THIS MEDICATION MAY CAUSE HARM TO YOUR BABY:
Available studies suggest the use of erythromycin during pregnancy poses a low risk of harm to the baby. There have been reports of infantile hypertrophic pyloric stenosis and heart defects in newborns exposed to erythromycin in pregnancy, but there is no conclusive evidence proving an association between erythromycin and these negative effects. Infants exposed to erythromycin while breastfeeding should be monitored for signs of thrush, dehydration, irritability, and diarrhea. It is recommended to use this medication during pregnancy only if clearly indicated.
What is erythromycin?
Erythromycin is a macrolide antibiotic that is currently available as a generic or brand name medication. Erythromycin is available as oral tablets or capsules, injectable reconstituted suspension/solution, topical, and ocular (for eyes). Brand names of erythromycin include E-mycin™, ERYC™, E.E.S.™, Erygel™, Erythrocin™, and Robimycin™. Oral tablets and capsules are taken by mouth several times daily up to a specified maximum dose for 7-21 days depending on the indication.
What is erythromycin used to treat?
Erythromycin is used to treat bacterial infections such as Chlamydia trachomatis, impetigo, Lymphogranuloma venereum, Legionnaire disease, nongonococcal urethritis, and pertussis as well as off-label indications such as acne vulgaris, granuloma inguinale, and Bartonella infections in adults, adolescents, and children. Untreated infections during pregnancy can harm both mother and baby. Possible bacterial infections that can occur during pregnancy are sexually-transmitted infections and non-sexually transmitted infections. Depending on the infection and after assessing the risks versus benefits of treatment, your physician may prescribe an antibiotic during pregnancy to treat an infection.
You can read more about bacterial infections during pregnancy here.
How does erythromycin work?
Erythromycin works by interfering with bacterial protein synthesis and replication, and inhibiting bacterial growth.
If I am using erythromycin, can it harm my baby?
Available evidence suggests erythromycin poses a low risk to the developing baby when used during pregnancy. Erythromycin estolate, a topical form of erythromycin, is contraindicated during pregnancy due to the risk of liver toxicity. Erythromycin is recommended during pregnancy only if clearly needed.
Evidence from animal studies with erythromycin:
When given to pregnant female rats at doses up to 0.25% of their diet, there were no harmful effects or negative developmental effects. Pregnant rats given 1-12 times the maximum recommended human dose of erythromycin and pregnant mice given 25 times the maximum recommended human dose showed no increase in birth defects.
Evidence for the risks of erythromycin in human babies:
Erythromycin does cross the human placenta to reach the developing baby, but only in low amounts. Erythromycin estolate has been associated with liver toxicity in pregnant women. The Collaborative Perinatal Project, the Boston Collaborative Drug Surveillance Program, and the Hungarian Case–Control Surveillance of Congenital Abnormalities found no evidence of birth defects with early pregnancy or first trimester erythromycin exposure in pregnant women. Studies evaluating second or third trimester exposure to erythromycin have reported no increased risk of birth defects. The National Birth Defects Prevention Study found no substantial increase in the risk of most birth defects with erythromycin; however, the study did identify an increase in skull and limb defects with erythromycin exposure 1-3 months after conception. A study in Michigan Medicaid patients found a 4.6% rate of birth defects with first trimester exposure to erythromycin, which is similar to the risk of birth defects in the general population not exposed to erythromycin.
An analysis of over 2 million infants in 9 studies found erythromycin use during the first two weeks after delivery has been associated with an increased risk of pyloric stenosis; however, some studies have not found any increase in risk of pyloric stenosis, particularly when erythromycin exposure occurs during pregnancy or breastfeeding. The Swedish Medical Birth Registry reported an increased incidence of pyloric stenosis in 1,844 infants exposed to erythromycin early in pregnancy. The Slone Epidemiology Center Birth Defects Study compared over 4800 infants with heart defects or infantile hypertrophic pyloric stenosis to infants without birth defects, finding no association between first trimester exposure to erythromycin and heart defects or third trimester erythromycin exposure and infantile hypertrophic pyloric stenosis. Research including a Danish study and a study of Tennessee Medicaid patients suggest there is no evidence that erythromycin exposure during pregnancy increases the risk of infantile hypertrophic pyloric stenosis (IHPS). Erythromycin has been described for use in pregnant women infected with group B β-hemolytic streptococcus during the third trimester of pregnancy as well as genital mycoplasma during pregnancy, Chlamydia infection, and preterm, prelabor rupture of fetal membranes. The use of erythromycin to treat premature rupture of membranes did show an increased risk of reports of cerebral palsy from parents of infants in one study that compared pregnant women exposed and not exposed to erythromycin. However, follow-up of these infants at 11 years of age found no difference in development or need for educational assistance. Erythromycin used for genital mycoplasma during pregnancy has been associated with decreased loss of the baby and low birth weight.
