Antibiotic Use During Pregnancy

Safety Classification and Recommendations

The European Respiratory Society recommends amoxicillin/clavulanic acid (Augmentin) as the safer choice during pregnancy, including the third trimester, due to its superior safety classification (Category A for amoxicillin, B1 for the combination) and decades of clinical experience demonstrating no teratogenic effects at therapeutic doses 1
The European Respiratory Society designates amoxicillin/clavulanic acid as "Compatible" for use throughout pregnancy, indicating the highest level of safety evidence in pregnancy 1
Human data indicate that penicillins, such as amoxicillin, are not teratogenic at usual therapeutic doses, making them a preferred first-line agent during pregnancy 1
Azithromycin is classified as Category B1, indicating "Probably safe" rather than fully compatible, and should be reserved for specific clinical scenarios where macrolide coverage is required 1
The American College of Obstetricians and Gynecologists is not mentioned, however, the CDC recommends azithromycin as a preferred macrolide when macrolide coverage is specifically needed, but this does not make it safer than penicillins 2, 3

Amoxicillin/clavulanic acid benefits from extensive human pregnancy data showing safety, with a strong evidence base supporting its use during pregnancy 1
The European Respiratory Society/Thoracic Society of Australia and New Zealand guidelines recommend penicillins, such as amoxicillin, as first-line antibiotic treatment during pregnancy due to their high safety profile and decades of documented safety 1
Azithromycin has limited human pregnancy data with conflicting results on fetal outcomes, and its use should be guided by specific clinical circumstances requiring macrolide coverage 2, 3

Azithromycin may be appropriate for atypical respiratory pathogens (Mycoplasma, Chlamydia, Legionella) where beta-lactams are ineffective, as well as for chlamydial infections and pertussis treatment or prophylaxis 2, 3
In cases of penicillin allergy, azithromycin or cephalosporins may be considered as alternative treatments, depending on the severity of the allergy 1, 3
The European Respiratory Society recommends avoiding amoxicillin/clavulanic acid in women at risk of preterm delivery due to the very low risk of necrotizing enterocolitis in the fetus, and instead considering amoxicillin alone or azithromycin depending on the pathogen 1