This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Abortion, Subject name: Gynaecology & Obstetrics
MC cause of abortion in first trimester is, defect in: 
Select and explain. 
A. Placenta, B. Uterus, C. Embryo, D. Ovarian
C: Embryo
Answer: C: Embryo 
Explanation: Ans. is c, i.e. EmbryoRef. Dutta Obs. 7/e, p 159, 160; Williams Gynae 1/e, p 138As explained earlier most common cause of abortion in first trimester are chromosomal abnormalities involving the zygote or embryo.