Abnormal labour and Induction of labour Flashcards
What percentage of pregnancies are induced?
10-20%
What are obstetric indications for induction of labour?
- Uteroplacental insufficiency
- Prolonged pregnancy - 41-42 weeks
- Pre-labour PROM
- IUGR
- Oligo/anhydramnios
- Abnormal uterine/umbilical dopplers
- Abnormal CTG
- Severe pre-eclampsia/Eclampsia
- Unexplained antepartum haemorrhage
- Chorioamnionitis
What are medical indications for induction of labour?
- Severe hypertension
- Uncontrolled DM
- Renal disease with deteriorating renal function
- Malignancies
What is induction of labour?
An attempt to artificially instigate labour using medications +/- artificial rupture of the amniotic membranes (performing amniotomy)
Methods of induction of labour
- Membrane sweeping
- Prostaglandin gel/oessary (most common)
- Oxytocin with/wtihout artificial rupture of membranes
How is cervical ripening assessed?
Bishops Scoring
- Dilatation
- Effacement
- Position
- Consistency
- Station
What are absolute contraindications to induction of labour?
- Abnormal lie
- Known pelvic obstruction
- Placenta praevia
- Foetal distress
- Cephalopelvic disproprtion
What is the Bishop’s score used to determine?
Gives a score on cervical change - higher the score the more progressive change there is, indicating that induction of pregnancy is likely to be successful and when an amniotomy is likely to be possible
What are the relative contraindications to induction of labour?
- Previous C-section
- Asthma
Why is previous C-section a relative contraindication to induction of labour?
Uterus has a scar which increases risk of dehiscence/rupture if labour is artificially induced. The risk of rupture is increased with the use of prostaglandins
Why is asthma a relative contraindication of induction of labour?
Prostaglandins can cause respiratory smooth muscle contraction
Complications of inducing labour
- Higher risk of intstrumental or caesarean
- Utrenie hyperstimulation
- Uterine rupture
- Failed induction
- Cord prolapse/shoulder dystocia
- Infection
- Prematurity
What medications are used in the induction of labour?
- Prostaglandin analogues - Dinoprostone, Misoprostol
- Oxytocin
What type of prostaglandin analogue is Dinoprostone?
Prostaglandin E2 analogue
What type of prostaglandin analogue is Misoprostol?
Prostaglandin E1 analgogue
What is the mechanism of action of prostaglandin analogues in induction of pregnancy?
Encourage cervical dilatation and effacement - ripening
What are adverse effects of prostaglandin analogues used for induction of labour?
- Severe/hypertonic contractions
- Nausea and vomiting
- Bowel upset
- Pyrexia
- Hypotension
What needs to be regularly monitored when using prostaglandin analogues?
Foetal heart - CTG
What is the mechanism of action of oxytocin in the induction of labour?
Initiates uterine contraction by attaching to uterine oxytocin receptors, increasing the frequency and force of contractions
What type of drug is oxytocin?
Cyclic nonapeptide
How are prostaglandin anaolgues administered?
PV
How is oxytocin administed for induction of labour?
IV
When is amniotomy performed in induction of labour?
Once cervix has effaced an dilated - Bishops > 7
When is oxytocin given in induction of labour?
Often used following prostaglandin treatment, once amniotomy has been performed
What monitoring needs to be done whilst giving a women an oxytocin infusion for induction of labour?
CTG monitoring
What are risks of using oxytocin use in induction of labour?
- Uterine hypertonicity
- Hypotension
- Hyponatraemia
What does amniotomy cause release of?
Local prostaglandins - causes cervical ripening and myometrial contractions
Why is oxytocin often given at the time of amniotomy in induction of labour?
Decreases induction-delivery time, thereby decreasing both the foetal and maternal risk of sepsis
What are risks of trying to induce labour?
- Prematurity
- Drug side effects
- C-section due to failed induction
- Atonic PPH
- Intrauterine infection with prolonged induction
Why should you monitor U+Es in someone being given oxytocin?
Has similar effects to ADH - look for dilutional hyponatraemia
How would you induce for intrauterine death at term?
25 mcg misoprostol every 2-4 hrs
When is labour augmentation required?
When contractions reduce frequency or strength in active labour even after spontaneous onset of labour
What needs to be determined before using medications to augment labour?
