The drug of choice to treat Chlamydia infection in pregnancy is:

From the options listed in the question erythromycin is the drug used in the treatment of chlamydial infections in pregnancy. Erythromycin should be given for 7-10days. According to the latest recommendation Azithromycin 1gm as a single dose is the drug of choice in Chlamydia infection during pregnancy. As a prophylaxis to ophthalmia neonatorum 1% erythromycin ointment is applied to the infant's eye soon following bih. Neonatal infection is treated with erythromycin for 14-21days. Ref: Williams Obstetrics, 23rd Edition, Page 1241 ; Practical Gynecology, 2nd Edition, Page 200 ; Textbook of Obstetrics By DC Dutta, 6th Edition, Page 294-5