Midwives will go on strike for the first time in their 133-year history on October 13.
They voted to walk out for four hours in a dispute over pay.
Ante-natal and post-natal appointments will be targeted by the action, scheduled to start at 7am on Monday, October 13.
Midwives in England will join NHS members of the Unison and Unite unions, who have already voted in favour of strike action scheduled for the same day.
The RCM said 82.2 per cent of its members voted to say they were prepared to take part in the strike, while 17.8 per cent were not.
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More than 94 per cent of midwives say they're prepared to take part in action short of a strike.
The yes vote follows the rejection by employers of the Independent NHS Pay Review Body's (PRB) recommendation of a one per cent pay rise for NHS staff.
Cathy Warwick, RCM chief executive said: "This is a resounding yes from our members. It could not send a clearer signal about the level of discontent on this issue to those denying them a very modest one per cent pay increase."
A Department of Health spokesman said: "We are disappointed that RCM is planning industrial action and has rejected our proposals to give NHS staff at least one per cent additional pay this year and at least a further one per cent next year.
"NHS staff are our greatest asset, and we've increased the NHS budget to pay for thousands more clinical staff since 2010, including more than 1,700 more midwives since May 2010.
"We want to protect these increases and cannot afford a pay rise on top of increments - which disproportionately reward the highest earners - without risking frontline jobs."
A spokesman for NHS England said: "NHS organisations have tried and tested plans to deal with a range of disruptions including industrial action.We are working with the NHS to ensure there are robust plans for October 13 that protect the safety, welfare and service provided to patients."
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