endometrioma on the number of oocytes retrieved for in vitro

chromosomal aberrations that could underlie the development of low ovarian reserve and POR. Taken together, POR as an early sign for low ovarian reserve has numerous risk factors; several of which are well established, others are controversial and additional factors are still emerging. To estab-lish a clear diagnosis of POR in accordance with the Bologna cri-teria, risk factors should be clearly defined. Although a key step has been introduced by the POR working group, the job is yet to be accomplished. Specific guidelines should be developed and pursued, in accordance with current knowledge and evidence, to direct clinicians and investigators to look for relevant risk factors to be incorporated into the diagnosis of POR. Doing that will reduce bias even more and ensure that all three criteria will be simple, clearly defined and reproducible. Furthermore, it is not unusual for women above the age of 40 to