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Updated: Jul 4, 2026

Biaxial Basal Tone and Passive Testing of the Murine Reproductive System Using a Pressure Myograph
Published on: August 13, 2019
[Rectal and anal straining pressures in primigravidae]
Wilmar Artur Klug1, Helly Angela Caram Aguida, Jorge Alberto Ortiz
1Departamento de Cirurgia da Santa Casa de São Paulo, S. Paulo, SP. klug@doctor.com
Objective:
This study intended to evaluate rectal and anal straining pressures in primigravidae, at simulated defecation.
Methods:
The present study is based on 60 women from de Antenatal Care of Santa Casa de Misericórdia - São Paulo. Patients were divided into four groups of 15: a)
Control Group:
nuligravidae; b) 1st trimester primigravidae; c) 2nd trimester primigravidae; d) 3rd trimester primigravidae. All patients underwent rectal and anal measurements to obtain: a) Resting rectal pressure; b) Straining rectal pressure; c) Minimal straining anal pressure.
Results:
Data was analyzed using statistical methods and reached, the same results: it was observed that the straining rectal pressure decreased from 53.9 +/- 17.9 in control group a to respectively 36.3 +/- 19.6 in group b, 38.1 +/- 16.2 in group c, 30.5 +/- 17.0 in group d, of pregnant women. The minimal anal straining pressure decreased from 46.9 +/- 1.6 in the control group a to 37.5 +/- 15.5 in group b, 32.2 +/- 6.2 in group c , 32.9 +/- 8.7 in group d, during pregnancy.
Conclusion:
Straining rectal and anal pressures both decreased during pregnancy in comparison with the control group, counterbalancing one another to reach a new point of equilibrium during defecation.
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