Stages Of Labour Flashcards
1
Q
What is the definition of labour
A
process whereby the products of conception are expelled from the uterus
2
Q
When does labour normal occur?
A
Between 37-42 weeks
Lasting 3-18 hours
3
Q
How is labour diagnosed?
A
When regular, painful uterine contractions lead to effacement and dilatation of the cervix
Commonly with show and or SROM
4
Q
What is the Show in labour?
A
Pink/white mucus plug (operculum) from the cervix
(Comes out when cervix dilates)
5
Q
How would you know someone had had their SROM?
A
History: liquor drainage PV (colour clear)
Speculum exam: pool of fluid in posterior fornix
Tests: amnisure or u/s (rarely)
6
Q
Does the presence of the Show mean someone is in active labour?
A
Not always
7
Q
What can be mistaken for SROM?
A
Urinary incontinence
Vaginal discharge
8
Q
How do you confirm there was ROM?
A
AmniSure test
9
Q
What is the AmniSure test testing for?
A
PAMG-1
10
Q
What is PAMG-1?
A
One of the amniotic fluid proteins (1,000-10,000 times higher concentration in amniotic fluid than cervicovaginal fluid)
11
Q
How do you carry out an AmniSure test?
A
Swab vaginal discharge and dip into testing agent and read from test strip
12
Q
When does the FDA recommend doing an AmniSure?
A
As part of an overall clinical assessment ie not on its own
13
Q
How is labour diagnosed based on history?
A
Regular painful uterine contraction
+/- SHOW
+/- rupture of membranes
14
Q
How is labour diagnosed based on physical examination?
A
Palpability of contractions
Cervical effacement
Cervical dilation
15
Q
What are some theories on what initiates labour?
A
Oxytocin theory:
- produced from post pituitary
- stimulates uterine contraction
- (increased production and incr expression of uterine receptors)
Oestrogen stimulation/progesterone withdrawal:
- Higher levels of oestrogen-v- progesterone make uterus more sensitive to substances that stimulate contractions
Foetal initiation theory:
- foetal adrenal glands release cortisol at term – alters prostaglandin production
Uterine distension:
-Uterus can only distend so far before contraction
Prostaglandin cascade theory:
-released from foetal membranes, myometrium
16
Q
What are the stages of labour?
A
1st, 2nd and 3rd
17
Q
What happens in the first stage of labour?
A
Initiation of full cervical dilatation (10cm)
18
Q
What happens in the second stage of labour?
A
Full dilatation to delivery of foetus
19
Q
What happens in the third stage of labour?
A
Delivery of foetus to delivery of placenta
20
Q
Which stage of labour is the slowest?
A
First
21
Q
What are the stages of labour?
A
22
Q
When is labour in that stage one?
A
From diagnosis of labour until cervix fully dilated (10cm)
23
Q
How long is the first stage of labour?
A
8 hours nullip
5hrs multip
24
Q
What can stage 1 of labour be divided into?
A
Latent phase
Active phase
25
What is the latent phase of labour? (First stage)
Slowly 1st 4 cm
Over several hours
26
What is the active phase of the first stage of labour?
1cm/hr for nullip
2cm/hr for multip
(<16hrs)
27
What is cervical effacement?
Incorporation of cervical canal (initially tubular) into lower uterine segment
(Pulling the thinning cervix up into part of the uterus)
28
How does cervical effacement proceed?
From internal os to external os
29
What accompanies cervical effacement?
Show +/- ROM
30
What is the normal pre-labour cervical length?
2-4cm
31
How is cervical effacement described?
As a %
- use fingers to determine if effaced
32
What does cervical effacement look like?
33
How is cervical dilatation measured?
34
How does the reporting of cervical dilatation and effacement compare?
Dilatation 0-10cm
Effacement 0-100%
35
When does the second stage of labour encompass?
From full cervical dilatation to the expulsion/delivery of the foetus
36
What is the happening during the passive stage of the second stage of labour?
Full dilatation -> head reaches pelvic floor
Before urge to push
37
How long does the passive stage of the second stage of labour usually last?
Only minutes
38
What is happening in the active stage of the second stage of labour?
Irresistible urge to push
Push with contractions
39
How long does the active stage of the second stage of labour last?
40 min in nullip
20 min in multip
40
What is the case if the active stage of the second stage of labour is >1hr?
Spontaneous delivery unlikely
41
What is perineal trauma?
Damage to the genitalia during childbirth
42
How common is perineal trauma?
85% some degree of trauma
60-70% need suturing
43
What has been injured in a 1st degree tear?
Perineal skin and/or vaginal mucosa
44
What has been injured in 2nd degree tears?
