Intrauterine pressure progression during long-term treatment. Barusiban inhibited OT-induced increases in IUP in near-term pregnant monkeys (GD ca. 141 to 163 or delivery) . In general, IUP was lowest throughout the last about three weeks of pregnancy in barusiban-treated females (150 μg kg-1 h-1, orange), compared to OT controls (green), or fenoterol-treated females (3 μg kg-1 h-1, yellow). Barusiban was particularly effective in maintaining low IUP near the end of gestation. OT control and fenoterol-treated animals gave preterm birth, barusiban-treated animals continued pregnancy till term, when the treatment was stopped, and the mothers delivered normally. Data shown are means ± SEM for n = 3 (controls, barusiban) or n = 2 (fenoterol).