Sue Hawkins, of the campaign group Support Stafford Hospital, said they expected that Jeremy Hunt "probably will" dissolve the trust.
She said they hoped that Mr Hunt would reflect some of their concerns in his announcement.
She told BBC Breakfast the concern was primarily over obstetrics.
A simple birth can change to needing a Caesarean section very quickly. Are those patients going to make it in time 18 miles up the road?
Infrastructure - the M6 - often accidents, often shut, Stafford has got a very poor network of roads. We get gridlocked very easily. We are seriously concerned about safety.
She said 50,000 people had marched in a small town of only around 60,000 - although the surrounding area is bigger - showing their support for retaining these acute services.
"Treatment would obviously move to neighbouring trusts but we have a very high proportion of elderly. What is going to happen?"
More top news
Nearly 750,000 people worldwide have died with Covid-19.
Marion County Sheriff Billy Woods said he had weighed both sides of the issue.
It was not until August 15 1945, days after US atomic bombs fell on the Japanese cities of Hiroshima and Nagasaki, that the battle in Asia w