miscarriage risks miscarriage risks miscarriage risks are those circumstances, conditions, and substances that increase the risk of miscarriage. some risks are modifiable and can be changed. other risks cannot be modified and can't be changed. risks can be firmly tied to miscarriages and others are still under investigation. in addition, there are those circumstances and treatments that have not been found effective in preventing miscarriage. when a woman keeps having miscarriages, infertility is present. anatomical defect in the mother amniocentesis chorionic villus sampling age >30 smoking and exposure tobacco smoke obesity diabetes thyroid disorders (e.g. hypothyroidism) alcohol use cannabis use chromosomal abnormalities infectious diseases radiation exposure endocrine genetic and chromosome abnormalities autosomal trisomy monosomy x (45, x) triploidy structural abnormality of the chromosome double or triple trisomy uterine structural abnormalities uterine fibroids cervical abnormalities hormonal abnormalities reproductive tract infection tissue rejection autoimmune disorder coeliac disease lupus antiphospholipid antibody syndrome anti-thyroid autoantibodies placenta abnormality previous miscarriage eating disorders bulimia nervosa and anorexia nervosa hyperemesis gravidarum illicit or recreational drugs caffeine food poisoning salmonella listeriosis toxoplasmosis some surgeries and medications antidepressants nonsteroidal anti-inflammatory drugs, such as ibuprofen methotrexate retinoids trauma chemotherapy polycystic ovary syndrome (pcos) luteal phase defect mycoplasma genitalium infection rubella (german measles) cytomegalovirus bacterial vaginosis sexually transmitted infections hiv, chlamydia, gonorrhoea and syphilis malaria chemicals ddt lead formaldehyde arsenic benzene ethylene oxide working conditions night shift work >40-hour work week lack of accommodation for strenuous working conditions psychological stress