Mechanical luteinization of follicles before oocyte retrieval is often overlooked: a case report.

We describe a 26-year-old IVF patient, with primary infertility, who underwent oocyte retrieval following ovarian stimulation. During the procedure, we encountered premature follicular luteinization confined to large follicles in the right ovary, while the smaller follicles in the left ovary were not affected. Repeated blood tests in the late follicular phase ruled out premature LH rise and showed an abnormal progesterone rise. We maintain that ovarian tissue mechanical pressure may lead to abnormal follicular luteinization, independent of the LH surge.