Dual ovarian stimulation and random start in assisted reproductive technologies: from ovarian biology to clinical application.

Abstract

The opportunity to use gonadotropins to stimulate the growth of antral follicles coming from different follicular waves available in different moment of the menstrual cycle allowed the implementation of innovative protocols in assisted reproductive technologies. The purpose of this review is to explore the possible advantages related to these new controlled ovarian stimulation (COS) strategies. Women exhibit major and minor wave patterns of ovarian follicular development during the menstrual cycle, as it is in animal species. These observations led to the introduction of two new strategies for COS: the random start and the double ovarian stimulation within a single menstrual cycle. The use of gonadotropin-releasing hormone antagonist COS protocols, started randomly at any day of the menstrual cycle, is today a standard procedure in those cases where obtaining oocytes is an urgent task, such as in case of fertility preservation for malignant diseases or other medical indications.On the other hand, in poor prognosis patients, double ovarian stimulation has been suggested with the aim of maximizing the number of oocytes retrieved within a single menstrual cycle and, in turn increasing the chance to obtain a reproductively competent embryo. Randomized control trials are necessary to confirm these preliminary findings.