Thousands protest against threat to Horton hospital services
An estimated 5,000 campaigners encircled a hospital to protest about the potential downgrading of services.
A consultant-led maternity unit is among the services under threat at Banbury's Horton General Hospital.
The Oxford University Hospitals NHS Trust (OUH) is looking at planned care, urgent care, maternity and children's services.
Medical director Dr Tony Berendt said decisions would be made in the interests of patient safety.
The 'Hands Around Our Horton' protest was supported by Banbury's Conservative MP Victoria Prentis, who said she was "absolutely thrilled" to see so many supporters turn out.
"I was born in the Horton and generations of my family have been treated there countless times," she said.
"I am worried that mothers' and babies' lives will be put at risk if they have to be transferred to Oxford during labour.
"I know how quickly things can go wrong and it's really important to have consultants to hand."
If proposals go ahead, specialist services could be transferred almost 30 miles to Oxford's John Radcliffe Hospital.
Val Ingram, from the Save our Horton group, said the campaigners were "simply amazing for turning out in droves to support the hospital".
Dr Berendt said: "We still have a number of obstetrician vacancies unfilled so we wouldn't be able to run a safe rota.
"We have no alternative but to look at contingency plans."
The OUHT board of directors will meet on 31 August to decide whether obstetric services at the Horton Hospital will be suspended from the end of September.
If they are, the unit would be midwife-led until enough obstetricians are in place.
In 2008 campaigners won a battle to stop maternity and children's services being transferred elsewhere.