This sheet is about exposure to mifepristone in pregnancy and while breastfeeding. This information is based on available published literature. It should not take the place of medical care and advice from your healthcare provider.
What is mifepristone?
Some brand names for mifepristone are Korlym® and Mifeprex®.
The product label for mifepristone recommends people who are pregnant or planning to become pregnant not use this medication. However, it is important to talk with your healthcare providers before making any changes to how you take your medication. Your healthcare providers can talk with you about using mifepristone and what treatment is best for you.
I am taking mifepristone, but I would like to stop taking it before getting pregnant. How long does the drug stay in my body?
The time it takes the body to metabolize (to process) medication is not the same for everyone. In healthy non-pregnant adults, it takes between 5 and 20 days, on average, for most of the mifepristone to be gone from the body.
I take mifepristone. Can it make it harder for me to get pregnant?
While the medication is in the body, mifepristone can make it harder to get pregnant.
Does taking mifepristone increase the chance of miscarriage?
Miscarriage is common and can occur in any pregnancy for many different reasons. Mifepristone can cause the uterus to contract (get tight and then relax), which can increase the chance of miscarriage. The increased chance of miscarriage can depend on how much mifepristone is taken (dose), when in pregnancy it is taken (timing), the use of other medications, and other factors.
Does taking mifepristone 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. There are case reports of birth defects following the use of mifepristone during pregnancy. However, most infants born after exposure to mifepristone do not have birth defects. In early pregnancy, mifepristone is sometimes used in combination with another medication called misoprostol, which can increase the chance of birth defects. This makes it hard to know if the birth defects in these case reports are due to one of the medications, the combination of medications, or other factors.
Does taking mifepristone in pregnancy increase the chance of other pregnancy-related problems?
Studies have not been done to see if mifepristone increases the chance of 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 mifepristone in pregnancy affect future behavior or learning for the child?
Studies have not been done to see if mifepristone can increase the chance of behavior or learning issues for the child.
What screenings or tests are available to see if my pregnancy has birth defects or other issues?
Prenatal ultrasounds can be used to screen for some birth defects. Ultrasound can also be used to track the growth of the pregnancy. Talk with your healthcare provider about any prenatal screenings or testing that are available to you. There are no tests available during pregnancy that can tell how much effect there could be on future behavior or learning.
Breastfeeding while taking mifepristone:
Mifepristone gets into breast milk in small amounts. In 1 study, no medication was found in the breast milk of 2 women who took a single 200 mg mifepristone pill. Based on the amount of medication found in the breast milk of 10 women who took a single 600 mg mifepristone pill, it was estimated that a fully breastfed infant would get a small amount (less than 1%) of the dose taken. The authors of this study have suggested that breastfeeding does not need to stop after taking a single dose of mifepristone. There is no information available about breastfeeding while taking mifepristone for longer periods of time, such as treating hyperglycemia. The manufacturer has recommended pumping and discarding milk during long-term therapy with mifepristone and for 18 to 21 days after the last dose. Be sure to talk to your healthcare provider about all your breastfeeding questions.
If a man takes mifepristone, could it affect fertility or increase the chance of birth defects?
Studies have not been done to see if mifepristone could affect a man’s fertility (ability to get a woman pregnant) or increase the chance of birth defects above the background risk. In general, exposures that men 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/.
Please click here for references.
