Fetal Diagnostic Testing (unit 3) Flashcards
1
Q
diagnostic testing
A
- used to evaluate fetus for genetic/congenital disorders
* genetic screening, amniocentesis, etc
2
Q
antepartum testing
A
- done AFTER problem is detected and goal is to evaluate how fetus is tolerating
- NST, kick counts, U/S, etc
3
Q
ultrasound
A
•produces image based on echos
•visualization of fetus and surrounding structures
•dark spots= fluid
•white spots= tissue
•transabdominal or transvaginal
*need full bladder for transabd. if < 20 wk
4
Q
best U/S for viewing internal organs
A
•2D
5
Q
biggest risk of U/S
A
•missing something
6
Q
benefit of 3D U/S
A
•identifying cleft lift and palate
7
Q
standard U/S
A
•general survey of fetus, amniotic fld.
8
Q
specialized U/S when…
A
•abnormalities exist on basic U/S
•MSAFP
*hx of congenital abnormality
9
Q
limited U/S when…
A
- need specific info needed
- emergency
- testing BPP, AFI, fetal weight, fetal position, confirmation of cardiac activity
10
Q
1st trimester U/S
A
•transvaginal- uterus, gest. sac (6-8 wk), embryo •used to -detect ectopic (transvag) -multifetal -confirmation (FHR @ 6-7 wk) -gestational age (BPD)
11
Q
2nd trimester U/S
A
*standard U/S •trasnabdominal •confirm GA/fetal viability •evaluate fetal anatomy •locate placenta •detect congenital abnormalities •assist w/ PUB or amnio
12
Q
3rd trimester U/S
A
- confirm viability
- detect macrosomia/IUGR
- fetal position
- AFV, fetal breathing/activity
- amnio or BPP
13
Q
fetal sex determination via U/S
A
•after 18 wks
14
Q
GA assessment via U/S
A
•most accurate if done early (1st trimester)
15
Q
how does 2nd trimester U/S compare to LMP
A
•not very accurate at that point b/c there can be a difference of 1-2 wks
16
Q
when is crown to rump embryo length most accurate
A
•7-12 wk
17
Q
positioning U/S
A
- wedge under hip in late trimesters
* lithotomy for transvag
18
Q
screening tells us…
A
•there is a RISK of an issue
19
Q
diagnostic tells us…
A
•there IS an issue
20
Q
Alpha-Fetoprotein Screening (MSAFP)
A
•fetal liver protein (AFP) produced in predictable amnt. until 20 wks
•maternal serum tested for anomolies @ 16-18 wks
*key mom blood determinant screening
21
Q
MSAFP anomalies
A
- 80% open NTD and open abd wall defects
* 33% trisomy 21
22
Q
factors that influence MSAFP results
A
- GA (validity affected if really off on dates)
- maternal weights
- race
- maternal dz
23
Q
what does MSFP detect
A
- spina bifida
* ancephaly
24
Q
anecephaly
A
- no brain
- folic acid supp prevent
- 95% fatal
- organ donor
25
triple marker test
* MSAFP+hCG+Estriol
* 80% detection ONTD
* 60% detection trisomy 21
* 50% detection trisomy 18
26
quad screen
•maternal AFT (fetal liver protein)
•hCG (placenta hormone)
•unconjugated estriol (uE3)- fetus/placenta protein
•inhibin A (ovaries/placenta protein)
*anomalies associated w/ preterm, IUGR, preeclampsia, fetal loss
27
nunchal transluscency
* 1st trimester screening (10.5-13.5 wk)
* looking for free hCG/PAPP-A levels
* combined w/ fld. collection from fetus neck
* screening test- NOT diagnostic
28
elevated AFP d/t...
* **open neural tube defect
* mutifetal gestation
* abd. wall defect
* renal anomalies
* maternal IDDM
29
low AFP d/t...
