Pregnant women should be screened for syphilis serology. Pregnant women who present with stillbirth after 20 weeks of gestation should also undergo serologic screening for syphilis. Patients with syphilis in pregnancy who receive penicillin treatment in the second trimester are at risk of preterm delivery and intrauterine asphyxia if a sudden gi-hai reaction occurs. In this case, if abnormal fetal movements or contractions are detected, the necessary medical monitoring and treatment should be given. Stillbirth is a very rare complication of penicillin therapy, but even if stillbirth is possible, treatment should not be delayed because penicillin therapy can prevent further fetal damage. Alternatives to penicillin for the treatment of syphilis in pregnancy have not yet been identified. Patients with a history of penicillin allergy should be treated with penicillin, if necessary, after desensitization. Doxycycline and tetracycline are contraindicated during pregnancy, and erythromycin should not be used because it does not reliably cure fetal syphilis. After treatment, pregnant women with syphilis should have a monthly serum test for syphilis before delivery and be observed as a general syphilis patient after delivery. Infants delivered by pregnant women with adequately treated syphilis should be observed until they are seronegative; serologic reaction tests can be done 2 – 3 times 1-3 months after birth. If symptoms are found to appear, treatment should be given promptly. In particular, the infant should be followed up with clinical and serologic tests and treated for syphilis in pregnant women who are not adequately treated or are not treated with penicillin. If maternal syphilis infection occurs late in pregnancy, infected infants are often asymptomatic at birth and may be serologically negative; these infants should receive immediate “exsanguination” treatment if the mother is not treated adequately, or is not treated with penicillin, or if appropriate follow-up cannot be assured.