Obs - Labour Flashcards
when can you say some1 isi going nto labour?
Diagnosis of labour is made when painful uterine contactions accompany dilatation and effacement of the
cervix.
what are the stages of labour?
First stage: cervix opens to full dilatation
Second stage: full dilatation to delivery of the fetus
Third stage: delivery of fetus to delivery of placenta
what are the diameters of the pelvc inlet and outlet?
Inlet = transverse diameter: ~13cm, AP diameter = 11cm
The outlet, the transverse diameter (11cm) and the AP diameter is 12.5cm
what is the Attitude of a fetus?
the degree of flexion/extension of the head
can be vertex, brow or face
Ideal attitude = maximum flexion (vertex presentation)
how many cm is fully dilated?
10cm
describe the events of the 1st stage of labour?
Fetus: Descent, flexion and internal rotation
2 phases:
Latent phase = cervix dilates slowly for first 3cm – takes several hours
Active phase = 0.5-1cm/h (nullips) or 2cm/h (multips)
o Shouldn’t last >12h
describe the events of the 2nd stage of labour?
Full dilatation of the cervix to delivery
Passive stage = full dilataion until head reaches pelvic floor and woman experiences desire to push
o May last a few minutes or longer
Active stage = when mother is pushing
o Pushes with contraction
o Usually takes 40 minutes (nulliparous) or 20 minutes (multiparous)
o If it takes >1h, unlikely to be SVD
describe movements of baby in the 2nd stage of labour?
Head comes up and out of the pelvis
Head restitutes (external rotation 90degrees) to adopt transverse position
Shoulders then deliver
Anterior shoulder first, aided by lateral body flexion in posterior derection
Then posterior shoulder aided by lateral body flexion in anterior direction
Rest of body follows
what iis the overview of thee mechanisms of labour
Stage 1:
Descent
Flexion
Internal rotation
Stage 2:
Extension
External rotation/restitution
Enters inlet as OT -> OA in midcavity and delivery -> OT again with restitution when head is outside. PAGE 60 NINA
why is left lateral postion adopted in examination or labour in heavly pregnant women?
to prevent aortocaval compression which could lead to Low BP and reduced CO
if woman gets low bp due to epidural, what you do?
Iv fluids +- ephedrine
giive iv fluids prophylactically if using epidural
If GA used in labour/delivery, what are the risks and how s this mitigated?
aspiration of gastric contents
giive ranitidine
how would you manage fever in labour?
If feveer > 38C
Cultures of vagina, urine and blood taken
IV abx if fever 38C or risk factors for sepsis
what is the most common cause of failure to progress (or slow progress)?
ineffective uterine action or incoordinate uterine activity
how would you manage ineffective uterine action?
Amniotomy
Oxytocin (syntocinon infusion ‘drip’)
what could cause hyperstimulation/ Hyperactive Uterine Action
too much oxytocin
side effect of PGE2 administration to induce labour
placental abruption
how is hyperstimulation treated?
Tocolytic (salbutamol) IV or SC
how would you manage an OP presentation?
attempt normal vaginal delivery
if not achieved in 1 hour:
ventouse
or rotational forceps - keillands
how would you manage an OT presentation?
Ventouse
dont use forceps where head is not in a DIRECT position!
a woman is in labour. On VE the anterior fontanelle,
supraorbital ridges and the nose are palpable
vaginally. meaning? rx?
Brow presentation - hyperextended
C-Section
how would you manage a face presentation?
vaginal delivery if chin anterior
otherwise c-section
how can you determine fetal hypoxia/distress in labour?
- Colour of liquor: meconium
o Indication for caution and CTG surveillance - Use Pinard’s stethoscope or hand held Doppler
- CTG
- Fetal ECG
- Fetal scalp sampling
Scalp blood pH <7.20 (capillary) indicates significant hypoxia
can do cord ph but not often done
what are the causes of hypoxia in labour?
o Placental abruption o Hypertonic uterine states o Use of oxytocin o Umbilical cord prolapse o Maternal hypotension
what does the term fetal distress refer to?
hypoxia that might result in fetal damage
or death if not reversed or the fetus delivered urgently delivered.
you find that a fetus has meconium stained liqour in-utero. what does this mean? rx?
the presence or absence of meconium is not a reliable indicator of fetal well-being.
It is an indication for caution (and hence closer surveillance with a CTG) because (i) the fetus may aspirate it, causing
meconium aspiration syndrome, and (ii) hypoxia is
more likely.
If meconiium is thick - amniofusion of
saline into the uterus to dilute the meconium reduces
the incidence of meconium aspiration
what findings on ctg are abnormal?
tachy/bradycardia
Hyperstimulation = >5 in 10 minutes AND fetal distress (if no distress -> tacchysystole)
Loss or increase in baseline variability
Variable decelerations:
o Classically reflect cord compression
o Can lead to hypoxia
Late decelerations
o Persist after the contration is completed
o Suggestive of fetal hypoxia
persistent bradycardia would require?
immedate delivery
bun ctg monitoring
how would you know a fetus is distressed/hypoxic before dong a FBS?
CTG abnormalities
how iiis fetal distress managed overall?
Place woman in left lateral position
Oxygen and IV fluids
Stop oxytocin infusion
VE to exclude prolapse or rapid progress
FBS and rapid delivery if pH <7.20
Second scalp in 30 min if >7.20
Sustained bradycardia or impossible FBS deliver by quickest route
what are the indications for CTG use?
indications for ctg:
Prelabour risk factors include pre-eclampsia, IUGR,
previous caesarean section, induction.
In labour risk factors include the presence of meconium,
the use of oxytocin, the presence of a temperature >38 °C, during the administration of epidural analgesia.
when can a woman NOT have an epidural?
