This sheet is about exposure to fluconazole 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 fluconazole?
Fluconazole is a medication that has been used to treat yeast and fungal infections. It can be taken orally (by mouth), injected (by shot), or given by IV (into a vein). It is mostly used as a single oral dose of 150 milligrams (mg) to treat vaginal yeast infections. For severe fungal infections involving the whole body, higher IV doses of up to 800 mg daily have been used. Fluconazole is sold under the brand name Diflucan®.
The product label for fluconazole recommends women who are pregnant not use this medication except in cases of severe or potentially life-threatening fungal infections. However, the benefit of using fluconazole might outweigh possible risks. Your healthcare providers can talk with you about using fluconazole and what treatment is best for you.
I take fluconazole. Can it make it harder for me to get pregnant?
Studies have not been done to see if taking fluconazole can make it harder to get pregnant.
Does taking fluconazole increase the chance of miscarriage?
Miscarriage is common and can occur in any pregnancy for many different reasons. Studies on the use of fluconazole and miscarriage have mixed results.
One study included almost 600 women who filled prescriptions for oral fluconazole in pregnancy. The study suggested an increased chance of miscarriage with any dose of fluconazole during early pregnancy. A second study also looked at pregnancies with a filled prescription for oral fluconazole. The study suggested a higher chance of miscarriage with a single dose of fluconazole for vaginal yeast infection between weeks 7 and 22 of pregnancy. This study has flaws that make it hard to confirm that the chance of miscarriage was truly higher in this group. Also, studies based on prescriptions/prescription records cannot tell if a person took the medication. This makes it hard to know if the study outcomes are related to the medication or other factors. As there can be many causes of miscarriage, it is hard to know if a medication, the medical condition being treated, or other factors (such as age, health, other exposures) are the cause of a miscarriage.
Two studies involving over 500 pregnancies with use of low-dose oral fluconazole in the months before or during the pregnancy did not find an increased chance of miscarriage. The U.S. Food and Drug Administration (FDA) made a statement in October 2019 saying that available studies do not provide definite evidence of an increased chance of miscarriage with a single 150 mg dose of oral fluconazole.
Does taking fluconazole 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 fluconazole, might increase the chance of birth defects in a pregnancy.
Studies on the use of fluconazole and birth defects have mixed results. It is unlikely that the use of a single 150 mg dose of oral fluconazole during pregnancy would increase the chance of birth defects. Some studies suggest a small increase in the chance of heart defects or other birth defects with doses above 150 mg up to 300 mg during the first trimester. It is not always clear in these studies if the medication was given in a single dose or in multiple doses at different times. Other studies do not report an increased chance of birth defects with any dose up to 300 mg.
The use of high-dose fluconazole for many weeks might be associated with a higher chance of birth defects. A pattern of birth defects of the head, face, bones, and heart has been reported in five children born to four women who took high doses (400 to 1200 mg per day) of fluconazole for many weeks during pregnancy to treat severe fungal infections. These cases alone cannot prove that fluconazole caused these problems, but the similar pattern of birth defects in these children has raised concern that the high doses of fluconazole might have been the cause.
Does taking fluconazole in pregnancy increase the chance of other pregnancy-related problems?
Studies have not found an increased chance of preterm delivery (birth before week 37) or low birth weight (weighing less than 5 pounds, 8 ounces [2500 grams] at birth) following a single dose of fluconazole. Studies have not found an increased chance of stillbirth in pregnancies exposed to fluconazole.
Does taking fluconazole in pregnancy affect future behavior or learning for the child?
Studies have not been done to see if fluconazole 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, such as heart defects. Ultrasound can also be used to watch 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 fluconazole:
Fluconazole passes into breast milk in small amounts. These amounts are estimated to be less than the dose that could be given directly to an infant to treat an infection. Taking a single dose of fluconazole while breastfeeding is unlikely to cause problems for the breastfed infant. If you suspect the baby has any symptoms, such as stomach upset or diarrhea, contact the child’s healthcare provider.
If a person who is breastfeeding has a yeast infection of the breast, the infant might also have oral thrush (a yeast infection in the mouth). If the child does have oral thrush, they will need their own medical treatment because the amount of fluconazole that passes into the breast milk is not enough to treat the child’s infection. If you suspect the baby has oral thrush or other symptoms, contact the child’s healthcare provider. Be sure to talk to your healthcare provider about all your breastfeeding questions.
If a man takes fluconazole, could it affect his fertility or increase the chance of birth defects?
Studies have not been done in humans to see if fluconazole could affect men’s fertility (ability to get a partner pregnant) or increase the chance of birth defects. One study in laboratory animals found lowered sperm count while the animal was exposed to fluconazole. Sperm counts returned to normal two months after stopping treatment. In general, exposures that fathers or sperm donors 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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