the stages of labour

Question 1

labour

Answer 1

Labour is the physiological process by which the fetus , placenta and membranes are expelled through the birth canal after 24 weeks

Question 2

labour has .. how many stages

Answer 2

3

Question 3

latent phase

Answer 3

Period of time not necessarily continuous contractions and some cervical changes , including cervical position , consistency , effacement and dilation of up to 4cm

Question 4

Established first stage of labour

Answer 4

Regular contractions
Progressive cervical dilation of 4cm until 10cm (full dilation)

* A standard duration of latent phase is not established and can vary from one women to another 
* Duration of active stage is from 4- 5cm till full dilation - usually does not extend beyond 12 hours  Usually does not extend beyond 10 hours in subsequent labours

Question 5

uterine contractions

Answer 5

Within this stage of labour , cervical effacement , dilation and fetal descent are all aided by effective uterine contractions
Each uterine contraction starts at the fundus near one of the cornua then spreads across the fundus to the lower segment

Question 6

contraction and retraction

Answer 6

Following each contraction the muscle fibres do not completely relax but retain some shortening zof contraction - this is called retraction - leads to progressive shortening and thickening of the upper segment , reducing the uterine cavity

Question 7

dilation

Answer 7

is gradual opening of the cervix measured in cm from 1 cm - 10 cm

Question 8

membranes

Answer 8

• Spontaneous rupture of membranes - often occurs during the first stage of labour
  
  • For some women this can happen before labour starts
  • Some babies can be born within the membranes which is known as the caul
  • In some labours membranes may need to be artificially ruptured
    When membranes have ruptured it is vital we continue to assess the colour of the liquor as it can reflect fetal well being

Question 9

passive (second stage)

Answer 9

The finding of full dilation of the cervix before or in the absence of involuntary expulsive contractions

Question 10

active

Answer 10

Second stage of labour - involuntary or active pushing with a finding of full dilation of the cervix or the baby is visible

* Duration varies from one women to another 
* In first labour birth is usually completed within 3 hours  In subsequent labours birth is completed in 2 hours

Question 11

physiology of second stage

Answer 11

• Contractions change in character
  
  • Fergusons reflex - surge of oxytocin
  • Membranes can rupture
  • Soft tissue displacement

Question 12

signs that birth is imminent

Answer 12

• Nausea and vomiting due to vagal stimulation
  
  • Uncontrollable urge to push with contractions
  • Bulging of perinium with contractions
    Feeling of burning as perineum is stretched

Question 13

rhombus of michealis

Answer 13

• Kite shaped area of the lower spine that includes the sacrum and three lower lumbar vertebrae
  
  • As second stage begins rhombus Michalis moves backwards (the opening of the back - increasing the diameter)
    Women giving birth on all fours will tend to get a lump on the back

Question 14

anal cleft line

Answer 14

• Temporary change of skin discolouration - can be seen in an anal cleft of a women as they progress through labour
  Purple line can be a useful too to estimate the progress of labour in women who’s bodies show this sign

Question 15

midwife role in second stage of labour

Answer 15

• Fetal heart - every 5 minutes after a palpated contraction
  
  • Palpate women every 15 minutes to differentiate between the two heartbeats
  • hourly bp
  • Strength , length and frequency of contractions - every 30 minutes
  • Offer a vaginal examination hourly in the active second stage
  • Amniotic fluid (colour)
  • Fluid balance
  • Continue to take women’s emotional and psychological needs into account
    Assess progress , which should include the women’s behaviour , the effectiveness of pushing and fetal wellbeing

Question 16

what happens to cardiac output in labour

Answer 16

due to pain increased hr , increases in circulating catecholamines and blood from the uterus going into the circulation following contractions (300 - 500ml)

Increased by 20% during the first and 50% in the second stage

Can lead to increased bp and respiratory rate

Question 17

what happens to the digestive system in labour

Answer 17

• Most women become less hungry in labour - due to pain and physical effort involved - often feel nauseous
  A lot of discussion that eating can cause gastric aspiratio

Question 18

what happen to the renal system in labour

Answer 18

• The bladder displaces into the abdominal cavity - causing retention of urine and difficulty passing urine
  
  • Full bladder may increase pain , reduce efficiency of uterine contractions and delay descent of the presenting part
    Can prevent uterus contracting effectively post birth , increasing the risk of PPH

Question 19

what changes happen to the endocrine in labour

Answer 19

• Progesterone increases up to full term of pregnancy
  
  • Fetal cortisol production increases at term , which increases oestrogen production and the formation of oxytocin receptors on the uterine muscle
    oxytocin is responsible for contractions

Question 20

hormones involved in labour

Answer 20

• Oxytocin (brings on contractions , calming effect , helps with pain)
  
  • Beta - endorphins (pain relief)
  • Epinephrine and norepinephrine (fight or flight hormones can inhibit oxytocin)
    Prolactin (mothering hormone helps with breastfeeding)

Question 21

factors that affect the success of labour

Answer 21

Type of pelvis
Size of fetus
Parity
Fetal station
Uterine contraction and activity
Induction of labour
Fetal positioning
Regional analgesia
Maternal pushing effort

Question 22

third stage of labour

Answer 22

stage from the birth of the baby to the expulsion of the placenta and membranes

Question 23

what happen in third stage

Answer 23

• During the third stage of labour the placenta separates from the uterus and the uterus contracts to push it out . This stage ends with the placenta is expelled and the uterus return to normal
  
  • The length of the stage depends on how its managed
  • Active management - if the placenta isn’t out within 30 minutes its considered too long
  • Physiological management - if it takes longer than 60 minutes its considered too long

Question 24

mechanism of birth

Answer 24

Mechanisms of birth
* Descent
* Flexion
* Internal rotation - head
* Crowning
* Extension
* Restitution
* Internal rotation - shoulders
* Lateral flexion - shoulder
Birth

Question 25

decent and flexion

Answer 25

Decent and flexion
* The fetus descends through the pelvic outlet towards the pelvic floor
As the Fetal head comes into contact with the pelvic floor flexion occur

Question 26

internal rotation

Answer 26

Internal rotation
When the occiput meets the resistance of the pelvic floor muscles , it rotates forward approximately 45 degrees

Question 27

crowning and extension

Answer 27

Crowning and extension
The occiput escapes under the pubic arch with increased extension and the head is crowned

Question 28

restitution

Answer 28

When the head is born , it rotates to be in line with the shoulders , which have moved into the AP diameter. Visible head movement on the perineum is known as restitutio

Question 29

internal rotation of the shoulders and lateral flexion

Answer 29

At the same time the shoulders undergo a similar rotation to the head as they travel to the pelvis . From the transverse to the AP diameter
The anterior shoulder births first followed by the posterior shoulder

Question 30

birth

Answer 30

With gentle axial traction the remainder of the body is born