Emergency Contraception: When to Use It, How to Use It, and What are its Side Effects

Commonly referred to as the morning after pill, the emergency contraceptive (EC) pill is a contraceptive method that is taken after unprotected sex, or when an alternative birth control method (e.g. condoms) has failed. Used to prevent unintended pregnancies, EC pills primarily work by stopping or delaying the release of an egg (ovulation). It is important to note that EC pills only work to prevent pregnancy, and do not interfere with an already existing pregnancy - i.e. if a fertilized egg has already been implanted in the uterine lining.

Types of EC pills

In Singapore, two types of emergency contraception pills are available: progestin-only pills and antiprogestin pills. While progestin-only pills are usually effective for up to 72 hours, antiprogestin pills are effective for up to 5 days after unprotected sexual intercourse.

How to use it

EC pills are to be taken orally as a single dose (which can consist of one single pill or two pills taken 12 hours apart). As the effectiveness of EC pills is time-dependent, it is recommended to take the pill as soon as possible after unprotected sex. For progestin-only pills, the efficacy rate is the highest when taken within 24 hours (up to 95%). After this 24-hour window, the efficacy rate gradually decreases to 58% at the 72-hour mark. Antiprogestin pills have an efficacy rate of 85% and their efficacy rate does not drop for 5 days after intercourse. However, it is still recommended that the pill be taken as soon as possible.

Repeated EC use

EC pills should not be used as a regular form of birth control or as a substitute for other traditional birth control methods. Although there are presently no long-term risks associated with frequent EC usage, short-term side effects such as unpredictable and irregular periods can still be experienced. More importantly, despite being highly effective in preventing pregnancy after unprotected sex, EC pills are still comparatively less effective at pregnancy prevention compared to other traditional birth control methods like contraceptive pills, contraceptive patches, and the IUD. Unlike these traditional birth control methods, the hormone and/or components in EC pills do not remain in the body over an extended period of time. Therefore, there is a higher risk of pregnancy should EC pills be used as the sole form of birth control. Additionally, it is also helpful to note that EC pills also do not protect individuals against sexually transmitted infections (STIs).

Side effects of EC pills

The most common side effects are:

· Nausea

· Headaches

· Fatigue

· Menstrual cycle changes

· Abdominal pain

These side effects are short-term and will subside as time passes. However, if vomiting occurs after taking an EC pill, consult your doctor to see if a new dose is required.


EC pills are a highly effective method for pregnancy prevention in the event of unprotected sex or the failure of an existing birth control method. However, as their effectiveness is time-dependent, EC pills should be taken as soon as possible after unprotected sex. Despite being a safe and effective method in preventing unintended pregnancies, it should not be used as a regular form of birth control. Ease carries not only the both types of EC mentioned, but also carries a range of long-term birth control options. Should you require an EC pill, you can request one here. Alternatively, if you would like to explore other birth control methods, you can visit our website to learn more.