Teratogens Flashcards
Embryology
● Implantation occurs 6-9 days post-conception
o Before implantation, most teratogens will not be able to have an effect
● Organogenesis – 7-10 weeks after LMP
o “Classic teratogen period”
o Many women are unaware they’re pregnant
● Neural tube closure – 37-44 days after LMP
● Differentiation, growth, and maturation - >13 weeks after LMP – 2nd and 3rd
trimesters
Accutane
● Isotrentinoin
● Severe anomalies
o CNS anomalies, ear anomalies, cardiovascular defects, thymus anomalies,
intellectual disability
● Affects neural crest migration
ACE Inhibitors
● Critical period: 2nd and 3rd
trimester (NOT 1st
trimester)
● Symptoms: Renal tubular dysplasia, oligohydramnios/Potter sequence, pulmonary
hypoplasia, IUGR, large anterior fontanelle
Alcohol
Fetal alcohol syndrome
o CNS involvement, learning problems and behavioral problems
o Ptosis, short palpebral fissures, smooth philtrum, thin upper lip vermilion
Androgens
● Virilization of female fetuses
Anti-convulsants
● Valproic acid, Carbamazepine
● 6-15% risk for major malformations
● Myelomeningocele, NTDs
● Oral clefting
● CHDs
● Limb defects
● Dysmorphic features: hypertelorism, broad flat nasal bridge with upturned nose,
fingernail hypoplasia
● Developmental delay
Cocaine
● Pregnancy loss
● Placental abruption
● Growth retardation
● Microcephaly
Cytomegalovirus (CMV)
● Most are asymptomatic
● May see:
o Growth restriction, Cerebral calcifications, Ocular abnormalities,
Hepatosplenomegaly, Hearing loss
Maternal Diabetes
● Caudal regression
● CHDs – coarctation of the aorta
● CNS – NTDs and holoprosencephaly
● Duodenal atresia
● Limb defects
● Single umbilical artery
● Macrosomia
● Polyhydramnios
● Miscarriage
HIV/AIDS
● No risk to fetus, however there is a risk to be transmitted if the child passes through the
birth canal – C-section usually required, breast feeding can also transmit
● AZT (one of many AIDS-related drugs) has teratogenic effects
o Dysmorphic features
o Polydactyly/syndactyly
o Albinism
o Anemia
o Chromosomal damage
Immunosuppression
● Pencillamine to treat rheumatoid arthritis
● Causes cutis laxa phenocopy
Infections
● Almost all infections can have an impact on CNS development
● Important to stay up to date on vaccines
o Toxoplasmosis – can be contracted from cat feces – important to test cat for toxo
before pregnancy
● Extremely early infections may lead to embryonic death and reabsorption without
knowledge of pregnancy, or may lead to miscarriage
● Majority of fetuses exposed to infections will be developmentally/physically healthy at
birth
Lithium
● Ebstein’s anomaly – abnormally formed leaflets in tricuspid valve which lead to valve
dysfunction
Maternal PKU
● Microcephaly
● Intellectual disability
● Dysmorphic features
● CHDs
Mercury
● Dose-dependent
● Leads to congenital Minamata disease – severe CNS impairment
● Pregnant women should avoid fish high in mercury
Obesity
● Growth abnormalities
● Congenital abnormalities
● NTDs
● Hydrocephalus
● CHDs
● Gastroschisis
● Miscarriage
● Higher risk for child to have diabetes
Opioids
● Heroin, methadone
● Some suggest children exposed to opiods in the womb have a higher risk of
neurodevelopmental delays and behavioral concerns, however there is some debate as
to whether this is due to nature vs. nurture in the post-natal period
Radiation
● Increased fetal risk for malignancy
● 5 rads or higher is concern
SSRIs
● Critical period: All trimesters
● Symptoms: Congenital heart defects, anencephaly, craniosynostosis, omphalocele
● Possible association with persistent pulmonary hypertension
● Potential effects on gross motor function and language development
Thalidomide
● First known medical teratogen
● Prescribed for morning sickness
● Severe limb reduction defects
Thyroid Dysfunction/Anti-Thyroid Drugs
● Goiter
● Growth delay
● Developmental delay
Warfarin
● Critical period: 6-9 post conception, 8-11 weeks LMP
● Symptoms: Nasal and limb hypoplasia, stippled epiphyses
