Gynaecology & Obstetrics General d0d3eb3c Most common cause of spontaneous aboion is? A Chromosomal abnormality B Uterine malformations C Immunological D Infections High-Yield Explanation Chromosomal abnormality REF: Dutta 6th ed p. 159 Most common cause of spontaneous aboion is chromosomal abnormality, trisomy of chromosome 16.