Defining and Managing Normal and Abnormal Second Stage of Labor

Area of Science:

• Obstetrics and Gynecology
• Reproductive Medicine
• Maternal-Fetal Medicine

Background:

• The current definition of prolonged second stage labor by the American College of Obstetricians and Gynecologists (ACOG) is based on historical data from the 1950s.
• Modern obstetric populations and practices have significantly evolved since the establishment of these labor norms.
• Existing definitions may not accurately reflect contemporary labor progression.

Purpose of the Study:

• To evaluate the current definition of prolonged second stage labor.
• To assess the diagnostic yield of existing criteria in modern obstetric practice.
• To highlight the discrepancy between historical labor norms and current obstetric realities.

Main Methods:

• The study reviews the ACOG Practice Bulletin No. 49 criteria for prolonged second stage labor.
• Analysis of diagnostic rates for nulliparous and multiparous women based on ACOG definitions.
• Comparison of current diagnostic rates with the historical context of labor norms.

Main Results:

• A prolonged second stage is defined as >2 hours (nulliparous, no epidural) or >3 hours (nulliparous, with epidural).
• For multiparous women, it's defined as >1 hour (no epidural) or >2 hours (with epidural).
• These criteria diagnose 10-14% of nulliparous and 3-3.5% of multiparous women.

Conclusions:

• The current ACOG definition of prolonged second stage labor, based on 1950s data, may lead to overdiagnosis in contemporary obstetric settings.
• Evolving obstetric practices and patient populations necessitate a re-evaluation of labor norms.
• Further research is needed to establish updated, evidence-based definitions for labor progression.