Researchers say they have discovered a new contraceptive which could be taken just before sex.
Scientists from Stanford University, California, have discovered what they claim is a 'promising' on-demand therapy, as an alternative to taking the Pill every day.
The researchers say the new contraceptive is given in two tablets and works by disrupting ovulation, the stage during a woman's menstrual cycle when she is most likely to get pregnant.
The Pill also works in a similar way, but is taken daily rather than just before sex.
Both patients and medics are said to be 'very interested' in the development of this 'on demand' contraceptive.
Condoms and diaphragms are currently the only 'on-demand' contraception options available.
A study with nine participants who were monitored for two menstrual cycles where their ovulation patterns were identified.
On the third menstrual cycle, the participants were then given the drug before they had scans and blood tests to measure hormone levels.
The drug was thought to be effective if it showed it was disrupting ovulation.
The findings, published in the journal BMJ Sexual & Reproductive Health, said the drug was effective as a contraceptive for six of the women while eight met some criteria for incomplete ovulation.
The results were said to be promising by researchers but further studies are needed into the drug and its side effects.