Among the changes, approved by the Rugby World Cup Board following a comprehensive tournament review, is a revised match schedule with the addition of a quarter-final stage and longer rest periods between matches.

Also agreed is an increase in squad size in an attempt to enhance player welfare and ensure the tournament continues to deliver compelling, competitive rugby.

Despite calls to increase the number of teams competing from 12 to 16, the current format will remain in the short term while World Rugby focuses on increasing the competitiveness of the 15s game via the competitions and high-performance strands of the 2017-2025 Women’s Plan.

However, it is claimed the revised match schedule guaranteeing longer rest periods - four days between pool matches, and five or six days during the knock-out rounds - will greatly benefit player welfare by aiding recovery and preparation, while the addition of the quarter-final stage will allow teams a further opportunity to play for a higher position.

With the longer rest periods and additional play-off stage, the total tournament window will increase from 23 to 35 days.

Following feedback from teams and players, and World Rugby's commitment to prioritising player welfare, the review also concluded that squad size should increase by two from 28 to 30 players.

World Rugby says the changes build on the success of the record-breaking 2017 Women's Rugby World Cup in Ireland.

Last year’s edition was the best-attended, most-viewed and most socially-engaged ever, setting new standards for the tournament and extending the reach of the game around the world.

World Rugby claims that following on from the tournament there has been strong public expressions of interest from national member unions keen to take part in the host selection process for the 2021 event.

The deadline for formal expressions of hosting interest from unions is May 31, 2018.

Bid documents will be distributed to interested unions on June 1, 2018, while bid responses must be submitted by unions to World Rugby by August 10, 2018.

The World Rugby Council is due to select the host of the 2021 Women's Rugby World Cup on November 14, 2018.

Australia, England, France and New Zealand, the winners of the 2017 edition of the Women's Rugby World Cup, have all expressed interest in hosting the tournament.

"The launch of the host selection process for Women's Rugby World Cup 2021 is an exciting milestone and follows a fantastic 2017 for women’s rugby," World Rugby chairman Bill Beaumont said.

"The exceptional Women's Rugby World Cup in Ireland was the best attended of all time, inspiring on and off the field, and underscored why the event is such an attractive hosting proposition for unions and nations.

"We want to keep building the momentum, which is why we are introducing these changes to the format for the 2021 process.

"By ensuring an even more competitive and exciting tournament in the future, women’s rugby can continue to play an instrumental role in driving forward the development of the game and significantly broadening rugby’s global fan base."

In November of last year, Beaumont claimed the governing body has made "strong progress" with its player welfare reforms and pledged to continue research in the area to help prevent injuries in the sport.

Beaumont said the organisation had a "great base in leading injury-management programmes", including concussion and immediate pitch-side care, two elements which rugby has been criticised for in the past.

World Rugby also published data to support its claims, suggesting that global injury rates have not increased at elite international level.

It revealed that in 2012, a total of 56 per cent of players showing signs of concussion remained on the field.

This number reduced to 13 per cent after one year.

The data for 2016 to 2017, taken from 22 global elite competitions, showed that eight per cent are not being correctly removed.

This demonstrates "significant advances in sensitivity, awareness and cultural change", according to World Rugby.

World Rugby general manager Katie Sadler said that the changes to both squad sizes and the length of time between games was called for by all nations.

"We got feedback that player welfare was really important and we needed to increase the days in between [games] so the changes we made to the structure and format reflect this," she was reported as saying by BBC Sport.

In line with its 2017-25 Women’s Plan, World Rugby says it is determined to further the impact of its flagship women’s tournament and hopes the format amendments will boost the experience for players and fans alike.