Labour Flashcards
What is oestrogen’s role in labour?
Makes the uterus contract and promotes prostaglandin production
What is oxytocin’s role during labour?
Initiates and sustains contractions. It acts on the endometrial lining of the uterus to promote prostaglandin release.
What happens to the number of oxytocin receptors towards the end of pregnancy?
The number increases in myometrial and endometrial tissues.
How does a cervical sweep help to induce labour?
Sweeping fingers round the cervix catches the membranes around the cervix and promotes prostaglandin release.
How is pulmonary surfactant from the foetus involved in labour?
Secreted into amniotic fluid and stimulates prostaglandin synthesis
What happens during the first stage of labour?
Latent phase: 3-4cm dilatation, cervix shortens and softens, mild irregular uterine contractions
Active phase: 4cm onwards dilatation, slow descent of the presenting part, contractions become more rhythmic and stronger
What happens during the second stage of labour?
Starts with complete dilatation of the cervix -> delivery of baby
Should not extend 3 hours, 2 if multiparous
What happens during the third stage of labour?
Delivery of the placenta
On average lasts about 10 minutes
Describe True Labour contractions
Feels like a wave - pain starts low and rises until it peaks and then ebbs away. Abdomen will feel hard during a contraction with the fundus the hardest part. They are evenly spaced with the time between getting shorter as labour progresses
What is the normal foetal position?
Longitudinal lie, cephalic presentation
What is crowning?
Appearance of a large segment of foetal head at the opening of the vagina
What are the five elements that make up the Bishop Score?
Position of cervix Consistency Effacement - thinning of cervix Dilatation Station - in relation to ischial spines
What is the normal amount of blood loss during pregnancy?
Volume less than 500mls
What are the two methods of placental separation?
Matthew Duncan: most common; marginal separation
Schultz: separation from central aspect
How long after birth is normal for placental delivery?
Normally takes 5-10 minutes
Up to 30 minutes is considered normal.
What is etonox?
“gas and air”
50% nitrous oxide
50% oxygen
Used as an analgesic
What is TENS? And where is it administered?
Transcutaneous electrical nerve stimulation
Analgesic effect
Administered T10-L1, S2-4
What is the normal baseline heartrate for the foetus?
100-160bpm
What is the normal baseline variability that should be seen on CTG for the foetus?
5 or more bpm
When would tocolysis be given?
In premature labour situations. Suppresses uterine contractions.
Which position can the mother be put in to prevent vena cava compression?
Lie mother on left side.
What is the normal range for pH foetal blood sampling?
> 7.25
If reached below 7.2 then want to deliver the baby immediately - baby acidotic
What is classed as a term pregnancy?
27-42 weeks
During labour how often are contractions? (i.e. what is normal on a CTG)
4 contractions every 10 minutes
Should last about 1 minute
What causes baseline tachycardia in the foetus?
Maternal infection, increased foetal movements, severe hypoxia, hyperthyroidism, maternal/foetal anaemia
What causes baseline bradycardia in the foetus?
normal in post-dates foetus, epidurals, congenital heart defects.
What can cause reduced foetal baseline variability?
Foetal sleeping, foetal acidosis (from hypoxia), drugs (opiates, benzos), CHD
What is an acceleration on a CTG?
A >15bpm increase in the baseline heart rate for 15 seconds - reassuring alongside uterine contractions.
Describe a variable deceleration on a CTG
Rapid all from baseline with a variable recovery phase. Usually caused by compression of the umbilical cord and so can resolve if the mother changes position