Hundreds of health workers are expected to take part in a four hour strike tomorrow from 7-11am.
It will be followed a four day work to rule as they take designated breaks and refuse to work unpaid overtime.
Union officials have said emergency cases will still be seen and they hope to keep disruption to patients to a minimum.
However, bosses at East Midlands Ambulance Service (Emas) are appealing to people call 999 only for life-threatening emergencies.
They have warned that response to non-life threatening calls are likely to be affected and people could be asked to make their own way to hospital.
It is the first time in its history that the Royal College of Midwives have voted in favour of industrial action.
Members will join colleagues from five other unions in the stoppage.
The Society of Radiographers is due to take similar action the following week.
It is in protest at a Government decision to refuse a recommended one per cent pay rise for NHS workers.
Sue Noyes, Emas chief executive, said: "We recognise the right of our staff to take industrial action and we respect and understand that their decision to strike is a difficult one to make.
"Union colleagues have confirmed they will respond to life-threatening emergencies during the four-hour period and I thank them for putting the safety of our most acutely ill patients first.
"However, the action will affect all non life-threatening emergency calls we receive and it is inevitable we will face significant pressure."
She said training-courses and non-essentials meetings have been postponed and clinically trained managers and support staff would be on front line duty "where appropriate."
She added that telephone advice would be provided to non-life threatening calls and that "this may include asking people who are not in a life-threatening or serious condition to make their own way to an assessment centre via a friend or family member, taxi or public transport."
Suzanne Miller, region officer for the Royal College of Midwives in the East Midlands, said: "We have never before balloted for strike action. It is a momentous decision."
But she said midwives would be on duty for all mums going into labour or needed for emergency care.
She said some planned Caesarian sections and routine assessments might be deferred.
Rhana Azam, GMB national officer representing ambulance workers, said: "Staff take action with a heavy heart as their only priority is to deliver the best patient care.
"Even after staff voted to take strike action and action short of a strike the Secretary of State for Health has refused to meet with the unions representing NHS staffs."
Carol Brown, regional organiser for Unison whose members cover a range of professions from nurses to porters, said: "We hope the action is not going to have an impact on patient care."
Bosses at Leicester's hospitals have set up a central command centre to oversee services.
Phil Walmsley, head of operations at Leicester's hospitals, said: "Patient safety remains our top priority. We have developed contingency plans to ensure all our essential and critical services are delivered as normal, and that other services have minimal disruption."
He said patients should attend appointments as normal although some might be delayed or cancelled.
A spokesman at the Leicestershire Partnership NHS Trust, which runs community and mental health services, said it was not anticipating having to cancel clinics or appointments.
