Emergency contraception
Examples
Medicines
Progestin
Generic Name Brand Name levonorgestrel Plan B Combination birth control pills
Generic Name Brand Name estrogen and progestin Alesse, Min-Ovral, Ovral, Triphasil, Triquilar
Note: Plan B is specifically packaged for emergency contraception.
Emergency contraception is used after unprotected sex to prevent a pregnancy from starting. It is most effective when it is used as soon as possible after intercourse. It is not necessary to take a pregnancy test before using emergency contraception.
How to take emergency contraception
Birth control experts recommend having emergency contraception pills, or a prescription for them, on hand in case you ever need them. Emergency contraception is most effective when used as soon as possible after unprotected sex. Your risk of becoming pregnant increases as time passes.1
Two-dose Plan B is the first-choice method for emergency contraception.1 It requires fewer pills, is slightly more effective, and is unlikely to cause nausea and vomiting, compared with estrogen and progestin pills.
If you are using a type of regular birth control pills (named below), take only the active hormone pills. Be sure to avoid the inactive sugar pills in the pack, which are a different colour.
Emergency contraception Brand name and colour of hormone pills First dose* Second dose Plan B (white)—containing levonorgestrel, a type of progestin
Take 1 pill.
12 hours (or less) after the first dose, take 1 more pill.
Plan B (white)—containing levonorgestrel
Take 2 pills at once.
None
Ovral (white)—containing estrogen-progestin
Take antinausea medicine. One hour later, take 2 hormone pills.
12 hours after the first dose, take 2 more pills.
Min-Ovral (white); Triphasil (yellow); Triquilar (yellow)—containing estrogen-progestin
Take antinausea medicine. One hour later, take 4 hormone pills.
12 hours after the first dose, take 4 more pills.
Alesse (pink)—containing estrogen-progestin
Take antinausea medicine. One hour later, take 5 hormone pills.
12 hours after the first dose, take 5 more pills.
*The first dose may be taken up to 120 hours, or 5 days, after unprotected intercourse.
Intrauterine device (IUD)
As another option, a copper-bearing intrauterine device (IUD) can be inserted within 5 to 7 days after unprotected sex.
Generic Name Copper T 380-A (intrauterine device) How It Works
Contrary to what some people believe, emergency contraception pills do not cause an abortion. They prevent ovulation, fertilization, or implantation just like a birth control pill does.
Emergency contraception hormones prevent fertilization by stopping the ovary from releasing an egg (ovum). They also make the fallopian tubes less likely to move an egg toward the uterus. Emergency contraception is also thought to thin the lining of the uterus, or endometrium. The thickened endometrium is where a fertilized egg would normally implant and grow.
A copper IUD makes the uterus and fallopian tubes produce fluids that kill sperm and prevent fertilization. These fluids contain white blood cells, copper ions, enzymes, and prostaglandins.2 As emergency contraception, a copper IUD also prevents an already fertilized egg from implanting in the uterus.1
Emergency contraception does not protect against sexually transmitted infections (STIs).
Why It Is Used
Emergency contraception is meant to be used as a backup method for preventing pregnancy. For regular protection, be sure that you have:
- A birth control method that you know you can use every time you have sex.
- Condoms for protection from sexually transmitted diseases (STDs) every time you have sex.
You can use emergency contraception if you are not confident that you were protected against pregnancy during intercourse. This can happen if:
- You have unplanned sex without birth control.
- Your usual birth control method fails. For example:
- A barrier method, such as a condom or diaphragm, has torn or dislodged.
- You have missed taking birth control pills.
- An IUD has come out, either completely or partially.
- You are taking other medicines that may affect contraception medicines. These include some antiseizure, antibiotic, and antifungal medicines, and the herb St. John's wort.
- You are raped. Some emergency rooms offer emergency contraception as part of sexual assault care; others will provide emergency contraception when asked for it.
Be sure to plan with your health professional for your ongoing birth control needs.
How Well It Works
Emergency contraception effectiveness varies according to the method used.1
- A copper-bearing IUD is rarely followed by pregnancy—fewer than 1% of users become pregnant (6 per 1,000).
- Plan B (progestin-only) is rarely followed by pregnancy—about 1% of users become pregnant (12 per 1,000).
