How does emergency contraception work?
There are several mechanisms due to which emergency contraceptive pills prevent possible pregnancy. Firstly, they inhibit ovulation if an egg has not yet been released by the ovaries. Secondly, ECPs prevent pregnancy through changing the movement of an egg if it has already been released. Thirdly, they change the uterine lining, so that it is impossible for a fertilized egg to implant in the uterus.
Note, that emergency contraceptive pills cannot cause an end to the pregnancy if an egg has been fertilized and has already implanted in the uterus. Therefore ECPs are not an abortion causing medication. They also do not protect from sexually transmitted diseases, hence, a person at risk should be checked for STDs. Another problem that emergency contraceptives cannot solve is ectopic pregnancy which occurs when a fertilized egg implants anywhere outside the uterus. This condition needs special medical attention.
All emergency contraceptive pills require a doctor’s prescription. However, the situation might be different depending on the country, state and province. In some states you could get ECPs without prescription at a pharmacy, sexual health care center or from your doctor.
How to use emergency contraception?
Most ECPs should be taken twice. The first dose should be taken within 72 hours of unprotected vaginal sexual intercourse another after 12 hours after the first dose. Bear in mind that emergency contraceptives do not provide any protection against pregnancy for the rest of the menstrual cycle. Therefore additional birth control methods should be used.
Emergency contraceptive pills are rather effective in preventing pregnancy after unprotected sexual intercourse. Progestin-only ECPs have the efficiency of 89% in pregnancy prevention whereas combined progesterone and estrogen ECPs were found to be as much as 75% efficient when taken within 72 hours of unprotected sex.
Side effects of emergency contraception
Women who take emergency contraceptive pills may experience nausea and vomiting. Progestin-only ECPs are known to cause reduced side effects of this kind. Other most frequent side effects associated with ECPs are changes in menstrual cycle. Periods may become rarer or more frequent. They also may become heavier or lighter. ECPs may also cause tender breasts, dizziness and headaches.