Emergency contraception is a type of remedial contraception that is used to prevent unwanted pregnancy by taking pills or placing an intrauterine device (IUD) within a certain period of time after perceived contraceptive failure or unprotected sexual intercourse.1 Currently commonly used methods1?1 Copper-banded intrauterine device (IUD) Copper-banded IUD is inserted within 5 days of unprotected sexual intercourse, with a failure rate of about 0?1%. Hormonal drugs1?2?1 Mifepristone 1 tablet (10mg or 25mg) taken orally within 5 days (120 hours) after intercourse, failure rate is about 1%. Levonorgestrel 1 tablet (0?75 mg) orally within 72 hours after intercourse, repeated 12 hours later, or 1?5 mg orally in a single dose, with a failure rate of about 2%. Estrogen-progestin combination (Yuzpe method) Oral ethinyl estradiol 0?1mg and norethindrone 1mg (or levonorgestrel 0?5mg) within 72 hours after sexual intercourse, repeated 12 hours later, the failure rate of about 2%~3%. Domestic production and supply of such ready-made drugs, can be used to compound norethindrone short-acting oral contraceptives (each tablet containing norethindrone 0?3mg, ethinyl estradiol 0?03mg) or compound levonorgestrel short-acting oral contraceptives (each tablet containing levonorgestrel 0?15mg, ethinyl estradiol 0?03mg) to replace the oral 72 hours after sexual intercourse, 4 tablets, and then 12 hours after another 4 tablets. Advantages and disadvantages of emergency contraception for women who are not using contraception, or contraceptive errors and do not want to have children, or do not have stable contraception suffered from sexual violence, women can reduce the rate of abortion, to protect the physical and mental health of women. Different emergency contraceptive methods have different advantages and disadvantages. Copper IUD is one of the emergency contraceptive methods with the lowest failure rate so far. The interval between unprotected intercourse and IUD insertion is long, up to 120 hours. This method is suitable for women who cannot take hormonal emergency contraception. Another advantage of emergency contraception with a copper IUD is that it has the same contraceptive effect on sexual intercourse after emergency contraception, so it can continue to be used as regular contraception after emergency contraception, especially for women who wish to use long-term contraception and have no contraindications to placing an IUD. However, gynecological examination and vaginal cleanliness examination (including trichomonas, mycobacteria, etc.) must be carried out before the IUD is placed, and pelvic inflammatory disease, which is an infection of the reproductive tract that cannot be placed on the IUD, must be excluded. The method of IUD insertion is in accordance with the routine of birth control surgery. IUD emergency contraception is not suitable for adolescent girls and STDS high-risk groups, and should not be used on women who have not given birth. Hormonal drugs: No surgery, convenient, confidential, and widely used. The disadvantage is that the failure rate is higher than the copper IUD, but so far there is no evidence of the failure of emergency contraception these drugs have adverse effects on the embryo; unprotected intercourse to the drug to take a shorter interval, only 72 hours (mifepristone for 120 hours); on the use of emergency contraception after sexual intercourse does not have a contraceptive protective effect. Common adverse reactions3?1 Copper IUD3.1.1 Painful cramps and tenderness Painful cramps or tenderness may occur 24-48 hours after insertion of a copper IUD for emergency contraception, especially in women who have not given birth. If necessary, pain relievers such as aspirin, ibuprofen or acetaminophen (paracetamol) may be given. Drip bleeding and vaginal discharge After the copper IUD is inserted, drip bleeding may occur, but it does not last long; vaginal discharge may increase in the first few weeks, which is normal. If the discharge is heavy, smelly or accompanied by lower abdominal pain and/or fever, consult a doctor immediately. Heavy, prolonged and shortened menstrual periods often occur in the first few months after placement. Although some may improve, medical attention is usually required. If conservative treatment does not work, the implant can be removed and a new method of contraception used. Hormonal drugs3?2?1 Nausea The incidence of nausea is highest in women using the Yuzpe method of emergency contraception, at about 50%; levonorgestrel is second, at about 20%; and mifepristone is the lowest, at 6% to 7%. The duration of