A 29-year-old G2P1 at 39 weeks of gestation with a history of one previous vaginal delivery is admitted for induction of labour due to gestational diabetes mellitus. On examination, the cervix is 3 cm dilated, 90% effaced, soft in consistency, and the fetal head is at 0 station. Fetal heart rate is 140 bpm with normal variability. The patient has no contraindications to labour. After confirming fetal well-being with a 20-minute cardiotocograph, oxytocin infusion is started at 2 mIU/min. After 4 hours of oxytocin, the patient has had 3 contractions in 10 minutes, each lasting 45 seconds. The cervix remains at 3 cm dilation. What is the most appropriate next step?

Explanation

## Clinical Assessment of Labor Progress **Key Point:** The patient is experiencing inadequate uterine contractions (3 contractions in 10 minutes = 18/hour; adequate labor requires ≥200 Montevideo units or ≥5 contractions in 10 minutes). This represents **hypotonic uterine dysfunction** or inadequate labor augmentation. ## Oxytocin Dosing and Escalation Protocol | Time | Dose | Increment | Frequency | | --- | --- | --- | --- | | Initial | 2 mIU/min | Increase by 2 mIU/min | Every 30 min | | Standard protocol | Up to 20–40 mIU/min | — | — | | Maximum | 40 mIU/min | — | — | **High-Yield:** Adequate uterine contractions for labor are defined as: - **Frequency:** ≥3 contractions in 10 minutes - **Duration:** 40–60 seconds - **Intensity:** ≥25 mmHg above baseline (or ≥200 Montevideo units) ## Management Algorithm for Inadequate Contractions ```mermaid flowchart TD A[Induction/Augmentation of Labour]:::outcome --> B{Adequate contractions?}:::decision B -->|Yes| C[Continue current dose]:::action B -->|No| D{Maternal/Fetal compromise?}:::decision D -->|Yes| E[Cesarean section]:::urgent D -->|No| F[Increase oxytocin by 2 mIU/min]:::action F --> G[Reassess in 30 minutes]:::decision G -->|Adequate| H[Continue]:::action G -->|Inadequate| I{Reached max dose?}:::decision I -->|No| F I -->|Yes| J[Consider ARM or cesarean]:::action ``` **Clinical Pearl:** In a multiparous patient (G2P1) with favorable cervix and no maternal/fetal compromise, the uterus is often more responsive to oxytocin. Gradual escalation is appropriate before considering operative delivery. **Key Point:** Artificial rupture of membranes (ARM) can be considered after adequate contractions are established or as an adjunct to oxytocin, but should not replace oxytocin escalation in the first instance. ## Why Escalation is Appropriate Here 1. **Favorable prognostic factors:** Multiparous, soft cervix, head at 0 station, reactive FHR 2. **No contraindications:** No maternal or fetal distress 3. **Standard protocol:** ACOG recommends incremental oxytocin increases every 30 minutes until adequate contractions or maximum dose reached 4. **Time-efficient:** Patient has only been on oxytocin 4 hours; adequate trial not yet completed