Most common cause of first trimester aboion is.

Ans. is a i.e. Chromosomal abnormalities Aboion is spontaneous termination of pregnancy before the period of bility There are various definitions of aboion depending on the criteria for bility or survival of fetus. In the past, the criterion for bility was considered from 28 weeks onwards, but due to improvement in neonatal survival, this has been changed to 20th completed weeks". Another commonly used definition is the "-delivery of a fetus or any pa of product of conception with weight less than 500gms.'deg Incidence : About 15% of all conceptions end up in spontaneous aboions. Out of these 80% occur before 12 weeks i.e. in 1st trimester and among these 50-75% are due to chromosomal anomalies. Common causes of aboion : Petal factors Chromosomal abnormalities Hydropic degeneration of villi Multiple pregnancy Maternal factors Maternal infections like : TORCH infections, malaria,ureoplasma, chlamydia, brucella, spirochaetes Maternal medical disorders like : -- Hypeension -- Chronic renal disease -- Cyanotic hea disease -- Hemoglobinopathies Environmental factors like : -- Alcohol, caffeine. -- Exposure to radiation (> 5 rads) & anaesthetic gases Endocrine problems like : - Luteal phase defect (deficiency of progesterone) -- Thyroid abnormalities - hypothyroidism. - Poorly controlled diabetes mellitus -- PCOD Immunological causes : -- Antiphospholipid antibody syndrome -- Inherited thrombophilias Uterine factors like -- Cervical incompetence -- Mullerian anomalies - Large and multiple submucous leiomyoma -- Ashermann syndrome -- DES exposure in utero Others : Trauma; Subchorionic hematoma; Defective placentation Mnemonic to remember maternal causes of aboion--Mnemonic T = Trauma 12 = Infections/immunological causes M = Maternal medical diseases E' = Environmental factors/Endocrine problem D = Developmental/anatomical problems Mnemonic to remember maternal causes of aboion--Mnemonic T = Trauma 12 = Infections/immunological causes M = Maternal medical diseases E' = Environmental factors/Endocrine problem D = Developmental/anatomical problems