LC Exam 2: Birth defects Flashcards
Causes of birth defects
Infection: ToRCHES
Maternal dz: PKU, DM
Drugs: EtOH, folic antag, tetraogens
Most: multifactorial and unknown
Size cutoff for placental transport
<500 Da
Classifications of anomalies
Malformations: intrinsically abnml development process
Deformations: mechanical compression/restriction
Disruptions: destruction of developing tissue
DiGeorge abnormalities
22q11.2 CATCH-22 Cardiac abmnl (tetraology: Pass HOV) Abnml face Thymic hypoplasia Cleft palate Hypocalcemia **isotretinoin = phenocopy, +small ears, TBX-1 inhibition**
Developmental field
Group of tissues that respond as single developmental unit
Can be similar gene expression, location, timing, or processes
VACTERL association
Vertebral Anal atresia Cardiac Tracheal/Esophageal Renal Limb
Rubella infection by trimester
1st: cardiac, deafness, retionpathy/cataracts
2nd: cataracts, inflammatory/destuctive lesions
3rd: inflammatory/destuctive lesions
Neural tube defects: multifactorial
Single gene defects Chr d/o Tertaogen Amniotic bands Folic acid (diet, MTHFR gene, methotrexate)
Targeted screening
Screen with hx
Examine highest risk group for rare dz
Population screening
Whole pop
Can opt out
Screening vs. diagnosis
Screening identifies risk, need for dx
Diagnosis test is gold standard, definitive answer
Estimating GA: US
Screening test
Low, low risk
More accurate earlier in pregnancy
After 20 days, can be off by 2-3 weeks
Measurement for GA
Crown-rump length
Does Molly like tacos?
Text 720-947-9469 to find out (message: Does Molly like tacos)
Cervical length helps to predict what?
Preterm birth - shorter = higher risk
Possible with bimanual
More specific with US
Cervical shape changes on US
T rust
Y our
V aginal
U ltrasound
Good US age estimations in 2nd trimester
Biparietal diameter
Abdominal circumference
Femur length
Good US age estimations in 1st trimester
Gestational sac measurement
CRL
Placenta location can help locate
NTD serum markers
Elevated MS-AFP (main dx. marker)
Normal uE3 and HCG
Trisomy 21 serum markers
Decreased MS-AFP Decreased uE3 Increased HCG Increased inhibin A Decreased PAPP-A
Trisomy 18 serum markers
Decreased MS-AFP
Decreased uE3
Decreased HCG
Decreased PAPP-A
Trisomy 13 serum markers
Decreased PAPP-A
Cell free DNA testing advantages
Non-invasive, no miscarrage risk
High sen/spe
Available after 10 weeks
Good for aneuploidy
Screening vs. diagnosis
Screening identifies risk, need for dx
Diagnosis test is gold standard, definitive answer
