Objective: To compare the effect of 2 regimens of intravenous fluid therapy on the course of labor. Methods: In a prospective, randomized, double-blind study of 300 nulliparous pregnant women at term conducted at a teaching hospital, 153 women received 125 mL and 147 received 250 mL of intravenous fluid per hour. The groups were matched and analysis was done using the t, χ 2, and Fisher exact tests. P < 0.05 was considered statistically signifi- cant. Results: In the group that received intravenous fluid at a rate of 250 mL per hour the mean ± S.D. duration of labor was significantly shorter (253 ± 97 vs. 386 ± 110 min; P = 0.0001), the frequency of labor lasting both more than 10 h and more than 15 h was statistically lower (4.8% vs. 13.8% ; P = 0.001 and 0% vs. 4.5% ; P = 0.02, respectively), and the frequency of oxytocin administration was significantly lower (8.1% vs. 20.4% ; P = 0.001). There was a trend toward a lower frequency of cesarean deliveries in the 250- mL group (16% vs. 22.8% ; P = 0.1). Conclusion: A greater volume per hour of intravenous fluid than is commonly administered to nulliparous women in active labor is associated with significantly shorter duration of labor and lower frequency of both prolonged labor and oxytocin administration. Objective: To compare the effect of 2 regimens of intravenous fluid therapy on the course of labor. Methods: In a prospective, randomized, double-blind study of 300 nulliparous pregnant women at term conducted at a teaching hospital, 153 women received 125 mL and 147 received 250 mL of intravenous fluid per hour. The groups were matched and analysis was done using the t, χ 2, and Fisher exact tests. P <0.05 was considered statistically signifi- cant. Results: In the group that received intravenous fluid at The frequency of labor lasting both more than 10 h and more than 15 h was significant (253 ± 97 vs. 386 ± 110 min; P = 0.0001). lower (4.8% vs. 13.8%; P = 0.001 and 0% vs. 4.5%; P = 0.02, respectively), and the frequency of oxytocin administration was significantly lower (8.1% vs. 20.4%; P = 0.001) was a trend toward a lower frequency of cesarean deliveries in the 250-mL group (16% vs. 22.8%; P = 0.1). Conclusion: A greater volume per hour of intravenous fluid than is commonly administered to nulliparous women in active labor is associated with significantly shorter duration of labor and lower frequency of both prolonged labor and oxytocin administration.