* overestimation of GA
* trisomy 21
* hydatiform mole
30
what happens if MSAFP abnormal
* lots of false neg. so need further/other testing
| * further testing w/ specialized U/S, genetic specialists, etc
31
amniocentesis
```
•needle inserted into uterus and amniotic fld. withdrawn
•used if
-maternal age > 35
-family/past hx of genetic disorder
-abnormal AFP/EDC
-PG after 3+ SAb
*done after 14 wk
```
32
risks w/ amniocentesis
* ROM, labor, miscarriage
* fetal cord injury
* infection
* abruption
* fetal death (rare)
* Rh isoimmunization
* amniotic fld. embolism
33
what amniocentesis detects
* fetal karyotype
* fetal AFP or AChE
* fetal Rh sensitization
34
3rd trimester amniocentesis
* assess fetal lung maturity if delivery considered before 38 wks
* diagnose fetal hemolytic dz d/t maternal Rh sensitization
35
fetal lung maturity
* L/S 2:1 (3:1 in diabetic mom) AND PG positive = mature
| * PG neg = RDS
36
diagnosing fetal hemolytic dz
* done if mom antibody 1:8 or more
| * high levels of bili in amnio fld. if positive
37
RN consideration amniocentesis
```
•supine w/ hip wedge
•bladder EMPTY
•monitor fetal status
***Rhogam after if needed
•karyotype takes weeks
•educate s/sx of infection/bleeding
•encourage fld intake
```
38
chronic villus sampling
* 1st tri alternative to amniocentesis
* genetic testing @ 10-12 wks (earliest)
* sample from fetal placenta
* higher risk than amnio (limb defect)
* need FULL bladder
* Rhogam post procedure if Rh-
* transabdominal or transvaginal
39
Percutaneous umbilical blood sampling (PUBS)
•collecting fetal blood by fetoscope via umbilical vein under U/S guidance
*normally have to do in OR b/c often have to get baby out ASAP
40
indications for PUBS
* blood/chromosomal disorders
| * evaluate isoimmune fetal hemolytic anemia/need for transfusion
41
Cordocentesis (blood studies)
* PUBS method
* Kleihaur Betke test- ensures blood from fetus
* CBC
* IC for Rh
* blood gases
* karyotyping
42
PUBS risks
* preterm labor
* amnionitis
* cord laceration
43
third trimester testing
* goal to evaluate whether intrauterine environment is supportive to fetus
* if not, deliver baby ASAP
44
nonstress test (NST)
```
•primary means of EFM fetal surveillance if increased risk of UPI
•used if
-IDDM mom
-PIH
-IUGR
-previous stillbirth
-post term
-dec. fetal movement
*report as reactive or non-reactive
```
45
healthy fetus w/ intact CNS will have...
* accels w/ movement
| * indicates CNS fxn
46
reason for NST false non-reactive
* fetal immaturity
* sleep cycles
* medications
* chronic smoking
47
Reactive (normal) NST
•normal FHR w/ avg. variability
•> 32 wk- at least 2 FHR acc. of 15 bpm lasting 15 sec w/in 20 min
•28-32 wk- at least 2 FHR acc of 10 bpm lasting 10 sec w/in 20 min
*may have to wake baby w/ vibroaccoustic stim
48
Non-reactive (abnormal) NST
•doesn't meet FHR acc. criteria in 2 attempts (40 min)
•requires further testing in L&D
-CST or BPP
•may have to induce
49
contraction stress test (CST)
```
•assesses FHR response to stress
•requires EFM and induction of ctx
-pitocin
-nipple stimulation
•more accurate than NST
*invasive
```
50
negative (normal) CST
•no late decelerations
•minimum of 3 tx for 40-60 sec duration over 10 min
*reassurance that fetus will likely survive labor and that labor will occur in 1 wk
51
positive (abnormal) CST
•late decels in 50% of > ctx
•indicates UPI
•requires induction/c-section (baby out ASAP)
*POSITIVE=PROBLEMS
52
CST contraindications
```
•preterm
•placental malplacement
•multiple gestation
•prior C/S w/ classic incision (vertical)
-r/o uterine rupture
```
53
biophysical profile (BPP)
```
•U/S and EFM
•accurate indicator of impending fetal death
•5 parameters
-FHR (NST)
-fetal breathing movements
-fetal tone
-amniotic fld. vol. (AFV)
*less invasive than CST
```
54
fetal hypoxia leads to...
•alteration in movement, breathing, HR
55
scoring of BPP
```
•0 OR 2 for each of the 4 parameters
-FHR (NST)
-fetal breathing movements
-fetal tone
-amniotic fld. vol. (AFV)
•normal indicates CNS fxn and no hypoxia
•abnormal and low fld. means labor needs to be induced
```
56
BPP numerical interpretations
* 8/8- normal BPP didn't do NST
* 8/10- normal BPP and non-reactive NST
* 10/10-normal BPP and reactive NST
57
equivocal BPP
6
| *repeat 24 hr
58
abnormal BPP
4 or less
| *induce/c-section
59
amniotic fluid index (AFI)
* fluid pocket measurement
| * detects polyhydramnios & oligohydramnios
60
polyhydramnios
```
•AFI > 25
•d/t
-NTD
-GI obstruction
-twins
-hydrops
-DM
*r/o PTL, ROM -> cord prolapse
```
61
oligohydramnios
```
•AFI < 5
•associated w/ ROM
•r/o
-renal abnormalities
-IUGR
-cord compression
-deformity
-hypoplastic lungs
```
62
doppler blood flow analysis
•see how well baby being perfused
63
fetal kick count instructions
•eat
•lay on side peacefully
*should feel 10 movements in 2 hrs
*no move w/in 12 hrs warrants further testing
