A Trial to Compare the Efficacy and Safety of Ovarian Stimulation With GONAL-f® and Luveris® Starting on Day 1 Versus Day 6 in Women Undergoing Assisted Reproductive Technique

Inclusion Criteria: * Should be a female subject justifying an In Vitro Fertilization/Embryo transfer (IVF)/ET treatment * Should be between 36th and 42nd birthday (both included) at the time of the randomization visit * Have early follicular phase (day 2-4) serum level of basal FSH \<= 12 IU/L measured in the center's local laboratory during the screening period (i.e. within 2 months prior to down regulation start) * Have a regular spontaneous ovulatory menstrual cycle between 21 and 35 days in length * Presence of both ovaries * Normal uterine cavity, which in the investigator's opinion is compatible with Pregnancy * Have a negative cervical Papanicolaou (PAP or smear) test within the last 6 months prior to randomization * Have at least one wash-out cycle (defined as \>=30 days since the last dose of clomiphene citrate or gonadotrophin treatment) since the last ART cycle and/or clomiphene citrate or gonadotrophin treatment prior to starting GnRH agonist therapy * Be willing and able to comply with the protocol for the duration of the trial * Have given written informed consent, prior to any trial-related procedure not part of normal medical care, with the understanding that consent may be withdrawn by the subject at any time without prejudice to her future medical care * Have a male partner with semen analysis within the past 6 months prior to randomization considered adequate to proceed with regular insemination or intra-cytoplasmic sperm injection (ICSI) according to the center's standard practice Exclusion Criteria: * Had 2 (or more) previous ART cycles with a poor response to gonadotrophin stimulation defined as 6 (or less) mature follicles and/or 4 (or less) oocytes collected in any previous IVF cycle or previous cycles with a hyper response defined as 25 (or more) oocytes retrieved * Any medical condition, which in the judgment of the investigator may interfere with the absorption, distribution, metabolism or excretion of the drug. In case of doubt, the subject in question should be discussed with Merck Serono's Medical responsible * Had previous severe ovarian hyperstimulation syndrome (OHSS) * Polycystic ovary syndrome (PCOS; Rotterdam criteria) to reduce the risk of the occurrence of OHSS * Presence of endometriosis requiring treatment * Uterine myoma requiring treatment * Any contraindication to being pregnant and/or carrying a pregnancy to term * Extra-uterine pregnancy within the last 3 months prior to screening * History of 3 or more miscarriages (early or late miscarriages) due to any cause * Tumours of the hypothalamus and pituitary gland * Ovarian enlargement or cyst of unknown etiology * Ovarian, uterine or mammary cancer * A clinically significant systemic disease * Known infection with Human Immunodeficiency Virus (HIV), Hepatitis B or C virus in the trial subject or her male partner * Abnormal gynecological bleeding of undetermined origin * Known allergy or hypersensitivity to human gonadotrophin preparations * Any active substance abuse or history of drug, medication or alcohol abuse in the past 5 years prior to the screening visit * Entered previously into this trial or simultaneous participation in another clinical trial * Pregnancy and lactation period * Participation in another clinical trial within the past 30 days