What antibiotics are safe to use during pregnancy?

From the Guidelines

The safest antibiotics to use during pregnancy are penicillins, such as amoxicillin, and cephalosporins, such as cefazolin and cefuroxime, as well as macrolides like azithromycin, due to their established safety profiles and minimal risk to the developing fetus. These medications are often prescribed at standard adult dosages, for example, amoxicillin 500mg three times daily for 7-10 days for urinary tract infections 1. Cephalosporins provide good coverage for many infections and are considered pregnancy category B drugs, meaning animal studies show no risk to the fetus. Azithromycin is preferred over other macrolides like erythromycin due to its safety profile and efficacy.

Some key points to consider when prescribing antibiotics during pregnancy include:

• Penicillins and cephalosporins are generally safe and effective options for treating bacterial infections during pregnancy.
• Macrolides, such as azithromycin, are also considered safe and can be used as an alternative to penicillins and cephalosporins in certain cases.
• Tetracyclines, fluoroquinolones, and trimethoprim should be avoided during pregnancy due to potential risks to fetal development.
• The duration of antibiotic treatment may vary depending on the specific infection and the antimicrobial agent used, with some studies suggesting that longer courses of treatment may be more effective in preventing adverse outcomes such as lower birth weight 1.
• It is essential to weigh the benefits and risks of antibiotic use during pregnancy and to consider the potential consequences of untreated infection on both the mother and the fetus.

In terms of specific antibiotic recommendations, oral cephalexin and azithromycin are suggested as safe options for use in pregnant women with hidradenitis suppurativa who require systemic antibiotics 1. Additionally, amoxicillin and ampicillin are considered safe for use in pregnant women with asymptomatic bacteriuria 1. However, it is crucial to consult with a healthcare provider before taking any medication during pregnancy to ensure the safest possible outcome for both the mother and the baby.

From the FDA Drug Label

Teratogenic Effects: Reproduction studies have been performed in mice and rats at doses up to 2000 mg/kg (3 and 6 times the 3 g human dose, based on body surface area). There was no evidence of harm to the fetus due to amoxicillin. There are, however, no adequate and well-controlled studies in pregnant women Because animal reproduction studies are not always predictive of human response, amoxicillin should be used during pregnancy only if clearly needed.

Amoxicillin can be used during pregnancy, but only if clearly needed, as there are no adequate and well-controlled studies in pregnant women. The decision to use amoxicillin during pregnancy should be made with caution, considering the potential benefits and risks. 2

• Key points:
  • No evidence of harm to the fetus in animal studies
  • No adequate and well-controlled studies in pregnant women
  • Use during pregnancy only if clearly needed

From the Research

Antibiotics Safe in Pregnancy

The following antibiotics are generally considered safe to use during pregnancy:

• Penicillins, cephalosporins, and erythromycins, which have decades of clinical experience and documented safety for the fetus 3
• Beta-lactams, vancomycin, nitrofurantoin, metronidazole, clindamycin, and fosfomycin, which are considered safe and effective in pregnancy 4
• Macrolides, such as azithromycin and clarithromycin, although data on these newer agents is limited 3
• Aminoglycosides, which are safe to use if serum levels are carefully monitored in the mother 3

Antibiotics to Avoid in Pregnancy

The following antibiotics should be avoided in pregnancy:

• Tetracyclines, due to their known toxic effects on the fetus 3, 4, 5
• Quinolones, which should be avoided unless maternal necessity for their use justifies the exposure of the fetus to their toxicity 3, 4, 5
• Sulfonamides, which should be avoided unless maternal necessity for their use justifies the exposure of the fetus to their toxicity 3
• Fluoroquinolones, which are generally avoided in pregnancy 4, 5

Considerations for Antibiotic Use in Pregnancy

When prescribing antibiotics to pregnant women, it is essential to consider the following factors:

• The possible teratogenic risk of the antibiotic 6
• Changes in pharmacokinetics due to physiological changes in pregnancy 4, 5
• The potential toxicity of the drug to the fetus 3, 6
• The need to treat the mother while protecting the unborn child 6