Dual Stimulation

ABSTRACT The traditional concept of starting controlled ovarian stimulation (COS) exclusively in the early follicular phase has been challenged by the recent evidence on the multiple wave theory of follicular recruitment within a menstrual cycle. This understanding has led to the development of a new ovarian stimulation protocol for in vitro fertilisation (IVF) known as Dual stimulation or DuoStim, especially for poor responders. Dual stimulation implies follicular phase stimulation (FPS) followed by luteal phase stimulation (LPS) within the same menstrual cycle. The main advantage of this protocol includes an increase in the number of oocytes and embryos obtained per menstrual cycle, thus improving the chance of live birth per DuoStim cycle compared to single conventional stimulation. Dual stimulation appears to be beneficial for poor responders and advanced maternal age women, especially to rescue poor blastocyst yield after one conventional COS and avoid further maternal ageing between IVF attempts. This strategy appears to have led to a significant reduction in patient dropout rates in these women. It is also a relevant approach for patients undergoing the accumulation of embryos for pre-implantation genetic testing, where one aims to maximise the number of oocytes/embryos in a limited period. The majority of evidence has shown better performance of LPS in comparison to FPS in the context of the number of oocytes and embryos obtained in DuoStim cycles. However, mandatory freeze all, high cycle cancellation and lengthening of stimulation days in LPS are a few drawbacks. However, presently, multicycle counselling using DuoStim or similar protocols appears to be a relevant change needed in IVF to increase oocyte/embryo number in a short time frame and thus reduce attrition.