ANSWER: (B) PhenytoinREF: KDT 6th edition page 405, Katzung 12 th edition page 409See APPENDIX-32 below TERATOGENSTERATOGENGROUPCRITICALPERIODEFFECTTHALIDOMIDEsedative34-51 days after LMPExternal ear deformity (earliest),PHOCOMELLA (MC-four groups: 4-limb phocomelia, Upper limb phocomelia, Predominantly Upper-limb phocomelia, Predominantly lower limb defects), Facial Hemangioma, Esophageal atresia, TOF, Renal agenesisRETINOIC ACIDVitamin3-5 weekRetinoic add embryopathy; cranio-facial abnormalities, Microtia/Anotia (deafness)Missing jaw or one that is too smallDisorders of jaw formation (split jaw)Disorders of formation of aortic archThymic aplasia/ hypoplasiaDeformities in the CNS (MC- hydrocephalus)DIETHYLSTIL-BOESTROLHormone vaginal adenosis, erosions of the cervix and transversal cleavages in the vaginaALCOHOLRecreational Fetal alcohol syndrome: ASD, VSD, LBW, microcephaly, maxillary hypoplasia, flatnasal bridge, micrognathia, microphthalmia, hypoplastic upper lip, broad lower lip.COCAINERecreational / Narcotic addiction in the child, retarded growth, to malformations of the circulatory systemPHENYTOINAntiepileptic Fetal hydantoin syndrome: VSD, ASD, coarctation of aorta, PDA, Hypoplasticphalanges, Syndactyly, deft palate, cleft/hare lip, microcephaly - caused by areneoxide metaboliteVALPROATEAntiepileptic Neural tube defects, Coarctation of aorta, hypoplastic left side of heart, aortic stenosis, pulmonary atresia, VSDLITHIUMAntipsychotic3-8 weeksEbstein anomaly (me), cleft palate inexperimental animalsSTREPTOMYCINAminoglycosides4-8 weeksdamage of the 8th cerebral nerve- deafnessWARFARINAnticoagulant1st trimesterHypoplastic nasal bridge , chondrodysplasia 2ndtrimesterCNS malformation 3rd trimesterRisk of bleeding APPENDIX - 32TeratogensTeratogenGroupCritical periodEffectThalidomidesedative34-51 days after LMPExternal ear deformity (earliest), PHOCOMELIA (MC- four groups: 4-limb phocomelia, Upper limb phocomelia, Predominantly Upper-limb phocomelia, Predominantly lower limb defects), Facial Hemangioma, Esophageal atresia, TOF, Renal agenesisRetinoic AcidVitamin3-5 weekcranio-facial abnormalitiesMicrotia/Anotia (deafness)Missing jaw or one that is too smallDisorders of jaw formation (split jaw)Disorders of formation of aortic archThymic aplasia/hvpoplasiaDeformities in the CNS (mc-hydrocephalus)Diethvlstil-boestrolHormone vaginal adenosis, erosions of the cervix and transversal cleavages in the vaginaAlcohol {fetal alcohol syndrome)Recreational LBW, microcephaly, maxillary hypoplasia, flat nasal bridge, micrognathia, microphthalmia, hypoplastic upper lip, broad lower lip.CocaineRecreational/Narcotic addiction in the child, retarded growth, to malformations of the circulatory systemLithiumAntipsychotic3-8 -weeksEbstein anomaly (me), cleft palate in experimental animalsStreptomycinAminoglycosides4-8 weeksdamage of the 8th cerebral nerve- deafnessWarfarinAnticoagulant1st trimesterHypoplastic nasal bridge , chondrodysplasia 2nd trimesterCNS malformation 3rd trimesterRisk of bleedingRubellaViral1st trimestercardiac defects, cataracts and deafnessCytomegalovirusViralspontaneous miscarriage in 1st trimester, anomalies from 2nd trimesterRetarded growth, changes in the CNS (microcephaly, cerebral atrophy, hydrocephaly, cerebellar hypoplasia, chorioretinitis, atrophy of the eyes) and hepatosplenomegalyHerpes SimplexViralAs a rule, HSV occurs in late pregnancyMental deficiency, Microcephaly, Myocardiopathy, Spasticity, Retinal dysplasiaVaricellaViralOnly up to the 20th week.muscle atrophy, hypoplasia of the limbs and fingers, abnormalities of the eyes and the brain (mental deficiency)Toxoplasmosis(ToxoplasmaGondi.)intracellularparasite cerebral calcification, microcephaly, microphthalmia, chorioretinitis, microphthalmia, hydrocephalusCongenitalSyphilis Mental deficiency, hydrocephalus, deafness, blindness, bone malformations, Hutchinson's teeth (pathognomic)Critical Period:Before the 14th day an insult (injury) to the embryo will not cause an abnormality because the embryo either repairs the damage or dies (spontaneous miscarriage)Embryonic period, during which numerous mitotic divisions and organogenesis occur, the embryo is very vulnerable and most congenital abnormalities happen thenFetopathies are the abnormalities that occur after the 8th week and up to delivery. The sensibility to injurious substances is clearly reduced in the last two trimesters of pregnancy.In infectious etiology critical period might not coincide with the effects they cause as there critical period might be different from the incidence of infection in the pregnancy trimester.