2nd Stage of Labour Flashcards
What is the definition of the second stage of labour?
From complete dilation of the cervix to the complete birth of the baby
When does transition occur?
At the end of the first stage at around 8-9cm dilation
List SIX behavioural changes that may occur during transition?
- Less inhibited, may take clothes off
- Language becomes more earthy
- Can get easily irritated
- Gets more sweaty
- May express doubts or become more focused
- May become afraid or impatient and just want it over
Name SEVEN indications of the active second stage
- Involuntary maternal effort
- Expulsive contractions
- Baby is visible in the introitus
- Woman says the baby is coming despite any observations you have taken to the contrary
- Bulging vulva
- Pouting anus
- Rupture of membranes
What happens during the latent part of the second stage?
Contractions may ease off allowing the woman to rest a little before stronger, expulsive contractions start
What is the Ferguson Reflex?
When the descending head creates pressure which stimulates nerve receptors in the pelvic floor. This triggers a surge of oxytocin, resulting in increased contractions and the urge to push
What happens to the bladder during the second stage?
It is pushed upwards into the abdomen and the urethra becomes stretched
What happens to the rectum during the second stage?
Gets pushed in to the curve of the sacrum
For the pelvic brim, how many cm are the following diameters:
Antero-posterior
Right & Left Oblique
Transverse
Antero-posterior: 11cm
Right & Left Oblique: 12cm
Transverse: 13cm
For the pelvic cavity, how many cm are the following diameters:
Antero-posterior
Right & Left Oblique
Transverse
Antero-posterior: 12cm
Right & Left Oblique: 12cm
Transverse: 12cm
For the pelvic outlet, how many cm are the following diameters:
Antero-posterior
Right & Left Oblique
Transverse
Antero-posterior: 13cm
Right & Left Oblique: 12cm
Transverse: 11cm
How long are the submentobregmatic diameters of the fetal skull?
9.5cm
How long is the mentovertical diameter of the fetal skull?
13.5cm
How long is the suboccipitobregmatic diameter of the fetal skull?
9.5cm
How long is the occipitofrontal diameter of the fetal skull?
11.5cm
How long is the suboccipitofrontal diameter of the fetal skull?
10cm
What is meant by the mechanism of labour?
Refers to the mechanism by which the baby negotiates the birth canal
What causes flexion of the fetal head during descent?
As the head meets the resistance of the birth canal the occiput is pushed lower and the forehead is pushed up
What causes internal rotation and how much does it rotate?
The resistance of the pelvic floor causes the head to rotate 45 degrees or 1/8th of a circle
Name the EIGHT stages of the second stage
- Descent
- Flexion
- Internal rotation
- Crowning
- Extension
- Restitution
- Internal rotation of the shoulders
- Lateral flexion
What happens during restitution?
The baby untwists, moving the head back 1/8 to where it began, allowing the head and body to reallign
What happens during lateral flexion?
The anterior shoulder is born under the pubic arch and the posterior shoulder passes over the perineum
What is the “val salva” manoeuvre?
When the women is encouraged to push with her chin on her chest and holding her breath. Increases intra thoracic pressure and aims to push the baby down towards the rectum and through the birth canal
What is meant by physiological pushing?
Works with the boy’s natural rhythmic pushing is short lasting and doesn’t involve sustained holding of breath
What issues may arise from the val salva manoeuvre?
Decreases level of O2 to the baby and increases risk of bursting peripheral blood vessels
What issues may arise from physiological pushing?
Can take time for the women to get into and may be difficult if lying in the supine position
What are the benefits of a hands on approach?
The midwife can support the perineum, help flex the head and help ease the perineum over the presenting part.
The midwife can also use an anal pad and check for a cord around baby’s neck.
What are the benefits of a hands off approach?
Allows mum to feel in more control with the midwife verbally guiding her through pushing and allowing mum to pick up the baby herself once it is delivered
How often do NICE recommend that the frequency and strength of contractions should be recorded?
Every half an hour
How often should the frequency and strength of contractions be recorded in the Scottish handheld notes partogram?
Every 10 minutes
How often do NICE recommend vaginal examinations should be conducted during labour?
Hourly
What is a caput band why can it give in inaccurate assessment of descent?
The baby’s head can bulge a little into the cervix if mum is pushing before the cervix is fully dilated which may cause the midwife to believe the head is lower than it is
What is the anal cleft line and what causes it to appear?
A bluish purple line between the anus and the cleft of the buttocks.
Thought to be caused by vasocongestion in the basivertebral and intravertebral veins around the sacrum
What is the Rhomboid of Michaelas and what causes it?
Indicates displacement of the sacrum and coccyx (sacrum moves 1-2cm back)
Gives more room at the outlet and believed to straighten the curve of carus, making the birth canal straighter.
How often should the fetal heart be auscultated during the second stage?
After every contraction and at least every 5 minutes
What TEN things should be documented every 15 minutes?
- Progress
- PV loss
- Fetal heart
- Maternal condition
- Position
- Any change seen
- Bowels
- Urine
- Who is present
- Plan
After how many hours of the second stage should a woman be referred to the relevant clinician if birth is not imminent?
2 hours
What causes flexion and therefore reduces the size of the presenting part?
Fetal axis pressure once in the birth canal
Identify what signs a midwife can use to recognise the second stage of labour
- Anal cleft line should have reached the top of the cleft
- Anal pouting
- Rhomboid of Michaelis
- Appearance of the presenting part
- Palpation of fetal descent
- Expulsive contractions
- Transitional phase
Describe the latent phase of the second stage of labour
Begins at full dilatation of the cervix but the presenting part may not be visible. As the head descends, increasing pressure on the rectum will trigger the reflex stimulus for maternal expulsive pushing which is when the active phase begins
Describe the active phase of the second stage of labour
Begins with the onset of maternal expulsive pushing and ends with the birth of the fetus
What is the widest diameter of the pelvic inlet?
Transverse
What is the widest diameter of the pelvic outlet?
Anteroposterior
What happens during descent?
Fetal head descends in to the pelvis (sometimes occurs before labour)
Sagittal suture is in the transverse diameter of the pelvis
What happens during flexion?
Pressure transmitted from the fundus down the fetal spine (fetal axis pressure) will force the occiput lower than the sinciput, increasing flexion and causing the favourable suboccipitobregmatic diameter of 9.5cm
What happens during internal rotation?
Contraction pushes the leading part down onto the pelvic floor
The resistance of this muscular diaphragm brings about rotation
As contraction fades, the pelvic floor rebounds causing the occiput to glide forwards.
Occiput rotates 1/8 of a circle and slips beneath the sub-pubic arch and crowning occurs
What happens during crowning?
The occiput escapes from beneath the subpubic arch and the smallest possible diameters (suboccipitobregmatic and biparietal) distend the vaginal orifice. The head can no longer retract in between contractions
What happens during extension?
Once crowning has occurred, the fetal head extends, pivoting on the sub occipital region around the pubic bone
This releases the sinciput, face and chin which sweep the perineum and are then born by a movement of extension
What happens during external rotation?
Similar to rotation of the head
Rotates to lie in the widest diameter of the pelvic outlet
Anterior shoulder reaches the levator ani muscle first and therefore rotates anterior lay to lie under the symphysis pubis
Occurs in the same direction of restitution
Occiput of the fetal head now lies laterally
