Double Stimulation Followed by a Fresh Embryo Transfer

Infertility

The major goal of controlled ovarian stimulation (COS) is to increase the number of oocytes harvested in order to result in the generation of a higher number of available embryos, extended embryo culture, embryo selection and finally providing higher cumulative live birth rates in infertile patients. Moreover, with the idea of the multiple waves of follicular production, we could start to take full advantage of the whole follicular cohort, and not only of the follicular wave. In the context of low prognosis women such as women with poor ovarian response where, the success rates are very low due to the low number of oocytes retrieved and consequently of viable embryos), Dual stimulation may be of great value as a tool to improve outcomes. The reported advantage of DuoStim is retrieved of more oocytes within a shorter time span, resulting in an increase in the probability of having transferable embryos increases, and theoretically reducing time to live birth as well as cycle cancellation.

In assisted reproductive technologies (ART), despite the progress of the last decades, the achievement of a live birth still remains a challenge, especially for some categories of patients such as the one with poor ovarian reserve. One of the main tolls in reproductive medicine is controlled ovarian stimulation (COS) which is performed with the aim of obtaining multiple oocytes, so as to increase the chance of a live birth (LB) . In order to induce multifollicular development in ovarian stimulation, recombinant FSH (or other products based on FSH) are given at the beginning of the follicular phase for an average of 10-12 days. The reason for this timing is mainly due to the fact that the follicular phase is clearly the moment when the ovaries are recruiting new follicles in order to establish the dominant for the cycle. However, as previously described follicular production by the ovaries follows a pattern of multicyclic waves. More specifically, a wave is a synchronous growth of follicles that have similar diameter and that can be documented with ultrasound . Beside the very well-known follicular wave (which is the one exploited in the COS), 64% of the women has two waves (follicular and luteal) and 32% of women has up to 3 waves in a normal cycle (early follicular, late follicular and luteal) . The innovative concept of multiple waves of follicular development has been utilized in previous studies aiming to evaluate the effect of more than 1 stimulation cycles in a short period of time (less than 1 month). Specifically, two stimulation cycles have been performed in the same cycle by previous researcher (starting from the classical follicular COS and followed by a subsequent stimulation 5 days after the first oocyte retrieval) and it has been shown to be associated with improved cycle outcomes, alias higher number of oocytes retrieved and number of embryos obtained in total. Furthermore, in women with low ovarian response recent studies have suggested that the luteal phase stimulation appears to result in a higher number of oocytes retrieved as compared to the first follicular phase stimulation cycle . Nevertheless, in spite of the accumulating evidence, a common characteristic of all of the published trials up to date is that in all of them dual stimulation cycle was initiated in the classical follicular phase followed by second stimulation cycle 5 days after oocytes retrieval. This approach had two major limitations: 1. Owing to this extended protocol and the luteal phase start the lack of synchronization between embryos and endometrium, a freeze-only protocol was considered essential to be adopted . 2. The fact that the 2nd stimulation cycle (luteal phase) always started 5 days after the first stimulation cycle does allow an unbiased evaluation of whether the improved outcomes on the second cycle are attributed to the luteal phase initiation of stimulation or to a carry-over effect of the first stimulation cycle. Based on the above evidence we decided to design the current randomized trial which is, to our knowledge, the first to evaluate the benefit from the dual stimulation approach, not followed by a freeze-only strategy, but by fresh embryo transfer. In order to achieve this, we aim to compare the COS with the double stimulation (first luteal stimulation and then follicular ovarian stimulation) followed by fresh embryo transfer (ET) in poor prognosis patients undergoing in vitro fertilization/intra-cytoplasmatic sperm injections (IVF/ICSI) treatment. The current randomized trial will allow us to 1. compare the double stimulation with a single stimulation strategy followed by fresh embryo transfer and 2. perform comparison of a luteal phase (1st cycle of the double stimulation group) and a follicular phase stimulation (control group) in a randomized setting

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