This sheet is about exposure to oral levonorgestrel for emergency contraception in pregnancy and while breastfeeding. This information should not take the place of medical care and advice from your healthcare provider.
What is levonorgestrel (Plan B One-Step®)?
Levonorgestrel is a medication that has been used to prevent pregnancy. This fact sheet is about oral levonorgestrel used alone as a form of emergency contraception. Emergency contraception has been used to prevent pregnancy after unprotected sex or a contraceptive accident.
The oral form of levonorgestrel used for emergency contraception contains 1.5 milligrams of levonorgestrel, which is more than the amount used in birth control pills. It has been sold under the names Plan B One-Step®, Econtra EZ®, Preventeza®, AfterPill®, My Way®, Next Choice One Dose®, and Take Action®. It can be purchased over the counter and does not require a prescription. Plan B should be taken as soon as possible after unprotected sex to be most effective.
The use of emergency contraception may be desirable when no other contraceptive was present during sex (such as birth control pills, IUDs, or condoms) or there is reason to think a contraceptive has or may fail (such as a torn condom or not taking birth control pills on the required days). Levonorgestrel as emergency contraception is often referred to as a “morning-after pill” because it works best when taken within 12 hours of unprotected sex. However, it can be used up to 72 hours after unprotected sex. It is not guaranteed that use of oral levonorgestrel will prevent 100% of pregnancies. There is a small chance of having a pregnancy after taking levonorgestrel.
The oral form of levonorgestrel used for emergency contraception is not an abortion pill. It will not work if you are already pregnant, or if you think you are.
I have taken levonorgestrel (Plan B One-Step®). Can it make it harder for me to get pregnant?
Taking oral levonorgestrel to prevent a pregnancy does not affect the ability to get pregnant in the future.
Taking levonorgestrel may increase the chance of an ectopic pregnancy (when the egg is fertilized and attaches outside of the uterus where it cannot survive). There are studies that have shown a link between pregnancies involving levonorgestrel and ectopic pregnancies. There are also studies that have shown no significant link between the two. The chance of an ectopic pregnancy occurring after taking levonorgestrel is unknown. If emergency contraception fails, contact your healthcare provider if you notice any warning signs of an ectopic pregnancy such as sharp cramping or pain on one side of your body.
Does taking levonorgestrel (Plan B One-Step®) increase the chance for miscarriage?
Miscarriage is common and can occur in any pregnancy for many different reasons. Levonorgestrel does not increase the chance for miscarriage.
Levonorgestrel is used to prevent pregnancy by delaying or preventing an egg being released from the ovaries (ovulation). Emergency contraception such as levonorgestrel does not end a pregnancy that has already attached to the wall of the uterus (implanted).
Does taking levonorgestrel (Plan B One-Step®) increase the chance of birth defects?
Every pregnancy starts out with a 3-5% chance of having a birth defect. This is called the background risk. Exposure to levonorgestrel in pregnancy is not expected to increase the chance for birth defects above the background risk.
Does taking levonorgestrel (Plan B One-Step®) in pregnancy increase the chance of other pregnancy-related problems?
It is not known if levonorgestrel can cause other pregnancy-related problems such as preterm delivery (birth before week 37) or low birth weight (weighing less than 5 pounds, 8 ounces [2500 grams] at birth).
Does taking levonorgestrel (Plan B One-Step®) in pregnancy affect future behavior or learning for the child?
Studies have not been done to see if levonorgestrel can cause behavior or learning issues for the child.
Breastfeeding while taking (Plan B One-Step®):
Levonorgestrel gets into breastmilk in small amounts. When used as emergency contraception, levonorgestrel is not expected to be harmful to a child that is breastfeeding. A person who takes levonorgestrel as emergency contraception can breastfeed 3 to 4 hours after the dose (or after each dose if the two-dose method is used). Be sure to talk to your healthcare provider about all of your breastfeeding questions.
If a male takes levonorgestrel (Plan B One-Step®), could it affect fertility (ability to get partner pregnant) or increase the chance of birth defects?
Studies have not been done to see if levonorgestrel could affect male fertility or increase the chance of birth defects above the background risk. In general, exposures that fathers or sperm donors have are unlikely to increase the risks to a pregnancy. For more information, please see the MotherToBaby fact sheet Paternal Exposures at https://mothertobaby.org/fact-sheets/paternal-exposures-pregnancy/.
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OTIS/MotherToBaby recognizes that not all people identify as “men” or “women.” When using the term “mother,” we mean the source of the egg and/or uterus and by “father,” we mean the source of the sperm, regardless of the person’s gender identity.