Figure 4. Overview of low prognosis patients according to POSEIDON groups 3 and 4, including pathogenesis and treatment options. Reprint from: Haahr et al. Individualized controlled ovarian stimulation in expected poor-responders: an update. Reprod Biol Endocrinol. 2018;16:20. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY).