<prompt> Spontaneous aboion in 1st trimester is caused by:Trisomy 21MonosomyTraumaAll  <response>: Ans. is a, b and c i.e. Trisomy 21; Monosomy; and Trauma Common causes of aboion First trimester 1. Defective germplasm most common chromosomal anomalies : Trisomy most common Triploidy Monosomy X Tetraploidy Structural rearrangements including : translocation, deletion, inversion 2. Endocrine disorders : Luteal phase defect Thyroid abnormalities rare Diabetes 3. Maternal medical illness including -- Cyanotic hea disease - Hemoglobinopathies -- Inherited thrombophilia 4. Trauma Maternal excessive use of alcohol, caffine Mid trimester 1. Anatomical abnormalities Cervical incompetence Uterine malformationmullerian anomalies Uterine synechiae 2. Autoimmune disorders Antinuclear antibodies Antiphospholipid antibodies Maternal thrombophelia Rh and blood group incompatibility Low implantation of placenta Twins hydramnios Endocrine abnormalities -- Progesterone deficiency -- Thyroid deficiency -- Maternal diabetes -- PCOD 7. Genetic abnormalities -- Seen in 5-10 of 2nd trimester losses Fernando Arias 3e, p 326 Sub chorionic bleeding Maternaluterine infections Note: According to ACOG 2001, Infections are an uncommon cause of early aboions. Even in their study of IDDM--women-presumbly more susceptible to infection-simpson and coworkers 1996 found no evidence of infection induced miscarriage. 