This is lower than the 44% of women MPs Labour had in the last Parliament.
The SNP have selected women in 20 out of 59 seats they are contesting - or 33%. The Lib Dems have 191 female candidates out of 630 - or 30%.
The Conservatives are still compiling their list but currently have 177 women out of 621 candidates - 29%.
A record 191 women were elected in 2015 - around 30% of MPs.
Earlier this year, the election of Tory Trudy Harrison in Copeland took the number of women elected altogether in the past 100 years to 456 - roughly the same as the total number of male MPs in the 2015-2017 Parliament.
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MPs recommended in January that political parties should be fined if they failed to ensure at least 45% of their general election candidates were female.
The Women and Equalities Committee said the fact that 30% of current MPs were women represented a "serious democratic deficit", for "no good reason" and called for a change in the law after the next general election if that figure did not increase "significantly".
Both the Conservatives and Lib Dems are fielding a higher proportion of female candidates in the 2017 general election than they had as MPs in the last parliament.
Just over 21% of the Conservative MPs elected in 2015-17 were women.
Conservative MP Maria Miller, who chaired the Women and Equalities Committee in the last Parliament, told the World at One: "The Conservative Party has made significant progress, particularly under Theresa May and the the work she's done with the Women2Win campaign."
Mrs May was a founder of the campaign, which aims to increase the representation of women in the party, along with Tory peer Baroness Jenkin.
The SNP is fielding 20 women out of 59 SNP candidates in Scottish seats, or 33.4%. In 2015, the SNP had 36 male MPs and 20 women (35.7%).
The SNP's Kirsty Blackman told the BBC that the surprise timing of the election had meant "less time to reach out to candidates from non-traditional backgrounds".
The Lib Dems lost all their female MPs in their near-wipeout in the 2015 election.
The party was reduced to eight male MPs, though Sarah Olney's victory in last year's by-election in Richmond Park later gave them back one female MP.
Labour is fielding the largest proportion of female election candidates of the biggest parties - at 41%, BBC analysis shows.