Slow progress in labour — structured oral station (12 minutes)

Opening prompt — "The midwife wants syntocinon. What do you think?"

Model response — name the finding, then refuse to treat it blindly: ^[1][2]

• "She meets the RANZCOG C-Obs 31 definition of slow labour: less than a 2 cm increase in cervical dilatation over 4 hours from 5 cm."
• "But this is a para 2 with two previous spontaneous births, and slow progress in a multipara is a red flag, not a routine augmentation. Multiparous uteri usually work. When they stop, I think malposition, obstruction, a big baby or a uterine scar before I think inefficient uterine action."
• "So before any oxytocin I would do a full reassessment, and I would let my consultant know."^[1][8]

Examiner is listening for: the definition, the parity red flag, and reassessment before prescription. ^[1]

Probe 1 — "Reassess her. Be specific."

• Power: "I would palpate the uterus by hand for a full ten minutes — the tocograph tells me frequency, not strength. Four in ten that are weak and short is a different problem from four in ten that are strong and long."^[1]
• Passenger: "Vaginal examination for dilatation, effacement, station, and specifically the position from the sagittal suture and fontanelles, plus caput and moulding graded. If caput obscures the sutures I would use a transabdominal ultrasound to confirm the position."^[6]
• Passage: "I am looking for the combination that means obstruction — rising caput and moulding with a station that will not change — and for a palpable retraction ring."^[8]
• The person: "Bladder emptied and catheterised if needed, pain relief reviewed, hydration and ketones, temperature and pulse, and continuous one-to-one support."^[1]
• The fetus: "The trace is currently normal, with a baseline of 155 and normal variability. I would keep her on continuous monitoring if I start oxytocin."^[5]

Probe 2 — "The head is at minus 1, occiput transverse, caput plus one, moulding plus one, contractions weak. Now what?"

• "That is a passenger problem with a power problem on top, and no evidence of obstruction yet — caput and moulding are only plus one and the head has not stopped moving."^[6][8]
• "I would correct the free things first — bladder, analgesia, hydration, position change — and then, with my consultant's agreement, start oxytocin."
• "I would be honest with her about what oxytocin does: the Cochrane review of oxytocin for slow progress in the first stage found it shortens labour by about two hours and does not reduce caesarean birth."^[3]

Probe 3 — "Prescribe it."

• "30 international units in 500 mL of compound sodium lactate or sodium chloride 0.9%, so that 1 mL per hour equals 1 milliunit per minute."^[4]
• "Start at 1 milliunit per minute, increase no more often than every 30 minutes through 1, 2, 4, 8, 12, 16, 20, 24, 28, 32."^[4]
• "Target 3 to 4 contractions in 10 minutes, lasting 40 to 60 seconds, with a rest period of not less than 60 seconds — palpated, not read off the monitor."^[4]
• "Ceiling: Queensland allows 32 milliunits per minute with obstetric review before exceeding 20; NSW caps at 20. Given she is a multipara I would be cautious and involve my consultant before exceeding 20."^[4][8]
• "And I would state my reassessment criterion up front: a vaginal examination four hours after the infusion has produced regular adequate contractions. Less than 2 cm of further progress at that point means a decision, not another increment."^[1][8]
• "The Cochrane review of high-dose versus low-dose regimens found shorter labour and lower caesarean rates, but those differences disappeared on sensitivity analysis, so I would not use a high-dose regimen routinely."^[4]

Probe 4 — "Four hours later she is 7 cm. Caput is now plus three, moulding plus three, the head is still at minus 1 and she has haematuria. Contractions are five in ten."

This is the trap. Recognise it and change direction. ^[8][5]

• "This is obstruction, not inadequate power. Caput and moulding have both risen sharply, the station has not changed in four hours despite adequate contractions, and haematuria in a multipara with a thinning lower segment worries me about impending rupture."^[8]
• "I would stop the oxytocin now, call my consultant and the anaesthetist, keep her nil by mouth, take bloods including a group and hold, and plan a caesarean section."^[5][8]
• "Continuing to augment an obstructed multiparous uterus is how uteruses rupture. That is the specific reason caput and moulding are part of every examination."^[8]

Probe 5 — "Justify the caesarean to me as though I were the consultant on the phone."

Structure it. The examiner is scoring communication as much as knowledge. ^[8]

• Situation: "Para 2 at 39+4, spontaneous labour, 7 cm after eight hours in the active phase, on oxytocin for four hours."
• What I have excluded: "She was genuinely in the active phase from 5 cm. Bladder emptied, analgesia adequate, ketosis corrected, position confirmed occiput transverse by ultrasound."
• What I have tried: "Position change, mobility, oxytocin titrated to four to five contractions in ten minutes over four hours."
• What has happened: "One centimetre in four hours of adequate contractions, caput and moulding both up to plus three, station unchanged at minus 1, and now haematuria."
• My assessment and recommendation: "I believe this is obstructed labour in a multipara. I have stopped the oxytocin. I would like to proceed to caesarean section now rather than wait, because the alternative risk is uterine rupture. I have spoken to the anaesthetist and the theatre team, and I have started the conversation with her and her partner."^[5][8]

Probe 6 — "If she had instead reached full dilatation with an occiput-posterior head at the spines, what would you offer?"

• "Optimise first: bladder, analgesia, position, and adequate contractions. Then consider manual rotation to occiput anterior."
• "I would be honest about the evidence: the 2025 Cochrane review of prophylactic manual rotation early in the second stage concluded it is uncertain whether it prevents operative delivery, and called for better trials. It is a reasonable skill to offer, not a proven intervention."^[6]
• "The choice between rotational instrumental birth and caesarean turns on station, position, caput and moulding, my own skill set and my unit — and if there is genuine doubt, a trial of instrumental birth in theatre with immediate recourse to caesarean is the honest answer."^[7][8]