MFM Flashcards
When is AFP checked
Between 15 and 22 weeks gestation
High AFP causes
Open NTD
GI abn (liver necrosis, esophageal or intestinal obstruction, omphalocele, gastroschisis)
Renal abn
Masses
Multiple gestation
If unexplained elevation - ^risk of IUGR or fetal death
Low AFP causes
Trisomies
Fetal death
Inaccurate GA
Gestational trophoblastic disease
First trimester maternal screen
At 10-13 weeks
PAPP-A
B hCG
Combined with maternal age - detects 60-65% T21
+ nuchal translucency 10-14 weeks
Mat age + PAPP A + BhCG + NT detects 78-89% of T21 and 91% of T18
Abn nuchal translucency risk of aneuploidy
1 in 6
Normal is 0.5mm-2mm; >3mm is abn
Explanations for nuchal translucency:
Cardiac failure
Extracellular matrix abn
Abn lymphatic system
Hygroma testing
50% chance aneuploidy
If euploid 50% with major fetal malformation
If found -> get details US, fetal echo, offer CVS
Quadruple screen
14-20 weeks
AFP
Mat unconjugated estriol
BhCG
Inhibin A
Low AFP, high BhCG, low uE3, high inhibin A
T21 on quad
Detects 75-81%
Low AFP, low BhCG, low uE3, normal inhibin A
T18 quad
Detects 60%
T13 quad
Not helpful
Cell free DNA - obtained when & indications
9 weeks GA
Screening test
^ aneuploidy risk
RhD genotype
Sex identification in X-linked genetic disorders
Risk of CAH
Smith-Lemli-Opitz
Prenatal screen
Low uE3, low AFP, low bhCG
Turner syndrome quad screen
Low AFP, high BhCG, low uE3, high inhibin A if hydrops, low inhibin A if no hydrops
Timing of amnio, CVS, and PUBS
Amnio 15-20 wk
CVS 10-13 wk
PUBS >19 wk
Teratogenic effects:
ACEI
Greatest risk in 2nd & 3rd tri
Oligo, skull hypoplasia, renal tubular dysgenesis
Postnatal hypotension and oliguria
Teratogenic effects:
Alcohol
Worse earlier in gestation
Worse with greater amounts less frequently than chronic small amounts
Abn in 3 areas: physical, growth, neurodevelopment
Teratogenic effects:
Carbamazepine
Craniofacial defects, fingernail hypoplasia, growth restriction
NTD, developmental delay
Decreased placental transfer of vit K