39. Detection of fetal jeopardy during pregnancy

Question 1

what is a Non-stress-test (NST)?

Answer 1

screening test during pregnancy (antenatal period)
Continuous Fetal heart rate (FHR) is recorded and analyzed using external Doppler equipment
The mother reports each fetal movement, and the effects of the fetal movements on the HR is determined

Question 2

Normal baseline FHR is?

Answer 2

110-160BPM (bradycardia < 110, tachycardia > 160)

Question 3

how is an NST measured?

Answer 3

over a 15min period and is described as absent, minimal (<6BPM), moderate (6-25BPM), or marked (>25BPM)

Question 4

Possible causes of absent or minimal variation on an NST?

Answer 4

fetal hypoxia, maternal smoking

Question 5

what is considered RNST?

Answer 5

A normal fetus responds to fetal movement with acceleration in fetal HR of ≥15 BPM above the baseline for at least 15 seconds
* If at least 2 such accelerations (15/15/2) occur in a 20min interval, with moderate variability the fetus is regarded as being healthy and the test is said to be reactive (if baby is < 30 weeks you want 10/10/2 in 20min)

Question 6

Frequency of doing an NST?

Answer 6

35-37 w’ gestation → once weekly
38-39 w’ gestation → every second day or twice weekly
From estimated due date to delivery → repeat daily

Question 7

what is the management of a Abnormal (non-reassuring) NST in the antenatal period?

Answer 7

1. Repeat NST recording for an additional 20 min’.
   2.Measure amniotic fluid index (AFI)
2. Perform umbilical artery Doppler
3. Record FHR in relation to uterine contractions elicited by induced stimulation- VAS or CST
4. Evaluate biophysical profile (BPP)

Question 8

when is Vibro-acoustic stimulation (VAS) used?

Answer 8

vibratory sound stimulus is used to induce FHR accelerations.

Question 9

what is a Contraction stress test (CST)?

Answer 9

contractions are stimulated by IV infusion of diluted oxytocin, or by nipple stimulation (2-minutes self-stimulation through clothes every 5 minutes).

Question 10

what is an biophysical profile (BPP)?

Answer 10

combination of NST and US exam for a total of five components:
1. NST
2. breathing (US- 30 chest wall movements/10min)
3. fetal movements (US-3 body movements/3min)
4. muscle tone
5. AFI
Each has a 0-2 score.

Question 11

scores on a biophysical profile

Answer 11

Score of 8-10 is reassuring,
4-7 is equivocal –> do a contraction stress test (depends on gestational age, if >36 delivery is indicated no need for CST),
< 3 is abnormal (fetal demise)–> Deliver by C-section

Question 12

what does A high systolic/diastolic ratio (S/D) suggest on an umbilical artery doppler?

Answer 12

abnormal flow due to increased vascular resistance within the fetal/placental circulation.
When the flow becomes very abnormal, diastolic flow ceases and there can be reversal flow of from the placenta to the fetus.
If this occurs an emergency c-section is usually indicate.