Hepatotoxicity of erythromycin estolate during pregnancy.

Women in the second half of pregnancy, who were infected with genital mycoplasmas and who gave written informed consent, were randomly assigned to receive capsules of identical appearance containing erythromycin estolate, clindamycin hydrochloride, or a placebo for 6 weeks. Levels of serum glutamic oxalacetic transaminase (SGOT) were determined before and during treatment by a fluorometric method. All pretreatment levels of SGOT were normal (<41 units). Participants who received erythromycin estolate had significantly more abnormally elevated levels of SGOT (16/161, 9.9%) than did those who received clindamycin (4/168, 2.4%, P < 0.01) or those who received placebo (3/165, 1.8%, P < 0.01). Elevated levels of SGOT ranged from 44 to 130 U. Serum bilirubin levels were normal. Gamma-glutamyl transpeptidase activity was abnormal in six of six participants who had abnormal levels of SGOT while receiving erythromycin estolate. There were few associated symptoms, and all levels of SGOT returned to normal after cessation of treatment. The treatment of pregnant women with erythromycin estolate may be inadvisable.