Study Participants
In this study, 1,446 subjects (713 in the PCOS group and 733 in the
control group) were recruited from the Center for Reproductive Medicine,
Shandong University, China, from March to September 2019. Basic
demographic, socio-economic and life habits related characteristics were
assessed using questionnaires, while the income level, vaginal douching
frequency, and the frequency of sexual activity was matched between
women with PCOS and healthy controls. PCOS was mainly diagnosed using
Chinese Guidelines for the Diagnosis of PCOS18 based
on modified Rotterdam Criteria6. PCOS diagnosis
requires the presence of oligomenorrhea (menstrual cycle that lasts
longer than 35 days) or irregular uterine bleeding, combined with either
clinical/biochemical signs of hyperandrogenism or a polycystic ovary
indicated using ultrasonography (either more than twelve follicles (2–9
mm in diameter) and/or increased ovarian volume (>10
mm3) in each ovary). Women who were diagnosed with
congenital adrenal hyperplasia, testosterone-secreting tumors, Cushing’s
syndrome, or other causes that result in excess testosterone were
excluded. The subjects included in the control group had regular
menstrual cycles (21-35 days) and no clinical or biochemical evidence of
hyperandrogenemia. The exclusion criteria was antibiotic usage within
one month of swab sampling, vaginal douching or vaginal medication
within one week of sampling, irritation around the genital area or
abnormal vaginal discharge within one week of sampling, menstruation,
and sexual intercourse within 48 hours. In addition, the PCOS group was
divided into PA (PCOS phenotype A) subgroup (OA+HA+PCOM, n=171) and PD
(PCOS phenotype D) subgroup (OA+PCOM, n= 542). The study was approved by
the Institutional Review Board of Reproductive Medicine, Shandong
University. Written informed consent was obtained from all participants
enrolled in the study.