The UK has government health care. Sometimes, their National Health Service funds IVF. When it does, it usually just funds one cycle. Still, even that one cycle is sometimes successful. A successful cycle means one or more children, which means more health care costs.
The solution? Put in rules that force clinics to transfer fewer embryos - preferably only one. The claimed benefit is that that will reduce the chances of twins, but it will do so mostly by reducing the chances of success at all. Fewer pesky children to deal with means lower health care costs.
Fortunately, the UK now allows people to pay for their own health care if they want more than their national health insurance provides. If people need IVF, it seems fair to ask them to pay for their own, right? Unfortunately, the new rules will apply to clinics across the board - even prospective parents willing to pay for their own IVFs will now have to deal with lower success rates due to government restrictions.
Of course, it could be worse. The system could prohibit people from buying health care outside the government system at all, which is what some people are advocating in the U.S.