This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General obstetrics, Subject name: Anatomy
Pressure of normal uterine contractions is between 190-300 units. Which unit is being referred here? 
Select and explain. 
A. Montevideo units, B. mm of Hg, C. cm of water, D. Joules /kg
A: Montevideo units
Answer: A: Montevideo units 
Explanation: 1 Montevideo unit = Intensity of contraction x Number of contractions in 10 mins. It is used to define uterine activity. Clinical labour usually commences when the uterine activity reaches values between 80-120 Montevideo units i.e, 3 contractions of 40 mm Hg every 10 mins. During labour, Normal uterine contractions are between 190-300 Montevideo units . Ref: Williams Obs 23e pg 437.