If you have a mishap with a condom and fear an unwanted pregnancy, what do you do? You pop a morning-after pill and all your problems are behind you, right?

If you have a mishap with a condom and fear an unwanted pregnancy, what do you do? You pop a morning-after pill and all your problems are behind you, right?

And if you are taking antibiotics and realise the contraceptive pill will not be enough? You pop a morning-after pill and it's water under the bridge, right?

Wrong. Ever more users of morning-after pills report that they have fallen pregnant soon after taking their first dose of the emergency pill.

"Some women think of the morning-after pill as a contraceptive, but it's actually a DIY abortion method," said gynaecologist Michael Sangweni.

"There is no way that your body would not take a beating from a medicine that's that ferocious."

The morning-after pill deters fertilised eggs from being implanted in the uterine wall if taken within 72 hours.

It is frequently used after sexual assaults, after unplanned and unprotected sex, after a condom splits during intercourse or if the woman has omitted to take an ordinary contraceptive pill for more than three days.

The morning-after pill reduces the chance of pregnancy by 75percent to 85percent.

For the desperate, this pill remains a trusted friend because pharmacists don't usually give interviews. But some users either abuse the pill or use it wrongly, only to end up pregnant anyway.

"The morning-after pill has to be used within 72 hours of unprotected sex," said Jack Biko, another gynaecologist.

"If you lie to yourself and try to use it after that, it won't work."

He said that because taking the morning-after pill throws women's menstrual cycles off balance, they no longer know when they are ovulating.

"Calculation should be made from the cycle created by the use of the morning-after pill."

The pill not only prevents the fertilised egg from implanting itself in the womb, it also accelerates the secretion of ovulation hormones. This means someone who takes the pill too late - after 72 hours - might get a period even if implantation has taken place.

Taking an over-the-counter emergency pill also puts you at risk of an ectopic pregnancy.

"Ectopic pregnancy happens when a fertilised egg is unable to work its way quickly enough down the fallopian tube and into the uterus," said Sangweni.

"In 95percent of such cases the removal of a fallopian tube is necessary, minimising the patient's ability to conceive again."

And there are women who should not touch the morning- after pill at all.

These include women with a history of jaundice, liver or gall bladder disease, or with clogged arteries.