Williams, the winner in 2015 and 2016, did not defend her title last year while she was pregnant with her first child and is now ranked 449th in the world.

Many inside women's tennis feel players are being penalised with a drop down in the rankings, in the same way as injured players, when they take time off to give birth.

In the men's draw, nobody outside the top 32 is eligible for a grass-court seeding, but the rules aren't as clear on the women's side.

All England Lawn Tennis and Croquet Club chairman Philip Brook said: "It is totally different to an injury and we have empathy and sympathy for the point being made. It is a question that we will certainly address."

At the annual spring news conference, this year's prize pool was announced, with the men's and ladies winners receiving £2.25 million -- a rise of £50,000 from last year.

The total prize fund will be £34 million, a 7.6 percent increase from last year.

Injured competitors will be able to claim 50 percent of their first-round prize money -- up £4,000 to £39,000 -- if they withdraw on site by the Thursday before the start of the main draw. An injured player's replacement would take the other half of the prize money.

The 50-50 rule will be introduced in a bid to prevent injury withdrawals in the opening round.

Some players drew criticism last year when attempting to play their first-round matches despite being unfit in order to still claim the cash.

Any player who competes in the first round and "retires or performs below professional standards" may now be subject to a fine of their entire winnings.