Woman needs to be assessed for signs of causes of lack of progress of labour e.g. obstruction due to malposition, which contractions could result in harm to foetus
What is used to augment labour?
IV oxytocin infusion
What are reasons for slow progress at stage 1 of labour?
-
Power
- Inefficient uterine contraction (cervix won’t dilate) - syntocinon needed
-
Passenger
- Malposition
- Malpresentation,
- Large Baby
-
Passages
- Inadequate pelvis - CPD
When is failure to progress in labour suspected?
If there is:
- <2cm dilation in 4 h
- Slowing progress in parous woman
What is the term used to describe labour slow from onset?
1o dysfunctional labour
What is the term used to describe previously adequate progress which has slowed in the first stage of labour?
2o arrest
When would delay in 2nd stage of labour be suspected in a nulliparous woman?
If delivery is not imminent after 1 hr of active pushing
When would delay in 2nd stage of labour be suspected in a multiparous woman?
If delivery is not imminent after 1 hr of activ pushing - requires obstetrician review and consideration for CS
What would delay in the 2nd stage of labour always raise suspicion of in a multiparous woman?
- Malposition
- Disproportion
What are the main reasons for failure of labour?
Powers, passages and passenger:
- Powers - uterine inactivity
- Passages - CPD, inadequate pelvies
- Passenger - Large baby, malpresentation, malposition
What is the difference between malposition and malpresentation?
Malpresentation referes to foetal position in the uterus, whereas malposition refers to the orientation of the foetal head (e.g. OA, LOA etc.)
How would you monitor for foetal distress in labour?
- Intermittent auscultation
- CTG
- Foetal blood sampling
When would you consider advising against labour?
- Obstruction to birth canal - Major placenta praevia, masses
- Malpresentations - Transverse, shoulder, hand, ??breech
- Medical conditions where labour would not be safe for woman
- Specific previous labour complications - Previous uterine rupture
- Fetal conditions
What are the main complications that can occur in the 3rd stage of labour
- Retained placenta
- PPH
- Obstetric shock
- Inversion of the uterus
What is a first degree perineal tear?
Injury to skin only
What is a 2nd degree perineal tear?
Injury to the perineum involving perineal muscles
What is a 3rd degree perineal tear?
Injury to perineum involving anal sphincter complex
What is a grade 3a perineal tear?
Injury to perineum + <50% EAS thickness torn
What is a grade 3b perineal tear?
Injury to perineum and >50% EAS torn
What is a grade 3c perineal tear?
Injury to perineum and tear to IAS
What is a 4th degree perineal tear?
Injury to perineum involving anal sphincter complex (EAS + IAS) and the anal/rectal epithelium
What grade of tear is the following?
Grade 1
What grade of perineal tear is the following?
Grade 2 - injury to perineal muscles
What grade of perineal tear is the following?
Grade 3
What grade of perineal tear is the following?
Grade 4
What factors increase the risk of tears that involve the anal sphincters?
- Forceps delivery
- Nulliparity
- Shoulder dystocia
- 2nd stage > 1hr
- Persistent OP postion
- Midline episiotomy
- Birth weight > 4kg
- Epidural anaesthesia
- Induction of labour
When should episiotomy be considered?
- Complicated vaginal delivery - breech, shoulder dystocia, forceps, ventouse
- Extensive lower GI tract scarring - FGM, poorly healed 3rd/4th degree tears
- Foetal distress
What are the different types of episiotomy procedures?
- Mediolateral episiotomy - most commonly used in UK
- Midline episiotomy
How is an episiotomy performed?
- Epidural or regional block
- 2 fingers between babies head and perineum
- Scissors used to make sharp cut - 3-4cm long
What are general complications of perineal trauma (including episiotomy)?
- Bleeding
- Haemorrhage
- Pain
- Infection
- Scarring +/- potential disruption to anatomy
- Dyspareunia
- Fistula formation - very rare
What should be done before repairing a perineal tear?
PR examination - ensure no trauma to anal sphincter
What are the main indications for caesarian section?
- Foetal compromise
- Failure to progress in labour
- Breech presentation
- Repeat Caesarian section
What are indications for category 1 (immediate) C-section?
