Common 72-hour emergency contraceptive pills include progestin-based levonorgestrel tablets, estrogen-progestin complex preparation-based levonorgestrel ethinyl estradiol tablets, mifepristone tablets, and so on.
1. progestin as the main component of the emergency contraceptive pill: progestin contraceptives can inhibit ovulation, inhibit the fertilization of the egg to bed, but it can lead to secretion of the endometrium function, after stopping the use of progestins there will be a tendency to bleed, the commonly used drugs are levonorgestrel tablets, compound levonorgestrel tablets.
2. Estrogen-progestin compound preparation of emergency contraceptive pills: mainly for the operation of the fertilized egg in the fallopian tube, estrogen can accelerate the movement of the fallopian tube, if the fertilized egg is too fast to lead to an adverse outcome, resulting in failure of conception, common drugs for levonorgestrel ethinyl estradiol tablets and so on.
3. Mifepristone as the main component of the emergency contraceptive pill: mifepristone is a progesterone receptor antagonist, there is no progesterone, estrogen activity, its affinity with progesterone speed than progesterone 5 times stronger, so you can achieve a strong effect of induced labor suitable for anti-early pregnancy, fetal death of the uterus of induced labor.
However, Mifepristone can cause more serious nausea, vomiting symptoms, can induce uterine spasms leading to pain, is not suitable for ectopic pregnancy, heart, liver, kidney disease and allergies.
Emergency contraceptive pills should only be used as an emergency and should be used under a doctor’s supervision, not as a regular contraceptive to prevent serious adverse reactions.