P-647 Association between PCOS phenotype-D and euploid blastocyst rate per cohort of inseminated oocytes: a matched case-control study versus idiopathic infertile women
Authors: Rucci C , Vaiarelli A , Cimadomo D , Innocenti F , Pittana E , Ruffa A , Colamaria S , Argento C , Giuliani M , Guido M , Mazzilli R , Fabozzi G , Rienzi L , Ubaldi F  M , Gennarelli G 
Published: July 2024

Study question

Is there any association between PCOS phenotype-D and oocyte competence defined as euploid blastocyst rate (EBR) per cohort of inseminated oocytes?

Summary answer

Although higher fertilization and blastulation rates were reported in PCOS phenotype-D women versus idiopathic infertile patients, the EBR per cohort of inseminated oocytes was comparable.

What is known already

Several studies report poorer oocyte quality and cumulative-live-birth-rate (CLBR) in hyperandrogenic PCOS phenotypes, as defined according to the Rotterdam criteria. Increased androgen concentrations in follicular fluids are indeed associated with elevated serum-LH levels, which can block dominant follicle development inducing atresia and negatively impact fertilization rates and embryo development. Limited evidence exists in phenotype-D PCOS patients, namely women characterized by oligomenorrhea, ovarian PCO morphology and absence of hyperandrogenism. Here, we report the embryological and clinical outcomes in these women during ICSI cycles with preimplantation genetic testing for aneuploidies (PGT-A) at the blastocyst stage.

Study design, size, duration

Retrospective propensity score matched (PSM) case-control study. Among PGT-A cycles conducted by naïve patients with own oocytes (2013-2021), we excluded FNA/TESE. 58 phenotype-D PCOS patients were identified according to the Rotterdam criteria. These patients were matched for maternal age, number of cumulus-oocyte-complexes (COCs), and sperm quality, with 58 patients with idiopathic infertility, regular cycles, normal ovarian morphology, and no sign of clinical hyperandrogenism. The primary outcome was EBR per cohort of inseminated oocytes.

Participants/materials, setting, methods

GnRH-antagonist ovarian stimulation, ICSI, blastocyst biopsy, qPCR/NGS-analysis to assess uniform aneuploidies and vitrified-warmed single blastocyst transfers were conducted. The PCOS and control groups were similar for age (35.6±3.0 versus 36.0±3.9 years), COCs (23.1±6.7 versus 23.5±7.6), sperm factor, primary/secondary infertility, hormonal values, BMI (23.8±5.3 versus 22.0±2.8), and duration of infertility (3.6±2.2 versus 3.6±2.0 years). All intermediate embryological and clinical outcomes were assessed as secondary endpoints. Linear/logistic regressions adjusted for confounders were conducted to confirm statistically-significant differences.

Main results and the role of chance

No difference was reported in maturation rates, but women with PCOS showed better fertilization rates per cohort of inseminated oocytes (76.9±15.2% versus 67.3±20.4%, Mann-Whitney-U-test&lt;0.01), and blastulation rates per cohort of 2PN-zygotes (52±20.4% versus 43.7±20.7%, Mann-Whitney-U-test=0.03). Eventually, PCOS patients obtained more blastocysts than controls (5.8±3.1 versus 4.5±2.9, Mann-Whitney-U-test=0.02), despite similar numbers of metaphase-II oocytes in the groups (16.5±6.1 versus 16.5±7.0). All differences remained significant after adjusting for maternal age and sperm factor. Nevertheless, the euploidy rates per cohort of biopsied blastocysts were similar, thus involving comparable EBR per cohort of inseminated oocytes (21.7±14.1% versus 17.2±16%, Mann-Whitney-U-test=0.12). More patients obtained ≥1 euploid blastocyst in the PCOS versus the control group (N = 56/58, 96% versus N = 47/58, 81%, Fisher’s-exact-test=0.02), independently from maternal age, semen quality, and number of inseminated oocytes (Odds-Ratio: 6.5, 95%CI:1.3-33.7, p = 0.03). Lastly, all clinical outcomes per first vitrified-warmed euploid transfer were similar, thereby involving comparable LBRs (N = 28/54, 51.9% versus N = 26/47, 55.3% in the PCOS and control groups, p = 0.8; Odds-Ratio adjusted for blastocyst quality and day: 1.19, 95%CI:0.5-2.7, p = 0.68).

Limitations, reasons for caution

Although clinical hyperandrogenism was absent in both groups, biochemical hyperandrogenism was not assessed. Nonetheless, this pilot study paves the way for future more detailed investigations. 24% of cycles in the PCOS group were not concluded, therefore a CLBR comparison would be biased and was not reported.

Wider implications of the findings

The lower developmental competence in the control group suggests oocyte quality issues, other than chromosomal, underlying their “unexplained infertility” condition. In phenotype-D PCOS women, IVF is effective. Since &gt;50% of this subgroup of women had already failed multiple ovulation-induction and/or intrauterine-insemination attempts, an early referral to IVF deserves further investigations.

Trial registration number

Not applicable