<prompt> Most common cause of first trimester aboion:Genetic factorsEndocrine disordersImmunological disordersInfection  <response>: Common Causes of aboion First trimester: 1. Genetic factors 50 2. Endocrine disorders luteal phase defect, thyroid abnormalities, and diabetes 3. Immunological disorders autoimmune and alloimmune 4. Infection 5. Unexplained 