- Placental abruption with abnormal FHR/uterine irritability
- Cord prolapse
- Scar rupture
- Prolonged bradycardia
- Scalp pH < 7.2
What are indications for category 2 (urgent) C-section?
Failure to progress with pathological CTG
What are indications for category 3 (scheduled) C-section?
- Severe pre-eclampsia
- IUGR with poor foetal function tests
- Failed induction of labour
What are indications for a category 4 (elective) C-section?
- Term singlton breech
- Twin pregnancy with non-cephalic first twin
- Maternal HIV
- Primary genital herpes in 3rd trimester
- Placenta praevia
What intraoperative complications can occur in C-section procedures?
- Uterine/uterocervical lacerations
- Blood loss - Blood transfusion
- Bladder laceration
- Hysterectomy required
- Bowel laceration
- Ureteral injury
What postoperative complications can occur following C-section?
- Endometritis
- Wound infection
- Pulmonary atelectasis
- VTE
- UTI
What risk factors can increase with risk of infection developing post C-section?
- Preoperative remote infection
- Chorioamionitis
- Maternal severe systemic disease
- Pre-eclampsia
- High BMI
- Nulliparity
- Increased surgical blood loss
What can C-section increase the risk of in subsequent pregnancies?
- Uterine ruptue
- Pleacenta praevia
- Placenta accreta
- Antepartum still birth
What is preterm rupture of membranes?
DEfined as leakage of amniotic fluid in the abscence of uterine activity after 37 completed weeks of gestation
What can cause prelabour rupture of membranes at term?
- Unkown
- Clinical/subclinical infection
- Polyhydramnios
- Multiple pregnancy
- Malpresentations
What might be symptoms of prelabour rupture of membranes at term?
- Sudden gush of fluid leaking from the vagina
- Recurrent dampness
- Constant leaking
What might you see on examination in someone with prelabour rupture of membranes at term?
May need speculum exam:
- Fluid leaking from cervix on valsalva
- Liquor pooling in upper vagina
What are clinical features of chorioamionitis?
- Foetal tachycardia
- Maternal tachycardia
- Maternal pyrexia
- Raised leucocytes
- Rising CRP
- Irritable/tender uterus
How would you manage prelabout rupture of membranes at term?
Immediate induction (recommended after 24 hrs of rupture) or expectant managment
What are maternal causes of malpresentation?
- Multiparity
- Pelvic tumours
- Congenital uterine abnormalities
- Contracted pelvis
What are foetal causes of malpresentation?
- Prematurity
- Multiple pregnancy
- Intrauterine death
- Macrosomia
- Foetal abnormality
- Polyhydramnios
- Placenta praevia
What placental problems can cause malpresentation?
- Placenta praevia
- Polyhydramnios
- Amniotic bands
When should retained placenta be suspected?
If it is not delivered within 30 minutes of the baby in actively managed 3rd stage and in 1h in physiologically managed 3rd stage
How would you manage retained placenta?
- IV access, FBC and crossmatch
- Give Syntometrine or oxytocin
- Transfer to theatre if oxytocin not effective
What is regarded as delay in the 1st stage of labour?
<2cm/hr dilatation in 4hrs in any woman OR slowing progress
What Bishops score would indicate that a womans cervix is “ripe”?
>5
What is cord prolapse?
Umbilical cord prolapse is when, during labor, the umbilical cord comes out of the uterus with or before the presenting part of the baby. The concern with cord prolapse is that pressure on the cord will compromise blood flow to the baby and therefore foetal asphyxia.
Risk factors for cod prolalpse
- Prematurity,
- Breech presentation
- Multiple pregancy esp 2nd twin
- Polyhydramnios
- Uengaged head
- Transverse or unstable lie + PROM
- Placenta praevia
What is occulta cord prolapse
Descent of umbillical cord through cervix alongside the presenting part
What is overt cord prolapse
Descent of umbilical cord past the presenting part - EMERGENCY
Management of a cord prolapse
- Call for help
- Alert labour ward
- Alert neonatal team
- Put women either head down (left lateral position) or get her onto knee elbow position
- IMMEDIATE C section is best
Complications of cord prolapse
Infant death
Cerebral palsy
Hypoxic ischaemic encephalopathy
