The purpose of the study is to evaluate the clinical equivalence and the general tolerability of two different subcutaneous hCG preparations (hCG-IBSA, IBSA vs Ovitrelle, Serono) when administered to patients undergoing IVF.

This is a prospective, multicenter, randomized, investigator blind, parallel group, active control, phase III clinical trial. Patients meeting the eligibility requirements of the study will be randomly assigned to receive either the test drug (hCG-IBSA, IBSA) or the reference drug (Ovitrelle, Serono). Investigators will be blinded by not allowing them to have any contact with the study medications (supplied in boxes labeled in a manner that does not reveal the content of the boxes), and requesting that patients do not make any statements to the investigator that might indicate the treatment to which they were assigned. Equivalence testing with regard to the primary outcome variable will establish whether the two treatments are indeed similarly effective.

Inclusion Criteria:

• >/=18 and < 40 years old;
• BMI between 18 and 30 kg/m2;
• less than 3 previous completed cycles;
• both ovaries present;
• regular menstrual cycle of 25-35 days;
• infertility attributable to a tubal factor, American Fertility Society grade I or II endometriosis, male factor or unexplained factor.
• within 12 months of the beginning of the study, uterine cavity consistent with expected normal function as assessed through hysterosalpingogram, sonohystrogram or hysteroscopic examination;
• basal FSH level less than 10 IU/L;
• criteria for hCG administration fulfilled (at least 2 follicles with a diameter of 16 mm or more, with acceptable serum E2 concentration).
• a male partner with semen analysis within the past 6 months showing acceptable values of seminal parameters, defined as > 3x10 exp 6 spermatozoa/ml;
• qualified to receive 150 - 300 IU FSH as starting dose.

Exclusion Criteria:

• age < 18 and > o = 40 years;
• primary ovarian failure or women known as poor responders (i.e. requiring more than 300 IU of FSH as a starting dose in previous treatment cycles or having less than 3 oocytes retrieved, or with an E2 serum concentration < 3'000 pmol/L);
• ovarian cysts > 20 mm, or enlargement not due to polycystic ovarian syndrome;
• patients affected by pathologies associated with any contraindication of being pregnant;
• hypersensitivity to the study medication;
• any bleeding since stimulation;
• uncontrolled thyroid or adrenal dysfunction;
• neoplasias;
• severe impairment of the renal and/or hepatic functions;
• use of concomitant medication that might interfere with study evaluations (e.g. nonstudy hormonal medications, prostaglandin inhibitors, psychotropic agents);
• more than 18 days of FSH stimulation.