Labour Flashcards
Corticosteroids to help surfactant production
Dose:
- beclamethasone 12mg IM with 2nd dose 12-24hrs later
Benefits:
- help fetal surfactant production
- reduce mortality by 31%
- reduce complications of resp distress syndrome by 44%
- also help close patent ductuses
- protect against periventricular malacia, a cause of cerebral palsy
When to give:
- in all at risk of iatrogenic or spontaneous birth between 24+0 - 34+6 wks
- before all elective Caesarian sections up to 38+6 wks
- at 35-6 wks if delivery expedited for pre-eclampsia
Benefit occurs within 24hrs (and lasts 7days)
Preterm definition
Babies born before 37+6 wks.
Leading cause of perinatal mortality and morbidity.
6% of singletons, 46% of twins, 79% of triplets.
10% due to multiple pregnancy, 25% due to polyhydramnios, pyelonephritis or other infections.
In 40% cause is unknown, but abnormal genital tract colonisation has been linked.
In preterm labour:
- 50% contractions cease spontaneously
- treating cause may help
- tocolytics are unlikely to suppress contractions once membranes ruptured or cervix >4cm dilated
Give corticosteroids to help surfactant production.
Cerebral palsy is present in 20% born at 24-26wks.
Inter-uterine growth restriction (IUGR)
Neonates weighing <10th centile for gestational age.
Causes:
- multiple pregnancy
- malformation
- infection
- smoking
- diabetes
- HTN
- low Hb
- pre-eclampsia
- heart or renal disease
- asthma
- where placental insufficiency was cause, head circumference is relatively spared (baby has been starved)
10% are in women who only ever produce small babies
Effects of IUGR in later life:
- by age 23 mild cognitive problems have been overcome
- hypertension
- coronary artery disease
- type 2 diabetes
- autoimmune thyroid disease
Postmaturity (prolonged pregnancy)
Pregnancy exceeding 42wks.
5-10% of pregnancies, induction usually offered between 41-42 wks.
Problems:
- possible placental insufficiency
- larger fetuses
- fetal skull more ossified so less mouldable
- increased Meconium passage in labour
- increased fetal distress in labour
- increased Caesarian rates
Stages of normal labour
- show
First stage
- latent phase
- painful contractions, cervix effaces, then dilates to 4cm
- established phase
- contractions with dilations from 4cm at 0.5cm/hr
- takes 8-18hrs in primip, 5-12hrs in multip
Second stage
- passive stage
- complete cervical dilation but no desire to push
- active stage
- baby can be seen, full dilatation, with expulsive contractions and maternal effort
- expect birth within 3hrs in primip, 2hrs in multip
Third stage
- delivery of placenta
- physiological management - takes <1hr
- active management - use syntometrine, takes 5mins and reduces bleed
Premature rupture of membranes
Rupture of membranes prior to onset of labour in women 37+ wks of labour.
Occurs in 8-10%
60% go into spontaneous labour in 24hrs, if not then induce as higher rate of infection.
Induction of labour
20% induced.
Usually due to:
- hypertension
- pre-eclampsia
- prolonged pregnancy (41+ wks)
- rhesus disease
Cervical ripeness
- calculated using Bishop’s score:
(each given 0, 1, 2 points, score>5 is ripe)
- cervical dilatation (cm)
- length of cervix (cm)
- station above head (cm above ischeal spines)
- cervical consistency - firm/medium/soft
- position of cervix - posterior/middle/anterior
- if primips induced with unripe cervix, (bishop’s score 3 or less) the rates of prolonged labour, fetal distress, Caesarian are increased
- less marked in multips
Induction:
- ripen cervix using prostaglandin vaginal gel before induction if needed
- stretch and sweep
- amniotomy
- oxytocin via pump
Problems with induction:
- failed 15%
- uterine hyper stimulation
- iatrogenic prematurity
- infection
- bleeding (vasa praevia)
- cord prolapse (eg high head at amniotomy)
- higher rates Caesarian and instrumental delivery
- uterine rupture (rare)
Pain relief in labour
Waterbirth
Pethidine
- narcotic injection IM
- reversible with naloxone
- use in first stage or if birth not expected in next 3hrs as can cause neonatal respiratory depression
- expect analgesia in 20mins and to last 3hours
- give with antiemetic
- SE: disorientation, drowsy, delayed gastric emptying, neonatal respiratory depression
Nitrous oxide
- entonox/gas and air
- can be inhaled throughout labour
- self administered
- SE: nausea, light headed
Pudendal block
- sacral nerve roots 2,3,4
- uses lidocaine
- used with perineal infiltration for instrumental delivery (but not rotational forceps)
Spinal block
- used for rotational delivery or Caesarian
Epidural
- anaesthetises T11-S5
- may be used throughout labour
- SE: postural hypotension, urinary retention (catheterise), paralysis preventing voluntary effort in second stage, headache and urinary retention afterwards.