Involve the perineal muscle
45
What has the same degree of injury as a 2nd degree tear?
Episiotomies
46
What is involved in a 3rd degree tear?
Anal sphincter
47
What is involved in a 4th degree tear?
Anal mucosa
48
How are 3rd and 4th degree tears repaired?
In theatre with analgesia
Do spincter first then vaginal wall
Will need to avoid constipation and do physio
49
How do the internal and external anal sphincters differ?
Internal = involuntary - autonomic - relaxes on distension
External = voluntary
50
What is the major risk with 3rd and 4th degree tears?
Incontinence and infection so give antibiotics and physio
51
What are OASIS?
3rd and 4th degree tears
52
What are the different tears that women can have during labour?
53
What is the anatomy of the area that can be damaged during labour?
54
What are the short term complications of perineal trauma?
6% wound complications like infection and dehiscence
55
What are some longer term complications of perineal trauma? (5)
Dyspareunia
Incontinence
Fistula
Prolapse
Depression
56
What are the risks for OASIS? (6)
First baby
Long second stage
Large baby
Shoulder dystocia
IOL
Assisted delivery
57
Who is more at risk of OASIS nullip or multip?
6.1% for N
1.9% for M
58
What does stage 3 of labour encompass?
From delivery of the fetus to the delivery of the placenta
59
What happens to the placenta in stage 3 of labour?
Placenta shears away from the uterine wall and fibres contract to compress blood vessels
60
How long does stage 3 of labour last?
About 15 mins (>30 mins prolonged)
61
How much blood is lost in stage 3 of labour?
Up to 500mls
(Some studies average 150mls)
62
What are the 3 mechanical factors of labour?
**P**owers
**P**assage
**P**assenger
**3 Ps**
63
What is involved in the power in labour?
Uterine contractions forcibly expelling the foetus
64
What are the pressures involved in power in labour?
Intrauterine pressure (mmHg)
65
What is the normal resting tone intrauterine pressure?
10mmHg
66
At what intrauterine pressure are contractions painful?
25mmHg
67
What intrauterine pressure is seen in the first stage?
50mmHg
68
What intrauterine pressure is seen in the second stage?
100mmHg
69
What is meant by retraction?
When muscle fibres of the myometrium relax they do not return to their former length but become progressively shorter
70
What does the progressive retraction of the upper segment of the uterus do?
Stretches and thin out the lower segment causing effacement (pulling up of) and dilattaion of the cervix
71
Why is relaxation of the uterus between contractions so vital?
As reduced oxygenation to the baby if the contractions are constant and can cause fetal distress if no relaxation
72
What theory is there about what controls the uterine contractions?
73
How do the powers of labour change over the course of labour?
Increase in frequency, duration and amplitude
74
What is the power of the expulsive phase of labour?
60-80mmHg
75
What is relaxation vital for in labour?
Foetal oxygenation
76
What are Braxton-Hicks contractions?
Non-painful (can feel cramps) uterine contractions
77
How do Braxton-Hicks Contractions vary?
Vary in frequency, duration and amplitude
78
Do Braxton-Hicks contractions include cervical changes?
Little or no cervical changes
79
What is the approx amplitude of Brixton-Hicks Contractions?
15mmHg
80
When are Braxton-Hicks contractions seen?
Normal more from 30 weeks
But can be earlier
81
What is the suggested theory for Brixton Hicks Contractions?
? Improve uterine tone and promote uterine blood flow and foetal oxygenation
82
What are the 2 parts of the passage the baby has to get through in labour?
Bony pelvis
Soft tissue
83
What are the different measurements of the bony pelvis?
84
What is the size of the inlet of the bony pelvis?
13x11cm
85
What is the size of the mid-cavity of the bony pelvis?
Round
11cm
86
What is the size of the outlet of the bony pelvis?
11x12.5cm
87
What soft tissues does a baby have to pass through?
Cervix
Vagina
Perineum
88
What are the measurements of the bony pelvis?
89
What is the anatomical axis of the bony pelvis?
Curve of carus
(C-shaped)
90
What is the obstetric axis that the head passes through during labour?
J-shaped
(Down and back then forward and down)
91
What is a station?
The degree of descent of the (presenting part) head on vaginal examination
92
How is station expressed?
In terms of distance in cms from the ischial spines (in vaginal side walls at 3/9 o’clock position)
93
What are the ischial spines?
Bony prominences palpable vaginally
94
At what station is the head engaged?
Station 0
95
How are stations reported?
“Station of +2cm”
96
How are the stations represented?
97
What is cervical dilatation dependent on?
