This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General obstetrics, Subject name: Gynaecology & Obstetrics
Most common cause of the first-trimester aboion is 
Select and explain. 
A. Chromosomal anomalies, B. Infections, C. Rh incompatibilty, D. Cervical incompetence
A: Chromosomal anomalies
Answer: A: Chromosomal anomalies 
Explanation: Causes of 1st trimester aboion : Genetic factors -50% Endocrine disorders Immunological disorders Infection Unexplained Ref: Dutta Obs 9e pg 153.