This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous (Gynae), Subject name: Gynaecology & Obstetrics
Maximum teratogenic effect on heart of fetus is between- 
Select and explain. 
A. 2-4 weeks, B. 4 - 6 weeks, C. 6 - 8 weeks, D. 8-10 weeks
C: 6 - 8 weeks
Answer: C: 6 - 8 weeks 
Explanation: Ans. is 'c' i.e., 6-8 weeks Period of gestation and teratogenso Based on the gestation at exposure, a teratogen can either induce an embryopathy or a fetopathy.o From this perspective several critical periods of embryonic or fetal development are described:Preimplantation - fertilization to implantationEmbryonic - second through the ninth weekFetal - ninth week to termo Period of orsanosenesis (Embryonic -2-8 weeks of conception) is the time of maximum vulnerability, and each embryonic system has a period of maximum susceptibility.# Heart is typically affected if the teratogen acts between 6-8 weeks of gestation.# CNS maximum susceptibility between 17 - 30th post fertilization days.