* contractions
* pressure of the fetal head on cervix
* ability of the cervix to soften and allow distension (hydration of collagen)
98
What often happens to the soft tissue of the vagina and the perineum during labour?
Needs to overcome the pressure and it often tears or is cut
99
How does the passenger (ie the baby) present?
* cephalic (95%)
* breech (3-4%)
* shoulder/back/limb
100
What are the 3 main considerations of foetal head?
1. Attitude
2. Position
3. Size/moulding
101
What is **Attitude** in relation to the baby?
**Degree of flexion of the fetal head on the neck**
102
What is the ideal level of attitude?
Max flexion
103
What is the ideal max flexion attitude called?
Vertex presentation (9.5cm)
104
What is presenting in the Vertex presentation?
Between Bregma (ant font) and occiput
105
Why is Extension not the ideal presentation?
Results in larger diameter (eg brow or face presentation)
Can mean the foetal diameters are too large to deliver vaginally
106
What is the **Position** in relation to the baby in labour?
**Degree of rotation of the head on the neck**
107
How must the head rotate through labour?
90* during labour
108
What position is a baby usually delivered in?
Occiput anterior (OA)
109
What position is more difficult for the delivery of a baby?
OP (5%)
110
What position is not possible for delivery without assistance?
Transverse
111
How does the position impact the delivery?
Head must rotate 90* in labour - when you are talking about position of head in labour base it off back of the head/occipital
- normal is go in occipital transverse and turn occipital anterior
- if the go in and turn occipital posterior then need an instrument or to rotate them
- if they go in occipital posterior then need assistance with instruments
112
How do you define the position of the baby during delivery?
Anterior Fontanelle = ♦️
Posterior Fontanelle = 🔺
113
What is **moulding** with regard to the size of the head?
**as head is compressed in the pelvis, the sutures allow the bones to come together and overlap slightly
114
How is Moulding expressed?
* 0 = sutures not touching
* +1= sutures touching
* 2+= sutures overlap but is reducible
* 3+= sutures overlap and not reducible
115
What is Caput?
Swelling due to pressure on the scalp during delivery
116
What is cephalopelvic disproportion?
Head is too big to pass through the bony pelvis
117
What is **Caput Succedaneum**?
Odematous swelling within superficial CT layer of scalp
118
What causes Caput Succedaneum?
Pressure of cervix/lower uterine segment
119
How long does Caput Succedaneum last?
Disappears in 24-48 hours
120
What are the cardinal movements of the foetus during labour?
* Engagement
* Descent
* Flexion
* Internal rotation
* Extension
* Restitution
* External rotation
* Expulsion
*Everybody Don’t Forget I Enjoy Really Expensive Escorts
* Pelvic floor is shaped like a gutter (V) so he turns to line up with it at internal rotation
Extension when releases from pelvic floor
Restitution is turning head slightly to line up with shoulders
Then their shoulders hit the pelvic floor and turn to side and so head externally rotates again and then they are expelled
Cardinal movements = think of us using the doll in the pelvis *
121
What are the 7 cardinal movements of the foetus during labour?
122
**MCQ**
Which of the following is correctly matched?
1. First stage of labour: from full cervical dilatation to delivery of the foetus
2. Attitude: the degree of rotation of the foetal head during delivery
3. Position: the degree of flexion of the foetal head during delivery
4. Anterior fontanelle: diamond shaped
5. Moulding: Connective tissue swelling in the scalp post-delivery
4.
123
**MCQ**
Which of the following statements is true?
1. Cervical dilatation is normally expressed as a percentage
2. The second stage of labour is usually the longest stage
3. The AmniSure test checks for the PAMG-1 protein
4. Average blood loss in the third stage is > 500ml
5. The final cardinal movement of the foetus in delivery is extension
3.
124
What is used to aid monitoring in labour?
Partogram = progress in labour
125
What does the Partogram monitor about the maternal condition during labour?
Obs:
* temp: >38 or >37.5 on 2 occasions
* BP: increased or decreased
* HR
* urine: volume, ketones, protein
126
What parts of the foetal condition does the partogram monitor in labour?
* abdominal palpation
* foetal heart monitoring
* liquor
- intact membrane (I)
- Clear (c)
- Meconium stained (m1/2/3)
- blood stained (b)
- absent (a)
*moulding
- 0, +1, +2, +3
127
What two ways can foetal heart be monitored for the partogram?
* Intermittent auscultation (every 15 mins in 1st stage, or every 5 mins in 2nd stage - 60 sec after contraction)
* CTG
128
How is progress of labour assessed on the partogram?
* 2-4 hourly VE
- cx dilatation (marked with X)
- descent (marked with O)
*monitor contractions
- on palpation or CTG
- dots/lines/shaded squares
129
What can cause failure to progress in labour?
