Labour: Normal and Abnormal Delivery Flashcards
What is foetal lie?
The relationship between the long axis of the foetus and the long axis of the mother
What can foetal lies be?
Longitudinal: parallel
Oblique
Transverse
What is presentation of the foetus?
The part of the foetus that will present first (lying over the inlet)
What can foetal presentations be?
Cephalic (vertex, face, brow)
Breech (footling, frank)
Shoulder
What is engagement of the foetus?
Descent of the foetal head into the pelvis
Described as <=2/5 of the head palpable abdominally, above the pubic symphisis
What is Attitude of the foetus?
Relationship of the foetal head to other body parts (flexed/extended)
What is the denominator’
The arbitrary chosen point of the presenting part of the foetus used to describe the position of the foetus
What is the denominator for a vertex cephalic foetus?
occiput
What is the denominator for a brow cephalic foetus?
frontal
What are the diameters of the pelvic inlet?
Transverse 13.5
AP 11
What are the borders of the pelvic inlet?
Anterior - pubic symphysis
Lateral - ilium
POsterior - sacrum
What are the diameters of the pelvic outlet?
Transverse 11
AP 13.5
What are the borders of the pelvic outlet?
Anterior - inferior border of pubic symphiosis
Lateral - inferior ramus of pubis, ischial tuberosity, ligaments,
Posterior - coccyx
What do the measurements of pelvic inlet and outlet mean for the baby head?
At the pelvic inlet - head should be transversals
At pelvic outlet - head should be OA
Where does the head rotate from transverse to OA?
In the mid pelvis
As diameters in the mid pelvis are quite similar (around 12 cm
How many types of pelvis are there, and which is the most common and best for childbirth?
FOUR types of pelvis
Gynaecoid is the best for labour
Where is the occiput on the baby’s head?
Over the posterior fontanelle
Where is the vertex on the foetal head?
The area between the parietal bones and the anterior and posterior fontanelle
What is caput and how is it graded?
Caput = swelling on the foetal scalp due to pressure against the cervix
Graded subjectively from 1 to 3
What is moulding ?
Overlapping of skull parietal vibes of the foetus as thee baby’s head is squeezed through the maternal pelvis
What it severe moulding an indication of ?
Obstructed labour
What is the best cephalic position for spontaneous vaginal birth? and which positions should you avoid?
OA is the best
OT (occipito-transverse) or OP (occipito-posterior) are bad
What is the cervix like before labour?
Long, firm, closed
Covered internally by a protective mucous plug
What happens to the cervix for labour to progress?
Softens, shortens, thins out (EFFACES), dilates
What is the cellular action of prostaglandins and oxytocin?
They increase cellular calcium
Thereby they stimulates contraction
What is retraction of the uterus?
Progressive shortening of the uterus due to actin-myosin interactions along the whole length of the filament
What happens to the uterus because of retraction?
Upper segment becomes thicker and actively contracting
Lower segment becomes thinner and stretched out
This results in the cervix being taken up (effaced) into the lower segment of thee uterus
What is the function of progesterone during late gestation
Progesterone maintains uterine relaxation (suppresses prostaglandin and oxytocin release)
What hormone opposes the action of progesterone?
oestrogen
What hormonal changes occur prior to labour?=
Decrease in progesterone receptors
Increase in oestrogen
Synthesis of Prostaglandin by chorion and decidua
Synthesis of CRH by placenta
What is the function of CRH?
Potentiates prostaglandins and oxytocin
What is the function of prostaglandins and oxytocin
to cause myometrial contractions
What is the Ferguson reflex?
pressure of the foetal presenting part against the crvix causes increased oxytocin release from the maternal putuitary
This stimulates uterine contractions
This in turn increases pressure on the cervix
What is labour?
The presence of strong regular painful contractions resulting in cervical changes (dilatation, effacementI) and aiming to expel the foetus
What occurs in the first stage of labour?=
Painful contractions + cervical changes (from 0 to 10cm dilation)=
What are the two phases of the first stage of labour=?
Early phase: time from onset of contractions to 4cm dilation ( and full effacementI)
Active phase: time from 4cm dilation to full cervical dilation (10cm)
What is the normal rate of dilation in the active phase of the first stage of labour?
1cm every 2h
What is the second stage of labour?
The PUSHING STAGE
From full dilatation of the cervix to delivery of the foetus
What are the two phases of the second stage of labour?
Passive phase: from full dilation to onset of involuntary exclusive contractions (no maternal urges foetal head is high in the pelvis, so some time is reccomended so the head can make its way down to the pelvis)
Active phase: maternal urge to push because the head is so low that it causes a reflex to bear down
What is the third stage of labour?
Delivery of the placenta and membranes
How long is a normal third stage of labour?
LESS than 30 mins
What are the 7 steps of labour?
Every darn fool in Egypt eats raw eggs
Engagement - foetal head enters pelvis in transverse position. Largest part of the head passes through pelvic inlet; only 2/5ths of head palpable from the abdomen
Descent
Flexion - head presses against chest as it descends into narrower mipelvis
Internal rotation - foetal shoulders internally rotate by 45 degrees, so head goes to OA position and shoulders at T position can pass through pelvic inlet
Extension - crowning of the head, as the occiput escapes from underneath the pubic symphysis
Restitution (External rotation) - head externally rotates for shoulders (OA position) can pass through the pelvic outlet
Expulsion . anterior shoulder out first, then posterior, then whole body
How do you diagnose delay in the active first stage?
