Funding: the study was supported by RFBR grant №. 20-04-60093.

Author contribution: Lomova NA — analysis of clinical data, systematic analysis, manuscript writing; Chagovets VV — mass spectrometry-based metabolome analysis, statistical analysis of the results, manuscript editing; Dolgopolova EL — collection and preparation of biological matrix samples in the red zone, statistical analysis of the results; Novoselova AV — mass spectrometry-based metabolome analysis, mass spectrometry data processing; Petrova UL — collection and preparation of biological matrix samples in the red zone; Shmakov RG — analysis of clinical data in the red zone, systematic analysis, manuscript editing; Frankevich VE — preparation of the study, systematic analysis, manuscript writing and editing.

Compliance with ethical standards: the study was approved by the Ethics Committee of the National Medical Research Center for Obstetrics, Gynecology and Perinatology named after Academician V. I. Kulakov (protocol № 13 dated December 10, 2020); the study met the requirements of the Declaration of Helsinki, International Conference on Harmonization (ICF), Good Clinical Practice (GCP), and Federal Law № 323-FZ “On the Basics of Protecting Citizens' Health in the Russian Federation” of November 21, 2011; the informed consent was submitted by all patients.