Treatment of syphilis in pregnancy.

Only penicillin has been adequately studied in treating syphilis during pregnancy. It is safe for the fetus and highly effective in doses currently recommended by the USPHS. Since these schedules appear to represent a minimal effective dose, smaller amounts should never be used. Whether higher doses would produce higher cure rates is not known. Penicillin is the drug of choice and the standard against which all others must be measured. Tetracyclines in any dose or form should not be used because of toxicity to both mother and child. Erythromycin (except the estolate) and cephalosporins are promising because of low toxicity, but their efficacy has not been established.