<prompt> Which of the following is teratogenic: March 2011FolateCyanocobalaminVitamin AVitamin C  <response>: Ans. C: Vitamin APharmacological doses of vitamin A are teratogenic and in pregnancy the daily dose must not exceed 6000-8000 IU.Synthetic analogues of vitamin A:TretinoinIsotretinoinEtretinateAcetretinTeratogenic drugsDrugs and medications:- Tobacco Caffeine- Drinking alcohol ethanol fetal alcohol spectrum disorder,- Isotretinoin 13-cis-retinoic acid- Temazepam- Nitrazepam- Aminopterin or methotrexate- Androgenic hormones Busulfan- Captopril, enalapril- Coumarin- Cyclophosphamide- Diethylstilbestrol-Phenytoin diphenylhydantoinLithium- Methimazole- Penicillamine- Tetracyclines- Thalidomide- Trimethadione- Flusilazole- Valproic acidEnvironmental chemicals:- Polycyclic aromatic hydrocarbons polynuclear aromatic hydrocarbons- Polychlorinated biphenyls PCBs- Polychlorinated dibenzodioxins a.k.a dioxin,- Organic mercuryIonizing radiation:- Atomic weapons fallout Iodine-131, uranium- Background radiationDiagnostic x-rays- Radiation therapyInfections:- Cytomegalovirus- Herpes virus- Parvovirus B19- Rubella virus German measles- Syphilis- Toxoplasmosis An easy way to remember maternal infections is TORCH: Toxoplasmosis, Other agents, Rubella, CMV and HSV.Metabolic imbalance:- Alcoholism Diabetes- Folic acid deficiency- Iodine deficiency- Hypehermia 