prenatal diagnosis, fetal do & fetal therapy Flashcards
3 major categories of diagnostic evaluation
fetus high risk for genetic or congenital do
fetus unknown risk from common congenital abnormalities
fetus discovered utz’ly to have structural or dev’tal abnormalities
comprises 8% of conceptuses
most common cause of congenital defect
aneuploidy
aneuploidy accounts for _% 1st trim abortion & _% of all stillbirths & neonatal death
50% & 5-7%
indications for prompt invasive diagnostic procedure
women >35 y/o at delivery
women who previously carried fetus w/ autosomal trisomy
women or their partners who have chromosomal translocation or carriers of chromosomal inversion
hx of triploidy
repetitive spontaneous 1st trim. abortion
parental aneuploidy
intrinsic abnormality programmed in devt regardless of whether a precise genetic etiology is known
malformation
genetically normal fetus develops abnormally of mechanical forces imposed by uterine mvmt
deformation
more severe changes in form of fx occurs when genetically normal tissue is modified as result of specific insult
disruption
multiple structural or dev’tal abnormalities occurring together in one individual; can have same cause (give 1 ex)
syndrome (trisomy 18)
all anomalies developed sequentially as a result of one initial result (give 1 ex)
sequence (oligohydramnios leading to pulmo hypoplasia, limb contracture & facial deformities)
particular anomalies occur together frequently but do not seem to be linked etiologically (give 1 ex)
association (VATER)
(3) components of combined 1st trim. screening performed during _wks
hCG
PAPP-A
NT on utz
(11 & 14 wks)
what can be offered if NT measurement is at least 3mm or exceeds 99th percentile?
targeted sonography w/ fetal echocardiography
(4) components of quad screening testing performed during _wks
MSAFP hCG inhibin estriol (15-21 wks)
quad screening result in down syndrome
low MSAFP
high hCG
low estriol
high inhibin
women at high risk of pregnancy w/ NTD are offered w/? (2)
targeted sonography and mAFP testing
this marker is a glycoprotein synthesized by YS in early gestation then later on by liver and fetal GIT
AFP
upper limit of normal in MSAFP
2.5 MoM
differentiate screening from diagnostic test
S: provide information not to dictate a course of action
D: provides info that screening does not
conditions associated w/ elevated MSAFP
underestimated GA multifetal gestation fetal death MTD gastroschisis omphalocele cystic hygroma intestinal obstruction liver necrosis renal anomalies cloacal exstrophy OI sacrococcygeal teratoma congenital skin abnormality pilonidal cyst chorioangioma of placenta placenta intervillous thrombosis placental abruption oligohydramnios preeclampsia fetal growth restriction maternal hepatoma or teratoma
low estriol is associated w/ 2 uncommon but important condition
smith-lemli-opitz syndrome
c-linked ichthyosis
differentiate integrated & sequential screening
I: combined 1st trim screening + quad screening; aneuploidy risk is calculated from 7 parameters
S: combined 1st trim screening then inform px w/ result. if the risk is above threshold, she’ll receive counseling and offered dx testing
differentiate stepwise & contingent sequential screening
S: high risk are offered invasive testing and the remaining receive 2nd trim. screening
C: highest risk are offered invasive testing; moderate risk receive 2nd trim. screening; lowest risk & negative result have no further testing
this test works by identifying DNA fragments derived from apoptotic trophoblast and can be performed anytime after _wks?
cell-free dna screening (9-10wks)
if cell-free dna screening is performed as secondary screening, a normal result is reassuring, Tor F?
false (not reassuring)
most common fetal abnormality
cardiac defect
soft signs associated with fetal trisomy 21
aberrant right subclavian artery brachycephaly clinodactyly echogenic bowel echogenic intracardiac focus flat facies nasal bone hypoplasia NT thickening renal pelvis dilation sandal gap shortened ear length single umbilical artery short femur & humerus widened iliac angle
what is considered abnormal measurement of NT?
> 6mm
focal papillary muscle calcification neither structural nor functional cardiac abnormality is associated with?
trisomy 21
bilateral echogenic foci is associated with?
trisomy 13
what is considered abnormal measurement of pelvis dialtion?
> 4mm
bowel that appears as bright as fetal bone
echogenic fetal bowel
classical form of cystic fibrosis
abnormal sweat Cl level chronic pulmo ds pancreatic insufficiency liver ds obstructive azoospermia
most common cause of familial mental retardation
fragile x syndrome
accumulation of GM2 gangliosides in CNS, progressive neurodegeneration, & death
tay-sachs ds
most common prenatal diagnostic proced. w/c involves transabdominal withdrawal of amniotic fluid done bet. 15-20 wks
amniocentesis
initial 1-2mL of fluid aspirated in amniocentesis is either discarded or used for AFP testing, T or F?
true
indications for amniocentesis
fetal genetic do
congenital infx
alloimmunization
assessment of fetal lung maturity
this is performed bet. 10-13 wks w/c involves obtaining chorionic villi transcervically or transabdominally
CVS
this is performed for assessment & treatment of platelet alloimmunization, for analysis of non-immune hydrops, & for fetal karyotype
cordocentesis
involves blastomere biopsy through a hole made in the zona pellucida
pre-implantation genetic diagnosis
most common causes of fetal anemia
red cell alloimmunization
congenital infx
alpha4-thalassemia
fetomaternal hemorrhage
procedures for identification of fetal anemia
cordocentesis
doppler of fetal MCA
detection of unbound antibodies in maternal serum
indirect coombs test
sensitization of D-negative individuals involves a single exposure of at least _mL of fetal erythrocytes
0.1mL
what can be done if titer is below critical value? reached a critical value?