A Swedish study found a possible increase in heart defects with erythromycin use in 2,531 infants exposed to erythromycin in early pregnancy; however, the authors were unable to identify if this increase in heart defects was truly associated with erythromycin or other confounding factors such as the patient’s disease state. A Norwegian study comparing 180,120 exposed to antibiotics (1,786 women exposed to erythromycin) during the first trimester and 163,653 women not exposed to antibiotics during pregnancy found no increase in the risk of heart defects or other birth defects. The Quebec Pregnancy Cohort found no association between first trimester erythromycin exposure and heart defects. An additional analysis of the Quebec Pregnancy Cohort found while erythromycin was not associated with an increased risk of miscarriage, other types of antibiotics were associated with miscarriage. First trimester exposure to erythromycin in the Quebec Pregnancy Cohort found an increased risk of urinary tract defects; however, the authors were unsure if other confounding variables impacted this outcome.
Bottom line: Studies in pregnant women who were exposed to erythromycin during pregnancy suggest there is no increase in the risk of birth defects. There have been reports linking erythromycin to infantile hypertrophic pyloric stenosis and heart defects, but these studies have noted limitations and may have not accounted for other confounding variables. It is recommended to use this medication during pregnancy only if indicated.
If I am using erythromycin and become pregnant, what should I do?
If you are using erythromycin and become pregnant, you should contact your doctor immediately. Your doctor will determine if your medication is medically necessary, or if it shoul
d be discontinued until after the birth of your baby.
If I am using erythromycin, can I safely breastfeed my baby?
Erythromycin is excreted into breast milk, however, the amount of this medication reaching the breast milk is expected to be low, and adverse effects in nursing infants are unlikely. Antibiotic use during pregnancy has been associated with minor diarrhea and/or irritability in nursing infants. Breastfed infants exposed to erythromycin should be monitored for irritability, thrush, dehydration, and diarrhea. Despite case reports of pyloric stenosis in breastfed infants, there is no conclusive evidence that erythromycin exposure in nursing infants causes infantile hypertrophic pyloric stenosis. The American Academy of Pediatrics and the World Health Organization classify erythromycin as compatible with breastfeeding. The manufacturer recommends using caution if taking erythromycin and breastfeeding.
Bottom line: Erythromycin passes into human breast milk, but it is expected to pose a low risk of harm to a breastfed infant. Infants should be monitored for signs of diarrhea, irritability, thrush, and dehydration.
If I am using erythromycin, will it be more difficult to get pregnant?
There is no information available on the effects of erythromycin on male or female fertility.
If I am using erythromycin, what should I know?
It is recommended to use this medication during pregnancy only if clearly indicated. Studies in pregnant women who were exposed to erythromycin during pregnancy suggest there is no proven increase in the risk of birth defects. There have been reports of infantile hypertrophic pyloric stenosis in infants exposed to erythromycin in late pregnancy, and reports of a possible association between erythromycin and heart defects. However, these associations have never been conclusively proven, and study authors have questioned the effect of confounding factors on study outcomes.
Erythromycin passes into human breast milk. There have been reports of breastfed infants developing infantile hypertrophic pyloric stenosis; however, an association between erythromycin and infantile hypertrophic pyloric stenosis has not been conclusively proven. Infants exposed to erythromycin while breastfeeding should be monitored for signs of diarrhea, irritability, thrush, and dehydration.
If I am taking any medication, what should I know?
This report provides a summary of the available information about the use of erythromycin during pregnancy and breastfeeding. Content is from the product label unless otherwise indicated.
You may find Pregistry's expert reports about infections and the individual medications used to treat infections here. Additional information can also be found in the resources below.
For more information about erythromycin during and after pregnancy, contact http://www.womenshealth.gov/ (800-994-9662 [TDD: 888-220-5446]) or check the following links:
Merck Manual: Infections during pregnancy
U.S. National Library of Medicine: LACTMED: ERYTHROMYCIN