Cephalexin Safety During Pregnancy
Cephalexin is safe to use during pregnancy and is considered a first-line antibiotic option for treating bacterial infections in pregnant women. 1, 2
Safety Classification and Evidence
Cephalexin is FDA Pregnancy Category B, meaning reproduction studies in animals have shown no harm to the fetus at doses up to 1.5 times the maximum human dose, though adequate well-controlled studies in pregnant women are limited. 2
The American Academy of Dermatology supports cephalexin use during pregnancy based on moderate quality evidence demonstrating no harm to the fetus. 1
Cephalosporins as a class, including cephalexin, are not teratogenic at usual therapeutic doses based on human data. 3
Clinical Applications During Pregnancy
Cephalexin serves as a first-line treatment option for various bacterial infections during pregnancy, including urinary tract infections, respiratory infections, and skin/soft tissue infections. 1, 4
For recurrent urinary tract infections during pregnancy, postcoital prophylaxis with cephalexin 250 mg as a single oral dose has proven highly effective, with only 1 UTI occurring during pregnancy after prophylaxis compared to 130 UTIs before prophylaxis in one study. 5
Oral cephalexin (500 mg every 6 hours) is equally effective as intravenous cephalothin for treating acute pyelonephritis in pregnancy in non-bacteremic patients, with 91.4% success rates. 6
Cephalexin offers a safer alternative to contraindicated antibiotics during pregnancy such as doxycycline and trimethoprim-sulfamethoxazole, which pose risks including congenital anomalies and preterm birth. 1
Advantages Over Other Antibiotics
Penicillins and cephalosporins represent first-line antibiotic choices during pregnancy, with cephalosporins being particularly useful when penicillin allergy exists or when broader coverage is needed. 4
Cephalexin reaches high bactericidal concentrations in the urinary tract and induces minimal resistance in gram-negative bacterial flora, making it particularly effective for urinary infections. 5
Important Considerations
While cephalexin is safe throughout pregnancy, the drug should only be used when clearly needed to treat bacterial infections, not viral infections. 2
Cephalexin is excreted in breast milk, reaching maximum levels of 4 mcg/mL at 4 hours post-dose and disappearing by 8 hours, so caution should be exercised when administering to nursing mothers. 2
No medicine can be described as absolutely safe during pregnancy, but cephalexin does not cause serious harm to the unborn child when used properly at appropriate doses. 4
Treatment with cephalexin that may have been inadvertently given does not justify termination of pregnancy. 4