1st Stage of Labour Flashcards
How does the uterus grow during pregnancy?
First 4 months = Hyperplasia (increased organ tissue due to cell proliferation)
Final 5 months = Hypertrophy (increased organ tissue due to cell enlargement)
What are the 2 segments of the uterus called?
Fundus and Isthmus
What is quiescence?
The continuous spontaneous contractibility of uterine muscle while remaining ‘quiet’ (when this becomes stronger = Braxton-Hicks)
When do Braxton-Hicks usually occur?
In the final 6 weeks of pregnancy
What might women notice towards the end of pregnancy?
- Mood swings
- Difficulty walking
- Relief of pressure at the fundus
- Increased pressure in the pelvis
- Nesting
What softens the cervix prior to labour?
- Increased vascularity and water content
- Structural changes in connective tissue
What is effacement?
The shortening and thinning of the cervix by contractions
What is the ‘show’?
The operculum (mucous plug that is seen during effacement or early dilation)
What is assessed using a BISHOP score?
- Station
- Position
- Consistency
- Length
- Dilatation
What does Cortisol do to encourage labour?
Affects and reduces maternal production of progesterone
What does Progesterone do to encourage labour?
Levels decrease (as it inhibits contractions)
What does Oestrogen do to encourage labour?
Levels increase, stimulating oxytocin receptors in the myometrium and encouraging the placenta to release prostaglandins
What do Prostaglandins do to encourage labour?
Ripen the cervix and induce labour
How can prostaglandin synthesis be stimulated?
- Sex
- VE and sweep
- ARM
What does Oxytocin do to encourage labour?
Encourages the uterus to contract
What is the Ferguson’s reflex?
Pressure on the cervix from the PP increases oxytocin production, causing contractions
What does Relaxin do to encourage labour?
Promotes cervical ripening
(but also inhibits contractions and levels are usually low in late pregnancy - high levels are associated with preterm labour)
What are the 3 phases of the 1st stage of labour?
- Latent Phase
- Active Phase
- Transitional Phase
What occurs in the latent phase?
- Cervix dilates up to 4cm
- Effacement
- Irregular contractions
- Can take up to a few days
What occurs in the active phase?
- Regular contractions (approx. 4:10)
- Dilation from 4-10cm (approx. 0.5cm/hr)
What are some common features of the transitional phase?
- Panic and fear
- Nausea
- Heavy show
- Urge to push
- Irritability
- Slowing of contractions
- Asking for more pain relief
What role does Elastin have?
Hormone that enables contraction and retraction and allows the uterus to regain shape after delivery
Where are the contractions strongest?
At the fundus
How do the 2 segments of the uterus work together?
- Upper segment contracts and retracts strongly to expel the foetus
- Lower segment contracts slightly and dilates to allow expulsion
What is the Retraction Ring?
A ridge that forms between the upper and lower segment
What is the Bandl’s Ring?
An exaggerated Retraction Ring located above the symphysis which can be a sign of obstructed labour
What are some external signs of established labour?
- Rocking
- Toe curling
- Purple line
- Mexican hot legs
What is the average duration of 1st stage?
Primip = 8-18 hrs Multip = 5-12 hrs
How can delay in 1st stage be diagnosed?
- <0.5cm per hr
- VE (descent/rotation of foetus)
- Changes in contractions not present
What interventions should be considered if 1st stage is delayed?
- ARM
- Analgesia
- Synto
- More regular VEs
What temperature should the water be for a pool birth?
1st stage = 35-37.5
2nd stage = 36.5-37.5
What is the association between pethidine and pool births?
If IM pethidine is given, you must wait 3-4 hours before the woman gets in to the pool
When should a partogram be commenced?
Onset of established labour (4cm, cont 3-4:10) or when oxytocin is commenced
What should be done if a woman comes into ANDU with a suspected SROM?
- Midwife speculum (if LR)
- Lie down for 30 mins before
- CTG not needed if LR
