RT Book, Section A1 Cunningham, F. Gary A1 Leveno, Kenneth J. A1 Bloom, Steven L. A1 Dashe, Jodi S. A1 Hoffman, Barbara L. A1 Casey, Brian M. A1 Spong, Catherine Y. SR Print(0) ID 1160775530 T1 Intrapartum Assessment T2 Williams Obstetrics, 25e YR 2018 FD 2018 PB McGraw-Hill Education PP New York, NY SN 9781259644320 LK obgyn.mhmedical.com/content.aspx?aid=1160775530 RD 2024/10/10 AB To study the forces exerted by labour, a rubber bag was inserted into the uterus which was connected with a manometer. In this way it was found that the intra-uterine pressure, in the intervals between the contractions, was represented by a column of mercury 20 millimeters high, 5 of which were due to the tonicity of the walls and 15 to its contents. During the pains, however, the mercury rose considerably, reaching a height of from 80 to 250 millimeters.—J. Whitridge Williams (1903)