A 28-year-old primigravida is in the second stage of labor for 2 hours with adequate contractions and full cervical dilatation. The fetal head is at +2 station in the occiput anterior position. Maternal exhaustion and non-reassuring fetal heart rate tracing necessitate instrumental delivery. Which is the most common indication for operative vaginal delivery in this clinical scenario?

## Most Common Indication for Operative Vaginal Delivery **Key Point:** Prolonged second stage of labor (defined as >2 hours in nulliparous women and >1 hour in multiparous women) is the single most common indication for operative vaginal delivery, accounting for approximately 40–50% of all instrumental deliveries in modern obstetric practice. ### Epidemiology of Indications | Indication | Frequency | Timing | Clinical Context | |---|---|---|---| | **Prolonged second stage** | 40–50% | After 2 hrs (primigravida) | Adequate contractions, no descent | | **Fetal distress** | 20–30% | Any time in 2nd stage | Non-reassuring FHR pattern | | **Maternal exhaustion** | 10–15% | Late 2nd stage | Fatigue, pushing ineffective | | **Cephalopelvic disproportion** | <5% | Variable | Relative, not absolute | **High-Yield:** In the scenario presented, the patient has been in the second stage for 2 hours (meeting the criterion for prolonged second stage), making this the primary indication. Fetal distress and maternal exhaustion are concurrent but secondary indications. ### Why Prolonged Second Stage Is Most Common 1. **Objective definition** — Clear time cutoff (2 hours nulliparous, 1 hour multiparous with epidural) makes it easily identifiable and documentable. 2. **Epidemiological reality** — Most operative vaginal deliveries occur when labor has stalled despite adequate uterine activity and full dilatation. 3. **Modern obstetric practice** — Increased use of epidural anesthesia and oxytocin augmentation has shifted the threshold for intervention toward the prolonged second stage category. **Clinical Pearl:** The presence of fetal distress or maternal exhaustion in this case is an *additional* indication, but the *primary* reason for intervention is the prolonged second stage itself. In clinical practice, multiple indications often coexist. **Warning:** Do not confuse "most common indication" with "most urgent indication." Fetal distress is more urgent but less common overall than prolonged second stage.