OB assessment

1. Diagnostic Fetal Assessment
tests
Sandy Warner RNC-OB, MSN
August 3, 2011
Inpatient Review Class

2. Prenatal Assessments and
screening
 Chorionic Villous sampling:
 10-12 wk using U/S to aspirate
trophoblastic tissue
 Can be done either transabdominally or
transvaginally
 Detects chromosome abnormality
 Risks: miscarriage, bleeding, infection &
PROM

3. Prenatal Assessments and
screening cont.
 Triple or Quad Screen
 Blood drawn between 15-20 wks
 Can detect Down’s syndrome, other
chromosomal abnormalities and neural
tube defects
 Values of blood tests added together to
determine risk
 Screening tool – further testing needed for
definitive diagnosis

4. Ultrasound
 Developed in WWII with submarines
 Diagnostic use since 1950s
 Definition: transmission of sound
waves to investigate an object
 (Kline-Fath & Bitters, 2007)

6. Placental grading
 Grade 0 – smooth, dense w/o
echogenic areas
 Grade 1 – undulations present, some
echogenic areas
 Grade 2 – deeper and > indentations,
more echogenic areas
 Grade 3 – dense echogenic areas w/
indentations, areas of calcification

8. Amniocentesis
 Trans-abdominal needle aspiration of
10-20 ml of amniotic fluid for lab
analysis
 Done under ultrasound
 Requires sterile technique and time out

9. Amniocentesis
 Indications:
 Genetic
 R/O infection
 Fetal lung maturity
 Assess for bilirubin with hemolytic
incompatibility

10. Amniocentesis
 Timing:
 Early – performed between 11-14 wks
 Significantly higher pregnancy loss
 Post procedure fluid loss
 2nd trimester – performed between 15-20 wks
 Usually for genetic screening
 3rd trimester
 Usually for fetal lung maturity
 (Gilbert, 4th edition, pg 93)

11. Cordocentesis /
Fetal Blood Transfusion
 Blood Transfusion for
anemia
 How much blood is
given?
 Graph is used correlating
the hematocrit of donor
blood to the hematocrit of
the fetus to determine
donor blood volume to be
given

12. Cordocentesis /
Fetal Blood Transfusion

13. Amnioreduction
 Reduces amount of amniotic fluid
around fetus
 Procedure like amniocentesis only with
tubing to suction canister or stopcock
 Done to relieve maternal symptoms or
with twin to twin transfusion syndrome

14. Amnioreduction

15. Fetal MRI
 Superior soft tissue contrast test
 Does not use radiation
 Used for fetal brain, spinal deformities,
lesions, masses
 Also can assess placental and cord malformations
 Also used to measure lung volume
 Research still continuing for PPROM pts
 (Kline-Fath & Bitters, 2007)

16. Fetal MRI Con’t
 Not recommended in first trimester
(no documented studies on harm
from heat or sound, but not recommended)
 Not used routinely, only after U/S not able to detect
 Contrast dye not recommended
 Informed consent
 (Kline-Fath & Bitters, 2007)

17. Fetal Echocardiogram
 Timing: between 18-22 weeks
 Indications:
 Family history congenital heart defects
 Maternal diabetes
 Drug exposure
 Teratogenic exposure
 Chromosomal abnormalities
 Non-immune hydrops
 Maternal PKU
 Fetal arrhythmias
 Queenan, Hobbins & Spong (4th edition, 2007)

18. Vibroaccoustic Stimulation (VAS)
 Artificial acoustic stimulation
 Done after 25 wks gestation when fetus can hear
 After 10 minutes of baseline and no
accelerations, place the artificial larynx on the
maternal abdomen over the fetal head

19. Vibroaccoustic Stimulation
 Provide 5-10 sec stimulation near fetal
head, wait one minute
 If no acceleration repeat cycle for a
total of three times
 if non-reactive after 40 minutes,
proceed with further evaluation

20. Vibroaccoustic Stimulation
 Fetuses 28 weeks or greater respond
to VAS with a consistent increase in
heart rate.
 Observed changes are greater as term
is approached.

21. Vibroaccoustic Stimulation
(VAS)

22. References
 Gilbert, E. S., (2011) 5th edition Manual of High Risk
Pregnancy and Delivery.
 Kline-Fath, B. & Bitters, C. (2007) “Prenatal Imaging”
Newborn and Infant Nursing Reviews, Vol.7, No. 4.
 Mattson, S. & Smith, J.E., (2011) 4th edition Core
Curriculum for Maternal-Newborn Nursing.
 Queenan, J.T., Hobbins, J. C., & Spong, C. Y. (2005)
4th edition, Protocols for High-Risk Pregnancies