Observations on intra-uterine resting-phase pressure in at term pregnancy in different body positions

Investigations were conducted into the influence of body position on intra-uterine resting phase pressure in women in labour. A micro pressure sensor was placed in the uterus and rectum of 14 women immediately after artificial rupture of the fetal membranes. A significant increase in the intra-uterine resting-phase pressure was experienced when the body position was changed from supine to sitting and also from supine to standing. The intrarectal pressure, a parameter of the intra-abdominal pressure, also showed this significant increase by the same magnitude. The increased resing-phase pressure in the uterus, when the women are in a standing or sitting position, is therefore the result of extra-uterine factors.