Normal Labour & Delivery Flashcards
What is labour?
The process in which the foetus and the placenta leave the uterus
At what weeks gestation does labour occur?
37 and 42 weeks gestation
What two factors are required for labour to commence?
Cervical ripening
Myometrial excitability
What two factors are required for labour to commence?
Cervical ripening
Myometrial excitability
What is cervical ripening?
It is softening of the cervix that occurs before labour, allowing it to dilate.
What does cervical ripening occur in response to?
The breakdown of cervical tissue via oestrogen, relaxin and prostglandin release
Prostaglandins is of particular importance
How does cervical ripening initiate labour?
This means that cervix offers less resistance to the presenting part of the foetus during labour
What hormone can be prescribed to induce cervical ripening, and thus labour? What is another name for this?
Prostaglandin E2
Dinoprostone
What causes myometrial excitability? Why?
A relative decrease in progesterone in relation to oestrogen, that occurs towards the end of pregnancy
This is because progesterone typically inhibits contracts and oestrogen increases the number of gap junctions between smooth muscle cells, increasing contractility
What are Braxton Hicks contractions?
They are occasional irregular contractions of the uterus
These are not true contraction and they do not indicate the onset of labour
When do Braxton Hicks contractions?
Third and second trimester
When does the first stage of labour occur?
It occurs from the onset of labour (true contractions) until the cervix is fully dilated to 10cm
What two processes occurs in the first stage of labour?
Cervical dilation
Cervical effacement
What is cervical effacement?
Shortening of the cervix
What are the three phases of labour stage one?
Latent phase
Active phase
Transition phase
At what cervical dilation does the latent phase of labour stage one occur?
The latent phase occurs from 0 to 4cm dilation of the cervix
How fast does the latent phase of labour stage one occur?
It progresses at around 0.5cm per hour
What is the longest phase of labour stage one? How long does it typically last?
Latent phase
Hours to several days
What type of contractions occur in the latent phase of labour stage one?
Irregular
Short lasting, occurring every two to three minutes
Mild in nature
What type of contractions occur in the latent phase of labour stage one?
Irregular
Short lasting, occurring every two to three minutes
Mild in nature
At what cervical dilation does the active phase of labour stage one occur?
It occurs from 4 to 10cm dilation of the cervix
How fast does the active phase of labour stage one occur?
It progresses at around 1cm per hour
How long does the active phase of stage one labour typically last?
Eight to twelve hours
What type of contractions occur in the active phase of labour stage one?
Stronger
More regular
More painful
What type of contractions occur in the transition phase of labour stage one?
It occurs from 8 to 10cm dilation of the cervix
How fast does the transition phase of labour stage one occur?
It progresses at around 1cm per hour
What type of contractions occur in the transition phase of labour stage one?
Regular
Intense
Strong
Painful, where it is typical for patients to experience physical changes, such as shaking, vomiting or the need to empty their bowels
When does the second stage of labour occur?
It lasts from 10cm dilation of the cervix to the delivery of the baby
How long does the second stage of labour last?
This stage varies between two to three hours, depending on if the woman is nulliparous or multiparous
What are the two phases of second stage of labour?
Passive phase
Active phase
When does the passive phase of the second stage of labour occur?
The passive phase occurs when the cervix is fully dilated, however the woman has no urge to push with contractions
This phase lasts until the head of the foetus reaches the pelvic floor
When two cardinal movements occur during the passive, second stage of labour?
Rotation
Flexion
When does the active, second stage of labour occur?
This occurs when the woman starts to push with contractions. This phase occurs once the head of the foetus reaches the pelvic floor
When does the third stage of labour occur?
It is from the completed birth of the baby to the delivery of the placenta
How long does the third stage of labour last?
Five to thirty minutes, however, can last as long as an hour
What are the two ways in which the third stage of labour can be managed?
Physiological
Active
How do we physiologically manage the third stage of labour?
It involves the placenta being delivered by maternal effort without medications or cord traction
How long does physiological management of labour stage three take?
60 minutes
How do we actively manage the third stage of labour?
It involves the midwife or doctor assisting in the delivery of the placenta
It involves the prescription of intramuscular oxytocin to help the uterus contract and expel the placenta
It also involves controlled cord traction
How long does active management of labour stage three take?
