Simultaneous measurements of intrauterine pressure, including the head-to-cervix pressure, by an open-end catheter and a strain gauge.
An open-end catheter and a small strain gauge were tied and introduced into the uterine fundus during the labor of 8 parturients. As the tied probes were progressively withdrawn, the pressures given by each were simultaneously recorded. Normally the measurements are identical, but when the free ends of the probes are located between the head and the cervix, striking differences appear, the strain gauge giving much higher figures. Conversely, two intrauterine open-end catheters give the same results even if one is located in the fundus and the other is between the head and the cervix. It is suggested that the strain gauge measures a pressure which is not reliable enough because the area of application of the stress cannot be known accurately.
D002404:Catheterization; D005260:Female; D006801:Humans; D007743:Labor, Obstetric; D011247:Pregnancy; D011312:Pressure; D014590:Uterine Contraction