In intrauterine pressure catheter readings, which value represents the peak intrauterine pressure during a contraction?

• A. 65 to 70 mm Hg
• B. 6 to 10 mm Hg
• C. 95.1 F
• D. 136

Answer: (A)

Peak intrauterine pressure is the maximum pressure recorded during a contraction on an intrauterine pressure catheter. It is measured in millimeters of mercury (mm Hg). During a contraction, the uterus compresses against the amniotic fluid, causing a rise in pressure; the highest point of that rise is the peak. For a typical moderate contraction, this peak usually falls around 65–70 mm Hg, which is why that range best represents the peak value. The resting baseline tone is much lower, usually in the 5–15 mm Hg range, so values like 6–10 mm Hg reflect baseline tone rather than the contraction’s peak. Temperatures or other non-pressure values (for example, 95.1 F) do not describe intrauterine pressure.