Obstetrics: Labour Flashcards
What are the three stages of labour?
First stage (Latent) up to 3/4cm dilatation First stage (Active stage): 4cm - 10cm dilatation Second stage: Full dilatation - delivery of the baby Third stage: Delivery of the baby - expulsion of the placenta and membranes
Describe what happens in the first stage of labour
Latent: Mild irregular uterine contraction, cervix shortens and softens. (can last a few days)
Active: 4cm - full dilatation. There is a slow descent of the presenting part and contractions progressively become more rhythmic and stronger.
When is the second stage of labour considered prolonged?
Nulliparous women: 3 hours with regional anaesthesia, 2 hours without
Multiparous women: 2 hours with regional anaesthesia, 1 hour without.
How long on average does the third stage of labour last?
10 minutes
After how long would you wait in the third stage of labour before you started to make preparations for surgical removal?
1 hour
Is the risk of post partum haemmorrhage higher with expectant or active management of the third stage?
Expectant. Active managment is preferred for lowering the risk of PPH.
What is involved in the active management of the third stage of labour?
Oxytocin 10 units Ergometrine 1ml. Cord clamping and cutting Controlled cord traction Bladder emptying Injection of oxytocin directly into the cord.
What is the difference between braxton hicks contractions and labour contractions?
Braxton hicks contractions are irregular and do not increase in frequency or intensity and resolve with ambulation or change in activity.
Labour contractions are evenly spaced and the time between them gets shorter and shorter and the get more intense and painful over time. The cervix also thins in true labour.
What is the normal fetal position before labour?
Longitudinal lie. Cephalic presentation with the presenting part being the vertex. Head is flexed initially in occipito anterior position and then the head engages in occipito transverse.
What five parameters are evaluated when looking at the cervix?
Effacement Dilatation Firmness Position Level of the presenting part
What is the bishops score?
Method of grading the position, consistency, dilatation and station of the fetus in the pelvis in order to determine if it is safe to induce labour.
What does a bishops score of less than 5 tell us?
Labour is unlikely to start without induction.
What does a bishops score of between 5 and 9 tell us?
It is likely that induction will be needed
What does a bishops score of more than 9 tell us?
Labour in likely to commence spontaneously
What are the three classical signs that indicate separation of the placenta?
- Uterus contracts, hardens and rises
- Umbilical cord lengthens permanently
- Gush of blood variable in amount.
What physiological mechanisms are in place to maintain haemostasis in labour?
- Tonic contraction - the lattice pattern of the uterine muscles strangulate the blood vessles
- Thromobosis of the torn vessel ends as pregnancy is a hyper coagulable state.
- Myo tamponade - opposition of the anterior and posterior walls.
How long does it take for the tissues to return to the non pregnant state?
~ 6 weeks
What medications are in an epidural anaesthesia?
Levobupvicaine +/- opiate
What the main side effects of epidural anaesthesia?
- Hypotension
- Atonic bladder
- Dural puncture
- Headache
- Back pain
What level of dilatation suggests that there might be a failure to progress in stage 1 of labour?
Nulliparous: Less than 2cm in 4 hours.
Parous: Less that 2cm in 4 hours or slowing in progress
What are the “three p’s” that can cause a failure to progress in labour?
- Powers (Inadequate contractions)
- Passages (short stature/trauma/shape of pelvis)
- Passenger (Large baby, malposition)
What does a partogram emasure?
Fetal heart Amniotic fluid Cervical dilatation Descent Contractions Obstruction/Moulding Materal observations
When is a partogram started?
As soon as the woman enters the labour ward
How is the fetus monitored in a normal first stage of labour?
Intermiitent auscultation of the fetal heart using a pinard stethescope or a doppler ultrasound immediately after a contraction for at least 1 minute every 15 minutes.
What are the indications for a continuous CTG in labour?
- Maternal pulse over 120 bpm on 2 occasions 30 minutes apart
- Temperature of 38 or above on a single reading or above 37.5 on 2 consecutive occasions 1 hour apart.
- Suspected chorioamniotitis or sepsis
- Pain that is different from the pain usually associated with contractions
- Pre term/post dates
- Hypertenion/Pre eclampsia
- Induction
- Epidural
- Diabetes
What is chorioamnionitis?
Inflammation of the fetal membranes (amnion + chrion) due to bacterial infection. It is most associated with prolonged labour and the risk in increased with each vaginal examination that is performed in the final month of pregnancy.
A woman who has had a prolonged labour has a temperature of 39 degrees, a heart rate of 120bpm, a very tender uterus and has passed fouls melling amniotic fluid. What are you worried about?
Chorioamnionitis
How is the fetus monitored in the second stage of a normal labour?
Every 5 minutes during and after a contraction for 1 minute and check maternal pulse at least every 15 minutes.