Ovarian stimulation in ART - Unwinding pressing issues.

ABSTRACT

Conventional controlled ovarian stimulation (cCOS) can cause significant discomfort, including ovarian hyperstimulation syndrome (OHSS). Clearly, management of OHSS and poor responder patients requires new strategies to overcome these problems and facilitate the birth of a healthy child with the fewest stimulation cycles. Several alternative methods have been developed. Non-conventional controlled ovarian stimulation (non-cCOS) is based on low-dose stimulation regimens and is often termed "light", "soft", "mini", "minimal", "mild", "low cost", or "low dose IVF". Non-controlled ovarian stimulation therapies (non-COS) include natural cycle IVF or a mixture between non-controlled and non-cCOS, termed "modified natural IVF" or "antiestrogen/aromatase inhibitor/low dose FSH-cycles", in which cycles are monitored but not controlled. These approaches promise to reduce the physical, emotional, and financial burden of IVF therapy while maintaining acceptable pregnancy rates. Such approaches might reduce the risk of OHSS. However, the overall cost per baby increases due to the higher number of stimulation cycles required, and the inconvenience of ovum pick-up still remains. The primary focus should be to obtain several good quality blastocysts after a single cCOS cycle. Thus, adequate numbers of mature oocytes are mandatory. What is more difficult and expensive for patients several non-COS/non-cCOS cycles to obtain a baby or a single cCOS cycle with a high probability to obtain more than one child? Classic cCOS using the GnRH agonist long protocol followed by single embryo transfer (SET) at the blastocyst stage and aseptic vitrification of surplus embryos optimizes the IVF outcome. This strategy, combined with outpatient management in the case of OHSS, minimizes inconvenience and risks of OHSS. Accumulation cycles (AC) by repeated COS with subsequent freezing of blastocysts, combined with preimplantation genetic screening (PGS), is a promising new approach for low responders, especially in cases of advanced maternal age (AMA).