The Effect of LH-Priming During Early Follicular Phase in IVF Treatment.

Inclusion Criteria: * Females between the ages of 18- 38 years (both included) at the time of randomisation * Patients for whom treatment with gonadotrophins and GnRH agonist (long protocol) in IVF setting is considered appropriate according to the criteria of the participating centre * Infertility for at least 1 year before randomisation (except for tubal infertility) * A maximum of two previous consecutive unsuccessful IVF cycles (i.e. not resulting in an ongoing pregnancy * 25- 34 days of menstruation cycle * Body mass index (BMI) \< 29 kg/m2 Exclusion Criteria: * Any clinically significant systemic disease (e.g., insulin dependent diabetes) * Endocrine or metabolic abnormalities (pituitary, adrenal, thyroid, pancreas, liver, or kidney) which can compromise participation in the study * Any concomitant medications that would interfere with evaluation of study medications. Specifically, any non-study hormonal therapy (except for thyroid medication), prostaglandin inhibitors (NSAIDs, including aspirin) and psychotropic agents (phenothiazine's, major tranquillisers) at the time of study entry. Note: these medications are disallowed for the study duration. * Presence of clinically significant uterine fibroids * Undiagnosed vaginal bleeding * Tumours of the ovary, breast, uterus, adrenal gland, pituitary or hypothalamus * Pregnancy, lactation or contraindication to pregnancy - must be confirmed by negative urinary pregnancy test at randomisation