Is in Vitro Maturation of Oocytes Influenced by the Origin of Gonadotropins Used in Maturation Medium: is There a Difference in Efficiency When Using Urinary Versus Recombinant Produced Follicle Stimulating Hormone and Human Chorionic Gonadotropin

In vitro maturation is a valid option for PCO(S) patients in the daily ART clinic, however maturation and embryologic development are not yet matching the efficiency levels obtained by standard COS treatment (Ho et al. 2019). To further enhance embryo quality after IVM, media and supplements should be efficient, safe and pure. It has been described that a threshold of FSH activity is necessary for maturation in human IVM (Cadenas et al. 2021), but hCG might be redundant (Ge et al 2008).

Until now, the investigators have been using highly purified urinary derived gonadotropins to supplement IVM media. However in the last decades more recombinant products are available and thoroughly characterized. In ART, both urinary derived and recombinant produced hormones are used to induce multiple follicle growth and ovulation in an ovarian stimulation cycle. Due to the fear of transmis-sion of pathogens (though not yet documented) and of intolerance caused by contaminants, recombinant products are often preferred in the clinic, with no indications of differences in effectiveness and safety (Nahuis 2009). In an in vitro bioassay, contaminating proteins may alter biological re-sponses with undesired effects. uFSH is documented to contain e.g. Insulin-like growth factor binding protein 1 (IGFBP7), that may inhibit oestrogen production, and Eosinophil Derived Neurotoxin (EDN), with known inhibitory effects on mouse oocyte maturation (Bassett 2009). Hence it is important in an in vitro system to use products with the highest purity available.

Moreover the oligosaccharide sialylation is different depending on the production method, altering the acidity and hereby the half-life in the body, but more importantly for an in vitro system, also the receptor binding potency (Bassett 2009, Riccetti 2017).

Hence, before changing our standard system for a theoretically better alternative, The investigators need to test the efficiency of recombinant hormones compared to the routinely used urinary hormones in terms of oocyte maturation efficiency in the in vitro maturation system.

PCOS patients eligible for an IVM cycle to treat infertility will be included. Patients will receive a mild ovarian stimulation protocol, identical to our standard IVM care program.