Labour Flashcards
Define Labour
process in which foetus and placenta are expelled by the uterus, with painful uterine contractions and cervical effacement and dilatation
What is effacement and what is an indicator of effacement
tubular cervix is drawn up into the lower segment until it is flat, commonly accompanied by a ‘show’ or pink/white mucous plug from the cervix and/or rupture of membranes → release of liquor
What are the stages of labour
First stage: latent and active
Second stage: passive and active
Third stage
Describe the first stage of labour
Latent: painful contractions and cervix effacement → dilation to 4cm
Active: regular painful contractions and dilation from 4cm → fully dilated (10cm)
What is the average duration of time that the first stage of labour takes and how should dilatation be progressing
8 hours nulli, 5 hours multi (Should not exceed 16h)
Should be progressing 1cm/h in nullis and 2cm/hour in multis
Describe the second stage of labour
Passive: cervix is fully dilated before involuntary expulsive contractions (no pushing) where rotation and flexion occur
Active: pushing, baby is visible, expulsive contractions or other signs of full dilatation
What is the average duration of time that the second stage of labour takes
Passive: <1 hours
Active: 40 mins (nulli), 20 minutes (multi)
If >hour, spontaneous delivery will become unlikely
Describe the third stage of labour (what it is, duration of time, normal blood loss)
Physiological - no uterotonics and delivery of placenta by maternal effort
Lasts about 15 minutes
Normal blood loss up to 500mL
What are the steps in the mechanism of labour
- Engagement (usually OT)
- Descent to below the level of the ischial spines
- Flexion as a result of pressure of the presenting part against the pelvic floor
- Rotation to OA position so that the largest occiptofrontal diameter occupies the longest AP diameter of the pelvic outlet. The largest foetal diameter a the shoulder (Bisacromial), occupies the longest diameter of the inlet (transverse)
- Extension and delivery of the foetal head underneath the symphysis
- Restitution with rotation of the foetus so that the bisacromial diameter occupies the longest anteroposterior diameter of the pelvic outlet
- Delivery of the shoulders and the rest of the body
What needs to be monitored as a measure of progression throughout labour
Lie
Presentation
Engagement
Attitude
Position (± denominator)
Station
Caput
Moulding
Define lie in labour and its types
relationship between the long axis of the foetus with respect to the long axis of the mother
Longitudinal: spine is parallel with mother’s spine
Oblique: diagonal
Transverse: spine of foetus is perpendicular to the axis of the mother
Define presentation and what are the three main types
the part of the foetus that lies over the inlet of the pelvis.
The three main presentations are cephalic, breech, and shoulder.
Define engagement
The widest diameter descends into the pelvis
Descent is described as 5ths palpable abdominally
When more than 1/2 the head has entered the pelvis, it is said to be engaged
<2/5 palpable = engaged
>3/5 palpable = not engaged
2/5 palpable = 3/5 engaged
Define attitude, what are the common attitudes and what is an indicator of
Relationship of foetal parts to each other
The basic attitudes are flexion and extension
Flexion = chin approaches the chest and in extension when the occiput nears the back
It is an indicator of the efficiency of labour.
Well flexed (vertex - 9.5cm)
Deflexed
Extended Or Brow (largest diameter - 13cm)
Hyperextended or Face
Define denominator in labour
A chosen point on the presenting part of the foetus used in describing position. Each presentation has its own denominator i.e. occiput, sacrum, mentum, frontum
What are the denominators for the following presentations: vertex, brow, facial, breech, shoulder
Vertex: occiput
Brow: frontal
Facial: mentum
Breech: sacrum
Shoulder: acromion/scapula
Define the position of labour and what is the ideal position
Describes which way the baby is facing
Occiput anterior (OA)
How do you assess for position in labour
- Using a finger, locate the sagittal suture
- Run your finger around in a circle from the sagittal suture
- If you can feel 3 sutures, it is the posterior fontanelle, If you can feel 4 sutures it is the anterior fontanelle
Define station in labour
Relationship of the presenting part to the ischial spine, measured in centimetres above (-) or below (+) the ischial spines
Define caput in labour
Description of swelling on baby’s head
Graded from 0 (non) to +3 (marked)
Indicator that baby is not passing easily through
What is caput succedaneum
diffuse swelling of the scalp caused by the pressure of the scalp against the dilating cervix. It may extend over the midline
Define moulding and its degrees
the parietal bones of the baby’s head overlap
0 - No moulding
+ 1 - bones touching but not overlapping
+2 - overlapped but can be reduced
+3 - overlapped and irreducible
What are the forces of labour
Power: The degree of force expelling the foetus i.e. contractions
Passage: The dimensions of the pelvis
Passenger: How easily the foetal head fits through the pelvis, diameter of the foetal head
Describe power as a force of labour
Contractions arise in one of the many pacemakers situated in the uterus.
In established labour they last 45-60 seconds, every 2-3 minutes (3 in 10)
This pulls up the cervix (effacement) and dilates the cervix, aided by the pressure from the foetal head
How is the female pelvis divided into planes and where do you find the largest diameter)
Inlet: Bordered by pubic symphysis, sacral promontory and iliopectineal line (transverse largest)
Midplane: Bordered by the posterior surface of the symphysis, the ischial spines and the sacrum at level S4-S5
Outlet: Bordered by the lower margin of the symphysis (pubic arch), the ischial tuberosities and the tip of the coccyx (AP largest)
Describe the foetal head
The head is oblong in transverse section
Its bones are not fused yet
Anterior fontanelle (bregma) lies above the forehead
Posterior fontanelle (occiput) lies on the back of the top of the head
Between the fontanelles is the vertex
In front of the bregma is the brow
What are the most common shapes of pelvis and which is most ideal for childbirth
Gynaecoid (most common and ideal)
Anthrapoid next most common
What factors determine how easily the foetal head fits through the pelvis
Attitude or flexion
Position
Size of foetal head
How do you use a partogram
When 4cm dilated: draw an alert line (Diagonal, 1cm/hour)
Draw a parallel line to the alert line 2 hours after the alert line
Record frequency and strength of contraction, descent of the head, station, amount and colour of amniotic fluid, obs, urine
