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Systematic review
Current evidence for ART practice: the Cochrane of Cochranes on optimising outcomes
  1. Joyce C Harper1,2,
  2. Daniel R Brison3
  1. 1UCL Centre for PG & D, Institute for Women's Health, University College London, London, UK
  2. 2Centre for Reproductive and Genetic Health, London, UK
  3. 3Department of Reproductive Medicine, St Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Sciences Centre, Manchester, UK
  1. Correspondence to : Dr Joyce Harper, UCL Centre for PG&D, Institute for Womens Health, University College London, 86-96 Chenies Mews, London, WC1E 6HX; joyce.harper{at}

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Commentary on: OpenUrlPubMed


Assisted reproductive technology (ART) is a complex and expensive field of medicine. As such, new technology and new procedures are continually being developed with the aim of improving success rates. In the majority of cases, these are brought into clinical practice without sufficient research and development or scrutiny via randomised controlled trials (RCTs).1 Efficacy and safety issues should be considered before clinical application, including long-term follow-up of children.2 ,3

The issue with performing high-quality RCTs is that they are expensive to run and take several years to obtain the results. Most ART is conducted in a private or patient fee-paying setting, so the commitment to undertake such studies is limited.


Farquhar and colleagues scanned the Cochrane database for all reviews on ART, providing a comprehensive review of Cochrane reviews. They split ART into a number of areas, with the aim of determining which methods were effective for each step of the ART cycle, with the aim of significantly improving live-birth rates. Fifty-four systematic reviews were included. Where possible, the reviews were separated into four categories: those that suggested the intervention was ‘effective’, ‘promising’, ‘ineffective’ or ‘possibility ineffective’.


Of the reviews that were included in the study, 18 suggested ART were ‘effective’, 12 ‘promising’, 3 ‘ineffective’ and 10 ‘possibly ineffective’. A further 11 cases remained, from which no conclusion could be drawn.


When describing outcomes, the authors distinguished between clinical pregnancy and live birth. The endpoint of RCTs in ART should ideally be live birth, but unfortunately this is frequently not the case. Authors are unwilling to wait nearly a year to collect live-birth data, while journals are less willing to publish out-of-date studies. Most of the RCTs in this analysis report only clinical pregnancy and not live-birth results. Therefore, while the data are clear that ultrasound improves clinical pregnancy rate, too few of the studies report live-birth rate to draw any conclusion. In order to avoid confusion, perhaps the authors should comment that insufficient data were available rather than stating that there was no effect on live-birth rate.

The review emphases the lack of consistent results in many areas of ART, even when several RCTs are included. It reflects gaps in our understanding. In many cases clinics will continue to use a technique even when there is no evidence that it is effective. In daily practice, clinics often take an unscientific approach with an ‘n’ of one (ie, by writing up a case report), when a difficult patient has been successful using a new technique. This can overshadow their scientific reasoning, even when several reported RCTs show the technique to be ineffective.

Farquhar and colleagues conclude that their study provides the most up-to-date evidence on ART cycles. They state that ‘using the best available evidence to optimise outcomes is best practice’. They further conclude that their review could be used to inform guidelines.

This is a valuable systematic review; the authors have gathered together and evaluated all available RCTs in the field of assisted reproduction, effectively producing a review of reviews, a ‘Cochrane of Cochranes’ for ART. As is common in this field there are inconsistencies between RCTs, even with endpoints such as clinical pregnancy versus live-birth rate. Nonetheless, this article should be essential reading for all practitioners and policymakers in the field of ART.


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  • Competing interests DRB is a minor shareholder in Novocellus Ltd, a University of York spin-off company developing methods for diagnosing embryo health.