8- Complicated pregnancy (complicated labour) Flashcards
cardiotocography (CTG) measures
o Fetal heart rate
o Uterine contractions
when are CTGs used
in third trimester of complicated pregnancies
how are readings obtained for CTG
1) 2 transducers on pregnant abdomen
- Purple- fetal heart rate (placed on anterior shoulder of foetus)
- Pink- uterine contraction (measures tension of abdominal wall)
2)Mother also presses a button when she feels fetal movements
Interpreting CTG
- Top trace- fetal heart trace
- Middle- when women feels fetal movement
- Bottom- tocometry trace
CTG divided into 10 minute blocks represented by 10 small boxes
Interpreting CTG
- Top trace- fetal heart trace
- Middle- when women feels fetal movement
- Bottom- tocometry trace
CTG divided into 10 minute blocks represented by 10 small boxes
Interpreting CTG
DR C BRAVADO
define risk
Assessing risk factors of pregnancy i.e. high risk or low risk
Examples:
- Meconium stained liquor
- Fever
- IUGR
contractions
frequency
duration
freqeucny of contractions
Baseline rate
average heart rate of the fetus
normal FHR
110-160 bpm
fetal tachy
> 160bpm
Causes
- Fetal hypoxia
- Chorionamnionitis (take temp of mum)
variability
beat to beat variability
- From 5-25 BPM= normal
-E.g. Good variation:
bad variation
bad variation= minimal variation
causes of decreased variability
- Sleep (should be shorter than 40 mins)
- Drugs e.g. opiate/ mag sulphate
- Fetal hypoxia
accelerations
- Increase in FHR by >15 bpm for >15s
- sign of a healthy fetus
decelerations
Reduced fetal heart rate by more than >15bpm for >15s
Split into:
1) Early
2) Variable
3) Late
early decelerations
Trough of deceleration coincides with peak of contraction
* Secondary to head compression – physiological and not pathological
variable decelerations
- Most common type
- Vary in shape, form and timing in relation to contractions
- Cause: umbilical cord compression
- Concerning characteristics
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o Lasting >60s
o Biphasic shape (W shape)
o No shouldering – sign foetus is compensating well
o Reduced baseline variability within deceleration
o Failure to return to baseline
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late decels
- Starts after the contraction begins and persists after the contraction ends
- Secondary to
~~~
o Maternal hypotension
o Pre-eclampsia
o Uterine hyperstimulation
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Overall assessment
- Normal
- Suspicious: a single non-reassuring feature
- Pathological: two non-reassuring features or a single abnormal feature
- Need for urgent intervention: acute bradycardia or prolonged deceleration of more than 3 minutes
The outcome of the CTG will guide management, such as:
- Escalating to a senior midwife and obstetrician
- Further assessment for possible causes, such as uterine hyperstimulation, maternal hypotension and cord prolapse
- Conservative interventions such as repositioning the mother or giving IV fluids for hypotension
- Fetal scalp stimulation (an acceleration in response to stimulation is a reassuring sign)
- Fetal scalp blood sampling to test for fetal acidosis
- Delivery of the baby (e.g. instrumental delivery or emergency caesarean section)
management of fetal bradycardia
Fetal Bradycardia
There is a “rule of 3’s” for fetal bradycardia when they are prolonged:
- 3 minutes – call for help
- 6 minutes – move to theatre
- 9 minutes – prepare for delivery
- 12 minutes – deliver the baby (by 15 minutes)
physiology of fetal hypoxia: COMPENSATED RESPONSE
fetus is unable to increase RR. Therefore a number of adaptations to decrease myocardial workload to reduced the amount of oxygen required:
1) Reduced fetal heart rate causing deceleration
- decreases myocardial workload to use less oxyegn
2) Reduced movement to reduce heart rate
3) Release of catecholamines- conserves oxygen
* Increase HR to get oxygenated blood from placenta
* Peripheral vasoconstriction redistribute blood
* Glycogenolysis to increase energy supply
THIS IS A COMPENSATED RESPONSE- HOWEVER THIS CANNOT LAST FOREVER
physiology of hypoxia : DECOMPENSATED
Compensation cannot last forever
1) Hypoxia to brain
- Loss of baseline FHR variability
2) Myocardial hypoxia and acidosis
- Unstable baseline
- Stepwise pattern to death
ABCE approach to predict next change in CTG
complications in labour
1) premature labour
2) failure to progress
3) malpresention/ malposition
3) fetal distress
4) VBAC
5) Shoulder dystocia
premature labour definitions
Rupture of membranes (ROM): The amniotic sac has ruptured.
Spontaneous rupture of membranes (SROM): The amniotic sac has ruptured spontaneously.
Prelabour rupture of membranes (PROM): The amniotic sac has ruptured before the onset of labour.
Preterm prelabour rupture of membranes (P‑PROM): The amniotic sac has ruptured before the onset of labour and before 37 weeks gestation (preterm).
Prolonged rupture of membranes(also PROM): The amniotic sac ruptures more than 18 hours before delivery.
define prematurity
birth before 37 weeks gestation
babies are considered non-viable below
23 weeks gestation
- at 23 weeks 10% chance of survival
- 24 weeks onwars- increased chance of survival- full resus offered
prophylaxis of preterm labour
1) Vaginal progesterone
2) Cervical cerclage
vagianl progesterone prophylaxis: MOA
Offered to women with a cervical length less than 24mm on vaginal US between 16 and 24 weeks
Given vaginally
- maintains pregnancy
- prevents labour by decreasing activity of the myometry and preventing cervix remodelling