This sheet is about exposure to St. John’s wort 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 St. John’s wort?
St. John’s wort (Hypericum perforatum) is a flowering plant that has been used as an herbal supplement. It is available as a tablet or capsule, liquid extract, tea, and as a cream or ointment. It is also sometimes mixed with other herbal ingredients in combination products. St. John’s wort has most commonly been used to help symptoms of mild to moderate depression. MotherToBaby has a fact sheet on depression at: https://mothertobaby.org/fact-sheets/depression-pregnancy/.
There are many compounds in St. John’s wort. The amount and quality of these compounds can vary widely and be affected by the soil the plant was grown in, and how the plant was harvested, dried, and stored. St. John’s wort can interact with many medications (change how well they work in the body or cause side effects), including birth control pills. If you are taking any medication, talk to your healthcare providers to review the chance of interactions between your medication and St. John’s wort.
In the United States, St. John’s wort is a dietary supplement. Unlike prescription medication, dietary supplements are not regulated by the Food and Drug Administration (FDA) in the same way and do not have set standards for preparation, safety, or effectiveness. For information on supplements in general, please see the fact sheet on herbal products at https://mothertobaby.org/fact-sheets/herbal-products-pregnancy/.
Sometimes when women find out they are pregnant, they think about changing how they take supplements or their medication. It is important to talk with your healthcare providers before making changes in how you take your medication or supplements. Your healthcare providers can talk with you about the benefits of treating your condition and the risks of untreated illness during pregnancy. Your healthcare team might discuss medication options that have been better studied for use in pregnancy.
I take St. John’s wort. Can it make it harder for me to get pregnant?
It is not known if St. John’s wort can make it harder to get pregnant.
Does taking St. John’s wort increase the chance of miscarriage?
Miscarriage is common and can occur in any pregnancy for many different reasons. It is not known if St. John’s wort can increase the chance of miscarriage. One study found the chance for a miscarriage in women taking St. John’s wort during pregnancy to be similar to the general population’s chance for miscarriage.
Does taking St. John’s wort 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 St. John’s wort, might increase the chance of birth defects in a pregnancy. St. John’s wort has not been well-studied with use in pregnancy. Three studies that looked at pregnancies with use of St. John’s wort did not report an increase in birth defects.
Does taking St. John’s wort in pregnancy increase the chance of other pregnancy-related problems?
A study that included 39 women who reported using St. John’s wort early in their pregnancies did not find a higher chance for preterm delivery (delivery before 37 weeks of pregnancy) or poor growth in the babies. A second study of 54 infants prenatally exposed to St. John’s wort found a similar rate of live birth and preterm delivery when compared to babies not exposed to St. John’s wort. There is one case report of a woman who started taking St. John’s wort at week 24 of pregnancy and developed thrombocytopenia but had a normal delivery. Thrombocytopenia is a condition where the blood does not have enough platelets (cells that help your blood to clot). Some reports suggest that St. John’s wort can affect how a person’s blood clots. It is not known if the low platelet count in this case report was related to St. John’s wort or another factor.
Does taking St. John’s wort in pregnancy affect future behavior or learning for the child?
Studies have not been done to see if St. John’s wort can increase the chance of behavior or learning issues for the child.
Breastfeeding while taking St. John’s wort:
St. John’s wort gets into breastmilk. In 5 women who were breastfeeding full-term older infants (10-22 weeks of age), the amount of St. John’s wort that the infants received through breastmilk was found to be small. The parents reported no negative effects in their infants. Another study that looked at 33 women who took St. John’s wort and breastfed reported an increased amount of crying (colic) and being very sleepy (lethargy) in their infants when compared to infants of women with depression who were not taking St. John’s wort. The infants did not need medical treatment. If you suspect the baby has any symptoms from the St. John’s wort such as colic, drowsiness, or poor feeding, contact the child’s healthcare provider. Be sure to talk to your healthcare provider about all of your breastfeeding questions.
If a male takes St. John’s wort, could it affect his fertility or increase the chance of birth defects?
St. John’s wort has not been well studied to see how it might affect male fertility (ability to make healthy sperm) or increase the chance of birth defects above the background risk. There are case reports of sexual difficulties (reduced desire or ability to perform) in men taking St. John’s wort; similar things were reported in laboratory animal studies. Experimental laboratory data have suggested that St. John’s wort might have spermicidal effects (kill sperm or reduce ability to swim towards the egg). In general, exposures that men 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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