Step Down FSH Approach and Late Follicular Phase in Progesterone Level

Inclusion Criteria: * Primary / secondary infertility with the indication for IVF/ICSI * Patients age 18 - 40 years * 60 kg up to and including 90 kg * BMI of 18-32 kg/m2 * Menstrual cycle length of 24-35 days Exclusion Criteria: An individual who meets any of the following criteria will be excluded from participation in this study: Exclusion criteria: * presence or history of an endocrine abnormality * abnormal outcome of blood biochemistry or hematology * relevant ovarian-, tubal- or uterine-pathology that could interfere with the ovarian stimulation treatment * history of ovarian hyper-response (more than 30 follicles ≥ 11 mm) or ovarian hyper-stimulation syndrome (OHSS), polycystic ovary syndrome (PCOS) * History of poor ovarian response, according to the Rotterdam-criteria (Ferrarretti et al.) * ovarian reserve parameter, indicating the risk of poor ovarian response (AFC \< 5 and AMH \< 0,5ng/ml) (14)