Why can I still get pregnant after taking emergency contraceptive pills?

In daily life, female friends may have unprotected sex for some reasons, or contraceptive failure such as condom breakage, slippage, incorrect calculation of the safe period, or accidental injury. In these cases, they can consider taking emergency contraceptive drugs.

However, some women still get pregnant after taking emergency contraceptive pills! What is the reason?

Let us first understand the contraceptive principle of emergency contraceptive pills.

A common type of emergency contraceptive is a single progestin, which contains levonorgestrel. Its contraceptive mechanism is to significantly inhibit ovulation and prevent the implantation of fertilized eggs, increase the viscosity of cervical mucus, and increase the resistance to sperm penetration, thereby exerting a rapid contraceptive effect.

Another new type of emergency contraceptive is an antiprogestin whose ingredient is mifepristone. It has the effects of terminating early pregnancy, preventing implantation, inducing menstruation and promoting cervical ripening. It competes with progesterone for receptors to antagonize the effect of progesterone. It also has a certain binding force with glucocorticoid receptors and can significantly increase the sensitivity of the pregnant uterus to prostaglandins.

That is to say, taking emergency contraceptive pills at different times during the menstrual cycle can produce three different effects: inhibiting ovulation, interfering with the fertilization process, or preventing the fertilized egg from implanting in the uterus.

For women who don't want to get pregnant for the time being, is it safe to take emergency contraceptive pills?

This is not true!

Surveys show that the effectiveness of emergency contraceptive pills is about 80%, which means that about 20% of women fail to take emergency contraceptive pills! The main factors that affect the effectiveness of emergency contraception are:

1. If you have had multiple unprotected sexual intercourse before taking emergency contraceptive pills, and the fertilized egg has successfully implanted in the uterus after the previous sexual intercourse, emergency contraceptive pills will no longer have a contraceptive effect. That is to say, taking emergency contraceptive pills when you are already pregnant will not terminate the pregnancy.

2.

Emergency contraceptive pills can only work for unprotected sex that has already occurred once. Women who have unprotected sex again after taking the pills may still become pregnant. Therefore, you should not have unprotected sex after taking the medicine until your menstruation resumes.

3.

The effectiveness of contraception is related to the length of time between sexual intercourse and the use of the drug. The earlier the contraceptive pill is used after sexual intercourse, the better the effect. As the duration of taking the pill increases, the contraceptive failure rate tends to increase. Some women fail to use the drug according to the instructions in the drug instructions and take the drug for more than 72 hours.

4.

Taking emergency contraceptive pills while taking other medicines. For example, during antibiotic treatment, contraceptives should not be used for contraception, because antibiotics can inhibit the reproduction of bacteria in the intestines, reduce the decomposition of hormone conjugates, and reduce enterohepatic circulation. Drugs such as penicillin, ampicillin, tetracycline, etc. can destroy normal bacteria in the intestines, reduce bacterial activity, and interfere with the normal circulation of steroid hormones in the liver and intestines, resulting in a decrease in the concentration of steroid hormones in the blood, which can lead to contraceptive failure.

5. Severe nausea and vomiting shortly after taking the medicine, or diarrhea, fever, etc. while taking emergency contraceptive pills, will also affect the absorption of emergency contraceptive pills and lead to contraceptive failure.

6. Even if some women do not make mistakes in taking the medicine, due to individual differences, the absorption and utilization of the medicine may be different, which may also cause contraceptive failure.

How can I reduce the risk of emergency contraceptive failure?

1. Master the time. Emergency contraceptive pills must be taken within 72 hours after the event, and the earlier the pill is taken, the better the effect. If taken after 72 hours, the failure rate will be higher.

2. Medical emergency contraception can only work for unprotected sexual intercourse this time. After taking emergency contraceptive pills, other reliable contraceptive measures should be taken when having sex before the next menstruation.

3.

Emergency contraceptive pills can only be used once during a menstrual cycle; the second time they are used they may be ineffective. It can only be used 2-3 times a year. Frequent use may cause hormone disorders in the body and cause other gynecological symptoms such as irregular menstruation.

4.

It is best to take levonorgestrel after a meal or before bedtime to reduce adverse reactions such as nausea. Do not eat for 2 hours before or after taking mifepristone. This will facilitate the absorption of the drug. If vomiting occurs within 2 hours of taking the drug, you should take another dose.

5. People with colds, fever, acute enteritis and vomiting should not use emergency contraceptive pills, as this will affect the absorption of emergency contraceptive pills.

6. After taking emergency contraceptive pills, you should calculate your menstrual cycle. If you find that your period is overdue, you should go to the hospital in time to check whether the emergency contraception has failed.

Emergency contraception is only an emergency method, not a regular contraceptive measure. Its effectiveness is significantly lower than that of conventional contraceptive methods, and because of the high dosage (the dosage of one emergency contraceptive is generally equivalent to 8 days of conventional short-acting oral contraceptives), the side effects are also significantly higher than conventional contraceptives, such as changes in the menstrual cycle. You should choose the contraceptive method that suits you instead of relying on emergency contraceptive pills.

Excessive and frequent use of emergency contraceptive pills may also cause harm to the body, leading to menstrual disorders, prolonged bleeding or spotting, and causing inconvenience to women's life and work.

So, can we still keep the child left after the emergency contraceptive pill fails?

Relevant research believes that within 2 weeks from the beginning of fertilization, the effect of any embryotoxic drugs, toxic and harmful substances on the embryo is "all" or "none". In other words, the effect of emergency contraceptive pills or other toxic and harmful substances on the embryo is: either it causes miscarriage of the child, or it has no effect at all, the child is fine, and the pregnancy can continue.

Fertilization usually occurs in the middle of the menstrual period. During this period, if you take emergency contraceptive pills without knowing you are pregnant or become pregnant after taking emergency contraceptive pills, don't be too nervous. As long as the child survives, there is generally no problem. If you don't plan to have a baby for the time being, you need to go to the hospital as soon as possible to proceed to the next step.