Risk Factor: BM
Class: Anti-infectives/ Cephalosporins
Fetal Risk Summary
Cefaclor is an oral, semisynthetic cephalosporin antibiotic. Reproduction studies in mice, rats, and ferrets found no evidence of impaired fertility or fetal harm at doses up to 12, 12, and 3 times, respectively, the human dose (1). Cephalosporins are usually considered safe to use during pregnancy (see other cephalosporins for published human experience).
In a surveillance study of Michigan Medicaid recipients involving 229,101 completed pregnancies conducted between 1985 and 1992, 1,325 newborns had been exposed to the antibiotic during the 1st trimester (F. Rosa, personal communication, FDA, 1993). A total of 75 (5.7%) major birth defects were observed (56 expected). Specific data were available for six defect categories, including (observed/expected) 19/13 cardiovascular defects, 8/2 oral clefts, 1/0.7 spina bifida, 1/4 polydactyly, 2/2 limb reduction defects, and 3/3 hypospadias. The data for all defects, cardiovascular defects, and oral clefts are suggestive of an association between cefaclor and congenital defects, but other factors, such as the mother’s disease, may be involved. However, similar findings were measured for another cephalosporin antibiotic with more than a thousand exposures (see Cephalexin). Positive results were also suggested for cephradine (339 exposures) but not for cefadroxil (722 exposures) (see Cephradine and Cefadroxil). In contrast, other antiinfectives with large cohorts (see Ampicillin, Amoxicillin, Penicillin G, Erythromycin, and Tetracycline) were not associated with congenital defects.
Breast Feeding Summary
Cefaclor is excreted into breast milk in low concentrations. Following a single 500-mg oral dose, average milk levels ranged from 0.160.21 g/mL during a 5-hour period (2). Only trace amounts of the antibiotic could be measured at 1 and 6 hours. Even though these levels are low, three potential problems exist for the nursing infant: modification of bowel flora, direct effects on the infant, and interference with the interpretation of culture results if a fever workup is required. Although not specifically listing cefaclor, the American Academy of Pediatrics classifies other cephalosporin antibiotics as compatible with breast feeding (3).
- Product information. Ceclor. Eli Lilly and Company, 1997.
- Takase Z. Clinical and laboratory studies of cefaclor in the field of obstetrics and gynecology. Chemotherapy (Tokyo) 1979;27(Suppl):668.
- Committee on Drugs, American Academy of Pediatrics. The transfer of drugs and other chemicals into human milk. Pediatrics 1994;93:13750.