II. Pathophysiology

  1. Teratogens cause birth defects, Stillbirths, IUGR

III. Risk Factors: General Teratogen Susceptibility

  1. Week 0-2: Pre-organogenesis
    1. Not Sensitive to malformation
    2. Significant exposure is lethal
  2. Week 3-8: Embryonic Period
    1. Greatest sensitivity to environmental exposures
    2. Fetal mass increases 2.5 Million fold first trimester
    3. Major malformations occur
  3. Week 9-38: Fetal Period
    1. Decreasing sensitivity
    2. Functional defects and minor malformations occur

IV. Causes: Occupational Exposures

  1. General
    1. Household products also present Teratogen Exposure risk (Heavy Metals, solvents, Pesticides)
    2. High risk industries for Teratogen Exposure include laboratory work, dry cleaning, printing, manufacturing and agriculture
  2. Lead Exposure
    1. Gestational Hypertension
    2. Placenta Previa
    3. Preterm delivery
    4. Fetal loss
    5. Fetal Growth Retardation
    6. Fetal neurodevelopmental conditions
    7. Birth defects
  3. Mercury Exposure
    1. See Mercury Content in Fish
    2. Preterm birth
    3. Fetal neurodevelopmental conditions (potent Neurotoxin)
  4. Solvents (Trichloroethylene, Chloroform, Benzene)
    1. Ensure adequate ventilation if at risk of exposure
    2. Associated with risk of Miscarriage, Stillbirth, preterm birth and IUGR
  5. Plastics (Vinyl Chloride)
  6. Pollutants (Polychlorinated or Polybrominated Biphenyl)
  7. Pesticides (Organophosphates)
  8. Gases (Carbon Monoxide, Inhalation Anesthetics)
  9. Radiation (e.g. XRay)
    1. See Radiation Exposure in Pregnancy
    2. See CT-associated Radiation Exposure

V. Causes: Home Exposures

  1. Medications
    1. See Medications in Pregnancy
    2. Reevaluate all OTC and prescribed medications
  2. Substances
    1. See Substance Abuse in Pregnancy
    2. Tobacco Cessation
      1. Tobacco associated with 4600 U.S. perinatal deaths per year
    3. Alcohol Abstention
      1. See Fetal Alcohol Syndrome
    4. Marijuana
      1. Associated with low birth weight and NICU admission
      2. Heavy use is associated with Cannabinoid Hyperemesis and Preterm Labor
      3. Avoid in pregnancy
        1. Metz (2018) Obstet Gynecol 132(5): 1198-1210 +PMID:30234728 [PubMed]
        2. Bailey (2020) Perinatol 40(10):1477-82 +PMID:32139807 [PubMed]
  3. Foods
    1. See Nutrition in Pregnancy
    2. See Mercury Content in Fish
      1. Avoid excessive large fish intake (e.g. shark, swordfish, tilefish or king mackerel) due to mercurcy contamination
  4. Vitamins
    1. Avoid Vitamin A in excess of 3000 IU per day
    2. Avoid Vitamin D in excess of 400 IU per day
  5. Herbals associated with Miscarriage
    1. Devil's claw root
    2. Barberry
    3. Dong Quai
    4. High concentrations of Ruta, Hydrastis or Oregano
  6. Other Herbal Teratogens
    1. See Herbal Remedy
      1. Exercise caution regarding overall risks of herbal contamination and lack of standardization
    2. Ginkgo
    3. Ephedra
    4. Ginseng
  7. Other home exposures
    1. Avoid hot tubs and saunas in first trimester
      1. Associated with Neural Tube Defects and Miscarriages
    2. Avoid hair dyes and treatments in first trimester
      1. May be associated with childhood Acute Leukemia
      2. Couto (2013) Chem Biol Interact 205(1): 46-52 [PubMed]

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