Women who want a private room after giving birth on the NHS can expect to pay up to £450 a night, an analysis has shown.
Hospitals offer "amenity rooms" at four and five-star hotel prices to women who would like a side room rather than receiving care on a general ward.
Some rooms include extras such as slippers and a stocked fridge, or offer private breastfeeding consultations.
Women are told they will still receive the usual NHS care given to women who opt for a ward.
Amenity rooms at the Royal Surrey Hospital in Guildford cost up to £450 a night, the Press Association analysis shows.
The Shere Suite - billed as a "superior en-suite room for new mothers" - costs £450 a night and includes extras such as toiletries and the use of a fridge.
Meanwhile, at the Chelsea and Westminster Hospital in London, amenity rooms, all with en-suite, cost £300 per night.
Oxford University Hospitals offers private rooms for £450 a night where partners can stay, while its other amenity rooms range from £122 to £255 a night.
The Patients Association said the practice showed the NHS had an "ongoing scramble" for cash and said pursuing money in this way should not become a "routine part of how the NHS operates".
The Royal College of Midwives (RCM) expressed concern that midwives may feel the need to provide extra care to women who have paid for a room.
The most recent Care Quality Commission (CQC) review of 190 maternity units found 36% required improvement, 2% were inadequate, 57% were good and 4% were outstanding.
Last year's National Maternity Review found that postnatal care after birth was one area where women raised the most concerns and improvement was needed.
Rachel Power, chief executive of the Patients Association, said charging women for private rooms may be one area "where clarity is needed about what patients can and can't expect from the NHS".
She added: "These charges smack of the NHS's ongoing scramble for cash as its inadequate funding settlement really begins to bite.
"That said, it also highlights that inpatient or residential care has a 'hotel' dimension as well as a care dimension - you will need board and lodging, as well as your medical care.
"For permanent residential settings such as nursing homes, distinguishing between the two might make sense, but doing so for acute care leaves a bad taste in the mouth.
"While there's nothing to stop well-heeled people paying extra for luxuries, over and above that, pursuing money in this way surely should not be a routine part of how the NHS operates."
Louise Silverton, director for midwifery at the RCM, said it was vital that, where amenity rooms were offered, "there remains enough room for all women".
She added: "We know lack of postnatal beds is often a reason for temporary closures of services. This service must be an add-on and not affect the availability of beds.
"I would also stress that any money earned from such schemes should be reinvested directly into the maternity service of the trust, and not lost and absorbed into other services.
"Also, it is important that trusts ensure women know what they are and are not paying for.
"The midwifery care should be the same for all the women using a service, and I do have some concerns if midwives feel they have to provide extra care to those paying for a room."
The analysis found that amenity rooms with en-suite cost £195 per night at East and North Hertfordshire NHS Trust.
Cambridge University Hospitals said its amenity rooms, which cost £150 per night, offer the "same care in a quieter setting" but women still need to share bathrooms.
At Barnet Hospital, which has a range of rooms on offer, women are told they "will be treated as an NHS patient but are paying for the privacy of a single room".
A side room with no en-suite costs £100 a night, one with a toilet only costs £125 and a room with a full en-suite is £150.
Meanwhile, the cost of a private room with en-suite at Ashford and St Peter's in Surrey is £200 a night, while a room with a bathroom shared with another room is £130 a night. A single amenity room sharing ward facilities is £85 per night.
Hillingdon Hospitals' rooms cost £174 a night or £123 if sharing a bathroom, while at Epsom Hospital an amenity room with en-suite is £150 per night.
At Watford General Hospital, prices are £200 per night for a room with en-suite or £100 with no en-suite.
The Royal Surrey website said its Shere Suite is "furnished to higher standards and is equipped with a bedside cot, en-suite bathroom, fridge and comfortable fold-away bed for partners.
"For new parents' comfort, towelling slippers are provided and a gift set of natural pampering products in a keepsake box is for the new mother. There is also a Royal Surrey teddy bear for the new arrival.
"The room is also stocked with refreshments and each day residents will be offered their choice of meal from the standard NHS menu."
Short notice bookings are available if the room is not in use, at a cost of £395. The hospital also offers a range of cheaper single rooms with en-suite facilities.
In a statement, the hospital said new parents who require a side room after birth for medical reasons "always take priority for these facilities".
Anyone paying could be asked to leave if the room was needed by a new mother with a higher medical need.
It added: "Any income made from the sale of these rooms is invested directly back into maternity care, ensuring that access to the latest state-of-the-art equipment and birthing facilities are available for all."
It said parents booking this room also get a one-to-one antenatal class with a specialist midwife, a tour of the maternity unit and its facilities at a time chosen by the parents, a baby feeding consultation, and open visiting hours between 8.30am and 10pm.