Background: Polycystic ovarian syndrome (PCOS) occurs in 4% to 7% of all women of reproductive age and 50% of women presenting with subfertility. Subfertility affects 15% to 20% of couples trying to conceive. A significant proportion of these women ultimately need assisted reproductive technology (ART). In vitro fertilisation (IVF) is one of the assisted reproduction techniques employed to raise the chances of achieving a pregnancy. For the standard IVF technique, stimulating follicle development and growth before oocyte retrieval is essential, for which a large number of different methods combining gonadotrophins with a gonadotrophin-releasing hormone (GnRH) agonist or antagonist are used. In women with PCOS, the supra-physiological doses of gonadotrophins used for controlled ovarian hyperstimulation (COH) often result in an exaggerated ovarian response, characterised by the development of a large cohort of follicles of uneven quality, retrieval of immature oocytes, and increased risk of ovarian hyperstimulation syndrome. A potentially effective intervention for women with PCOS-related subfertility involves earlier retrieval of immature oocytes at the germinal-vesicle stage followed by in vitro maturation (IVM). So far, the only data available have derived from observational studies and non-randomised clinical trials.

Objectives: To compare outcomes associated with in vitro maturation (IVM) followed by vitro fertilisation (IVF) or intracytoplasmic sperm injection (ICSI) versus conventional IVF or ICSI, among women with polycystic ovarian syndrome (PCOS) undergoing assisted reproductive technologies (ART).

Search methods: We searched the Menstrual Disorders and Subfertility Group (MDSG) Specialised Register of controlled trials to May 2013 for any relevant trials identified from the title, abstract, or keyword sections. This was followed by a search of the electronic database MEDLINE, EMBASE, LILACS and CINAHL, without language restriction. We also performed a manual search of the references of all retrieved articles; sought unpublished papers and abstracts submitted to international conferences, searched the clinicaltrials.gov and WHO portal registries for submitted protocols of clinical trials, and contacted experts. In addition, we examined the National Institute of Clinical Excellence (NICE) fertility assessment and treatment guidelines and handsearched reference lists of relevant articles (from 1970 to May 2013).

Selection criteria: All randomised trials (RCTs) on the intention to perform IVM before IVF or ICSI compared with conventional IVF or ICSI for subfertile women with PCOS.

Data collection and analysis: Three review authors (CS, MK and NV) independently assessed eligibility and quality of trials. Primary outcome measure was live birth rate per randomised woman.

Main results: There were no RCTs suitable for inclusion in the review, although there are currently three ongoing trials that have not yet reported results.

Authors' conclusions: Though promising data on the IVM technique have been published, unfortunately there is still no evidence from RCTs upon which to base any practice recommendations regarding IVM before IVF or ICSI for women with PCOS. Meanwhile, the results of the above-mentioned ongoing trials are awaited and, of course, further evidence from good quality trials in the field is eagerly anticipated.