A 28-year-old primigravida at term is in active labor. Her partograph shows that she has crossed the alert line for cervical dilation. She is contracting 2–3 times in 10 minutes with adequate uterine contractions. What is the drug of choice to augment labor in this scenario?

Explanation

## Management of Prolonged Labor Using Partograph **Key Point:** When the partograph shows crossing of the alert line (indicating slow progress of labor) with inadequate uterine contractions, oxytocin is the first-line agent for labor augmentation in active labor. ### Why Oxytocin? 1. **Mechanism of action:** Oxytocin increases the frequency, duration, and intensity of uterine contractions by binding to oxytocin receptors on myometrial smooth muscle. 2. **Timing:** Used when labor is in the active phase but progress is inadequate (alert line crossed on partograph). 3. **Safety profile:** Has a short half-life (~1–2 minutes), allowing rapid titration and quick reversal if hyperstimulation occurs. 4. **Reversibility:** Unlike ergot alkaloids, oxytocin does not cause tetanic contractions and can be discontinued immediately if complications arise. ### Partograph Alert and Action Lines | Feature | Alert Line | Action Line | |---------|-----------|-------------| | **Position** | 2 cm to the left of the expected progress line | 3 cm to the left of the expected progress line | | **Meaning** | Slow progress; assess and plan | Inadequate progress; intervention needed | | **Action** | Reassess, consider augmentation if in active labor | Augment with oxytocin or consider operative delivery | **High-Yield:** Oxytocin is the standard agent for labor augmentation when the partograph alert line is crossed in a woman with inadequate uterine contractions in active labor. ### Oxytocin Dosing Regimen - **Starting dose:** 2–5 mIU/min IV infusion - **Increment:** Increase by 2–5 mIU/min every 15–30 minutes - **Maximum dose:** Usually 20–40 mIU/min (rarely up to 60 mIU/min) - **Monitoring:** Continuous fetal heart rate monitoring and uterine contraction assessment **Clinical Pearl:** The goal is to achieve 3–4 contractions in 10 minutes, each lasting 40–60 seconds, with adequate relaxation between contractions. **Warning:** Avoid oxytocin if there is a contraindication to vaginal delivery (e.g., placenta previa, vasa previa, cord prolapse, or cephalopelvic disproportion).