- Combined birth control pills (estrogen and progesterone) are more likely than Plan B to be followed by pregnancy.
The sooner pills are used after unprotected sex, the more likely they are to prevent pregnancy.
Side Effects
Hormonal methods of emergency contraception
Side effects of hormonal methods include the following:
- Nausea or vomiting is most likely when using special doses of birth control pills with estrogen plus progestin. Non-prescription antinausea medicines, such as Dramamine or Pepto-Bismol, can prevent or reduce nausea. Plan B (progestin-only pills) seldom causes nausea, so antinausea medicine is not usually recommended.
- Caution: If you vomit within 2 hours of taking a dose, call your health professional for advice. You may need to repeat the dose.
- Pregnancy is possible after using emergency contraception. Although your next period may be slightly late, a delay of 3 weeks or longer may be a sign of pregnancy. If this happens, call your health professional to see whether you need a pregnancy test.
- Some women have breast tenderness, fatigue, headache, abdominal pain, or dizziness after taking emergency contraception.
Call your health professional if side effects, such as headache, dizziness, or abdominal pain, continue for longer than 1 week after using emergency contraception.
IUD method of emergency contraception
Side effects during the first few days after having an IUD inserted include:
- Uterine cramping.
- Vaginal bleeding.
See your health professional if you do not have your period within 21 days after using emergency contraception.
See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)
What To Think About
In Canada, emergency contraception pills are available directly through pharmacists. However, some pharmacists may refuse to sell emergency contraception, based on their personal beliefs. If this happens to you, ask for the location of a pharmacist who will, or contact:
- The Canadian Federation for Sexual Health online at http://www.cfsh.ca, or call 1-888-270-7444.
Contrary to what some people believe, emergency contraception pills do not cause an abortion. They prevent ovulation, fertilization, or implantation, just like a birth control pill does.
Advantages
All of the methods for emergency contraception effectively prevent an unintended pregnancy after unprotected sex. Each has different advantages.
- Experts recommend Plan B (progestin) as the top choice for emergency contraception. It requires fewer pills, is less likely to cause nausea and vomiting, and is slightly more effective than pills with both estrogen and progestin in them.
- Women who can't take estrogen for health reasons are advised to use Plan B.
- The combination of estrogen plus progestin is the least expensive emergency contraception method and is more widely available.
- Plan B and estrogen-progestin do not help or hurt an embryo if you are already pregnant.1
- Insertion of a copper-bearing IUD is the most effective and the most expensive emergency method.
Disadvantages
Emergency contraception use is not recommended if you know or suspect you are already pregnant. If you may already be pregnant, see your health professional.
Hormonal
- If you have a history of blood clots, use Plan B, which is a progestin-only pill. (Estrogen makes blood clots more likely.)
- If you are having a migraine headache at the time that you need emergency contraception, use Plan B. Use of estrogen-progestin is not recommended. (Estrogen can start migraines or make them worse.)
If hormonal emergency contraception does not work and a pregnancy develops and grows, there is no known risk to the embryo.1
IUD
- If you have a pelvic infection, including any kind of sexually transmitted infection (STI), an IUD is not the right emergency contraception for you. Inserting an IUD can spread infection into your uterus and fallopian tubes, causing pelvic inflammatory disease.
- If you have been pregnant for 5 to 7 days or longer, inserting an IUD is dangerous. It can cause a miscarriage and a serious infection in the uterus (septic abortion).
- Inserting an IUD is expensive. However, if you are planning to leave it in for long-term birth control, an IUD becomes cost effective as time goes by.
In countries other than Canada, these emergency contraception choices and other choices may be available or regulated differently.
If emergency contraception is not available or you are early in an unplanned pregnancy, talk to your health professional about medical pregnancy care options or abortion as soon as possible.
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| Author: | Merrill Hayden Carrie Henley | Last Updated: August 16, 2006 |
| Medical Review: | Adam Husney, MD - Family Medicine Joy Melnikow, MD, MPH - Family Medicine Kirtly Jones, MD - Obstetrics and Gynecology Femi Olatunbosun, MB, FRCSC - Obstetrics, Gynecology and Reproductive Medicine | |
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| Topic Contents | |
| Examples | |
| How It Works | |
| Why It Is Used | |
| How Well It Works | |
| Side Effects | |
| What To Think About | |
| References | |