Intrapartum Flashcards
RANZCOG recommendations
for birthing unit
Where on-site services cannot be provided, women should be informed of the limitations of services available and the implications for intrapartum and postpartum care
Formal systems for safe and timely transfer
Amongst women selected for low obstetric risk, ~25% will develop peripartum complications necessitating transfer to an obstetrician led services
Timely access to - obstetric, midwifery, neonatal / paediatric, anaesthetic, operating theatre, resuscitation services
Further requirements: - ICU consultation, haematology, blood bank
Audit of outcomes and intervention
RANZCOG recommendations for labour care
Partogram
Routine obs on EWS
Women should be encouraged to ambulate freely according to comfort, where it does not compromise maternal and fetal observations in labour
- Cochrane 2013 - first stage of labour may be approx 1h 20m shorter for women who are upright or walk around
VE within 4h of arrival
Most trials do 2 hourly cervical assessments
Compromise: 4 hourly VE
Encourage clear fluids and light diet in active phase of labour to minimise risk of aspiration pneumonitis
All women should give birth in a position where they can rapidly access treatment in the event of sudden unexpected complications
RANZCOG post-partum recommendations
“Active” management of third stage is recommended for all women
Skin-to-skin contact should be facilitated as appropriate
Provide debriefing opportunities following adverse outcome or experience not meeting expectations
Delayed cord clamping benefits
75% of blood within 1st min, no increase in PPH
In term infants - increased hot, reduced iron deficiency at 6/12
- However increased polycythaemia and jaundice
Preterm
- Reduced transfusion, infection, NEC, IVH
Failure to progress
- 1st stage before established
No upper limit to the length of the ‘latent phase’ can be defined
Not uncommon for labour to stop and start before finally established
Recurrent or prolonged episodes of spurious labour may contribute to a legitimate decision for IOL in some women
Failure to progress
- 1st stage labour
PRIMIP
10th centile for progress of cervical dilatation in labour is 0.9 cm/hour (primigravida)
Threshold at which slow cervical dilatation merits a recommendation for oxytocin:
- Individualised with an informed discussion with the woman
- Commonly 1cm/hr for most women in spontaneous labour
- May be as high as 1cm / 2hr in women prioritising low intervention
MULTIP
10th centile for progress of cervical dilatation is 1.2cm/hr (multigravida)
Caution for augmentation as increased risk of uterine rupture compared to primigravida
Failure to progress
- 2nd stage
Progress includes flexion, rotation and descent
Normal for primigravida = up to 2 hours
Normal for multigravida = up to 1 hours
Factors contributing to labour
Passage
- Size of maternal pelvis
- Compliance of the cervix and soft tissue
- CPD
Passenger
- Size of fetal head
- Presentation and position of fetus
- Degree of fetal moulding
- Malpresentation, malposition
Powers
- Efficiency of uterine contractions. Effective UA is generally sustained for >40s
- Inadequate UA, dehydration, epidural
Dimensions of the maternal pelvis
Transverse diameter AP diameter
Pelvic inlet 13 11
Mid pelvis 12 12
Pelvic outlet 11 13
Pelvic inlet - transverse > AP, therefore foetus enters transverse and rotates (widest foetus diameter, is the AP)
Diameter names and dimensions for different presentations
Vertex - flexion of the fetal head
Suboccipitobregmatic (9.5cm)
- Below the occiput to the centre of the anterior fontanelle
Face
Submentobregmatic angle (9.5cm)
- Angle between the neck and chin and the centre of the anterior fontanelle
Deflexed OP
Occipitofrontal (11.5cm)
- Occiput to the root of the nose
Brow
Mentovertical (13-14cm)
- Chin to the centre of the sagittal suture
Incidence of malpresentations
OP 10% at the start of labour Brow 0.2% Shoulder 0.3% Breech 3% Face 0.2%
Mechanism of OP in labour
Deflexion occurs due to:
- the opposition of the fetal and maternal spines
- The longer BPD enters the narrower part of the pelvis while the bitemporal diameter enters the wider part.
