Can a pregnant patient be given antibiotics?

Can Pregnant Patients Be Given Antibiotics?

Yes, pregnant patients can and should be given antibiotics when medically indicated, as untreated infections pose significant risks to both mother and fetus, including preterm birth, low birth weight, and spontaneous abortion. 1, 2

Safe First-Line Antibiotics in Pregnancy

The following antibiotics are considered safe throughout all trimesters based on decades of clinical experience and guideline recommendations:

Penicillins (Category B)

• Amoxicillin is safe during pregnancy, with reproduction studies in mice and rats showing no evidence of fetal harm at doses up to 3-6 times the human dose. 3
• Amoxicillin-clavulanic acid can be safely administered during pregnancy. 4
• All penicillins are classified as Category B and considered first-line agents. 5, 6

Cephalosporins (Category B)

• Cephalexin, along with other cephalosporins, is safe throughout pregnancy and represents a first-line alternative. 7, 5
• Piperacillin-tazobactam is classified as Category B and explicitly listed as "compatible" for use during pre-conception and first trimester. 8

Macrolides

• Azithromycin is considered a safe first-line alternative with moderate-quality evidence. 7, 5
• Erythromycin is safe during all trimesters (Category B), though the American Academy of Dermatology notes some concerns about adverse outcomes including elevated liver enzymes. 7, 5

Other Safe Options

• Clindamycin is a safe first-line alternative with moderate-quality evidence. 7, 5
• Metronidazole can be given for pouchitis, perianal Crohn's disease, or intra-abdominal abscesses. 4
• Nitrofurantoin, fosfomycin, and vancomycin are generally considered safe and effective. 1

Antibiotics Strongly Contraindicated in Pregnancy

Tetracyclines - Avoid Throughout Pregnancy

• Doxycycline and all tetracyclines should be avoided after the fifth week of pregnancy due to binding to fetal bones and teeth causing permanent discoloration, transient suppression of bone growth, and potential exacerbation of maternal fatty liver. 7, 5, 2

Fluoroquinolones - Avoid Throughout Pregnancy

• Ciprofloxacin and other fluoroquinolones should be avoided due to potential fetal cartilage damage. 7, 5

Trimethoprim-Sulfamethoxazole (Co-trimoxazole) - Trimester-Specific Avoidance

• Avoid during first trimester and near term due to increased risk of preterm birth, low birthweight, kernicterus, and neural tube defects from trimethoprim's interference with folic acid metabolism. 7
• If trimethoprim must be used, at least 400 μg daily folic acid supplementation is mandatory. 7, 5

Antibiotics Requiring Extreme Caution

Aminoglycosides (Category D)

• Gentamicin and tobramycin should be used with extreme caution due to risk of fetal ototoxicity (deafness) and nephrotoxicity. 4, 5
• If gentamicin must be used, levels need particularly careful monitoring. 4
• Inhaled tobramycin is compatible during pregnancy, but systemic formulations should be avoided. 7, 5
• Reserved only for life-threatening gram-negative infections when other options have failed. 2

Other Category C Agents

• Vancomycin, imipenem, rifampicin, and teicoplanin are Category C, meaning risk cannot be ruled out and risk-benefit must be carefully weighed. 5

Critical Clinical Principles

When to Treat

• Initiation of antimicrobial therapy must be based on clear-cut necessity, as untreated infections during pregnancy can cause abortion in early pregnancy and preterm labor/premature delivery in later trimesters. 6, 2
• Antibiotics must be chosen to save the life of the mother while trying to avoid fetal damage. 4

Dosing Considerations

• Pregnancy causes pharmacokinetic alterations including increased glomerular filtration rate, increased total body volume, and enhanced cardiac output, which may require dose adjustments or careful monitoring. 1
• Blood levels should be checked to ensure efficacy and avoid toxicity, as drug pharmacokinetics are altered in pregnancy. 4

Timing of Risk

• First trimester exposures carry the highest risk for congenital malformations, while third trimester and delivery exposures risk neonatal complications. 7

Common Clinical Pitfalls to Avoid

• Do not withhold necessary antibiotics due to pregnancy concerns - untreated infections pose greater risks than most appropriate antibiotics. 2
• Avoid amoxicillin-clavulanate in women at risk of preterm delivery despite general safety. 7
• Monitor for reduced oral contraceptive efficacy as amoxicillin may affect intestinal flora, leading to lower estrogen reabsorption. 3
• Do not delay surgical intervention for severe infections (such as endocarditis with acute valvular regurgitation) until after delivery if maternal indication is urgent. 4