This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: First-Trimester Spontaneous Abortion, Subject name: Gynaecology & Obstetrics
Commonest cause of first trimester miscarriage is: 
Select and explain. 
A. Syphilis, B. Cervical incompetence, C. Chromosomal abnormalities, D. Rhesus isoimmunisation
C: Chromosomal abnormalities
Answer: C: Chromosomal abnormalities 
Explanation: Ans. (c) Chromosomal abnormalitiesDutta 6th/160With respect to first trimester abortions, 75% of the abortions take place before 16thweek and out of these, about 75% occur before the 8thweek of pregnancy.* Chromosomal abnormality in the conceptus is the commonest cause of miscarriage.* Autosomal trisomy particularly Trisomy 16 is the commonest cause for spontaneous abortion.