Low Dose GnRHa Early Luteal Phase Down Regulation Versus GnRHa Ultra-short Protocol for Poor Ovarian Response

Inclusion Criteria: * At least two of the following three features must be present: i. Advanced maternal age (≥40 years) or any other risk factor for POR (poor ovarian response); ii. A previous POR (≤3 oocytes with a conventional stimulation protocol); iii. An abnormal ovarian reserve test (i.e. AFC \<7 follicles or AMH \<1.1 ng/ml). Exclusion Criteria: * Contraindications for IVF/ICSI * Contraindications for pregnancy * Primary ovarian insufficiency * AFC \<3 * PGD/PGS