The study will focus on important aspects related to follicle recruitment using exogenous gonadotropins in patients with polycystic ovaries:

1. Early follicle recruitment in patients with polycystic ovaries using corifollitropin alfa: does administration of this drug result in earlier and higher FSH (follicle stimulating hormone) concentrations above the threshold for follicle recruitment in an IVM (in vitro maturation) cycle preceded by oral contraceptive suppression, in comparison to normal daily administration of rFSH (recombinant follicle stimulating hormone, Puregon)?;
2. The maturation rate of the obtained oocyte-cumulus complexes in standard IVM media registered for clinical use: does stimulation with corifollitropin alfa versus recombinant FSH have an impact on the maturation rate and developmental capacity of the oocytes ?

Inclusion Criteria:

1. Subfertile patients between 18-36 years old eligible for ART treatment
2. BMI 18-30
3. Polycystic ovaries (PCO) according to the Rotterdam criteria (at least 12 antral follicles per ovary as observed on a baseline ultrasound scan), with or without hyperandrogenism, with or without oligoamenorrhoea. In other words, patients are eligible if they have PCO morphology. A diagnosis of PCOS (polycystic ovary syndrome) based on Rotterdam criteria is not compulsory.

Exclusion Criteria:

1. Antral follicle count (AFC) <24
2. Anti-müllerian hormone (AMH) <3,25 in non-OCP (oral contraceptive pill) users and <4,00 in current OCP users (using Elecsys platform (Roche Diagnostics))
3. Couples requesting PGD (preimplantation genetic diagnosis)
4. Non-obstructive azoospermia in the male partner