Moves to overhaul hospital care have been criticised by leading doctors.
Hospitals are being reconfigured across the country
Reviews taking part across England are likely to see the creation of regional super centres at the expense of district general hospitals.
Leeds University birth expert James Drife has warned against hospitals losing specialist maternity care.
Doctors' leaders have questioned the creation of super GP surgeries known as polyclinics. The government said patient care would be improved.
The government argues advances in medical technology and restrictions on doctors' working hours means it is no longer possible to provide the most up-to-date care from all 200-plus acute hospitals.
Reviews are in the pipeline in all 10 NHS regions in England. These are looking at a range of specialist care, including A&E, maternity, paediatrics, heart care and intensive care.
It seems likely that a series of regional centres of excellence will be created in these specialities, with the traditional district general hospitals being downgraded.
To compensate, community services will need to be beefed up with the preferred model being the polyclinic.
These are health centres which can house a range of care including GPs, physios, social care and specialisms like diabetes and dermatology that would have taken place in hospitals in the past.
A review of the health service in London has already recommended a series of polyclinics be set up, with similar decisions expected to be taken elsewhere.
One consequence of hospitals losing specialist maternity care - that is to say consultant obstetricians - is that more birthing units will rely on midwife-led care.
But Professor Drife said maternity mortality was kept low because emergencies were managed effectively by consultants, the British Medical Journal reported.
Complications such as pre-eclampsia were hard to predict so it was not possible to decide which women were "low risk" cases and therefore suitable for birth at midwife-led units, he said.
He added: "It is disturbing that in an era of evidence-based medicine, midwife-led units are being promoted before their safety has been established."
Professor Drife said research suggested there was a slightly higher risk of a baby dying in midwifery care than under the care of consultants.
Meanwhile, Dr Hamish Meldrum, chairman of the British Medical Association, has warned against the London polyclinic proposals.
"It would be much better to invest in existing GP services and where necessary district general hospitals, rather than imposing costly, unproven polyclinics."
Health Minister Ben Bradshaw said: "The new polyclinics will treat people closer to home... offering a much wider range of services than most GP practices. That will mean patients having to make fewer visits to hospital."
And the Department of Health said what was important about maternity changes was to give women "informed choice".
The government was supported by Lesley Page, visiting professor of midwifery at King's College London.
She said the shift away from home births to hospital births over the last 50 years had resulted in "dehumanisation" and lack of personal care and midwife-led units could go someway to rectifying this.