What is the likelihood of success of contraception if the emergency contraceptive pill is taken after an unprotected sexual encounter, also known as the morning-after pill? It is widely accepted clinically that the success rate of the emergency contraceptive pill is over 80% to 90%. The emergency contraceptive pill is a highly effective progestin, which mainly acts as a contraceptive by inhibiting ovulation and changing the function of the fallopian tubes and the endometrium. For example, the most widely used levonorgestrel tablet, one tablet is taken within 72 hours after an unprotected sexual intercourse, and then one tablet is taken 12 hours later, and the contraceptive effect can be more than 98% when taken correctly. Also, studies have shown that levonorgestrel has comparable efficacy and safety for emergency contraception, reducing the risk of unwanted pregnancy by 60% to 93%, with an estimated failure rate of 2%. Another study has confirmed that a single dose of mifepristone 10 mg within 72 hours of unprotected sex is comparable to levonorgestrel for emergency contraception. However, it is also believed that mifepristone, when taken correctly, has a contraceptive success rate of over 99%, and the earlier it is taken, the better the results. Therefore, as long as the pill is taken in the correct way, the probability of contraception can also reach 99%. The incorrect method of using the pill will make the success rate of emergency contraceptive pill greatly reduced. Studies have shown that some of the cases of failure after using the emergency contraceptive pill are not the failure of the contraceptive method itself, but are caused by the wrong use. Therefore, when taking the emergency contraceptive pill, you must pay attention to the following points: 1. It should be taken within 72 hours after unprotected sex (preferably within 12 hours), and the earlier it is taken, the better the effect. If more than 72 hours, the efficacy is lower. 2.Emergency contraceptive pills only have contraceptive effect on the latest unprotected intercourse before taking the pill. If unprotected sex occurs again in other time periods, there is also the possibility of pregnancy. 3. If vomiting occurs within 2 hours after taking the pill, you should take one more dose as soon as possible to avoid affecting the contraceptive effect. It is important to know that even if the emergency contraceptive pill is taken correctly, there is a certain chance that an unplanned pregnancy will occur. So don’t think that if you take some emergency contraceptive pills after passion, you’ll be fine. The emergency contraceptive pill is often not as reliable as you think, its failure rate is much higher than other contraceptives, and safety issues are also greater, and it cannot be used as a regular means of contraception. References: [1] Cai Xiaohui. Taking the emergency contraceptive pill,why you still got shot[J]. Health Expo, 2019(7):1. [2] Ma Peiqi. The development and selection of emergency contraceptive pills. Shanghai Medicine, 2013,34(3):52-54. [3] Hu Yun. Why do you still get pregnant after taking the pill? [J]. Health care literature, 2020, No. 15, 13, 2020. [4] Cheng Linan. Safety of the emergency contraceptive pill[J]. Journal of Practical Obstetrics and Gynecology, 2014, 30(7):3.