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
[{'content': 'Most common cause of spontaneous abortion in first trimester: \nSelect and explain. \nA. Chromosomal anomalies, B. Uterine anomalies, C. Antiphospholipid antibody syndrome, D. Hypothyroidism', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans: A (Chromosomal anomalies) Ref: Dutta: Textbook of Obstetrics 7th ed pg 160Explanation:COMMON CAUSES OF MISCARRIAGEFirst TrimesterGenetic factors Endocrine Immunological disorders InfectionUnexplainedSecond TrimesterAnatomicCervical incompetenceBicomuate uterusSeptate uterusUterine synechiaeUterine fibroidMaternal medical illnessUnexplained', 'role': 'assistant'}]