with micronized progesterone (utrogestan) and dydrogesterone (duphaston).