Less than 2 cm dilation in 4 hours (same if nullip or multip)
How do you diagnose delay in the active second stage=
First labour: >2h
Subsequent labour: >1h
What is done to the baby once it is delivered?
Keep baby’s head dependent (so mucous can drain out)
Clamp and cut the cord
Give baby Apgar score at 1 min and 5 mins of age
Give vitamin K
What is active management of the third stage?
RECCOMENDED TO ALL WOMEN
Controlled cord traction + ergometrine
Why is active managanebt of the third stage important =
It reduces risk off PPH
What is the cause of prolonged latent phase?
None, just common in primes
How do you manage prolonged latent phase?
Manage away from suite with simple analgesia, mobilisation, reassurnce
Very frustrating for woman
What are causes of the poor progress in first stage of labour?
- dysfunctional uterine activity (common in primes/older women) with irregular, weak, infrequent contractions
- cephalopelvic disproportion (anatomical disproportion between foetal head and maternal pelvis)
How many contractions are ideal per 10 mins?
4-5 in 10 minutes
What do you do if delay in the first stage of labour its confirmed=?
- ARM
- If poor progress after 2 more hours, give SYNCTOCINON
- If poor progress after 4-6h, offer C section
What is synctocinon?
An oxytocin infusion
Start it slowly, then increase gradually
beware of excessive contractions
What are cephalopelvic disproportion causes?
MATERNAL
- small maternal pelvis (prior fracture, metabolic bone disease)
- Fibroids in lower uterine segment
FOETAL
.- Macrocephaly in foetus (e.g. due to obstructive hydrocephalus)
- Macrosomic baby
What causes poor progress in second stage?
- Secondary dysfunctional uterine activity (exacerbated by epidural)
- android pelvis (narrow, causes delay in internal rotation)
- resistant perineum
- persistent OP position
How do you treat Secondary dysfunctional uterine activity
rehydration
IV synctocynon
How do you manage poor progress in second stage=
- Instrumental vaginal delivery
- episiotomy
What two things make you worry about foetal distress in labour?
Fresh meconium (thick, dark green or black) Abnormal CTG
What does healthy meconium look like?
thin and light
What does healthy meconium indicate?=
Foetal gut maturity
What do you do if you see abnormal meconium ?
CTG (contiunous foetal monitoring)
If suspicious, perform immediate vaginal examination (exclude malpresentation / cord prolapse)
Potentially perform foetal blood sampling
What are good pain relief methods in labour?
- Paracetamol
- Opiates (diamorhone, pethidine) but give with antiemetic
- Nitrous oxide (entonox)
- Epidural
What is a negative effect of epidural?
It INCREASES instrumental delivery
Does NOT increase C sec rates
What is a risk in women with previous C sec wanting a VBAC?
Risk of uterine scar rupture
How many women does uterine scar rupture occur in for VBAC?
1 in 200
What is the percentage of VBAC women who have a successful VBAC?
70%
What are risks of uterine rupture to the mother?
Shock
Need for blood transfusion
Operative repair
Hysterectomy
What is the risk of uterine rupture to the foetus?
Hypoxia
permanent neuro injury
perinatal death
What are signs of uterine rupture
Severe lower abdominal pain Vaginal bleeding Haematurai Cessation of contractions Maternal tachycardia Foetal tachycardia Foetal head no longer palpable on exam
What relative contraindications for VBAC?
> =2 prior CS
Need for Induction of labour
Prior labour suggesting cephalopelvic disproportiuon
What is an absolute contrainfication for VBAC and why=
Previous CLASSICAL C SECTION scar
Because this means the scar is in the upper uterus
so higher chance of rupture
What are the complications of breech presentation?
- cord prolapse
- cord compression
- damage to visceral organs / brachial plexus
When is vaginal delivery acceptable with twins=?
If the first twin is cephalic
What do you do if the first twin is breech?
C sec
What percentage of pregnancies in the UK are induced?
25%
What are indications for induction of labour?
Prolonged pregnancy >41 weeks (increased risk of stillbirth, meconium aspiration…)
PROM (prelabour rupture due to risk of amnionitis)
PET, GDM, OC
Deteriorating maternal illness
Unexplained APH
Twins > 38 weeks
What are ABSOLUTE CONTRAINDICATIONS for IOL?
Placenta previa
Severe foetal compromise
What is the Bishop score?
Quantify the appropriateness of induction based on how far cervical changes have progressed
- high score = favourable Cervix = short and easy IOL
- low score = unfavourable cervix = long IOL; likely fail
What order do you use methods of induction?
- Membrane sweep
- Prostaglandin
- ARM
- Oxytocin infusion
What is the membrane sweep?
introduction of a gloved finger into cervix and rotate around inner rim of cervix
Should stimulate prostaglandin production
When is membrane sweep appropriate?
> 40 weeks
What forms of prostaglandins. can you give?
Prostin (gel) - at least 2 doses 6 hours apart vaginally
Propess (pessary) - leave in place for up to 24h
What must you exclude before doing a membrane sweep’
Placenta previa
How do you regulate oxytocin infusion?
Start slow
Increase gradually every 30mins
What are disadvantages of IOL?
more pain
Higher risk of instrumental delivery
Increased risk of PPH due to uterine atony
Foetal compromise due to uterine hyperstimulation
What is a risk of performing ARM if head is too high?
Cord prolapse
What are the options if IOL fail?
Rest then try again
OR
Csec
