Hip Extension Failed to Reduce Delivery Lacerations

A study of 1,206 first-time mothers found no significant reduction in perineal injuries using hip extension techniques.

Updated on Oct. 6, 2026 in Pregnancy

Hip Extension Failed to Reduce Delivery Lacerations

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A randomized controlled trial conducted between April 2021 and July 2025 at Massachusetts General Hospital found no statistically significant difference in higher-order perineal lacerations between mothers using hip extension and those using traditional flexed positioning. The results were published on September 22, 2026.

Why it matters

Researchers sought to determine if adjusting maternal positioning during the crowning stage of vaginal delivery could mitigate the risk of significant perineal trauma. Understanding these outcomes helps clinicians refine labor practices to improve recovery prospects for first-time mothers.

The study included 1,206 nulliparous participants with a median age of 32 years. Obstetric anal sphincter injury rates were 8.3% for the intervention group compared to 8.0% for the usual care cohort.

The players

Massachusetts General Hospital

This tertiary care institution in Boston served as the primary site for the clinical study.

The details

Participants were randomized to either flexed or extended hip positioning at the point of complete cervical dilation. Although an as-treated analysis suggested reduced odds of higher-order lacerations for those who successfully maintained hip extension, many participants in the intervention group ultimately delivered with flexed hips.

The clinical trial collected data from April 2021 to July 2025.
The findings were formally published on September 22, 2026.

The Big Picture

This study challenges established assumptions within the clinical protocols for nulliparous vaginal delivery regarding the impact of maternal positioning on perineal integrity. The findings suggest that the physical mechanics of delivery may be less influential on injury rates than previously hypothesized.

Expectant parents should discuss labor positioning preferences with their obstetricians to understand the current evidence-based approaches at their specific facility. The findings emphasize that while positioning is a common topic in birth plans, it may not significantly alter the clinical risk of perineal injury.

The takeaway

While hip extension is sometimes suggested to improve birth outcomes, this data indicates it does not offer a significant advantage for reducing tearing in first-time births. Patients should prioritize open communication with their care teams regarding delivery options and expectations.