A new study has found more than half of unintended pregnancies are the result of women having unprotected sex.
And almost a third of those pregnancies ended in abortion.
The survey, published on Monday in the Medical Journal of Australia and collected by researchers from La Trobe University, gives a rare insight into how women react to a positive pregnancy test.
Of the 2571 women interviewed, 1390 had been pregnant in the past 10 years and more than a quarter of those pregnancies had been unintended.
Most women who had unintended pregnancies (205 of 362 women) did not use contraception at the time.
Those that did relied on the pill (64%), condoms (27%), long-acting reversible contraception (6%), a diaphragm (1%) or the withdrawal method (2%).
La Trobe University researchers found that of those who had accidental pregnancies, 30 per cent had abortions.
In 94 cases where pregnancy was unwanted, 78 (83 per cent) had abortions.
Professor Taft said more research was needed to explore the reasons women were not using contraception and to determine where education would be helpful.