In Patients with Only One or Two Oocytes, Is IVF-ET or ICSI Better?

One of the aims of assisted reproduction technologies (ART) is the recruitment of multiple follicles ensuring the recovery of good-quality oocytes upon controlled ovarian hyperstimulation (COH). In recent years, the number of patients in whom few oocytes are obtained in response to COH is increasing. This phenomenon mainly is probably related to the postponement of childbearing to the fourth decade of life. In this group of patients, multifollicular response to COH remains a challenge, but the optimisation of laboratory strategies may help to maximize their chances of pregnancy. Ovarian response to COH varies widely among patients and is strictly dependent on the size of the ovarian pool of resting follicles, the so-called ovarian reserve. In women with a reduced ovarian reserve, a poor ovarian response results in a low number of retrieved oocytes despite the high dose of gonadotropins administered. Hence, although tests for predicting ovarian reserve are available, the parameter that best categorises a woman as a ‘poor responder’ remains the ovarian response itself. The incidence of poor ovarian response (POR) is estimated between 9 and 24 %. This value increases with age reaching about 50 % in women over 40 years. Women who respond poorly to COH have pregnancy rates that vary from 7.6 to 17.5 %, while in normal responders, they vary from 25.9 to 36.7 %. Female age plays a distinct role in predicting poor response to COH; in fact, older poor responders have lower pregnancy rates (ranging between 1.5 and 12.7 %) compared with younger poor responders (ranging between 13.0 and 35 %). A second predicting factor of pregnancy outcome in poor responders is the degree of poor response. A lower number of retrieved oocytes results in fewer embryos to transfer and a lower chance of pregnancy, in addition to the expected negative effect of poor ovarian function on oocyte quality. The choice of the technique of fertilisation to use in poor responder patients in the absence of male factor infertility is still the object of controversy. It is well known that ICSI is usually preferred when a male factor exists, but often this technique is chosen even in case of non-male factor indication with the aim to avoid fertilisation failure. However, some recent studies suggest that the use of ICSI is not strictly necessary, and its use in the absence of indication is questionable. Natural selection of the fertilising sperm resulting from conventional IVF may improve reproductive success in poor responder patients with favorable semen quality. As a consequence, we recently compared reproductive outcomes following conventional IVF or ICSI in patients in whom only one or two oocytes were retrieved at ovarian pickup by taking into account the impact of reproductive aging. We retrospectively analysed a total of 425 cycles (386 patients) attending ART at the Centre of Infertility and Assisted Reproduction of the Department of Clinical and Experimental Medicine of Pisa University between January 2007 and July 2012. Patients were all poor responders and were included in the study when only one or two oocytes were retrieved during ovarian pickup and male factor infertility was absent. We suggest that obtaining one or two oocytes in one cycle is not an indication for ICSI when the sperm sample is apparently normal. However, a relevant factor to the choice of IVF technique under these conditions is represented by female age. Despite the effects of a low ovarian reserve, oocytes from young poor responder patients can still benefit from the advantage of IVF probably counting on biological resources definitively lost with ageing.