This sheet is about exposure to oral levonorgestrel for emergency contraception in pregnancy and while breastfeeding. This information is based on published research studies. It should not take the place of medical care and advice from your healthcare provider.
What is levonorgestrel?
Levonorgestrel is a medication that has been used to prevent pregnancy (contraception). Levonorgestrel is available in different forms, either by itself or combined with other medications. This fact sheet is about the pill form of levonorgestrel used by itself as a type of emergency contraception. Emergency contraception helps prevent pregnancy after unprotected sex or a birth control accident (such as a broken condom or a missed birth control pill).
Some brand names of emergency contraception pills that contain levonorgestrel are Plan B One-Step®, Econtra EZ®, Preventeza®, AfterPill®, My Way®, Next Choice One Dose®, and Take Action®. These products can be purchased over the counter and do not require a prescription.
The levonorgestrel emergency contraception pill is often referred to as a “morning-after pill” because it works best when taken as soon as possible after unprotected sex (within 12 hours). However, it can be used up to 72 hours after unprotected sex. It works by delaying or preventing an egg from being released from the ovaries (ovulation). It is not guaranteed to prevent 100% pregnancies, even if taken right away. The levonorgestrel emergency contraception pill will not work if you are already pregnant.
I have taken levonorgestrel. Can it make it harder for me to get pregnant?
Taking levonorgestrel to prevent a pregnancy does not make it harder to get pregnant in the future.
There have been reports of ectopic pregnancy (when a fertilized egg attaches outside of the uterus, where it cannot survive) after the use of levonorgestrel emergency contraception pills. However, large studies looking at outcomes in women who used levonorgestrel emergency contraception pills have not shown that the medication greatly increases the chance of ectopic pregnancy. Contact your healthcare provider if you notice any warning signs of an ectopic pregnancy after taking emergency contraception, such as sharp cramping or pain on one side of your body.
Does taking levonorgestrel increase the chance of miscarriage?
Miscarriage is common and can occur in any pregnancy for many different reasons. Levonorgestrel does not increase the chance of miscarriage. Emergency contraception such as levonorgestrel does not end a pregnancy that has already attached to the wall of the uterus (implanted).
Does taking levonorgestrel increase the chance of birth defects?
Birth defects can happen in any pregnancy for different reasons. Out of all babies born each year, about 3 out of 100 (3%) will have a birth defect. We look at research studies to try to understand if an exposure, like levonorgestrel, might increase the chance of birth defects in a pregnancy. If a woman takes levonorgestrel and still becomes pregnant, it is not expected to increase the chance of birth defects.
Does taking levonorgestrel in pregnancy increase the chance of other pregnancy-related problems?
Studies have not been done to see if levonorgestrel can increase the chance of 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 in pregnancy affect future behavior or learning for the child?
Studies have not been done to see if levonorgestrel can increase the chance of behavior or learning issues for the child.
Breastfeeding while taking levonorgestrel:
Levonorgestrel gets into breast milk in small amounts. When used as emergency contraception, levonorgestrel is not expected to be harmful to a child that is breastfeeding. Waiting 3 to 4 hours to breastfeed after taking the dose (or after each dose if a two-dose method is used) will lower the amount of levonorgestrel the child might get in the breast milk. Be sure to talk to your healthcare provider about all your breastfeeding questions.
If a man takes levonorgestrel, could it affect fertility or increase the chance of birth defects?
Studies have not been done to see if levonorgestrel could affect men’s fertility (ability to get a woman pregnant) or increase the chance of birth defects. In general, exposures that fathers or sperm donors have are unlikely to increase 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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