This sheet talks about exposure to erythromycin during a pregnancy or while breastfeeding. This information should not take the place of medical care and advice from your health care professional.

What is erythromycin?

Erythromycin is an antibiotic. It can be taken by mouth to treat infections, particularly those of the skin, upper respiratory tract and pelvis. It can also be used in topical forms for treatment of skin conditions and as an ointment for eye infections. Some brand names include Eryc®, Emgel®, Erygel®, E-mycin® and Ery-Tab®.

I just found out that I am pregnant. Should I stop taking erythromycin?

Talk with your healthcare provider. It is important to discuss the benefits of treating your medical condition versus stopping the medication.

Does using erythromycin increase the chance for miscarriage?

Miscarriage can occur in any pregnancy. No studies have looked specifically at exposure to erythromycin and the chance of miscarriage. However, studies that have looked at erythromycin and the chance for birth defects have not seen a higher rate of miscarriage.

Does using erythromycin in the first trimester increase the chance of birth defects?

In every pregnancy, a woman starts out with a 3-5% chance of having a baby with a birth defect. This is called her background risk. It is unlikely that using erythromycin increases the chance of birth defects. A couple of studies have suggested that using erythromycin in the first trimester might be associated with a small increased chance of heart defects, but the majority of studies have not found an increased chance of heart defects or other birth defects.

Could using erythromycin in the second or third trimester cause other pregnancy complications?

Some reports suggest that using erythromycin during pregnancy might be associated with an increased chance of pyloric stenosis (a narrowing of the opening from the stomach to the small intestines). Other studies have not supported this finding. In addition, the majority of studies have not shown an increased chance for other adverse outcomes when erythromycin in used later in pregnancy.

Does using erythromycin in pregnancy cause long-term problems in behavior or learning for the baby?

One study that followed children up to age 11 years found that being exposed to erythromycin during the pregnancy did not make them more likely to need special assistance in school.

Can I take erythromycin when I am breastfeeding?

Small amounts of erythromycin can get into breast milk, but these amounts are unlikely to affect the nursing infant. In one study, a higher chance of pyloric stenosis was seen in infants whose breastfeeding mothers were prescribed erythromycin at the time of birth or within ninety days after delivery. While we know the mothers were prescribed the medication, we do not know if they actually took it. An analysis of other available studies on this topic did not find an association between using erythromycin while breastfeeding and a higher chance for pyloric stenosis in the infant.

Short-term use of erythromycin is generally considered compatible with breastfeeding. As with any antibiotic, the breastfed infant should be closely observed for adverse effects such as diarrhea, diaper rash, or thrush (yeast infection in mouth). Contact the baby’s healthcare provider if you notice any symptoms. Talk to your healthcare provider about all of your breastfeeding questions.

If a man takes erythromycin, could it affect his fertility (ability to get partner pregnant) or increase the chance of birth defects?

There are no studies looking at possible risks to a pregnancy when the father takes erythromycin. In general, medications that the father takes do not increase risks to a pregnancy. For more information, please see the MotherToBaby fact sheet on Paternal Exposures at https://mothertobaby.org/fact-sheets/paternal-exposures-pregnancy/pdf/.

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