Units are calculated by internally (not externally) measuring peak uterine pressure amplitude (in mmHg), subtracting the resting tone of the contraction, and adding up the numbers in a 10-minute period. Uterine pressure is generally measured through an intrauterine pressure catheter.
Montevideo units can be more simply calculated by summing the individual contraction intensities in a ten-minute period, a process which should arrive at a result identical to the original method of calculation.
Generally, above 200 MVUs is considered necessary for adequate labor during the active phase.
If, for instance:
- Peak uterine pressure amplitudes were 50 mmHg
- during the 10 minute period of measurement 3 contractions occurred
- subtract the resting tone from the peak intensity of the contraction
- add the 3 contractions together to get the MVUs
- Montevideo units are calculated by obtaining the peak uterine pressure amplitude and subtracting the resting tone. Then adding up those numbers generated by each contraction within a 10-minute window.
- For example, five contractions occurred, producing pressure changes of 55, 50, 45, 65, and 50 mm Hg, respectively. The resting tone of the contractions is 10.
55-10 = 45 50-10 = 40 45-10 = 35 65-10 = 55 50-10 = 40
45+40+35+55+40 = 215 MVUs
- "MATERNITY GUIDE - Labor & Delivery". Retrieved 2010-03-28.
- Ball, RH; Espinoza, MI; Parer, JT (1994). "Regional blood flow in asphyxiated fetuses with seizures". Am J Obstet Gynecol. 170 (1): 156–261.