[Natural cycle in vitro fertilization cycle in poor responders].

Since the beginning of IVF, natural cycle In Vitro Fertilization (NC-IVF) has been largely replaced by IVF with ovarian stimulation. However, natural cycle IVF has several advantages: low cost, no risk of ovarian hyper stimulation syndrome, very low risk of multiple pregnancy. Nevertheless, natural cycle IVF is less effective with a high risk of cancellation due to premature rise of LH, and an increased risk of failed oocyte retrieval. Using GnRH antagonists in a modified natural cycle decreases the occurrence of a premature LH rise. In the context of a poor responder patient, natural IVF could theoretically yield a better quality oocyte coming from a naturally selected follicle and allow a transfer on an endometrium whose receptivity has not been distorted by controlled ovarian stimulation. However, the real place for it has yet to be defined as we lack published data. Only one randomised controlled study in poor responders showed a similar pregnancy rate to a standard protocol representing a cost-effective alternative. Available retrospective data seem to show the same trend especially in the sub group of younger patients (below 38). Natural cycle IVF is a low-risk, low-cost procedure whose interesting results should be further confirmed by large scale prospective studies.