This sheet is about exposure to azithromycin 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 providers.
What is azithromycin?
Azithromycin is an antibiotic that has been used to treat many bacterial infections, including lung infections (such as bronchitis and pneumonia), strep throat, and ear, sinus, and skin infections. It is also commonly used, including during pregnancy, to treat infections such as malaria, mycoplasma, and chlamydia. Brand names include Z-Pak®, Zithromax®, and Zmax®.
For more information on malaria, see our fact sheet at https://mothertobaby.org/fact-sheets/malaria/.
Sometimes when women 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.
I take azithromycin. Can it make it harder for me to get pregnant?
It is not known if taking azithromycin can make it harder to get pregnant.
Does taking azithromycin increase the chance of miscarriage?
Miscarriage is common and can occur in any pregnancy for many different reasons. Most studies on azithromycin and similar antibiotics have not reported an increased chance of miscarriage.
Does taking azithromycin 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 azithromycin, might increase the chance of birth defects in a pregnancy.
A few studies have suggested azithromycin might increase the chance of some birth defects. However, most studies have not found an increased chance of birth defects when azithromycin is used during pregnancy.
Does taking azithromycin in pregnancy increase the chance of other pregnancy-related problems?
Azithromycin is not expected to 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 azithromycin in pregnancy affect future behavior or learning for the child?
One study looking at over 8,000 children exposed to azithromycin or other antibiotics like azithromycin during pregnancy found no significant increased chance of attention deficit hyperactivity disorder (ADHD) or autism spectrum disorder.
Breastfeeding while taking azithromycin:
Azithromycin passes into breast milk in small amounts. The amount of azithromycin that gets into breast milk is lower than what would be given to a child to treat an infection. Short term use of azithromycin is generally considered compatible with breastfeeding.
There are some studies that suggest that the chance of pyloric stenosis (a condition where the muscles of the pylorus [the valve between the stomach and small intestine], get thicker and narrower, making it hard for food to pass through) might be increased when azithromycin is taken during the first two weeks of breastfeeding. Other studies have not reported an increased chance of pyloric stenosis. Overall, there is not enough information to determine if breastfeeding while taking azithromycin can increase the chance of pyloric stenosis.
Children who are exposed to azithromycin or other antibiotics through breast milk might have diarrhea or develop thrush (fungal infection of the mouth). If you suspect that your baby has symptoms such as forceful vomiting, weight loss, fussiness, lethargy, and signs of dehydration such as fewer wet diapers, contact your baby’s healthcare provider. Be sure to talk to your healthcare provider about all your breastfeeding questions.
If a man takes azithromycin, could it affect his fertility or increase the chance of birth defects?
Studies have not been done to see if azithromycin could affect men’s fertility (ability to make healthy sperm) 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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