* Powers: inefficient uterine contractions (N, Induced)
* Passenger: Foetal size (hydrops), disorder of rotation (OP or OT), disorder of attitude (brow or face presentation)
* Passage: CPD, normal pelvic variants, abnormal pelvic architecture, pelvic mass, cervical role
130
What is Friedman’s curve?
Cervical Dilatation
Prolonged latent phase: (20 hrs N, 14 hours M)
Protracted active phase dilatation- slow progress
< 1.2 cms/hour in primigravida
< 1.5 cms/hour in multip
Arrest disorders
-Arrest of Active Phase of cervical dilatation
No change in 2 hours
Descent:
-Protraction of Descent < 1cm/hr in N, < 2cm/hr in M
-Arrest of Descent
No change in 2 hours for nullip & 1 hour for multip
**outdated - dont need to know the numbers just the terms like protraction and arrest**
131
What are some possible interventions in arrested or protracted first stage?
* ARM
* Oxytocin infusion
132
What are some possible interventions in second stage of labour if arrested or protracted?
* oxytocin infusion
* assisted delivery
* episiotomy
* c-section
133
When should a woman come to hospital in labour?
Admitted when painful contractions are regular (5-10min intervals) or if SROM
134
What should be done as initial assessment of a women presenting in labour?
* Hx: pregnancy, past obs history
* Ex: temp, BP, HR, urine, abdominal exam (presentation), VE (cx, station, liquor)
*foetal heart
- intermittent auscultation
- CTG
135
What should be done for the mother in the first stage of labour?
- comfort/mobility
- hydration, eating
- urine
- psychological considerations (adrenaline inhibits contractions)
- support, attention, explanation
136
What analgesia can be offered during labour?
* Entonox
* opiates/Pethidine
* Pudendal N block
* epidural
* others = rubbing, TENS (early), water (body temp), hypnotherapy, acupuncture, heat, cold, massage
137
What are potential side effects of Entonox?
Lightheaded
Nausea
Hyperventilating
138
What are potential side effects of Opiates/Pethidine?
Sedation
Confusion
Nausea
Resp distress of baby if given <2 hours prior to delivery
139
What are the pre-requisites of epidural analgesia during labour?
**3 Cs**
**Consent
Cannula
Catheter**
- consent = written
- pre-load with IV fluids (hypotension may occur - may need ephedrine)
- urinary catheter in situ
140
Where is an epidural inserted?
Inject LA (+/- opioid) via an epidural catheter between vertebra L3/L4 or L4/L5
141
How do you dose an epidural?
Loading dose with top-ups
142
What does an epidural do?
Complete sense (-pressure) and partial motor block from upper abdomen down
143
What are contraindications of epidurals? (5)
* Sepsis
* Coagulopathy/A- coagulant
* Active neurological disease
* spinal abnormalities
* hypovolaemia
144
What are the advantages of an epidural? (5)
* pain free
* decrease BP in hypertensives
* abolish premature urge to push
* analgesia for instrumental or c-section
* if long labour
145
What are the disadvantages of epidurals? (7)
* risk of spinal tap and total spinal analgesia
* hypotension (give IVF)
* maternal fever
* poor mobility
* unitary retention (catheter)
* higher instrumental delivery
* local anaesthetic toxicity
146
What would you do in the first stage of labour if abnormal foetal HR on auscultation?
Then proceed to CTG
- if abnormal: O2, IV fluids, left lateral position, stop oxytocin
- if persists foetal scalp blood sample
- may need to consider delivery
147
What is required in order to be able to obtain a foetal blood sample?
ROM
Dilated 2-3cm
148
What needs to be done to obtain a Foetal Blood Sample?
* informed consent (verbal)
* left lateral position
* insert amnioscope into vagina and visualise foetal scalp
* clean and spray with **local anaesthetic (ethyl chloride** to improve hyperaemia)
* apply **silicone gel** (thin layer = blood clumps)
* use blade and capillary tube to take a small sample of blood to see how baby is tolerating labour
149
What determines if further assessment of abnormal CTGs is needed?
Foetal scalp pH
150
What is a normal foetal scalp pH?
>7.25 (lactate <= 4.1mmol/L)
- may need to repeat every 30-60min if CTG changes persist or worsen
151
What is a suspicious foetal scalp pH?
7.2 - 7.25 (4.2-4.8 mmol/L lactate)
-repeat after 30 min
152
What is an abnormal foetal pH?
<7.2 (>= 4.9mmol/L)
-deliver by LSCS or instrumental delivery if fully dilated
153
When is the second stage of labour slower?
