Letrozole Cotreatment Reduces Unexpectedly Poor Responses in Ovarian Stimulation With Follitropin Delta: A Strategy to Prevent High Anti-Müllerian Hormone (AMH) but Poor Response.

Background: Follitropin delta is a novel recombinant follicle-stimulating hormone preparation used for in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI). The dosage is determined using an original algorithm designed to achieve a target retrieval of 8-14 oocytes based on body weight and anti-Müllerian hormone (AMH) levels. However, unexpected poor responses, characterized by low oocyte retrieval numbers, occasionally occur in patients with high AMH levels who are otherwise expected to respond well.