nausea usually does not exceed 24 hours. Vomiting Vomiting occurs in about 20% of women using the Yuzpe method of emergency contraception; levonorgestrel in about 5%; and mifepristone in about 1%. It is thought that taking the pill with food or at bedtime may reduce the incidence of nausea and vomiting, but there is no definitive clinical information. If vomiting occurs within 2 hours of taking the pill, a refill should be given as soon as possible. Irregular uterine bleeding Some women may have spotting bleeding after taking the pill, which usually does not need to be treated, but the user should be informed of this situation and counseled and educated before and after taking the pill. Menstrual changes Most women have regular menstrual periods, but some have early or late menstrual periods. If menstruation is delayed for 1 week, a urine pregnancy test should be performed to determine whether emergency contraception has failed. World Health Organization (WHO) large-scale clinical trial results show that estrogen-progestin combination (Yuzpe method) and progestin alone emergency contraception on menstruation is basically the same: menstruation in the expected time before and after the 3 days of menstruation in 61%; menstruation more than 3 days in advance of the 11%; menstruation delayed by 4-7 days of the 15%, delayed more than 8 days of the 13%. The incidence of delayed menstruation was even higher when taking mifepristone emergency contraception. Delayed menstruation is more common than early menstruation after taking emergency contraceptive pills, mainly because emergency contraceptive pills affect ovulation. Other Breast tenderness, headache, dizziness, fatigue, etc. These symptoms are usually mild and last less than 24 hours. Conditions to be reported and precautions to be taken4.1 Copper IUD4.1.1 Pregnancy and ectopic pregnancy The failure rate of copper IUD for emergency contraception is very low, only 0.1%. In the diagnosis of pregnancy, care should be taken to identify ectopic pregnancies. In general, emergency contraception does not increase the risk of ectopic pregnancy. The incidence of ectopic pregnancy in failed emergency contraception is not known with certainty. If emergency contraception with a copper IUD fails, the pregnancy should be terminated. Once a pregnancy is diagnosed, a report is required. The contents of the report are: ① the number and time of unprotected sexual intercourse; ② the type of copper IUD placed, the time of placement; ③ the adverse reaction after placement and its time of occurrence, whether or not to deal with it, and the results of the treatment; ④ the diagnosis of pregnancy, including the diagnosis of the time and method of pregnancy, whether or not the pregnancy was likely to be pregnant before the use of emergency contraception, whether or not the pregnancy was ectopic, as well as the termination of the pregnancy, and so on. Pelvic inflammatory disease and other adverse events Fever and/or chills, lower abdominal pain or tenderness, purulent vaginal discharge, abnormal bleeding, heavy bleeding, or sensation of the presence of the IUD tail filament after the placement of the IUD with copper band suggests the possibility of pelvic inflammatory disease or other complications, which need to be reported (for details of the report, see the article on “Intrauterine devices” in this topic). (For more information on reporting, see the article “Intrauterine devices” in this topic). Precautions to avoid failure and rare adverse effects of emergency contraception with a copper IUD: Indications and contraindications should be understood, i.e., emergency contraception with a copper IUD is best suited for women who are in a stable sexual relationship, who are willing to use the IUD as a long-term contraceptive, and who meet the screening criteria for routine IUD use, and who place the device within 120 hours of unprotected sexual intercourse. The IUD should be used within 120 hours of unprotected intercourse, and women who meet the screening criteria for routine IUD use should be examined to rule out pregnancy, pelvic inflammatory disease, reproductive tract infections, and STDS. Many women who need emergency contraception after unprotected intercourse are at greater risk for STDS (e.g., if they have two or more partners), in which case the IUD is contraindicated. Hormonal drugs4?2?1 Pregnancy and ectopic pregnancy The failure rate of hormonal emergency contraception is higher than that of IUD, at 1%, than that of IUD. The failure rate of hormonal emergency contraceptive pills is higher than that of the IUD with