Overview

• Labour → onset of regular and painful contractions associated with cervical dilation and descent of the presenting part.

Making Diagnosis

Clinical Features

• 1st Stage: onset of labour (true contractions) → 10cm cervical dilation.
  • Involves cervical dilation and effacement (getting thinner).
  • The ‘Show’ → mucus plug in the cervix (prevents bacteria from entering uterus during pregnancy) falls out and creates space for baby to pass.
  • Latent Phase (0-3cm dilated, 0.5cm/hr, irregular contractions) → Active Phase (3-7cm dilated, 1cm/hr, regular contractions) → Transition Phase (7-10cm dilated, 1cm/hr, strong and regular contractions).
    • Active Phase → 1cm/hr in nulliparous, 2cm/hr in multiparous.
  • Braxton-Hicks Contractions (Painless + No Cervical Change) → occasional irregular contractions felt during second and third trimester. Not true contractions and do not indicate onset of labour.
  • Signs of Labour → show (mucus plug from cervix), rupture of membranes, regular + painful contractions, dilating cervix on examination.
• 2nd Stage: 10cm cervical dilation → delivery of baby.
  • Passive Phase → begins with full dilatation until head reaches pelvic floor and ends with onset of involuntary expulsive contractions (ie. no urge to push).
  • Active Phase → begins with onset of involuntary expulsive contractions and ends with the birth of the baby (ie. maternal urge to push).
  • Lasts approx. 1 hour. (40 mins in nullips, 20 mins in multips)
• 3rd Stage: delivery of baby → delivery of placenta.
  • Only lasts 5-10 minutes.
  • If after 1 hour the placenta is still retained, the patient should be taken to theatre and the placenta removed under general anaesthesia. (Up to 1 hour, IM syntocinon and breastfeeding can be used to stimulate spontaneous expulsion).
• Mechanisms of Labour : engagement → descent → flexion → internal rotation → crowning → extension → restitution → external rotation → expulsion.

Investigations

• Monitoring required during each stage ⇒
  • 1st Stage → foetal HR (every 15 mins), frequency of contractions (every 30 mins), maternal HR/BP/vaginal examination (every 1 hour), maternal temperature (every 4 hours).
  • 2nd Stage → foetal HR (every 5 mins), frequency of contractions (every 30 mins), maternal HR/BP/vaginal examination (every 1 hour).
  • 3rd Stage → monitor maternal observations for at least 2 hours, document volume of vaginal blood loss, examine delivered placenta for completeness, inspect vulva for evidence of tears.
• Fetal fibronectin (fFN) → indicator of preterm labour. Use if TVUSS to assess cervical length is contraindicated.

Management Plan

• DURING LABOUR ⇒

  • 1st Stage
    • One-to-One midwifery care. Vaginal examinations performed 4-hourly.
    • Normal progress around 1cm/hr.
      • Delay (<1cm over 2 hrs) → if membranes intact: ARM and review in 2 hrs. If membranes ruptured: oxytocin.
  • 2nd Stage
    • Prolonged 2nd Stage (≥3 hrs from full dilatation) → instrumental delivery. If not possible, then caesarean section.
      • Instrumental Delivery → abandon if no foetal descent following 3 pulls. A lower segment caesarean section should then be done for surgical delivery following this.
      • Forceps → smooth metal instruments fit around baby’s head (greater risk of trauma to mother). Can only be used if baby is OA (ie. doesn’t need to be rotated).
        • FORCEPS → fully dilated, occipito-anterior position, ruptured membranes, cephalic presentation, engaged presenting part (head not palpable in abdomen), pain relief, sphincter (empty bladder).
        • DO EPISIOTOMY FIRST.
        • Higher success rate than ventouse.
      • Ventouse → vacuum extractor cup placed directly over flexion point (greater risk of trauma to newborn). Use if baby is OP and needs to be rotated.
        • Prolonged ventouse delivery → greatest risk of haemorrhage in the newborn. Can’t be used if <34 weeks due to risk of intracranial haemorrhage.
  • 3rd Stage
    • Active Management → 10 IU IM Oxytocin (after birth of anterior shoulder) + deferred cord clamping (over 1 minute after delivery but less than 5 minutes) + controlled cord traction to remove placenta.
      • Early (<1 min) or Delayed (1-5 mins) cord clamping.
  • Pain Relief in Labour
    • During 1st Stage of Labour prior to Admission → paracetamol, co-dydramol or pethidine (’sleepy baby’, low baby RR, constipation).
      • Non-Pharmacological Methods → TENS, breathing techniques, massage.
    • In Hospital (depending on birth centre or labour ward) → entonox (nausea, light-headed, dry mouth), remifentanil patient-controlled analgesia, and epidural.

