Teratology-science dealing w/ causes, mechanisms, & manifestations of devo deviations, either structural, or functional

  •          this science involves recognizing the patterns of abnormalities and keeping track of pregnancy exposures

Teratogen-acts on somatic cells of developing organism

Mutagen-acts of the germ cells, altering genetic material-it’s the one that’s inherited…

  •          If you take out an environmental agent out of the environment, such that a 2nd pregnancy isn’t exposed, recurrence <0%

ALL-or-NOTHING period: 1st two weeks of pregnancy when mitosis is going on like crazy-exposrue to a teratogen during this time either causes significant birth problems so that pregnancy’s lost, or it causes no problems

  •          USUALLY, this is NOT a susceptible time for teratogens

Ø       Weeks 3-12-very susceptible time………..

Ø       CNS, EYES, & EXT. GENITALS-susceptible during entirety of pregnancy

Ø       Other organ systems, heart, arms…etc..susceptible until about the 8th week

Ø       Palate is susceptible from 6-12 weeks

Ø       CNS, brain mostly, is actually susceptible until 5th year of life

TIME and DOSAGE of exposure as well as GENOTYPES of mom and baby are important factors

  •          Mechanisms of fetal damage are varied-could be placental, related to thrombosis & vasculititis, viral, etc….
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TERATOGENS: infectious, chemical, maternal, radiation…….know mechanisms

 

THALIDOMIDE-results in phocomelia, defective dev. of arms and/or legs

  •          21-35 days-bad time to be affected b/c that’s when you get arm and leg buds
  •          shows specificity of time-baby’s arms can be affected, and legs unaffected, if exposure is time-confined
  •          was thought to be specific for limbs, but also affects other systems
  •          marked originally for morning sickness and was just re-marketed(Celgen) as a tranquilizer and for leprosy

 

ALCOHOL-concomitant w/ stillbirths, spontaneous abortions, and Fetal Alcohol Syndrome (FAS)

FAS-1/1000 live births, 1/100-750 in Native Amer.

  •          costs $320mil/yr for recognized cases-think of Health Care and schooling
  •          babies born small, and remain small, can have microcephaly(small head), extra epicantric folds(side eye-skin fold), small palpebral fissures, small mouth, micrognanthia, congenital heart disease, and mental retardation/hyperactivity
  •          Again: depressed nasal bridge, extra epicantic folds, short nose, upturned nose, smooth philtrum, thin upper lip
  •          Brain anomalies: thought to be b/c aberrant neural & glial tissue migration so there’s cerebellar dysplasia and heterotopic cell cluster abnormalities-brain exposure to alcohol causes abnormal development
  •          Problem is thought to be related to breakdown products of alcohol-acetaldehyde levels
  •          Higher acetaldehyde levels are high in mothers of FAS babes-not always seen w/ chronic alcoholics causes they the genes required to metabolize alcohol differently
  •          How much alcohol during pregnancy is safe? NONE-even <2 per day shows FAS symptoms; increasing your intake increases chances of FAS babe

 

COCAINE-most commonly crack-relatively common, approx. 15%

  •          causes prematurity, or placental abruption, then prematurity; prematurity = underdeveloped lungs, eyes, brain
  •          can see microcephaly, and thus small brain, and thus learning disabilities
  •          can see intestinal atresias, cardiac anomalies, limb reduction defects, and the MOST COMMON ANOMALY, urinary tract abnormalities
  •          Long Term Effects: CNS abnormalities leading to neuro-behavioral abnormalities

 

DIETHYLSTILBESTEROL(DES)-synthetic hormone given in 40s/50s for women w/ bleeding & threatening miscarriage

  •          originally seen as problem causing adenocarcinoma of the vagina in female offspring at a earlier-than-normal age…19
  •          DES is seen to cause vaginal adenosis-abnormal cells present at birth, but not present ‘til approx 21 yrs later
  •          Males can get genital tract problems: decrease sperm # and motility, increased # of abnormal sperm

 

RUBELLA syndrome-triad composed of cataracts, congenital heart defects, & microcephaly

  •          Rubella virus attack back of eye and inner ear specifically, causing retinopathy and hearing loss respectively
  •          almost no time during pregnancy is safe from this virus

 

HERPES I & II-both affected by stress-II lives on neural ganglia, can traverse out & cause it’s problems, then unnoticed

  •          baby severely affected during birth via birth canal-is less of a problem for babes w/ only transplacental infection
  •          babe’s affected via birth canal can have CNS abnormalities b/c the virus likes to attack the brain-can lead to convulsions, encephalitis, hepatosplenomegaly, and often, these children die
  •          Herpes II: older are more likely to get it; smarter and richer more likely-so the lady says-what a drag eh?

 

TOXOPLAMOSIS-protozoan-50-80% US woman are susceptible to 1o infection; 2o infection usually not a problem

  •          approx. 1/1000 births
  •          infection from eating raw meat, contaminated soil, unwashed veggies-lettuce, and cysts in undercooked meat-pregnant women should not eat pork, or uncooked or undercooked steak

 

TORCH Screen: Toxoplasmosis, Other, Rubella, Cytomegalo, Herpes

 

Ampetamines, bendictine, clomid, LSD, and tofranil are not known teratogens

 

PKU, thyroid diseases, increased androgens-can cause masculinization in female fetus

  •          mom w/ untreated PKU can have mentally retarded, underdeveloped, children
  •          mom w/ bicornate uterus-baby can have deformations and positional abnormalities

 

RADIATION-high doses, over 100R can cause skeletal malformations, microcephaly, congenital heart defects

  •          fetus’s chance of leukemia can increase 2 fold when exposed in utero