How effective is postinor?

Monday January 21 2019


By Dr Vincent Karuhanga

I took postinor on Sunday night and had unprotected sex on Wednesday night. Do you think I am pregnant or can I take another postinor for further protection? Lindsay

Dear Lindsay,
Emergency contraception can be used to prevent pregnancy by women who have had unprotected sex and risk unwanted pregnancy. Emergencies here include being raped and having a condom break but Ugandans wrongly use the contraception as if it is the regular type taking the commonly used Postinor pills many times a month, every month and in your case before even the emergency has happened.

Taking a pill three days before sex is not an emergency requiring that you see your family planning clinic to advise you about a more regular method of family planning. Also, wanting to take another Postinor also shows that you need a more regular method of family planning.
Taking another Postinor is not only expensive, it may not work and yet may cause lots of side effects including disturbing your periods so that you will not be aware that the pill has failed and you have become pregnant. Medical trials only assessed the safety of Postinor when used as advised. That is, using it within 72 hours of sex, one time in a month and not every month as one requires.

Postinor contains a progesterone hormone called levonorgestrel and may prevent pregnancy by temporarily blocking eggs from being released, by stopping fertilisation, or by keeping a fertilised egg from becoming implanted in the uterus. Postinor gets less effective with time and so should be taken within 72 hours after sex though its effect may linger on (though less effectively) for up to about five days.
Much as Postinor is taken after unprotected sex for which medical trials have confirmed its efficacy, since you were still in the five-day bracket, you may have been protected though less effectively. This then means you need to do a pregnancy test in case you miss your next period though as a side effect of the drug you can miss periods without being pregnant.

Since it is assumed that you are now not completely protected you may need to use a copper T contraceptive device which is not hormonal and works by stopping implantation of a fertilised egg in the uterus. The device must be placed in the womb within five days of having unprotected intercourse and should be kept in place for more than 12 days the longest time the fertilised egg takes to be implanted provided you do not get intimate again up to five days before removal (the sperm may survive for 2-5 days if it escapes being killed by the device). Better still, you may make the device your new regular contraceptive by letting it stay in for up to 10 years.