As a result of this deflexion the occipito-frontal diameter (12.5cm) enters the pelvis leading to delayed engagement.
Next depends on what enters pelvis first (as will rotate anteriorly) and therefore the extent of deflexion.
90% of cases occiput meets pelvic floor first and anterior rotation and flexion will occur = OA
10% of cases head will rotate into OT arrest or remain OP
- obstruction requiring c-section, manual rotation or instrumental delivery
- If vaginal delivery increased chance of perineal trauma as vulva and perineum distended and stretched by occipito frontal diameter
Face presentation
Result of hyper-extension of neck
Presents submentobregmatic which is similar size to OA presentation
SVB possible if chin anterior = mento-anterior
- MAD = mentoanterior delivers
- Oxytocinon can be used to increase flexion
- Forceps can be used but ventouse, FBS or FSE contraindicated
- Will have considerable bruising and facial oedema postnatally
Mento-posterior –> indication for CS
Brow presentation
Very deflexed head in mentovertical position
Usually needs c-section
Can have vaginal delivery if very small fetus or multip
Bishop score
Score from 0-3 for: Dilatation (cm) Length (cm). Consistency Position Station
Moulding definitions
0 - Bones are separated and the sutures can be felt easily
1+ - Suture lines touch
2+ Suture lines overlap and are reducible easily with pressure by your finger
3+ Suture lines overlap and are irreducible
Second stage pushing
Delaying active pushing until the woman has an involuntary urge or the fetal head is visible on the perineum has been shown to reduce the incidence of forceps delivery, the need for caesarean section and it also shortens the active bearing down phase of the second stage
The use of sustained valsalva bearing down efforts is associated with lower fetal pH and higher fetal pCO2 levels
Steps of labour
Descent Engagement Neck flexion Internal rotation Crowning Extension of presenting part Restitution
Role of hormones in labour
Oestrogen
- From 37 weeks levels of oestrogen > progesterone this increases sensitivity to and stimulates release of oxytocin and prostaglandins
Oxytocin
- Released by maternal pituitary, causes contraction of myometrial cells
Prostaglandins
- Released by myometrium in response to cervix stretching, stimulate myometrial contractility by sensitising myometrial cells to oxytocin
- Prostaglandin + oxytocinon = positive feedback loop of increasing cervical stretch and therefore increasing release of PG and oxytocinon causing escalating intensity of contractions
Relaxin
Glucocorticoids
Contraindications to tocolysis
Maternal cardiac disease
Hypertension
Placental abruption
Evidence for water immersion
Cochrane review
- Water immersion in the first stage a/w significant reduction in epidural / spinal / paracervical analgesia / anaesthesia rate
- Reduction in duration of the first stage of labour (mean difference 32.4 mins)
- 1 trial found significantly higher level of satisfaction with the birth experience
Evidence for water birth
Concerns have been raised about fetal safety and drowning
No evidence of increased maternal, fetal or neonatal risk
- Further research warranted
Observational evidence suggests that if conducted according to a protocol and women appropriately selected, waterbirth can be achieved safely
Cochrane
- No difference in assisted delivery rate, CS, use of oxytocin, perineal trauma or maternal infection
- No differences in Apgar scores <7 at 5 mins, NICU admissions, neonatal infection rates
Issues to consider with water birth
Fetal surveillance should still occur as per RANZCOG recommendations
VE to assess progress may be performed under water if deemed necessary
- There is no quality evidence attesting to the safety of VE whilst immersed in water
Oxytocin augmentation of labour may not be possible
Third stage
- No reliable evidence to establish risks and benefits
- Theoretical risks of water embolism
- Best practice - assist to exit pool after birth where can manage third stage and accurately assess blood loss
Positive GBS swabs are not a primary contraindication
Women with PROM (>18h) may utilise water immersion during labour and birth provided IV Abs are administered
ARM evidence for slow progress
Consider if delay in first stage, if no further change after 2h, then consider synt
Evidence that routine ARM shortens labour is largely lacking