B: repeat titer every 4 wks for duration of pregnancy
R: further evaluation required
chorionic villous is recommended for red cell alloimmunization, T or F?
false (not recomm)
what is the recommended test for detection of fetal anemia?
doppler of fetal MCA
what is the recom. of MCA is 1-1.5 MoM and slope is rising?
weekly doppler interoogation
what is the recom. of MCA is >1.5 MoM and AOG is <34-35 wks?
cordocentesis should be considered & followed by fetal transfusion
mgmt for severe fetal anemia
cordocentesis and fetal transfusion (thru umbilical vein preferably) are generally performed prior to 34-35 wks
peritoneal transfusion can be done in early 2nd trim.
at what hct level is transfusion recomm?
hct <30%
target hct of a non-hydropic fetus?
40-50%
MCA peak systolic velocity threshold for severe anemia
1.70 MoM
anti-D immunoglobulin recomm
postpartum admin. of anti-D immunoglobulin to at risk pregnancies w/in 72 hours of delivery
provision of anti-D immunoglobulin at 28 wks of gestation
prophylactic anti-D immunoglobulin
28 wks of gesttaion then 2nd dose after delivery
this test identifies presence of fetal D-pos cells in circulation of a D-neg women
rosette test
this test is used in D incompatibility or fetomaternal hemorrhage
most commonly used quantitative test for fetal red cells in maternal circulation
kleihauer-betke (KB) test or flow cytometry
IM & IV anti-D immunoglobulin dose
IM: 300 ug or 1500 IU
IV: 2 ampules (totaling 600 ug) every 8 hours
most common cause of severe thrombocytopenia among term newborn
alloimmune thrombocytopenia
empiric trt for alloimmune thrombocytopenia
IVIG & prednisone
recommended type of delivery for alloimmune thrombocytopenia
CS
ds causing rapid dec. in neonatal plt levels after birth w/ nadir at 48-72 hours
ITP
prenatal dx criteria of hydrops fetalis via utz
> 2 fetal effusion
1 effusion + anasarca
severe anemia is defined hgb value of?
<5 g/dL
what is the cause of 90% of cases of hydrops?
non-immune hydrops
dx tests for non-immune hydrops
indirect coombs tets
targeted utz
amniocentesis
kleihauer-betke test
an association bet. fetal hydrops & devt of maternal edema
mirror syndrome
what is triple edema?
fetus, mother, and placenta become edematous
recommended mgmt for mirror syndrome
delivery
HR in fetla tachyarrhythmia & bradyarrhythmia
T: >180 bpm
B: <110 bpm
this is characterized by an abrupt inc in fetal HR to 180-300bpm w/ 1:1 AV concordance
supraventricular tachycardia
most common etiology of pronounce fetal bradycardia
congenital heart block
what can be given for fetus w/ HR of <55bpm?
terbutalline
what can be given for fetus arrhythmia?
digoxin verapamil propanolol procainamide quinidine flecainide sotalol amiodarone
the most common arrhythmia
premature atrial contraction
most common etiology of androgen excess in female
CAhH
typical preventive regimen for CAH
oral dexamethasone
this malformation is a well-circumscribed lung mass that may appear solid & echogenic or may have one or multiple variably sized cysts
congenital cystic adenomatoid malformation
recom. proced. for guiding trt in thyroid ds
cordocentesis
ds w/c appears on utz as splod and/or cystic mass arising from anterior sacrum
sacrococcygeal teratoma
fetoscopic surgery is performed in TTTS at what wks?
16 & 26 wks
LHR prognosis
> 1.35 survival rate is 100%
<0.6 survival rate is 0%
mgmt for congenital diaphragmatic hernia
FETO
components of EXIT proced.
comprehensive pre-op
uterine relaxation
intraoperative utz
placement of stay-suture followed by uterine stapling device
continuous amnioiinfusion
delivery of fetal head, neck, & upper torso
fetal injection of IM vecuronium, fentanyl, atropine
fetal peripheral IV access, pulse ox, cardiac utz
following proced., umbilical lines placed prior to cord clamping
uterotonic agents
mgmt for px w/ prior fetus w/ ICH, but no maternal anti-HPA ab identified
maternal anti-HPA ab screening & crossmatch w/ paternal plt at 12, 24, 32 wks; no trt for negative result
mgmt for px w/ prior fetus w/ thrombocytopenia & maternal anti-HPA ab but no ICH
at 20 wks: IVIG 1g/kg/wk & prednisone 0.5mg/kg/d; or IVIG 2g/kg/wk
at 32 wks: IVIG 2g/kg/wk & prednisone 0.5mg/kg/d continue until delivery
mgmt for px w/ prior fetus w/ 3rd trim. ICH or prior newborn w/ ICH & maternal anti-HPA ab
at 12 wks: IVIG 1g/kg/wk
at 20 wks: either inc. IVIG to 2g/kg/wk or add prednisone 0.5mg/kg/d
at 28 wks: IVIG 2g/kg/wk & prednisone 0.5mg/kg/d continue until delivery
mgmt for px w/ prior fetus w/ ICH prior to 3rd trim. & maternal anti-HPA ab
at 12 wks: IVIG 2g/kg/wk
at 20 wks: add prednisone 1mg/kg/d continue both until delivery
