The purpose of the study is to evaluate immunogenic potential of FSH-IBSA in healthy volunteers undergoing controlled ovarian hyperstimulation (COH) in an oocyte donation program.

Inclusion Criteria:

• Healthy female volunteers undergoing controlled ovarian hyperstimulation for oocyte donation with the following characteristics:
• Able and willing to sign the Subject Consent Form and adhere to the study visit schedule;
• >=18 and <35 years old;
• Regular menstrual cycle (26 - 35 days);
• BMI between 18 and 30 kg/m2;
• First gonadotrophin treatment (i.e. naïve Subjects with regard to exposure to human derived or recombinant gonadotrophins);
• basal FSH <10 IU/L and E2 <80 pg/ml (~290 pmol/l);
• Normal TSH levels;
• Willing to perform at least two consecutive oocyte retrieval cycles (with a wash out period of two months).

Exclusion Criteria:

• Age <18 and >=35 years;
• PCOS;
• Endometriosis;
• Subjects with evidences of autoimmune or rheumatic diseases;
• Hypersensitivity to the active substance or to any of the excipients (lactose);
• Abnormal bleeding of undetermined origin;
• Subject found to be positive to anti-TSH antibodies (i.e. suffering from thyroidal diseases);
• Uncontrolled adrenal dysfunction;
• Neoplasia;
• Severe impairment of renal and/or hepatic function;
• Use of concomitant medications that might interfere with study evaluations (e.g. immunosuppressant, non-study hormonal medications, therapeutics proteins like insulin, growth hormone…).

All the subjects that started the stimulation.