# Teratogen --- **Teratogens** are substances which can cause abnormal [[prenatal development]], which can lead to birth defects and even death. The effect of the specific teratogens are relative to different sensitive periods during organ development. Some sensitive periods last for a certain period of time, like the closure of the neural tube at 3-5 weeks, but others last the whole pregnancy, like brain development. **Critical periods** are stages during development; after this time has passed the development cannot occur. For example, taking the drug **thalidomide** before a critical period of pregnancy prevents the development of the extremities. ![[critical periods of fetal development.png]] this is why we do a growth ultrasounds at around 20 weeks nuchal transparency helps determine increased risk of trisomy's. can also usually see neural tube defects at this point ## Potential Teratogens - medications - [[antiepileptic drugs|phenytoin]] - retinoids - used in acne meds, so some acne meds need a person to prove they have two forms of birth control active (and some say abstinence doesn't count in this case) - [[warfarin]] - alcohol - **Fetal Alcohol Spectrum Disorders** are the most common preventable cause of [[cognitive impairment]] - Alcohol-Related Neurodevelopmental Disorder (ARND) - Alcohol-Related Birth Defects (ARBD) - Neurobehavioral Disorder Associated with Prenatal Alcohol Exposure (ND-PAE) - Fetal Alcohol Syndrome (FAS) - No cure, but early intervention is supportive - Alcohol also linked to miscarriage, stillbirth, preterm birth - tobacco - linked to miscarriage, preterm labor, fetal growth restriction, low birth weigh - cannabis - changing legal context leading to increased use - may or may not be linked to IUGR, developmental delays - opioids - linked to pregnancy complications, and Neonatal Opioid Withdrawal Syndrome - cocaine and methamphetamines - linked to placental abruption, preterm labor, fetal growth restriction - infections - TORCH diseases are a list of the common ones - [[Toxoplasmosis]] - Other ([[HIV]], syphilis, [[varicella]], fifth disease, [[COVID-19]]) - Rubella - [[cytomegalovirus]] - Herpes simplex - medical conditions - malnutrition - both being underweight and overweight - [[diabetes mellitus]] - type 1, type 2 and [[gestational diabetes]] - [[preeclampsia]] - multiple gestation (i.e. twins, etc) - heat - pregnant people should avoid hot tubs, etc - stress - occupational exposures - agricultural workers: pesticides - healthcare workers: chemotherapy, infections - childcare workers: cytomegalovirus - industrial workers: solvents - environmental services: cleaning chemicals ## Nursing Considerations About half the pregnancies in the US are unintended, either because they are mistimed or unwanted. Teratogenic exposure can occur before someone even knows they are pregnant. This is why compassionate, evidence based preconception care should be included for every person who can get pregnant when they receive healthcare. ___