Multifollicular ovarian stimulation for IVF: more may not be better. Society of Gynecological Endocrinology

摘要

The aim to stimulate a high number of follicles has dominated ART practice for many years. The rationale behind this is that the more follicles developed, the higher the number of embryos available for transfer and, hence, the higher the chance of achieving a pregnancy. Nevertheless, concerns have been raised regarding a potential negative effect that multiple follicular stimulation might exert, either on endometrial receptivity or on oocyte quality. In ovarian stimulation for IVF, multifollicular development leads to supraphysiological levels of steroid hormones (namely progesterone and estra-diol). As a result, endometrial advancement has been described in endometrmm biopsies taken in early luteal phase (1) and, furthermore, when the advancement was more than 3 days on the day of oocyte retrieval, the pregnancy rate was zero (2). Interestingly, the group of patients with >3 days advancement had significantly higher progesterone levels on the day of HCG. As early as 1991, it was shown that modest preovulatory increases in serum progesterone levels are associated with lower pregnancy rates and higher pregnancy loss. The mechanism proposed to explain the adverse pregnancy outcome, following the premature progesterone rise, is that of a negative impact on endometrium receptivity.