Effect of repeated assisted reproduction techniques on the ovarian response

Abstract

Despite the increasing success of assisted reproduction techniques, most couples need more than one cycle of controlled ovarian hyperstimulation to achieve a pregnancy. The effect of several cycles on the ovarian response in subsequent cycles is a concern for gynaecologists and patients. In addition, egg donors have the possible risk of an ovarian reserve decrease. In this review, we present published evidence on the effects of repeated assisted reproduction techniques on the ovarian response. Recent available data indicate that ovarian response persists with subsequent cycles of controlled ovarian hyperstimulation in terms of oocytes being retrieved, although it is not clear whether an increased level of gonadotropins is required to achieve this response. There is a decrease in the number of oocytes retrieved in subsequent cycles due to increased female age as more cycles are needed. The oocytes retrieved in one cycle seem to come from the antral pool that otherwise would be atretic due to dominant follicle selection. The mechanisms involved in the recruitment from atresia of more than one follicle are discussed and it is shown that repetitive ovarian stimulation does not appear to affect the ovarian reserve. Published evidence shows that gonadotropins alter the physiologic selection of one single dominant follicle but do not accelerate the recruitment of follicles from further cycles, confirming that there is no detrimental effect on ovarian function after repetitive controlled ovarian hyperstimulation.