This shortens the length of this stage to around thirty minutes and reduces the risk of bleeding
What is controlled cord traction?
This is traction applied to the umbilical cord to guide the placenta out of the uterus and vagina
In what two circumstances should active management of labour stage three be selected?
Haemorrhage
If it prolongs for more than 60 minutes
What are cardinal movements?
It involve changes in the position of the foetus’s head during its passage in labour
What are cardinal movements described in relation to?
Vertex presentation, which is when the baby’s head is down in the birth canal
What are the seven cardinal movements of labour?
Engagement
Descent
Flexion
Internal Rotation
Extension
Restitution & External Rotation
Expulsion
What is engagement?
It occurs when the largest diameter of the fetal head enters the largest diameter of the maternal pelvic inlet
As the fetal head engages, the head moves towards the pelvic brim in either the left or right occipto-transverse position
What is descent?
It occurs when the baby’s head descends past the pelvic inlet into the pelvic cavity
What three factors cause descent?
Uterine contractions
Amniotic fluid pressure
Voluntary abdominal muscle contraction via maternal effort
What is flexion?
It occurs when the fetal head comes into contact with the pelvic floor
This causes flexion of the fetal neck, in which the chin flexes towards the chest
In this position, the fetal skull has a smaller diameter, which assists passage through the pelvis, and the narrowest area of the head is presented
What is the narrowest part of the baby’s head?
The occiput
What is internal rotation?
It occurs when the baby’s head rotates from a left or right occipto transverse position to an occipto-anterior position
This eventually results in crowning
What is crowning?
This is when the widest diameter of the fetal head negotiates through the narrowest part of the maternal bony pelvis
When is crowning clinically evident?
When the head, no longer retreats between contractions
What is extension?
It occurs when the baby’s head slips beneath the suprapubic arch, extending the fetal head and allowing it to pass through the pelvis outlet
What is extension?
It occurs when the baby’s head slips beneath the suprapubic arch, extending the fetal head and allowing it to pass through the pelvis outlet
What is external rotation?
It occurs when the baby’s head rotates to a transverse position, so that it faces the right of left medial thigh of the mother
What is external rotation?
It occurs when the baby’s head rotates to a transverse position, so that it faces the right of left medial thigh of the mother
What is restitution?
It occurs when the shoulders are rotating from a transverse position to an anterior-posterior position
This means that the shoulders are realigned with the head
What is expulsion?
It occurs when the baby’s anterior shoulder, then the posterior shoulder, then the rest of the body are born
How can we assist in the delivery of the anterior shoulders during expulsion?
The midwife applies downward traction to the fetal head
How can we assist in the delivery of the posterior shoulders during expulsion?
The midwife applies upward traction to the fetal head
What is fetal presentation?
A reference to the part of the fetus that is overlying the maternal pelvic inlet
How can we predict fetal presentation?
Abdominal examination
What is the cephalic presentation?
It refers to the baby being positioned head down, with chin tucked to its chest and the back of the head ready to enter the pelvis
What is the most common fetal presentation?
Cephalic presentation
What is the breech presentation?
It refers to the baby being presenting for delivery with the buttocks of feet first rather than head
What are the three types of breech presentation?
Complete breech
Frank breech
Footling breech
What is complete breech presentation?
It refers to both legs being flexed at the hips and knees
What is frank breech presentation?
It refers to both legs being flexed at the hip and extended at the knee
What is the most common breech prevention?
Frank breech presentation
What is the footling breech presentation?
It refers to both legs being extended at the hip, so that the foot is the presenting part
What do we do when the fetal presentation is breech?
We offer woman a c-section
What is the normal fetal heartrate, variability and acceleration?
It is between 110bpm and 160bpm
Variability = between 5bpm and 25bpm
Accelerations = 15bpms
When do we conduct intermittent ausculation of the fetal heartrate during labour?
When woman have a low risk assessment
What two methods can be used to intermittently auscultate the fetal heartrate during labour?
Pinard stethoscope
Handheld doppler
How often do we intermittently ausuclate the fetal heartrate during the first stage of labour?
