Fertility clinics must be clear with patients about their success rates and charges under new guidance published by the competition regulator.

The Competition and Markets Authority (CMA) has issued the guidance on IVF – the first of its kind – to address concerns such as unclear pricing and misleading success rates.

It has warned clinics that they could face enforcement action if they do not follow the rules.

The guidance, drawn up with the Human Fertilisation and Embryology Authority (HFEA), makes clear clinics’ legal obligations to treat people fairly and to help IVF patients understand their consumer rights.

They must provide the information that patients need so they can make a genuine comparison of clinics, including on price and success rates, and ensure they do not mislead patients, for example around the effectiveness of their treatments and what they will be paying.

Clinics must also ensure they do not mis-sell treatments, such as “add-ons” – optional extras offered by some clinics that can cost up to £2,500 per cycle.

Last February, the CMA raised concerns about some fertility clinics’ practices, such as providing unclear price information and advertising misleading success rates. It also identified a general lack of awareness that consumer law applies in the sector.

The regulator has worked with broadcaster Lorraine Kelly on a video that encourages people to read its guide for patients when buying treatment.

It has also written to clinics to draw their attention to the guidance, in partnership with the HFEA and Advertising Standards Authority (ASA).

The letter sets out the CMA’s expectation that clinics review and, if necessary, change their terms and practices to ensure they are meeting their legal obligations.

Louise Strong, consumer director at the CMA, said: “Buying fertility treatment is a big decision – it can be complicated, stressful and very expensive, with no guarantee of success. All patients deserve to have the information they need to make the right choices for them and be treated fairly.

“Our guidance should help clinics understand their legal obligations. In six months, we will be reviewing compliance in the sector and we will be ready to take enforcement action if businesses are breaking the law.”

The ASA has also issued an enforcement notice to clinics about how the services are advertised, in particular on their own websites.

HEFA chairwoman Julia Chain said: “As the fertility regulator, we have long been concerned about how some clinics offer their services, but our regulatory powers do not allow us to tackle the commercial aspects of the modern fertility market, where most patients pay for their own treatment.

“We welcome the opportunity to work with the CMA and ASA to develop this new guidance in this unique area of healthcare. This is a major step forward for fertility patients as it provides added protection by ensuring that all clinics adhere to consumer and advertising law in addition to our regulatory requirements.

“By working together with other regulators, we can combine our powers to provide added protection in an evolving, competitive and commercial healthcare market.”