INTRODUCTION: Emergency contraception is a safe and effective method to prevent an unwanted pregnancy after an unprotected or inadequately protected sexual intercourse. Several methods for emergency contraception (EC) are currently registered in many countries for use in an emergency to prevent a pregnancy following an unprotected, possibly fertile intercourse or after a contraceptive accident like condom rupture. Different methods have varying modes of action, time frame of efficacy, dosage schedule and unwanted effects. Since several methods are available it is important to decide the best method. EVIDENCE ACUISITION: In this article the available literature on emergency contraception has been reviewed and an attempt has been made to discuss the need for emergency contraception and compare different options for emergency contraception in terms of their efficacy in pregnancy prevention, their safety profile and unwanted side effects. EC repeated use and initiating a regular method after EC use are also discussed. EVIDENCE SYNTHESIS: Emergency contraceptive methods include copper Intra-uterine devices (IUD) and different types of pills like estrogen progestin combination pill (Yuzpe Regimen), Progestin only pill (LNG), antiprogestin pill (Mifepristone), and progesterone modulator Uripristal Acetate (UPA). There is a marginal difference in the mechanism of action, efficacy including time frame and ability to protect from pregnancy with regular doses in obese women, drug interactions and side effects. These are discussed in detail. CONCLUSIONS: Copper IUD is the most effective emergency contraceptive with advantage of providing continued contraception. However, it cannot be used universally due to lack of infrastructure and a trained provider as well as not being suitable option for women at risk of sexually transmitted infections. Amongst different pills LNG is more effective with fewer side effects than Yuzpe regimen. LNG and UPA are comparable with similar efficacy and side effect profile. UPA has a wider window of efficacy, in LNG efficacy declines after 72 hours. UPA is more suitable for obese women. Mifepristone is effective but is registered as EC pill only in few countries and use is limited as it is also used as an abortion pill. Yuzpe regimen is the least effective of all contraceptive pills as EC, and works only till 72 hours of unprotected sex, but is useful in places where dedicated methods are not available, as it is easily accessible. Any combined pill can be used in this regimen except triphasic pill.
