Weight loss help before IVF could increase chance of pregnancy

Targeted weight loss programmes could improve the IVF outcomes in prospective mothers with obesity, a review from the University of Oxford has revealed.

The review analysed data from 12 randomised controlled trials (RCTs) involving almost 2000 women with obesity who were offered a weight loss intervention before planned IVF. Interventions included diet programmes, exercise and weight-loss medications. Pre-IVF weight loss interventions were associated with 21 percent overall increase in total pregnancy rates, and a 47 percent increase in natural conceptions. The study suggests that targeted support could help women access NHS-funding and also increase their chances of conceiving both with and without medical assistance.

'Currently, women with obesity can face a double challenge with higher rates of infertility and potential exclusion from NHS-funded IVF. Our findings offer hope,' said Dr Moscho Michalopoulou, behavioural scientist at the University of Oxford and lead author of the study published in the Annals of Internal Medicine. 'Our work suggests that for many women with obesity, an intensive supported weight loss programme could help them to conceive naturally or make it possible to access IVF services.'

The authors noted that women with obesity are three times more likely to experience fertility problems than those with a BMI in the 'healthy' range. However, in England, NHS-funded IVF is restricted to women with a BMI under 30. The National Institute for Health and Care Excellence already recommends advising women with obesity that losing weight will likely increase the chances of conception. The study authors suggest that targeted weight loss support could offer a low-cost way for the NHS to improve access and outcomes.

'This isn't just about improving pregnancy rates – it's about improving equity of access to fertility treatment. We know that people from more deprived areas and those from certain ethnic backgrounds are more likely to live with obesity,' said Dr Nerys Astbury, from the University of Oxford, who led the research. 'Policymakers should consider whether integrating structured weight loss support into fertility services could improve outcomes for patients, while potentially reducing overall costs by increasing the number of women who conceive naturally.'

However, the authors noted some important limitations of the research, including that the studies included were small, and it was difficult to determine the benefits of particular interventions due to heterogeneity. Furthermore, many of the trials did not include data on live birth outcomes.

This research follows a recent increase in the availability of weight-loss medications. The authors noted that the GLP-1 class of weight loss medications – such as Wegovy or Mounjaro – are the most effective non-surgical option for significant weight loss. However, the UK's Medicines and Healthcare products Regulatory Agency (MHRA) currently advises that these medications must not be taken during pregnancy, while trying to conceive or while breastfeeding, as the effects are unknown.

The authors therefore emphasised the importance of access to targeted, supported weight loss programmes for women with obesity seeking fertility treatment. Writing in The Conversation, Professor Astbury, Dr Michalopoulou and Dr Pedro Melo, University of Oxford, concluded: 'The challenge now is making sure they're available to everyone who needs them, not just those who can afford to pay.'