Objective: To compare obstetric risk factors for failure of labor to progress in the first versus the second stage. Study design: A comparison was performed of all singleton, vertex and term deliveries with an unscarred uterus, complicated with non-progressive labor during the first and the second stages. Deliveries occurred between the years 1988 and 1999 in a tertiary university medical center. Results: Patients with non-progressive labor in the first stage (n = 1197) were significantly older, of higher birth order, and were more likely to have complications such as gestational diabetes, hypertensive disorders, premature rupture of membranes, meconium-stained amniotic fluid, hydramnios and oligohydramnios (p < 0.001 for all variables) as compared to patients with non-progressive labor in the second stage (n = 1545). In addition, pregnancies complicated with non-progressive labor in the first stage had a significantly higher rate of fetal macrosomia as compared to patients with non-progressive labor in the second stage (11.6% vs. 8.8%; p < 0.001). Conclusions: Higher rates of fetal macrosomia and high-risk pregnancies were noted among pregnancies complicated with non-progressive labor during the first vs. the second stage. The significant increase in Cesarean deliveries during the first stage of labor among high-risk pregnancies might reflect exaggerated concern of caregivers. This concern may influence an overall conservative attitude leading to the seemingly simpler mode of direct intervention by Cesarean delivery.