This sheet is about exposure to cephalexin 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 cephalexin?
Cephalexin is an antibiotic medication that has been used to treat infections such as Staphylococcus aureus (Staph) and Escherichia coli (E. coli). Some brand names for cephalexin are Keflex® and Keftab®.
Sometimes when people find out they are pregnant, they think about changing how they take their medication, or stopping their medication altogether. 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 the benefits of treating your condition and the risks of untreated illness during pregnancy.
Having certain infections (such as a Staph or E. coli infection )during pregnancy can increase the chance for pregnancy-related problems or infections in a newborn baby. MotherToBaby has fact sheets on Staph and E. coli infections here: https://mothertobaby.org/fact-sheets/staphylococcus-aureus-pregnancy/ and https://mothertobaby.org/fact-sheets/e-coli-pregnancy/.
I take cephalexin. Can it make it harder for me to get pregnant?
Studies have not been done in humans to see if cephalexin can make it harder to get pregnant. In animal studies, cephalexin did not affect fertility (ability to get pregnant).
Does taking cephalexin increase the chance of miscarriage?
Miscarriage is common and can occur in any pregnancy for many different reasons. In a study of 262 people who took cephalexin during pregnancy, there was no increase in miscarriages compared to a similar group of people who did not take cephalexin.
Does taking cephalexin 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. Information on the use of cephalexin in pregnancy is limited. In a study of 262 people who took cephalexin during pregnancy, there was no increased chance for birth defects above the background risk.
Does taking cephalexin in pregnancy increase the chance of other pregnancy-related problems?
Studies have not been done to see if cephalexin increases the chance for 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 cephalexin in pregnancy affect future behavior or learning for the child?
Studies have not been done to see if cephalexin can cause behavior or learning issues for the child.
Breastfeeding while taking cephalexin:
Cephalexin gets into breast milk in small amounts. In reports of 20 babies exposed to cephalexin through breast milk, 4 had diarrhea. There is one report of a baby getting a rash after being breastfed, due to a sensitivity to cephalexin. If you suspect the baby has any symptoms (such as diarrhea or rash), contact the child’s healthcare provider. Be sure to talk to your healthcare provider about all your breastfeeding questions.
If a male takes cephalexin, could it affect fertility or increase the chance of birth defects?
Studies have not been done to see if cephalexin could affect male fertility (ability to get partner pregnant) or increase the chance of birth defects above the background risk. Some infections, such as Staph or E.coli, might affect male fertility. 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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OTIS/MotherToBaby encourages inclusive and person-centered language. While our name still contains a reference to mothers, we are updating our resources with more inclusive terms. Use of the term mother or maternal refers to a person who is pregnant. Use of the term father or paternal refers to a person who contributes sperm.
