Four in ten pregnancies in the UK is unplanned, a UK poll suggests.
A large number of women are having unplanned pregnancies
The survey of 3,000 mothers, commissioned by evriwoman.co.uk, found almost half of women with unplanned pregnancies were using contraception.
Of these, 62% blamed problems with the Pill, 19% said it was due to a split condom, and 3% were too carried away to use contraception.
One in five women said they regretted the pregnancy.
The survey showed it is not just teenagers who are being complacent about contraception, but older women too.
Almost all the women surveyed were in their twenties and thirties.
Almost 70% of women on the pill said they forget to take it at least once a month, 10% forgetting to take it four times or more.
Dr Rosemary Leonard, a GP in London, said many women don't realise that missing one or more pills per cycle can double their chances of becoming pregnant.
"Often in my surgery I see the very real emotional and financial costs of an unplanned pregnancy and it can be frustrating to know that often it's because people have taken one too many risks with contraception."
She said women who have had unplanned pregnancies need to review their contraceptive methods and look at options such as hormonal implants, injections and patches, and IUS's (intrauterine systems).
"Many women might benefit from considering a method that does not need to be thought about every day, like the Pill does, or at the time of intercourse, like condoms."
Some 45% of survey respondents said they are considering a new method of contraception, of these 38% said they would choose the pill, 28% said condoms, and 15% considering a contraceptive patch or injection.
Having a baby also affected the sex drive of many women, with half of those questioned saying they had "gone off sex" due to no longer feeling attractive, being too tired, or fear that sex after a birth could be painful.
The survey was hosted on the website Bounty, an online community for mothers.
Toni Belfield, Director of Information at the Family Planning Association said the statistics come as no surprise.
"They reflect the realities of the issues facing couples trying to plan pregnancies and the consequences when pregnancy happens unexpectedly," she told BBC News Online.
"Our national helpline receives calls every day from women needing help and advice about this subject.
"This really highlights the need for both women and men to be supported in the choices that they make regarding their contraception and also supported if they are faced with an unplanned pregnancy."