Every fifteen minutes for a full minute - following a contraction
How often do we intermittently ausuclate the fetal heartrate during the second stage of labour?
We increase the frequency of auscultation to every five minutes or after every contraction
In what three circumstances do we step up from intermittent fetal heartrate auscultation to continuous auscultation?
An abnormality is detected on intermittent auscultation
Intrapartum complications arise
The woman is high risk
Which method is used to continuously auscultate the fetal heartrate?
Cardiotocograph (CTG) machine
What two things does a CTG machine measure?
Baby’s heart rate
Contractions in the uterus
How do we conduct a CTG externally?
There are two transducers being placed onto the abdomen of the mother
The first transducer is placed above the fetal heart to monitor the fetal heartbeat
The second transducer is placed near the fundus of the uterus to monitor the uterine contractions
How do we conduct a CTG internally?
It involves a fetal scalp electrode being inserted through the vagina and neck of the woman and placed on the baby’s scalp
When do we conduct a CTG internally?
Baby’s who present cephalically
Over 34 weeks gestation
Those without blood disorders
What mnemonic is used to interpret a CTG?
DR C BRaVADO
What does DR in DR C BRaVADO mean? (CTG interpretation)
Define Risk
This involves defining the risk based on the individual woman and pregnancy before assessing the CTG
What does C in DR C BRaVADO mean? How do we find this information on a CTG chart? (CTG interpretation)
Contractions
This involves assessing how many contractions occur within ten minutes
This information is located at the bottom of the CTG chart, where twenty boxes represents ten minutes, and a peak represents a contraction.
What does BR in DR C BRaVADO mean? How do we find this information on a CTG chart? (CTG interpretation)
Baseline Rate
This involves assessing the baseline fetal heart rate
This information is located at the top of the CTG chart
What does V in DR C BRaVADO mean? (CTG interpretation)
This involves assessing how the fetal heart rate varies up and down around the baseline
What does A in DR C BRaVADO mean? What do we expect to see? (CTG interpretation)
Accelerations
This involves assessing periods where the fetal heart rate spikes
This is a good sign that the fetus is healthy, particularly when they occur alongside contraction of the uterus
What does D in DR C BRaVADO mean? What do we expect to see? (CTG interpretation)
Decelerations
This involves assessing periods where the fetal heart rate drops
This is often a normal feature of labour. However, if they are prolonged or late, they can indicate fetal hypoxia
What is the next step if CTG monitoring shows prolonged or late decelerations?
A fetal blood sampling should be conducted
What does O in DR C BRaVADO mean? (CTG interpretation)
This involves assessing whether the CTG is normal, non-reassuring or abnormal
What is fetal blood sampling?
A procedure used to remove a small amount of blood from the fetus’ scalp
The blood sample is then run through a blood gas machine
When do we conduct a fetal blood sample?
CTG readings are abnormal
AND
The cervix is 8cm dilated
What are the three measurements checked in a fetal blood sample?
pH
Base level
Lactic acid level
What does a fetal blood sample assess for? What pH level indicates this? How do we manage this?
Whether the baby is suffering from hypoxaemia
A pH less than 7.2
Immediate delivery
What do we examine during labour to montior its progression?
Abdominal Palpation
Vaginal Examination
Amniotic Fluid
Contraction Palpations
External Signs
Why do we conduct abdominal palpation during labour?
It allows the assessment of the fetal lie, position, presentation and engagement
Why do we conduct vaginal examination during labour?
It allows the assessment of cervical dilatation and the position of the baby
What is the normal colour of amniotic fluid?
Clear, yellow or pink
What is an abnormal colour of amniotic fluid? What does this indicate?
Dark green or black
The presence of meconium
What is meconium?
It is the first faeces of the newborn and when present in amniotic fluid can indicate fetal distress
What do we palpate contractions during labour?
It allows labour progression to be estimated – with stronger and more regular contractions indicating a further progression into labour
How often do we palpate contractions during labour?
Ten minutes every thirty minutes during both the first and second stages of labour
What external sign do we look for during labour? What is this? What does it indicate?
Rhomboid of Michaelis
A rhomboid-shaped contour visible on the mother’s lower back
This indicates that the fetus head has progressed into the pelvis
