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42 terms

Teratogens - Embryology USD

What chemicals do what to a baby in utero.
STUDY
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Synthetic Progestins
VACTERAL (vertebral, cardiac, limb, renal, etc), slight increase in transposition of great vessels, 30% higher, causes hypospadius (urethra of penis opens on shaft or at scrotum)
Diethylstillbesterol (DES)
E2 replacement for miscarriage therapy, baby girls have a really high adenocarcinoma of vagina rate at 16-22yrs old if mom took it, male reproductive tract has issues too.
Clomiphine
Ovulation inducer, anacephaly chances rise
Insulin
Itself is harmless, but diabetic moms have vascular issues in general and baby gets caudal regression syndrome, where sacrum just doesn't form right, and the baby is HUGE because insulin is a growth factor to them. They go hypoglycemic the minute you cut their cord.
Corticosteriods
Not yet proven as a teratogen, but people are convinced they're bad somehow. It wrecks havoc in rats.
NSAID's
During the 3rd trimester, they cause early closure of the ductus arteriosis in the heart, so baby shunts blood to the lungs too soon!
Thyroxine
Iodine crosses the placenta easily! Goiter is caused by too much KI around, Cretinism by not enough. Thyroxine is partially responsible for synapse formation.
Drug Classifications A, B, C, D, X
A = Controlled studies show no risk
B = No evidence of risk in humans
C = Risk cannot be ruled out
D = Positive evidence of risk
X = Studies prove risk - "Contraindicated in Pregnancy"
Antineoplastic Agents
Folic Acid antagonists - highly teratogenic, produce anacephaly
Thalidomide
A sedative, once thought to be a miracle morning sickness drug.
Still used to treat leprosy.
Causes amelia/meromelia, FDA in US never approved it thanks to a doctor from South Dakota :)
Trimethadone
Anticonvulsant, for seizures, causes IUGR and cleft pallet/lip, and a very pointed eyebrow arch.
Dimethylhydantoin
Anticonvulsant, for seizures, causes fetal hydantoin syndrome, IUGR, clift lip, distal digital hypoplasia.
Tetracycline
Antibiotic, interferes with calcification, and stains baby's permanent teeth!
Streptomycin
Antibiotic, congenital hearing loss.
But it's really good at treating TB if mom has it...so sometimes it's worth it.
Penicillin
SAFE! Not a teratogen :)
Alcohol
Fetal Alcohol Syndrome
Diagnostic Criteria:
a) prenatal growth retardation and low birth weight
b) reduced palpebral fissures
c) Maxillary hypoplasia - "Indistinct philtrum"
d) Mental deficiency of some sort (Ethanol a common cause)
NO AMOUNT IS SAFE!
Cocaine
Abruptial Placenta risk high!
Cerebral infarct - baby has a stroke in the womb.
Marijuana/THC
IUGR, newborn's sleep patterns are odd
ACE Inhibitors
Hypoplasia of Calvaria - top of the skull doesn't close
Microcephaly
Heparin
Anticoagulant
SAFE--cannot cross placental barrier
Warfarin
Anticoagulant, causes CNS defects, limb issues, and nasal hypoplasia--your baby has no nose!
Rubella
"German Measles"
If mom gets it, baby can get:
-cataracts
-cardiac defects
-deafness
MMR vaccine wiped this out nicely, which is good--babies have a poor blood brain barrier!
Cytomegalovirus
Microcephaly - this infection is the cause of 25% of cases
Cerebral palsy?
Very hard to diagnose in mom
Herpes Simplex
Virus, cutaneous lesions are found on baby
Varicella
Mom's immunity does baby no good!
Mental deficiency, skin scarring, muscle atrophy
HIV
Baby can pick up virus and develop AIDS
Hypertelorism - far-apart eyes
Flared philtrum
Most risk in delivery and breast feeding
Toxoplasma Gondii
Microcephaly, intracranial calcification
Can come from mom eating contaminated meats or cleaning a cat's litterbox. It's airborne!!
Syphilis (Treponema pallidum)
80% of exposed babies will get hydrocephalus
Mental deficiency
Hutchinson's teeth are a sign of exposure
Radiation
Can cause growth retardation, microcephaly, spina bifida, cleft pallet/lip, etc. at high doses. Other malformations also possible, since radiation mutates DNA.

The scanner at the airport is HARMLESS to babies--the amount of radiation you receive in that scanner is equivalent to 3min of the flight you're about to get on. Exposure is cumulative though
Hyperthermia
Usually lethal to embryo if mom's temperature is over 104F for 24hrs or more.
If it lives, anacephaly is common.
Methyl Mercury
Seizures, blindness, cerebral palsy, mental deficiency
Nicotine
Causes hypoxia in baby
30% have IUGR, male babies at slightly higher risk
Retinoic Acid Overdose
Cleft pallet, hearing loss, facial cleft
Folic Acid Deficiency
Spina bifida! And other neural tube defects, mom should take no less than 400mcg a day.
Lead Poisoning
Crosses placenta and gets stuck there!
IUGR, neural defects, miscarriage risk
Mom doesn't need to be eating liver during pregnancy...
Organic Mercury
Minamata disease
Amniotic Bands
Rupture of amnion but intact chorion
Results in pinched off digits, hip dislocation (mostly in female babies), club foot, hyperextended knees.
Oligohydramnios
Too little amniotic fluid
Results in pinched off digits, hip dislocation (mostly in female babies), club foot, hyperextended knees.
Sometimes a signal of fetal kidney damage.
Ratios of Defect Types
30/1000 babies have one:
Neural: 10 babies
Cardiac: 8 babies
Other/Random: 6 babies
Renal: 4 babies
Limb: 2 babies
Listeria
Infection that mom can get from unpasteurized milk, lettuce, or bad meat--is usually lethal to baby, must be reported to the state when they happen.
Mechanisms of Teratology
Mutation, chromosomal nondisjunction/rearrangement, mitotic interference, altered nucleic acid function, lack of precursor nutrients, altered energy sources, enzyme inhibition, osmolar imbalance, odd membrane characteristics
Bicorunate Uterus
Mom's uterus is split into two horns, ancestral state (living examples include cows and sheep).
Baby doesn't have enough space: oligohydramnios, club foot, other IUGR-related deformations