Popular IVF “add-on” treatments fail to help women conceive and in some cases harm their chances of having a baby, the fertility regulator has warned.

A new traffic light system intended to protect desperate families from unscrupulous clinics has applied “red light” warnings to four of the 10 most commonly purchased procedures.

These include so-called “assisted hatching” which uses lasers to help the embryo hatch, and pre-implantation genetic screening (PGS), which the watchdog says risks damaging fragile embryos by cutting into them while testing for abnormalities.

Meanwhile the remaining six treatments, such as endometrial scratching and embryo glue, carry an “amber” designation, meaning that research has indicated some benefit but more robust evidence is needed.

Some of the add-on procedures are costing patients up to £3,500, on top of a price tag of around £5,000 for the IVF itself.

The website’s launch comes alongside publication of a new code of conduct requiring fertility clinics to inform patients about the paucity of evidence behind many of the therapies they offer.

It also demands an end to the culture of secrecy among some private providers which limits the ability of watchdogs and academics to assess how well or not various treatments are working.