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Mechanobiology in the Reproductive Tract
Published in Jiro Nagatomi, Eno Essien Ebong, Mechanobiology Handbook, 2018
Julie Anne MacDonald, Dori C. Woods
A uterine contraction is defined by the specific electrophysical behavior of the myometrial smooth muscle cells to simultaneously experience bursts of action potential discharge (Marshall 1962). These discharges result in increases in pressure within the uterus, which has been studied extensively, beginning in the 1950s with the work of Alvarez and Caldeyro (1950) wherein placental pressure was measured in laboring women, which established the quantitative relationship between contraction frequency and the intensity of pressure increase. These foundational studies are still clinically relevant today, as labor progression is monitored by tocodynamometry, which assesses intra-amniotic pressure (Gennisson et al. 2015). When contraction intensities are monitored over a 10-minute period by an intrauterine pressure cathether or external transducer, the resulting sum, or Montevideo units (Caldeyro-Barcia et al. 1957), provides a measurement for contractile activity during labor, with a baseline of above 200 Montevideo units for active labor (Rouse et al. 2001). The role for increases in uterine pressure may seem an obvious requirement for childbirth; however, uterine pressure has also been directly implicated for cervical dilation (Alvarez and Caldeyro 1950). A more subtle, but essential, factor in uterine contraction is the requirement for the entire organ to work in synchrony, that is, global contraction rather than several local contractions throughout the organ, and yet the mechanism for that coordination remains unclear.
Analysis and Interpretation of Uterine Contraction Signals Using Artificial Intelligence
Published in Saravanan Krishnan, Ramesh Kesavan, B. Surendiran, G. S. Mahalakshmi, Handbook of Artificial Intelligence in Biomedical Engineering, 2021
P. Mahalakshmi, S. Suja Priyadharsini
Shulgin and Shepel (2014) proposed a method to detect and characterize uterine activity. The fetal heart rate (FHR) and uterine contraction activity (UA) during pregnancy and labor are normally monitored using external tocography and ultrasound respectively. Given that these methods, however, are not accurate and sensitive enough, more precise methods are called for. Abdominal electrocardiography and EHG are safe and noninvasive techniques that monitor the FHR and uterine contractions during pregnancy. Signal processing methods are developed for three algorithms, based on the amplitude demodulation, spectrogram, and root mean square. The algorithms extract uterine activity signals from multichannel abdominal signals.
Application of intrauterine balloons in cervical ripening
Published in Expert Review of Medical Devices, 2023
An intrauterine balloon for cervical ripening is to stretch the lower uterine segment and increase the local production of prostaglandin [19,20]. Besides the local effect, the distended uterine cavity can also promote the release of oxytocin through the Ferguson reflex to induce uterine contraction [21]. Studies showed that the levels of interleukin-6, interleukin-8, matrix metalloproteinase-8, hyaluronic acid synthase, and nitric oxide synthase in cervical tissue were significantly increased after cervical ripening with an intrauterine balloon, which indicated that inflammation-immune response might also be involved in mechanical cervical ripening [22].