Women over 34 are being automatically refused IVF treatment on the NHS in 12 areas of England, the Victoria Derbyshire programme has found.
IVF should be offered to women until age 42, guidelines say, but new figures show around 80% of areas are failing to do this.
Campaign group Fertility Fairness said it "penalises women who take longer to find a partner".
Health Secretary Matt Hancock said "blanket bans" were "not acceptable".
Couples in Wales and Scotland are offered IVF until they are 42, as long as certain criteria are met.
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One 38-year-old woman, Charlotte - whose surname we are not using - told the BBC's Victoria Derbyshire programme she was considering moving house to a different area, having been told she was too old to qualify for the procedure in Southampton.
Southampton City Clinical Commissioning Group (CCG) has a cut-off age for women of 34.
"It's just unfair, because I am not over the hill," she said.
"To say that 35 and over is the end of having children is ridiculous."
Charlotte was first tested aged 34, and said the "most upsetting" aspect was not being told about the age limit sooner.
"I would have liked to have known when I was younger," she said.
"It would have enabled us to make a decision earlier about selling the house, and given us another year on what is already a timed situation."
Southampton City CCG said it had "taken into account the relative cost-effectiveness [of IVF] compared to other treatments that could be funded with the resources we have available".
Guidelines from health watchdog NICE recommend that women under 40 should be offered three full cycles of IVF, and those between 40 and 42 one full cycle.
But data from all 195 Clinical Commissioning Groups (CCGs) in England - obtained under the Freedom of Information Act by Fertility Fairness and analysed by the Victoria Derbyshire programme - shows that seven have stopped offering IVF on the NHS entirely.
Of the others, 12 deny treatment to women over 34 - offering only one full cycle to those under that age.
85 CCGs, some 43% of the total, have cut IVF for women over 39.
England's Health Secretary Matt Hancock told Victoria Derbyshire such restrictions were "not acceptable".
"Decisions on the treatments that are made available to people should be made on their clinical need," he said.
"There is a reason we have guidelines in the first place - and that's to provide the standard the country should expect."
The Royal College of Obstetricians and Gynaecologists blamed "inadequate government funding".
It said it was "very concerned that women and their partners are turning to costly private clinics for treatment".
Sarah Norcross, co-chair of campaign group Fertility Fairness, told the Victoria Derbyshire programme that it "penalises the women who take longer to find a partner or wish to put themselves on a secure financial footing before trying to conceive".
The group's 2018 report into IVF rationing found that 30 CCGs have "slashed NHS fertility services" in the last two years.
It said many CCGs were setting their own access criteria - with 27% now using a man's body mass index (BMI) to determine whether a couple can be referred for IVF on the NHS, and 8% stipulating men must be aged below 55.
NHS England said in a statement: "Ultimately these are decisions for local GPs, who rightly decide how best to balance the various competing demands on the NHS."
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