At the first visit to the IVF-clinic a CRF (CRF=Case Report Form) of demographics will be filled in regarding age, BMI, parity, presence of PCOS (PCOS=polycystic ovarian syndrome ), smoking and duration of infertility and a blood sample for serum-AMH is taken and frozen for later analysis. The serum-AMH level is constant during the menstrual period (La Marca et al 2006) and a blood sample can be taken on any cycle day. The AMH assay used is the Beckman Coulter AMH Gene II assay. Classification of the serum AMH values into expected low-, normal-, or high ovarian response is based on the data presented a large prospective cohort study of patients going through COH (Nelson et al 2009). Since that publication used an older assay the reference intervals are calculated and translated as described in a recent publication on AMH assays (Nelson et al 2012). Serum-AMH level increases during GnRH (GnRH= gonadotropin releasing hormone) agonist downregulation (Jayaprakasan et al 2008), thus the blood sample is preferably taken before start of down-regulation. A long GnRH agonist treatment protocol is used. Patients are down-regulated with GnRH agonist from luteal phase, or first cycle day when anovulatory patient, until estradiol is < 200 pmol/l. After down-regulation, an assessment of AFC will be performed by sonography, and the patient will be randomized.