Bed rest following embryo transfer during IVF has been linked with reduced pregnancy success.

In a meta-analysis of 188 randomised control trials, containing more than 59,000 participants, researchers across the UK analysed the safety and scientific validity of clinical interventions which aim to improve embryo transfer success rates. Across six of these trials, the implementation of bed rest, defined as more than 20 minutes rest following embryo transfer, reduced clinical pregnancy rates by 15 percent. These data provide support for guidelines issued by the American Society for Reproductive Medicine, which discourage this practice.

'This is the first study to present a comprehensive overview of all interventions offered to couples undergoing IVF to help us decide what is the best practice when performing an embryo transfer.' said lead author Dr Bassel Al Wattar from the UCL Institute for Women's Health and UCLH Reproductive Medicine Unit.

During IVF, the fertilised egg is transferred into the womb, with many 'add-ons' offered to assist endometrial receptivity or to encourage implantation, often despite empirical evidence. In addition to bed rest, the study also assessed the effectiveness of 37 other clinical interventions, including pharmacological assistance, acupuncture, and mindfulness techniques. Administration of Atosiban (a drug that promotes uterine relaxation) increased the chance of a successful pregnancy by 49 percent, similar to using ultrasound guidance for embryo transfer or having an intrauterine infusion of the hCG hormone, which provided a 27 percent and 23 percent improvement, respectively.

However, a primary limitation of the study is that the findings rely on academically available data, which often leads to a publication bias effect, potentially inflating the significance of certain interventions. 

Acknowledging this, Dr Al Wattar stated, 'While the current body of evidence remains imprecise for these additional interventions, they should not be offered routinely to all couples undergoing IVF pending further research to evaluate their effectiveness and safety.' Furthermore, the authors discourage the clinical incorporation of new and experimental techniques, such as endometrial scratching, prior to well-designed randomised control trials.

The study was published in Human Reproduction Update.

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Reproduced from BioNews with permission, a web- and email-based source of news, information and comment on assisted reproduction and human genetics, published by Progress Educational Trust.