Sepsis o Coagulopathy or anticoagulant therapy (unless LMWH) o Active neurological disease o Spinal abnormalities o Hypovolaemia
list some complications of epidural?
Puncture of dura mata leakage of CSF and severe headache
Inadvertent IV injection convulsions and cardiac arrest
o Inadvertent injection of local anaesthetic into CSF -> total spinal paraesthesia
in normal labour when is intrumental indicated?
If baby not delivered with 1 hour of pushing in 2nd stage
OP/OT
what is an active third stage?
when drugs given to stimulate uterine contraction to reduce incidence of PPH
Normal circumstance:
IM oxytocin
Ergometrine and oxytocine = Syntometrine - dont giive iif BP issues
followed by Controlled cord traction
If there is a retained placenta (third stage >30 minutes)
Oxytocin infusion started and 10 units injected into vein of cord and milked up
An hour is left for natural separation, after which the placenta is manually removed
Hand in uterus under general or spinal anaesthesia
what aree the levels of perineal trauma?
First degree Injury to skin only
Second degree Involving perineal muscles but not
anal sphincter
Third degree Involving anal sphincter complex
3a: <50% of external anal sphincter torn
3b: >50% of external anal sphincter torn
3c: internal anal sphincter also involved
Fourth degree Involving anal sphincter and anal
epithelium
how to manage perineal tears?
1 & 2 - suture under LA
3&4 - repair sphincters under epidural or spinal
- give laxatives and abx
what are the different birth options for women - wiithout complications?
Home birth - if low risk
Birth centre - midwiife led unit
Water birth - labour and delivery are
conducted in a large bath of water maintained at 37 °C.
Water is relaxing and analgesic. Baby. doesnt breath till surface
Epidural - allows fast labour, painless - labour ward or birth centre
c-section if valid reason eg trauma or medical contraindication
what is the Bishop score?
assesses the favourability of the cervix for induction of labour.
out of 10
if less than 6, cervical riipening agents may need to be used
what options for IOL are available ? indications?
Induction with PGE2 gel (2mg) eg Prostin - inserted into posterior vaginal fornix
Best for nullips and most multips with favourable cervixes
It either starts labour or induces cervical ripening
Another dose may be given a minimum of 6h later providing there is no uterine activity
Amniotomy + Oxytocin
Forewaters are ruptured with an amnihook = artificial rupture of membranes (ARM)
Oxytocin infusion then started within 2h if labour has not ensued
Can use oxytocin alone if SROM occurred
PGEs are equally effective
Natural
Membrane sweep
At 40 weeks, it chance of IOL and postdates pregnancy
what are contraindications for induction of labour?
Absolute Acute fetal compromise Abnormal lie Placenta praevia Pelvic obstruction e.g. mass or deformity cephalopelvic disproportion >1 CS
Relative
1 previous CS
prematurity
what are complications of IOL?
Inefficient uterine activity Risk CS or instrumental delivery Hyperstimulation -> fetal distress and uterine rupture PPH Intra- and postpartum infection
list some contraindications for VBAC?
Usual contraindications for CS
Vertical uterine scar
Multiple previous caesarean
- IF labour is giong on too long
chance of successful vbac?
60% first one, chances of success increases each subsequent vbac
what are the factors required before a woman is selected for a VBAC?
- uncompliicated ceasarean
- if it was very complicated c-section probably not vbac - if the c-sectoin wound has adhesions and keloids / poor healing?
- fetus has: longitudnal liie, cephaliic presentation , fetal size; not macrosomic or growth restricted, singleton pregnancies only.
what are the complicatoins of vbac?
0.7% risk of old c-section scar rupture during labour
may lead to emergency rescure c-sectiion
what is the different between scar dehiscence and rupture?
Serosa preserved - scar dehiscence
Endometrium myometrium and serosa breeched - scar rupture
what are special considerations in VBAC deliveries?
If they don’t spontaenoulsy go into labour; induce them -with a modified iniduction:
- no prostin/prostaglandins to induce
- can do balloon ripening
- can do AROM
- judiiciious use of syntocinon does not increase risk of scar rupture. (start low dose, tiitrate up gradually whilst monitoring mother and fetus) - only use if very low or no contractions.
how is prelabour term rupture of membranes managed?
await spontaneous labour or iniduce labour
if gettinig to 1.5 days, give abx against GBS
how do you know when there has been a uterine rupture?
- Basiic observations
- Pain around her previous scar, peritonism
- Abdominal distension
- Can perhaps feel baby in abdomen - as its left the
uterus - Blood stained liqour
- Blood stained urine
- Can no longer feel fetal head on VE - or fetal station is higher
when can you not attempt instrumental delivery
if not indcated eg woman can deliver naturally
fetal station is too high / head still palpable abdominally
how does uterine inversion present?
profound bradycardia + Low BP out of keeping with observable loss
What bishops score indicates likely spontaneous labour?
8+
Less than 6 indicates unlikely spontaneous labour - cervical ripening agents needed
equate the presenting diameters of a fetus to the attitude
Vertex/OA - Suboccipito bregmatic - 9.5cm (fully flexed)
OP - occipitofrontal - 11cm (deflexed)
Brow - Verticomental - 13.5cm (partial extension) -> not compatible with vaginal delivery
Face - submentobregmatic - 9.5cm (full extension)
how do you know if baby is brow presentation?
Can palpate orbital ridges and anterior fontanelle.
wha t are the mechanical factors influencing labour?
Power:
- degree of force expelling the fetus
- Poor uterine activity is a common feature of nullips and in IOL
- pressure from head adds to this
Passage:
- Bony pelvis and its dimensions
- Soft tissues eg cervix, vagina, perinuem and their ability to dilate
Passenger:
Diameter, attitude, position and size of fetal head
