Intrapartum CTG interpretation — structured SAQ (15 marks)

(a) Systematic description and grading (5 marks)

One mark for a systematic description in order, one for each correctly named abnormal feature, one for the grade with justification. ^[1][2]

• Contractions: 6 in 10 minutes — tachysystole (more than 5 in 10 minutes). With fetal heart rate abnormalities present this is hyperstimulation.^[1]
• Baseline: rising from 132 to 158 bpm over 90 minutes. A rising baseline is an abnormal feature even while the absolute value stays under 160.^[2]
• Variability: 4 bpm — reduced (3 to 5 bpm) rather than absent (under 3 bpm).^[2]
• Accelerations: absent.
• Decelerations: onset after the peak of the contraction with return after the contraction ends — late decelerations, and they are occurring with reduced variability.^[1][2]
• Grade: abnormal, at the level requiring immediate action. Late decelerations with reduced variability sit in the highest grade of the RANZCOG feature framework; a rising baseline plus late decelerations would in any case be two features requiring action, and two such features together escalate the grade.^[2][1]

Marks are lost for writing "pathological CTG" without naming a single feature, and for describing decelerations as "variable" when the timing is clearly late. ^[1]

(b) Reversible causes present and the action for each (4 marks)

One mark per cause correctly identified with a specific action. ^[3][2]

• Also perform a vaginal examination to exclude cord prolapse and reassess progress and station.^[3]
• Do not give facial oxygen for the trace alone: in a woman who is not hypoxaemic, maternal oxygen supplementation does not improve umbilical artery pH or neonatal outcomes.^[4]

(c) Further management when the trace does not improve (4 marks)

One mark each for senior escalation, the adjunct test with its correct place, the limits of that test, and a defined decision point. ^[2][6]

• Escalate by name: call the obstetric consultant to the bedside, inform the anaesthetist and theatre coordinator, and alert the neonatal team. Document the time of each call.^[2]
• Digital fetal scalp stimulation at vaginal examination — stroke the scalp for 15 to 30 seconds; an acceleration with sustained improvement suggests the fetus is not acidotic.^[1]
• Fetal blood sampling if available and not contraindicated: pH 7.25 or more normal, 7.21 to 7.24 borderline (repeat in 20 to 30 minutes), 7.20 or less abnormal; lactate 4.0 mmol/L or less normal, 4.1 to 4.7 mmol/L borderline, 4.8 mmol/L or more abnormal.^[2][6]
• State the limits: the sample is a single time point, the Cochrane review found no clear neonatal outcome benefit from lactate sampling over pH, and a normal result in a fetus with a rising baseline and falling variability does not license waiting. If the trace is deteriorating, deliver.^[6][1]
• Define the decision point out loud: "If there is no improvement within the next 20 to 30 minutes, or if any further feature appears, we deliver — by caesarean at 7 cm, since operative vaginal birth is not available at this dilatation."^[2][3]

(d) Acute bradycardia at 03:20 (2 marks)

One mark for the resuscitation and exclusion of acute causes, one for the timetable and delivery decision. ^[1][2]

• Immediately: call for help and declare an emergency; full lateral position; oxytocin already stopped; intravenous fluid bolus; correct blood pressure; vaginal examination to exclude cord prolapse; consider abruption and uterine rupture; check the maternal pulse to confirm the signal is fetal.^[2][3]
• By 3 minutes: urgent obstetric review at the bedside, theatre alerted, tocolysis considered if uterine activity persists.^[2][5]
• By 5 minutes: no recovery and no reversible cause corrected means prepare to expedite birth — move to theatre while resuscitation continues.
• Up to 9 minutes: if the rate recovers, reassess the decision against the whole clinical picture; if it does not, deliver by category 1 caesarean.^[2][1]
• Take paired umbilical cord gases at birth and have the neonatal team present.^[2]