Combined spinal epidural (CSE)
- gives quicker pain relief with little or no motor blockade allowing standing and other movement
- patient controlled dose
Multiple pregnancy
- predisposing factors
- possible features
- complications during pregnancy
- fetal complications
- complications of labour
Twins 3:200, triplets 1:10000
Predisposing factors
- prev twins
- fhx of twins
- increased maternal age
- induced ovulation and IVF
- race
Possible features
- uterus large for dates
- hyperemesis
- polyhydramnios
Complication during pregnancy
- polyhydramnios
- pre-eclampsia
- anaemia (increased requirements iron and folate)
- increased incidence APH (abruption and praevia)
- 1 placenta (monochorionic) risks veto fetal transfusion
- 1 sac (monoamniotic) risks entanglement
Fetal complications
- perinatal mortality higher, mainly due to prematurity (mean twins at 37wks, triplets at 33wks)
- growth restriction
- malformation rates higher esp if monozygotic
- severe disability rates higher
Complications of labour
- PPH
- malpresentation
- vasa praevia rupture
- cord prolapse
- premature placental separation and cord entanglement
Breech presentation
40% breech at 20wks, 20% at 28wks, 3% at term
Extended breech
- most common
- flexed at hips but extended at knees
Flexed breech
- hips and knees both bent so presenting part is mix of buttocks, external genetalia, and feet
Footling breech
- least common
- feet presenting part
- greatest risk of prolapsed cord
External cephalic version (ECV)
- turning breech by manoeuvring it through a forward somersault
- only if vaginal delivery planned
- at 36wks for primips, 37wks for multips
- success rate 40% in primips, 60% in multips
- CI if any abnormalities
Mode of delivery
- Caesarian may provide better outcome for fetus
- CI to vaginal if inadequate pelvis, footling or kneeling breech, baby v big or v small, prev section, hyperextended neck, no experienced clinician
- assisted breech delivery
- first is bitrochanteric diameter transverse
- then rotates so bitrochanteric is AP
- lateral flexion of trunk
- external rotation so transverse again
- shoulders enter transversely, rotate to exit AP
- body hangs for a minute
- when neck well seen then lift body and head delivered with forceps
Occipitoposterior presentation (OP)
In 50% the mothers have a long anthropoid pelvis
Diagnose antenatally by palpating
On examination the posterior fontanelle is in posterior quadrant of pelvis
Labour is prolonged due to degree of rotation needed
- in labour 65% rotate so OA at birth
- 20% rotate so transverse and arrest -deep transverse arrest
- 25% rotate so octopus truly posterior and birth by flexion of head from perineum
73% have spontaneous vaginal delivery
22% need forceps
5% need Caesarian
Other malpresentations
Face presentation
- 1:994
- 15% due to congenital abnormality
- 90% rotate so chin behind symphysis and head born by flexion
- if chin rotates to sacrum, need Caesarian
Brow presentation
- 1:755
- associated with contracted pelvis or v large fetus
- deliver by Caesarian
Transverse lie
- 1:400
- usual causes: multiparous, multiple pregnancy, polyhydramnios, placenta praevia, septate uterus
- high risk of cord prolapse
- external cephalic rotation may be tied
- need Caesarian if persists or recurs
Stillbirths / intrauterine fetal death
Babies born dead after 24 wks
Some hours after death, skin begins to peel - described as macerated rather than fresh stillbirths
If left, spontaneous labour usually occurs
Mother usually reports absent fetal movements, lack of heart sounds unreliable. Diagnose by lack of fetal movement eg heart on US.
Antepartum causes
- malformation
- congenital infection
- pre-eclampsia
- APH
- maternal disease
- hyperpyrexia
- post maturity
Intrapartum causes
- abruption
- maternal and fetal infection
- cord prolapse/knots
- uterine rupture
No cause found in 50%
Risk factors
- multiple pregnancy
- increased maternal age
- smoking
- obesity
TORCH infections in pregnancy
Toxoplasmosis Other (eg syphilis) Rubella CMV Herpes (and Hepatitis)
Operative delivery
10-13% in UK
Head must be engaged, membranes ruptured, cervix fully dilated, position known, adequate analgesia
Forceps
- used if delay in second stage, assisted vaginal breech delivery
- can cause facial bruising, maternal trauma, VII paralysis (temperary), brachial plexus injury
- can get rotational forceps
Ventouse
- forceps preferred in UK
- causes less maternal trauma than forceps
- forms chignon which resolves in 2days
- increased rare of fetal cephalhaematoma, failed delivery, fetal retinal haemorrhages
