40. Detection of fetal distress during labor Flashcards
how is auscultation of the FHR performed?
by listening from the beginning of one contraction to the beginning of the next contraction.
Repeat q30 min’ in the first stage of labor, q15 min’ in the second stage of labor, and up to q5 min’ in high-risk pregnancies.
what is a cardiotocography (CTG)?
Continuous electronic fetal heart rate monitoring
Fetal heart rate is analyzed against a uterine contraction recording.
Used to monitor fetal well-being during labor.
what is the frequency of doing a CTG during labor?
q30 min’ in the first stage of labor, q15 min’ in the second stage of labor, q5 min’ or continuous monitoring in high-risk pregnancies.
how is direct monitoring (invasive, internal) carried out?
by placing an electrode onto the fetal scalp to monitor heart rate, and inserting a transcervical catheter to monitor uterine contractions
how is indirect monitoring (non- invasive, external) carried out?
out by placing two transducers on the external surface of the abdomen, one is placed at the fundus, the other is placed closer to the pelvis
how are normal values on a CTG described?
Reactive NST
Steps of CTG
- baseline assessment- determination of the rate and variability ,FHR 110-160 BPM
- oscillations (variability)
3.Normal accelerations - No decelerations- other than DIP-0 or DIP-I.
Reasons for fetal tachycardia on CTG
FHR > 160 for > 10 min’
chorioamnionitis, maternal dehydration, hyperthyroidism
Reasons for fetal bradycardia on CTG
FHR < 110 for > 3 min’
fetal hypoxia, umbilical cord traction, placental abruption
when can reduced variability (silent CTG pattern) may be seen?
fetal sleep state, hypoxia (acidosis), fetal tachycardia, maternal sedation (drugs), prematurity.
what is the frequencies of normal oscillations (variability)?
frequency > 5 per 1 min’, amplitude 5-25 BPM.
what are normal accelerations (transient frequency increase?
represents fetal movements. FHR increases in response to uterine contractions (normal response). > 2 accelerations in 20 min’, increase by at least 15 BPM and lasts 15 sec’ (15 x 15 rule).
what does DIP-0 indicate?
Episodic contraction independent deceleration.
Due to momentarily umbilical cord traction.
is DIP-0 (spike type) a normal finding?
yes, artefacts from umbilical cord compression .
may be a sign of fetal danger if > 1 deceleration during 20 min’ recording
what causes DIP-I Early deceleration?
head compression → Vagus ↑
Deceleration on the same time of contraction
NORMAL FINDING
what causes DIP-II late deceleration?
(uteroplacental insufficiency). Deceleration onset, maximal fall, and recovery that is shifted to the right in relation to the contraction.
Asynchronous
what does DIP-II indicate?
Fetal danger sign.
FHR drop 15-45 BPM → moderate
FHR drop > 45 BPM → severe
what does DIP-III indicate?
Fetal danger sign.
Duration of deceleration 30-60 s' → moderate Duration of deceleration > 60 s' → severe
what is DIP-III?
Variable deceleration (severe cord compression).
Some decelerations are in the same time of the contraction. Some are not.
what is the management in case of an abnormal (non-reassuring) CTG during delivery?
- Search for the underlying cause and address appropriately when possible.
- In-utero resuscitation → initial interventions, aimed at improving uteroplacental perfusion and maternal/fetal oxygenation
- Administer 100% O2 by face mask.
- Rule-out cord prolapse.
- Consider terbutaline (tocolytic).
- Consider fetal scalp blood pH testing (pH < 7.21 implies fetal asphyxia).
- Procced with immediate delivery if persistent decelerations or fetal pH < 7.2.
In-utero resuscitation interventions in case of an abnormal CTG during delivery
- Reposition: change the woman’s position to the left lateral recumbent position, or if she is already on her side, switch positions to the other side.
- Discontinue or reduce infusion of uterotonic agents (oxytocin) to improve uteroplacental blood flow.
- Increase intravenous fluids by infusing 500-1000 mL of normal saline with 5% dextrose or Ringer lactate solution; ensure adequate intravascular volume and substrate for the fetus and placenta.
Absent baseline variability or Prolonged bradycardia in category III FHR is suggestive of?
severe metabolic dysregulation
Recurrent late decelerations in category III FHR is suggestive of?
↓ uteroplacental blood flow
Recurrent variable decelerations in category III FHR is suggestive of??
umbilical cord compression or decreased amniotic fluid volume
Sinusoidal pattern in category III FHR is suggestive of?
on admission → suggests severe fetal anemia; during labor → suggests fetal bleed
what criteria is predictive of abnormal fetal acid-base status in category III FHR?
- absent baseline variability
- recurrent late decelerations
3.recurrent variable decelerations - prolonged bradycardia
- sinusoidal pattern
what is the approach in cases of category FHR tracing?
delivery within 30 minutes