• PRETERM LABOUR → onset of labour (painful + regular contractions) <37 weeks gestation. (Diagnosis: cervical Length <15mm at >30/40 = preterm labour)

  • Risk Factors → previous preterm birth, short cervix (<25mm), multiple pregnancy, previous emergency c-section at advanced labour (10cm dilated).
  • Prevention ⇒
    • Prophylactic Vaginal Progesterone → start between 16-24 weeks gestation, continue until 34 weeks.
    • Prophylactic or Rescue Cervical Cerclage. Involves placing a band around the cervix to maintain it’s integrity.
  • Management ⇒

    • Admit to antenatal ward.

    • Maternal Corticosteroids → accelerates foetal lung maturation. 2x 12mg IM Betamethasone (24 hrs apart). (or 4x 6mg 12 hrs apart).

    • Tocolytics → delays delivery long enough for corticosteroid administration or transfer to neonatal unit. 1st line = nifedipine (CCB). 2nd line = atosiban (oxytocin recetor antagonist).

      <aside> 💡 First Step → Nifedipine + Betamethasone.

      </aside>

    • IV Magnesium Sulphate → for neuroprotection of neonate. If birth is expected within next 24 hours.

  • Complications → RDS, NEC, IVH, PVL.

• INDUCTION OF LABOUR → can be used when patients go over due date. Offered after 41 weeks gestation in uncomplicated pregnancy. Also offered in situations where early labour is beneficial (Maternal request, PROM when labour doesn’t start within 18-24 hrs, fetal growth restriction, pre-eclampsia, obstetric cholestasis, existing diabetes, intrauterine fetal death). (Induction not recommended → PPROM, Breech/Transverse Lie, Severe IUGR, Suspected Foetal Macrosomia).

  • Bishop Score (assessment of cervix) → scoring system to determine whether to induce labour. Five things are assessed (min score 0 and max score 13). Score ≥8 = high chance of spontaneous labour (cervix is more favourable). Score ≤6 = spontaneous labour unlikely hence induction needed.

    • Score ≤6 → offer IOL with vaginal prostaglandin first and reassess 6 hrs later.
    • Score >6 (7-8) → offer IOL with ARM followed by oxytocin infusion.

    

  Options for Induction:

  • Membrane Sweep → insert finger into cervix to stimulate the cervix. Stimulates physiological prostaglandins.
  • Vaginal Prostaglandin E2 (PGE2) → stimulates cervix and uterus. GIven as tablet/gel (1 dose, followed by 2nd dose after 6 hours - max 2 doses) or a pessary (1 dose over 24 hours).
    • Risk of Uterine Hyperstimulation. Can cause foetal hypoxia (late decelerations) by compressing umbilical and placental blood vessel. Treatment → continuous CTG monitoring, remove prostaglandin, give tocolytics (terbutaline - beta agonist) to reduce rate of contraction.
      • Defined as single contraction ≥2 mins or ≥5 contractions in 10 mins.
      • First step in patient’s management should be to reduce the rate of the oxytocin infusion to reverse the hyperstimulation and review the CTG in half an hour. Put mother in left lateral position to relieve pressure on maternal IVC and Aorta.
  • Cervical Ripening Balloon (CRB) → silicone balloon inserted into cervix and gently inflate to dilate the cervix. If low bishop’s score and prostaglandins contra-indicated.
  • Artificial Rupture of Membranes (if labour not ensued within 2 hours then also do Oxytocin Infusion) → only when there are reasons to not use vaginal prostaglandins.
    • Risk of Umbilical Cord Prolapse.
  • IV Syntoconin → offered if 2 hours after ROM, labour has not ensued.

  <aside> 💡 Membrane Sweeping → Propess (24 hours) → Prostin (if propess was insufficient – max 2x; 6 hourly) → ARM → Syntocinon → C-section

  </aside>

  Prepare Cervix = ripening balloon for 24 hours. If this doesn’t work will give you a gel in the vagina (PGE2). Once your cervix is ready we’ll rupture membranes. This should cause body to naturally start contractions. If not we’ll give you a drip (oxytocin) to start contractions.

  • When intrauterine fetal death has occured → oral mifepristone (anti-progesterone) plus misoprostol (prostaglandin) to induce labour.