1. Department of Obstetrics and Gynecology with a Course in Perinatology, People’s Friendship University of Russia, Moscow, Russia;
2. Department of Obstetrics and Gynecology no. 1, Rostov State Medical University, Rostov-on-Don, Russia;
3. Department of Obstetrics and Gynecology, Dagestan State Medical Academy, Makhahkala, Russia