Author contribution: Gavisova AA — study design, data acquisition and processing, manuscript writing, editing; Shevtsova MA, Biryukova DA, Lvova PO — study design, data acquisition and processing, literature review, manuscript writing, editing; Novoselova AV, Yushina MN — developing the LC-MS method for analysis of amino acids in blood plasma and follicular fluid, experimental data processing; Ibragimova MH — data acquisition, editing; Chagovets VV, Frankevich VE — statistical data processing, editing.

Compliance with ethical standards: the study was approved by the Ethics Committee of the Kulakov National Medical Research Center for Obstetrics, Gynecology and Perinatology (protocol № 12 dated 25 November 2021).