Can emergency contraceptives really be effective in preventing pregnancy?

　　Emergency contraceptives are one of the measures taken to prevent unintended pregnancies, but it’s important not to rely solely on them for protection. No method of contraception is absolutely foolproof.

　　Many of them go… hospital Proceed with it Abortion The girl who had the surgery actually took emergency contraceptives, but since these failed to prevent pregnancy, she had to endure this “second round of trouble.”

　　Currently, the active ingredient in emergency contraceptive medications available on the market is “levonorgestrel”. The mechanism by which it exerts its effect is through influencing.. women It affects the endocrine system, inhibits ovulation, and alters the consistency of cervical mucus, thereby interfering with.. sperm Combination with an egg in order to achieve contraceptive effects. If we compare the physiological environment of a mature, healthy woman to a “house” suitable for a baby to inhabit, then the effect of this drug is essentially to artificially destroy that “house”, preventing the eggs and sperm that could potentially conceive a baby from coming together and establishing a viable environment for fertilization.

　　International literature indicates that the contraceptive effectiveness of “levonorgestrel” is approximately 80%-85%. Although some experts in China have different opinions on this statistic, they also agree that the drug’s contraceptive efficacy should be in the range of 85%-90%. In other words, its effectiveness is not 100 percent; it is absolutely impossible for it to help girls “get out of trouble easily” with 100 percent certainty.

　　When it is necessary to take the medication, it is essential to follow the instructions carefully or use it under the guidance of a doctor. Under these conditions, taking it occasionally once a month is generally acceptable.

　　Currently, the simple, convenient, and effective emergency contraceptive methods that are actually available for use include the following ones：

　　1. Levonorgestrel tablets: It is a relatively new type of emergency contraceptive. The first tablet (0.75mg) should be taken within 72 hours after unprotected intercourse or if contraception has failed, and the second tablet (0.75mg) should be taken 12 hours later. This can be achieved by inhibiting follicular development, suppressing or delaying ovulation, and affecting.. uterus It affects various stages such as endometrial development and interferes with implantation, thereby achieving the goal of preventing pregnancy. The efficiency is around 98%. This product is an emergency contraceptive and should not be used as a regular method of contraception.

　　2. Mifepristone: Take one tablet within 72 hours (three days) after unprotected intercourse or if contraception has failed. Taking it in the first half of the menstrual cycle can inhibit ovulation; taking mifepristone in the second half of the menstrual cycle or when menstruation is delayed can cause the endometrium to shed, thereby inducing menstruation and terminating a pregnancy, with an effectiveness rate of around 99%. However, it must be taken under the guidance of a doctor and is generally available only at hospitals or family planning services.

　　Anti-pregnancy pills numbers 3 and 53: It is a remedial measure to be taken within 24 hours. One tablet should be taken immediately after intercourse (no later than 12 hours), followed by another tablet the next morning and another in the evening. Thereafter, one tablet should be taken daily for three consecutive days, totaling six days, with an effectiveness rate of up to 95%.

　　4. Short-acting oral contraceptives: Take 2-4 tablets immediately after intercourse, and then take another 2-4 tablets 12 hours later.

　　5,18-Methynylnorethisterone: It is a 48-hour emergency contraceptive pill, and here are the instructions for its use: Take one tablet within 48 hours after intercourse, and another tablet 12 hours later.