Just over a third (34%) intend to vote Yes while the rest remain undecided, a Survation poll of 1,000 women found.
However, the Scottish National Party remains the most popular party amongst women in Scotland, with the backing of 43% if there was a pending election, against 27% who back Labour and 15% who support the Conservatives.
Women for independence have a broad range of reasons for voting Yes, with an almost even split between oil money (20%), a desire for their "proud nation" to be independent (19%), dislike of the UK Conservatives (18%) and a belief that the economy would perform better (17.5%).
Concern over currency is the main reason for women voting No (32%), followed by concerns over the economy (27%) and pride in being part of the UK (26%).
Only 1.5% are voting Yes because they want Alex Salmond to be prime minister, against 16% who are voting No because they do not. Over half of No voters (51%) say his presence as leader of the Yes campaign will make them more likely to vote No.
Over half of women (55%) think Mr Salmond wants independence mainly because he wants to be prime minister, and the rest said it is because he thinks it would be best for the people of Scotland.
A majority of women described Mr Salmond as arrogant (55%) and ambitious (52%), while 29% described him as dishonest. A quarter described him as strong and intelligent, and a fifth said he is principled.
A majority of women described his deputy Nicola Stugeon as ambitious (51%), while two-fifths said she is intelligent. Many said she is strong (30%), principled (27%) and arrogant (26%).
Intelligence is Alistair Darling's top feature according to 43% of women, while over a third said he is principled. But nearly a third said he is arrogant, while a quarter said he is weak and ambitious.
Speaking on behalf of Better Together, Scottish Labour MSP Jackie Baillie said: "This poll is a major blow to Alex Salmond's failing campaign and confirms the momentum is with those of us who believe the brightest future for Scotland is as part of the UK.
"The more women in Scotland consider the consequences of separation for our pound, pensions and public services, the more we are saying no thanks.
"Alex Salmond is so obsessed with breaking up the UK that he is blind to the risks of separation. Women in Scotland aren't. We know that we can have the best of both worlds for Scotland - more powers for our Scottish Parliament guaranteed, and the strength of being part of something bigger. We should say no thanks to putting that at risk on 18 September."
Ms Sturgeon said that the poll showed increased support for Yes amongst women compared with a previous survey.
"There is a real risk of the Tories being re-elected next year, and in these circumstances a majority of women as well as men favour independence," she said.
"We believe women will vote Yes next month, because it is our one opportunity to protect our NHS from Westminster privatisation, create more jobs in Scotland, and transform childcare instead of wasting billions of pounds of Scottish taxpayers' money on Trident nuclear weapons."
Survation surveyed an online panel of 1,000 women between August 8 and 12.
Gail Lythgoe, campaign organiser for Yes Scotland said: "A Yes vote in September offers women throughout Scotland an opportunity for substantive societal change. By saying Yes, we can tell our children and grandchildren that we voted for a better and fairer Scotland.
"As women go to the polls, they'll be faced with two choices for Scotland's future. One of continued uncertainty that will come with increased Westminster cuts, cuts that would see Scotland's budget slashed and our valued public services seriously strained and damaged.
"The other path with Yes will safeguard the gains of the Scottish Parliament such as free personal care and the ending of prescription charges. We can also protect our NHS in a written constitution, declaring that it remains free and that our welfare system remains intact to support our most vulnerable."