The impact of previous conventional stimulation in a DOR setting
In clinical practices, it is difficult to tell DOR patients they may never achieve pregnancy despite aggressive treatment. Many DOR patients would go through conventional IVF first in hopes to obtained oocytes as more as possible, receiving a ‘heavy’ or a ‘conventional’ stimulation first. We further discuss if previous conventional IVF has influences on the outcomes of consequent minimal stimulation IVF.
Minimal stimulation cycles were divided into two groups according to whether the patient had gone through previous conventional IVF cycles. We discovered that in patients who had gone through conventional stimulation IVF, less oocytes were retrieved and poor oocyte quality was observed in next cycles. So, it is possible that conventional stimulation would in contrast cause adverse IVF results and is not very suitable for DOR population. The underlying mechanism is well discussed, most studies report increased oocyte aneuploidy, embryo mortality, fetal growth retardation, and congenital abnormalities have been studied at higher-dose stimulations, and these adverse effects seem to be cumulative, increasing by each stimulation cycle[19].
Patients in our study were further stratified by previous C-IVF cycles. We calculated the cumulative pregnancy rate according to previous cycles. After three cycles of previous IVF cycles, there is a significant drop in terms of pregnancy rate, indicating that more than two previous cycles may bring significantly adverse results in DOR woman. Even though COH has been the most crucial part of IVF treatment, more studies have proven the advantages of MS-IVF, including higher safety profile (lowering OHSS rate [20]), higher singleton birth weight [21] , higher patient satisfaction and lower financial cost. The aim of MS-IVF is to achieve “quality” and not “quantity” in terms of oocytes and embryos in the stimulated cycle.
Indeed, minimal stimulation IVF has been proven to be a safer, better tolerated, more woman-friendly and affordable way of conducting ovarian stimulation in IVF cycles.