The Royal Glamorgan hospital in Llantrisant could stop treating the most serious accident and emergency cases as part of a major NHS shake-up in south Wales.
Health officials say the "best fit" is to locate specialist services in Cardiff, Swansea, Merthyr, Bridgend and in a new hospital near Cwmbran.
But a consultation will include options involving the Royal Glamorgan.
NHS leaders believe services are currently spread too thinly.
They have warned some specialist hospital services are "on the edge" and could "collapse" unless big changes are made to the way they are delivered.
The Royal Glamorgan also stands to lose consultant-led maternity care and specialist baby care as part of the proposals for the future of hospitals in south Wales.
Five health boards have been drawing up the proposals, which include hospitals from Swansea, Cardiff and Newport, since the start of 2012.
They argue the changes are essential to ensure hospital care meets UK-wide professional standards and to deal with issues such as a shortage of doctors, an ageing population and financial pressures.
The plans involve:
- Consultant-led maternity care (obstetrics)
- Specialist baby care (neonatal)
- Specialist children's care (paediatrics)
- Emergency medicine (A&E)
At the moment eight hospitals in the region provide one or more of these services.
Aneurin Bevan Health Board (ABMU) medical director Dr Grant Robinson said: "We cannot continue to provide all these services in every location across south Wales.
"We need to concentrate these services to ensure all patients receive safe and sustainable care.
"Our clinicians believe that the best way to do this, while improving safety and the standard of care patients receive, is to concentrate these clinical services in fewer hospitals - either four or five."
The health boards have been evaluating since September whether concentrating all those services in four or five centres would be most suitable.
The centres would include the University Hospital of Wales (UHW) in Cardiff, Morriston Hospital near Swansea and a new hospital at Llanfrechfa Grange near Cwmbran.
This would incorporate some services from Nevill Hall hospital in Abergavenny and the Royal Gwent hospital in Newport.
A two month consultation will consider whether Prince Charles Hospital in Merthyr Tydfil, the Princess of Wales Hospital in Bridgend or the Royal Glamorgan Hospital would be the fourth or fifth centre.
But health officials said the option which is the "best fit" chooses the Bridgend and Merthyr Tydfil hospitals over the Royal Glamorgan.
The recommendation was based on criteria including travel times, the number of doctors needed, impact on ambulance services and cost.
The bosses of the five health boards said they were eager to listen to public opinion in the consultation.
They said the ideas had been developed with those on the NHS frontline and the different scenarios had already been discussed with the public over three months last year.
"We carried out this engagement because we wanted to hear the views of the public at an early point in the process - a clear majority said they understood why services need to change and supported the ideas," they said.
"Following agreement by all the boards to proceed to consultation, there will be a full and open process to listen to and consider the public's views about all the options."
The proposals had a frosty reception from opposition politicians, and the Labour Education Minister Leighton Andrews joined a campaign to maintain services at Llantrisant.
Health Minister Mark Drakeford told AMs he could not comment in detail about the proposals but said changes were unavoidable.
"Change is coming in the NHS in Wales, as it is in every other part of the United Kingdom."
"If issues do end up in relation to the south Wales plan on my desk for determination I will consider those carefully, I will consider them thoroughly, but I will not unduly delay making necessary decisions," he added.