Feeling Centimeters of Dilation: Why You’ve Never Heard of a Cervimeter

Rebecca Jackson

Science History Institute

Wednesday, March 1, 2023 2:30 pm EST

Watch on YouTube.

Come learn about an unlikely best practice for managing birth in today’s hospitals: measuring cervical dilation by hand!
Central to labor management is the use of a “partogram” chart to track cervical dilation in centimeters over time, from 0 until 10 cm, when a mother is deemed ready to push. The measurement of dilation is so central to labor management that it’s often used as a shorthand for labor progress itself, e.g. “You’re 4 centimeters along.”
We measure dilation the same way today as we did 100 years ago, approximated by the human hand. If you’re wondering how it’s possible to accurately “feel” centimeters—and why we haven’t replaced this with some technology to do it more precisely—brace yourself for a surprising backstory. In this talk, Rebecca Jackson will speed through a tour of the different instruments we’ve tried to make in the last century (mechanical, electromechanical, and electromagnetic devices, ultrasonic imaging, and more) and why all of these techniques ultimately failed. By the end, you’ll have a better idea of why the hand is still the best measuring technology we have.
About the Speaker
Rebecca Jackson is a historian and philosopher of science and medicine with particular interest in clinical measurement methodology, as well as history and philosophy of measurement more broadly. As a long-term fellow at the Science History Institute, she is conducting her dissertation research on four cases of successful patient-centric and non-standard clinical measuring practices from the 19th century to current debates.
Jackson is a PhD candidate in history and philosophy of science and medicine at Indiana University Bloomington (IU). Her educational background includes an MA in history and philosophy of science and medicine and a graduate minor in statistics from IU, as well as a dual BA in mathematics and creative writing from Ball State University. Her work on the history and philosophy of non-standard measuring practices has been featured in Perspectives on Science and Studies in History and Philosophy of Science.
About the Series
Our virtual Lunchtime Lecture Series takes a rigorous and entertaining approach to exploring topics for scholars and anyone interested in stories about the history of science, technology, and medicine. The talks help expand perceptions of the nature of science and how it’s done.