Boots has been accused of a "scandalous" failure to provide cheaper emergency contraception - despite promising to roll it out nationwide earlier this year.
Just 69 of the high street chain's nearly 2,500 shops now offer the less expensive version of EHC (Levonorgestrel), which costs £15.99.
It had promised to have the morning-after pill available in all stores by October, amid a backlash over its handling of calls to make the morning-after pill cheaper.
It comes after the chemist chain faced severe backlash in July for refusing to reduce the cost of the morning-after pill.
The company faced accusations of sexism and threats of a boycott after arguing it did not want to "incentivise" its use by reducing the price.
It later apologised for its "poor choice of words".
But a letter from more than 130 MPs, led by Labour's shadow public health minister Sharon Hodgson, states they are "deeply concerned" that Boots is "unable or unwilling" to keep its pledge.
The letter also called on Boots to consider reducing the price of its own-brand morning-after pill, which currently costs around £26, if they are having trouble sourcing the brand name.
The call was backed by the British Pregnancy Advisory Service. Its director of external affairs, Clare Murphy, said it was "scandalous" that Boots had not yet made the drug widely available.
"There can be absolutely no excuse for their pathetically slow pace of progress, other than the fact that they simply do not want to provide women with an affordable product," she said.
"If Boots cannot 'source' a new version of emergency contraception to sell at a lower price, then they should do the right thing and cut the price of the version they currently have in stock.
"Regardless of 'supply chain delays', affordable emergency contraception is entirely within their gift to give right now - and every day they refuse to do so, more women are being ripped off, or risking an unplanned pregnancy because they cannot afford Boots' inflated price tag.
In a statement, a spokeswoman for Boots said they "remain committed" to rolling out the new emergency contraception nationwide, but said their manufacturer had suffered a "batch failure due to quality issues".