Some areas of England are cutting back on IVF fertility treatment to save money, a charity believes.
Fertility Network UK, which monitors provision, says the situation is worsening and in stark contrast to that in Scotland, where women can get three full cycles of NHS-funded treatment.
An NHS England spokesman said Clinical Commissioning Groups had "to balance demands on the NHS locally".
IVF treatment has been restricted or halted in 13 areas since January.
Eight other parts of England are consulting on taking similar steps, says the charity.
It is not a new issue - IVF provision in England has been variable for years.
Guidelines from the advisory group NICE, issued 13 years ago, say the NHS should provide three full cycles of IVF treatment for women aged under 40 who have failed to get pregnant after two years of trying.
But the recommendations are not binding - it is up to local NHS providers to decide what to offer.
GP-led groups in Bristol, North Somerset and South Gloucestershire are proposing to restrict IVF to women aged 30 to 35. Only those with "exceptional circumstances" outside that age bracket would be considered for free treatment.
An NHS England spokesperson said: "Ultimately these are decisions for Clinical Commissioning Groups, who are under an obligation to balance the various competing demands on the NHS locally while living within the budget parliament has allocated."
Leceia Gordon-Mackenzie, deputy chief executive of Fertility Network UK, says patients are being let down.
"To deny those affected medical help is a short-sighted and a false economy.
"England pioneered IVF approaching 40 years ago, but that achievement is meaningless if only those who can afford to pay for IVF benefit from it. The Clinical Commissioning Groups need to understand the devastating impact these cuts have and stop failing patients who are already devastated and vulnerable."
Since 2010, Wales has offered two rounds of IVF to eligible women. In Northern Ireland, women are offered one IVF cycle.