This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Medical, surgical and gynaecological illness complicating pregnancy, Subject name: Gynaecology & Obstetrics
Antitubercular drug contraindicated in pregnancy: 
Select and explain. 
A. Streptomycin, B. Refampicin, C. INH, D. Ethambutol
A: Streptomycin
Answer: A: Streptomycin 
Explanation: Tuberculosis is a bacterial infection caused by M.tuberculosis and rarely by M.bovis.Spread is usually by droplet infection. The principles of chemotherapy are the same as in nonpregnant state.The first line drugs are INH,rifampicin,ethambutol and pyrazinamide.Streptomycin is contraindicated due to its teratogenicity.It can occasionally cause ototoxicity. Other anti TB drugs which contraindiacted in pregnancy are Kanamycin,Amikacin,Capreomycin,Fluoroquinolones. TEXT BOOK OF OBSTETRICS,Sheila Balakrishnan,2nd edition,page no.325