Emergency contraception is an effective way to prevent an unplanned pregnancy after unprotected sex or when your regular contraceptive method may have failed¹ (e.g. a condom breaks, you’ve forgotten to take your routine birth control pills, or you missed a dose of the birth control injection).²   This kind of contraception is also called “the morning after pill”, because it needs to be taken soon after you’ve had unprotected sex. Note that emergency contraception is designed to be taken after unprotected sex; it won’t work if you take it beforehand.²   Emergency contraception doesn’t reverse or end a pregnancy that has already begun; it prevents it from happening.² Depending on the type of pill, emergency contraception works by delaying or preventing ovulation (when an egg is released from the ovary), preventing fertilisation of the egg by the sperm, or preventing a fertilised egg from implanting in the uterus.¹

In South Africa, about 3 % of women use emergency contraception as their primary form of birth control.¹ However, emergency contraception is formulated as a temporary way to prevent pregnancy that should only be used in emergency situations – it is not meant to be used as a routine, long-term form of birth control. There are more appropriate methods to prevent pregnancy long-term such as regular birth control pills, intrauterine devices (IUDs) and implants.²   If you find yourself using emergency contraception multiple times, ask your doctor about other long-term contraceptive options. Also remember that emergency contraception offers no protection against HIV and other sexually transmitted infections.¹

There are two main types of emergency contraception pills, which are available over the counter at most pharmacies. While you don’t need a prescription for these medicines, you will need to fill out a patient information form at the pharmacy to determine where you are in your menstrual cycle.   Each type of pill has its own timeframe for when you should take it, but both types work best when taken within 24 hours of having unprotected sex. The term “morning-after pill” may be a little misleading because you don’t need to wait until the next day to take these medications.²   Ulipristal acetate pills vs levonorgestrel pills The active ingredient in newer emergency contraception pills is ulipristal acetate.³   Ulipristal acetate works by delaying or preventing ovulation (depending on when in your cycle you take it)³ but has no effect on implantation in the uterus. In other words, it helps to prevent pregnancy before it starts.⁴ This treatment may stop you from ovulating even if you take it just before ovulation occurs, which is important because it’s at this time in your cycle that fertility and the likelihood of becoming pregnant are highest.^3,5   It’s important to note that, while ulipristal acetate works well in preventing a pregnancy, it has no impact on your fertility. It won’t harm your chances of getting pregnant in the future.²   Studies show that ulipristal acetate is the most effective emergency contraceptive pill when used within the first 24 hours after unprotected sex.³  It can still be taken within 120 hours (up to five days) after unprotected sex, but it is more effective the sooner you take it.² This extended time limit is an important advance since women who previously might have thought that they were too late (after 72 hours) for an emergency contraceptive pill may now consider using this method.⁶   The second type of emergency contraception pills are those containing the ingredient levonorgestrel. Levonorgestrel is also most effective if taken in the first 24 hours after unprotected sex. There is a narrower timeframe for use than ulipristal acetate; levonorgestrel can only be used within 72 hours (up to three days) after unprotected sex.^2,6   Ulipristal acetate is more effective than levonorgestrel in the days leading up to ovulation, because it is the only emergency contraception pill which works even if ovulation is just about to occur. While ulipristal acetate delays ovulation for at least 5 days, in studies the effect of levonorgestrel just before ovulation was the same as a placebo, i.e. no contraceptive.⁷   Research has shown that the risk of pregnancy is reduced by almost two thirds by ulipristal acetate compared to levonorgestrel, when taken within the first 24 hours after unprotected sex.³

In most cases, you won’t need to see your doctor after taking emergency contraception pills. Ulipristal acetate and levonorgestrel pills have similar side effects that are usually mild or moderate and resolve spontaneously.³ These may include headache, stomach pain or cramping, spotting (light vaginal bleeding) and nausea.^2,6  

Some side-effects of the emergency contraceptive pill ²

  It is recommended after taking an emergency contraception pill to use a barrier method, such as condoms during sex, until your next period.³   If you are breastfeeding, the recommendation is to pause this for a few days after taking emergency contraception. Stop breastfeeding for one week after taking ulipristal acetate,³ and for 8-24 hours after taking levonorgestrel.⁶   Talk to a health professional if you have any concerns, and be sure to contact your doctor if you haven’t had your period within a week of when you expect it (a missed period is an early sign of pregnancy), or if you have severe abdominal pain or heavy vaginal bleeding, which could indicate a miscarriage or ectopic pregnancy.²   Also consider getting tested if you’re worried that you may have been exposed to sexually transmitted infections during unprotected sex.¹