British Fertility Society Policy and Practice Committee: adjuvants in IVF: evidence for good clinical practice.

Optimisation of the environment favourable for satisfactory ovarian response to stimulation and successful embryo implantation remains at the core of assisted conception programmes. The evidence base for the routine use of different adjuvants, alone or in combination, for women undergoing their first in vitro fertilisation (IVF) treatment cycle and for those with poor prognosis is inadequate. The aim of this document is to update the last review of the available literature carried out by the British Fertility Society Policy and Practice Committee (BFS P&P) published in 2009 and to provide fertility professionals with evidence-based guidance and recommendations regarding the use of immunotherapy, vasodilators, uterine relaxants, aspirin, heparin, growth hormone, dehydroepiandrosterone, oestrogen and metformin as adjuvants in IVF. Unfortunately despite the lapse of 5 years since the last publication, there is still a lack of robust evidence for most of the adjuvants searched and large well-designed randomised controlled trials are still needed. One possible exception is metformin, which seems to have a positive effect in women with polycystic ovary syndrome undergoing IVF. Patients who are given other adjuvants on an empirical basis should always be informed of the lack of evidence and the potential side effects.