Azithromycin Safety in First Trimester of Pregnancy

Safety Profile

Azithromycin is classified as a preferred macrolide antibiotic during pregnancy, with animal studies and anecdotal evidence suggesting its safety, according to the Centers for Disease Control and Prevention (CDC) 1, 2, 3
The CDC recommends azithromycin as the drug of choice during pregnancy, due to its safety profile compared to other macrolide agents 1, 2, 3

No conclusive evidence exists that azithromycin use during pregnancy causes adverse fetal outcomes, as stated by the CDC 1, 2, 3

For HIV-infected pregnant women requiring MAC (Mycobacterium avium complex) prophylaxis, the CDC specifically recommends azithromycin as the drug of choice during pregnancy 1, 2, 3
The CDC considers azithromycin the preferred macrolide when treatment is necessary during pregnancy, due to its pharmacokinetic properties and safety profile 2, 3

The CDC advises against confusing azithromycin with clarithromycin, which has been demonstrated to be a teratogen in animals and should be used with caution during pregnancy 1, 2
The CDC recommends using azithromycin only when clinically indicated during pregnancy, and being aware that some providers may choose to withhold medication during the first trimester out of caution, but this approach is not evidence-based when azithromycin treatment is necessary 1, 2

The CDC recommends azithromycin as an alternative treatment option for chlamydial infections during pregnancy, with a dose of 1g orally in a single dose, according to the MMWR Recommendations and Reports 4
Azithromycin can be used in the management of respiratory infections during pregnancy when clinically indicated, as stated in the European Respiratory Journal 5

The CDC recommends azithromycin as a preferred macrolide antibiotic during pregnancy, classified as FDA Pregnancy Category B, indicating animal reproduction studies have shown no evidence of harm to the fetus at doses up to 4 times (rats) and 2 times (mice) the human daily dose of 500 mg 6

For pertussis treatment and prophylaxis, azithromycin is the preferred macrolide, particularly for infants <1 month and by extension for pregnant women 6

Azithromycin has insufficient efficacy data for syphilis treatment in pregnancy and should not be used; penicillin remains the only proven effective treatment 7, 8

The European Respiratory Society classifies azithromycin as a B1‑category drug, indicating that it has been used by a limited number of pregnant women without an observed increase in fetal malformations and is considered “probably safe” for use during pregnancy. 9

An epidemiological study published in the European Respiratory Journal found that exposure of infants to macrolide antibiotics (including azithromycin) during the first 13 days of breastfeeding is associated with a very low risk of hypertrophic pyloric stenosis, with no increased risk after two weeks of exposure. This evidence is based on observational data and therefore represents low‑level evidence. 9