copper, ranging from 1% to 3%. Although emergency contraceptives also do not increase the risk of ectopic pregnancy, care should be taken to identify ectopic pregnancy in the diagnosis of pregnancy. Once a pregnancy is diagnosed, a report is required. Report content is mainly: ① unprotected intercourse occurs the number and time; ② take the name of the emergency contraceptive pill; ③ the actual method of taking the pill and the conventional method of taking the pill with or without the difference (including the dose, the time of taking the pill, the number of times, the interval between taking the pill, etc.); ④ after taking the pill adverse reactions (vomiting, etc.) and their time of occurrence; ⑤ the diagnosis of pregnancy, including: diagnosis of pregnancy time, method, is it possible to be pregnant before taking the pill? The diagnosis of pregnancy includes: when and how the pregnancy was diagnosed, whether the pregnancy may have occurred before the use of emergency contraceptive pills, and whether the pregnancy was ectopic; (6) the treatment of the pregnancy and the results, including the termination of the pregnancy, or the results of the continuation of the pregnancy and delivery (normal or birth defects). Severe vomiting If vomiting occurs within 2 hours of taking the Pill, the Pill should be repeated; if several episodes of vomiting occur, the Pill should be given intravaginally. Oral hormonal preparations have been shown to be absorbed through the vaginal mucosa. Reporting is required for intravaginal administration. The contents of the report are: ① the occurrence of vomiting after taking the drug; ② the name of the vaginal drug, dose, time of administration, the interval between two doses, etc.; ③ whether the contraception fails after the administration of the drug; if it fails, the pregnancy and its results (see the “pregnancy and ectopic pregnancy” for details). Hormonal emergency contraception to avoid failure and adverse reactions to the precautions: ① unprotected sexual intercourse, the earlier the time to take the pill, the better the effect of preventing unwanted pregnancy. ② Emergency contraceptive pills can only be used for a certain period of time after the previous sexual intercourse, for more than a certain period of time or unprotected sexual intercourse after taking the pills have no contraceptive effect. (3) pregnant women can not use emergency contraceptive pills, because emergency contraceptive pills have no abortive effect on the established pregnancy. Drugs that interact with conventional oral contraceptives (e.g., rifampicin, some anticonvulsants, etc.) may reduce the effectiveness of the Yuzpe method and progestin-only emergency contraceptives. If a woman is taking these medications for emergency contraception, the dose may be increased during one of the two regular doses, or an additional dose may be added. To minimize nausea and vomiting, mifepristone or levonorgestrel preparations should be used instead of the estrogen and progestin preparations in the Yuzpe method whenever possible. Meclozine 50mg can also be given orally as a single dose 1 hour before the first dose of estrogen or progestin as a preventive measure. According to foreign data, it can reduce the incidence of nausea by 30% and vomiting by 60%. Treatment of copper IUD Adverse effects of copper IUD (e.g. infection, menstrual changes, pelvic inflammatory disease, pregnancy, ectopic pregnancy, etc.) are described in the article “Adverse events of IUD and their prevention and treatment” in this topic. Hormonal drugs As the dosage of hormonal drugs for emergency contraception is small and it is a short-term medication taken once or twice, the adverse effects, such as nausea, vomiting, menstrual changes, etc., are not serious and last for a short period of time, and usually do not need to be dealt with. In case of severe vomiting, 5-10mg of Gastrofen (Metoclopramide) can be taken orally for symptomatic treatment. At the same time, emergency contraceptive pills should be given intravaginally. In the case of pregnancy resulting from the failure of emergency hormonal contraception, the woman’s wish to terminate the pregnancy or to continue the pregnancy can be respected. The available information suggests that emergency contraceptive pills, even if taken by mistake in the early stages of pregnancy, are not harmful to the mother or the fetus. Women who have failed to take emergency contraceptive pills may choose to continue their pregnancy. Ectopic pregnancies occurring after the use of emergency hormonal contraceptives are treated as ectopic pregnancies.