Fetal Diagnostic Testing (unit 3) Flashcards Preview

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1

diagnostic testing

•used to evaluate fetus for genetic/congenital disorders
•genetic screening, amniocentesis, etc

2

antepartum testing

•done AFTER problem is detected and goal is to evaluate how fetus is tolerating
•NST, kick counts, U/S, etc

3

ultrasound

•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

best U/S for viewing internal organs

•2D

5

biggest risk of U/S

•missing something

6

benefit of 3D U/S

•identifying cleft lift and palate

7

standard U/S

•general survey of fetus, amniotic fld.

8

specialized U/S when...

•abnormalities exist on basic U/S
•MSAFP
*hx of congenital abnormality

9

limited U/S when...

•need specific info needed
•emergency
•testing BPP, AFI, fetal weight, fetal position, confirmation of cardiac activity

10

1st trimester U/S

•transvaginal- uterus, gest. sac (6-8 wk), embryo
•used to
-detect ectopic (transvag)
-multifetal
-confirmation (FHR @ 6-7 wk)
-gestational age (BPD)

11

2nd trimester U/S

*standard U/S
•trasnabdominal
•confirm GA/fetal viability
•evaluate fetal anatomy
•locate placenta
•detect congenital abnormalities
•assist w/ PUB or amnio

12

3rd trimester U/S

•confirm viability
•detect macrosomia/IUGR
•fetal position
•AFV, fetal breathing/activity
•amnio or BPP

13

fetal sex determination via U/S

•after 18 wks

14

GA assessment via U/S

•most accurate if done early (1st trimester)

15

how does 2nd trimester U/S compare to LMP

•not very accurate at that point b/c there can be a difference of 1-2 wks

16

when is crown to rump embryo length most accurate

•7-12 wk

17

positioning U/S

•wedge under hip in late trimesters
•lithotomy for transvag

18

screening tells us...

•there is a RISK of an issue

19

diagnostic tells us...

•there IS an issue

20

Alpha-Fetoprotein Screening (MSAFP)

•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

MSAFP anomalies

•80% open NTD and open abd wall defects
•33% trisomy 21

22

factors that influence MSAFP results

•GA (validity affected if really off on dates)
•maternal weights
•race
•maternal dz

23

what does MSFP detect

•spina bifida
•ancephaly

24

anecephaly

•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