Operations and clinics have been cancelled because of the snow
Hospitals are reviewing treatment schedules because of concerns about patients travelling in the severe weather and shortages of key staff.
Northampton and Kettering general hospitals have cancelled all operations and out-patients appointments but accident and emergency remains open.
Bedford Hospital has asked staff to come in even if they are not working as many key people have failed to arrive.
Ambulance and fire services warn people to contact them only for emergencies.
A spokesman at Milton Keynes Hospital in Buckinghamshire said no clinics or elective operations had been cancelled but they were currently reviewing the situation.
"Snow and icy temperatures mean that driving conditions are difficult, and not all staff have been able to make it into work.
"Our dedicated staff who have been able to get in are offering as much cover as possible.
"If an appointment is not urgent, and getting into hospital is difficult, patients should reschedule."
The South Central Ambulance Service is still responding to all calls, but is urging people to think carefully before calling out an ambulance.
This was to ensure that all urgent cases were treated as quickly as possible, an ambulance spokesman said.
Bedfordshire and Luton Fire and Rescue Service has put contingency plans in place to ensure cover is maintained during this period of severe weather.
Acting Chief Fire Officer Graeme Smith said: "Firefighters at our full-time stations have been asked to remain on duty until we are certain that their replacements crews can make it for shift change.
"Retained firefighters have also been called in. As they all live within five minutes of their stations they have been able to get in on foot and are on standby at the moment.
"Our fully equipped four wheel drive vehicles are available to attend incidents in hard to reach areas and our crews are continually updated regarding road closures.
"We will review the situation hourly and return to normal duty as soon as it is safe to do so."
Call for staff
Bedford Hospital is asking any member of staff who can get into the hospital through the heavy snow to come in to work.
This includes any member of NHS bank staff or people who would not otherwise be working today.
The call comes after a number of staff have reported they are unable to get into the hospital due to heavy snowfall and subsequent transport problems and school closures.
Outpatient clinics are being cancelled for Thursday but planned surgeries are still going ahead. Patients are advised to phone ahead to check arrangements.
A hospital spokesperson said: "A number of staff have been unable to get to work due to the heavy snow, and we really do need any member of staff who can get to work safely to come in.
"Patients are also advised not to attend the A&E department unless they require urgent medical attention."