Nullip S and epidurals
154
How should a baby be delivered?
Mother in whatever position comfortable with - not flat on back
Attendant scrubbed and gloved
Swab pushing against perineum as it bulges to guard it
Woman asked to stop pushing and pant slowly once head crowns
Head delivers - check for nuchal cord
External rotation/ restitution
Maternal pushing and downward pull on head to deliver ant shoulder, then pull up to deliver post shoulder
Clamp & cut cord (doesn’t have to be immediately)
Record time of birth & apgar score
Skin to skin contact (keep warm)
155
When does oxytocin need to be considered in the second stage of labour?
If nullip and high station
156
What needs to be considered if an epidural in situ (numb) during second stage of labour?
Wait 1 hour before pushing
Directed pushing = 3 times for 10 second during a contraction (no urge)
157
What needs to be considered if baby can’t get out during second stage?
Instrumental delivery - if delivery not imminent after 1 hour
Episiotomy
158
What is an Episiotomy?
Surgical incision to increase diameter of vulva
159
What are the indication for an episiotomy?
* foetal distress
* head not passing over perineum -> large tear likely -> delay
160
What are the indications for instrumental deliveries?
**MEDALS**
**M** = medical problems (eg HTN/ cardiac disease and dont want them pushing)
**E** = exhaustion (maternal)
**D** = distress (foetal)
**A** = additional (eg breach)
**L** = long second stage
**S** = spinal tap
161
What are contraindications to instrumental delivery? (3)
* foetal bleeding disorders
* foetal predisposition to fracture
osteogenesis imperfecta
* vacuum (Ventouse) extractors
face presentation
<32 weeks
32-36 weeks - unclear re the ventouse but not recommended
162
What are the pre-requisites for instrumental delivery? (Operative vaginal delivery)
1. Full abdominal and vaginal examination
2 preparation of mother
3. Preparation of staff
163
What needs to be determined by the full abdominal and vaginal examination before instrumental delivery?
• Head
164
How must the mother be prepared before instrumental delivery of the baby?
• Clear explanation given and informed consent obtained
• (Effective) analgesia
• Empty maternal bladder, indwelling
catheter removed or balloon deflated
• Aseptic technique
• Intravenous antibiotics (new) (Augmentin)
165
How must staff preparation be insured before the use of instrumental delivery?
Operator must have knowledge, experience and skill necessary (K/S/E)
Adequate facilities
Back up plan
Anticipation of complications (SD, PPH)
Personnel trained in neonatal resuscitation present
166
What are the 3Ws of instrumental delivery?
Where to deliver?
What instrument? (Based on operators skill and clinical circumstance)
When to stop
167
What are the 3 types of vacuum extraction?
1. Metal cup
2. Kiwi cup
3. Soft cup
168
Where should the cup be placed?
2cm anterior to the posterior Fontanelle
169
What are the 2 types of forceps?
Non rotational NBF
Rotational KF
170
How do vacuum compare to forceps?
*vacuum more likely to:
- fail
- cause a fetal cephalohaematoma / subgaleal haemorrhage
- cause a neonatal retinal haemorrhage
*vacuum less likely to:
- cause significant maternal perineal and vaginal trauma
171
Why is the third stage fo labour actively managed?
Shortens 3rd stage = decreased risk of PPH and blood transfusion
172
How can the third stage of labour be actively managed?
1. Syntocinon 10 IU IM (syntometrine) with delivery ant shoulder (early cord clamping)
2. CCT (Brandt-andrews method) after placental separation
- fundus contracts/globular
- passage of blood
- cord lengthening
173
How is the third stage of labour managed physiologically?
3 features
- division after pulsation stopped
- delivery by maternal effort and gravity
- oxytocics only if haemorrhage
Spontaneous delivery
174
How long can physiological management of third stage of labour take?
Up to 60 minutes
175
What is there an increased risk of with physiological management of third stage of labour as opposed to active management?
PPH
176
What is the Brandt-Andrews Method of extracting the placenta?
177
What are the complications of the third stage of labour?
* incomplete placenta
* retained placenta
* haemorrhage
* acute inversion of uterus
178
What is seen in normal CTG?
Rate 110-160bpm
STV 5-25bpm
No declarations
Accelerations
179
What 4 things can cause a suspicious or pathological CTG?
* after an epidural
* hypert insulation (with oxytocin)
* haemorrhage
* fetal hypoxia or acidosis
180
What are the risks of oxytocin infusion?
• Can get fetal intolerance (abnormal CTG) and tachysystole
• May occur at low or high doses of oxytocin- it is essentially the effect on the fetus and the uterus that is the final arbitrator of safety.
