scholarly journals Linking Myometrial Physiology to Intrauterine Pressure; How Tissue-Level Contractions Create Uterine Contractions of Labor

2014 ◽  
Vol 10 (10) ◽  
pp. e1003850 ◽  
Author(s):  
Roger C. Young ◽  
Peter Barendse
Keyword(s):  
Tissue Level ◽  
Uterine Contractions ◽  
Intrauterine Pressure

scholarly journals Accuracy and Reliability of Uterine Contraction Identification Using Abdominal Surface Electrodes

2012 ◽  
Vol 5 ◽  
pp. CMWH.S10444 ◽  
Author(s):  
Barrie Hayes-Gill ◽  
Sarmina Hassan ◽  
Fadi G. Mirza ◽  
Sophia Ommani ◽  
John Himsworth ◽  
...  
Keyword(s):  
Root Mean Square Error ◽  
Pressure Measurement ◽  
Pressure Transducer ◽  
Uterine Contraction ◽  
Mean Square ◽  
Predictive Values ◽  
Surface Electrodes ◽  
Uterine Contractions ◽  
Intrauterine Pressure ◽  
Abdominal Surface

Objective To compare the accuracy and reliability of uterine contraction identification from maternal abdominal electrohysterogram and tocodynamometer with an intrauterine pressure transducer. Methods Seventy-four term parturients had uterine contractions monitored simultaneously with electrohysterography, tocodynamometry, and intrauterine pressure measurement. Results Electrohysterography was more reliable than tocodynamometry when compared to the intrauterine method (97.1 versus 60.9 positive percent agreement; P < 0.001). The root mean square error was lower for electrohysterography than tocodynamometry in the first stage (0.88 versus 1.22 contractions/10 minutes; P < 0.001), and equivalent to tocodynamometry in the second. The positive predictive values for tocodynamometry and electrohysterography (84.1% versus 78.7%) were not significantly different, nor were the false positive rates (21.3% versus 15.9%; P = 0.052). The sensitivity of electrohysterography was superior to that of tocodynamometry (86.0 versus 73.6%; P < 0.001). Conclusion The electrohysterographic technique was more reliable and similar in accuracy to tocodynamometry in detecting intrapartum uterine contractions.

POSSIBLE ROLE OF UTERINE CONTRACTIONS IN THE SHORT-TERM FLUCTUATIONS OF PLASMA ACTH CONCENTRATION IN FETAL SHEEP

1985 ◽  
Vol 106 (2) ◽  
pp. R9-R11 ◽  
Author(s):  
S.J. Lye ◽  
M.E. Wlodek ◽  
J.R.G. Challis
Keyword(s):  
Percentage Change ◽  
Plasma Acth ◽  
Short Term ◽  
Fetal Sheep ◽  
Uterine Activity ◽  
Fetal Plasma ◽  
Uterine Contractions ◽  
Intrauterine Pressure ◽  
Acth Concentration

ABSTRACT Uterine contractions, induced by the administration of oxytocin to sheep between d 123-144 of pregnancy, were associated with a mean transient decrease in fetal PaO2 of 2.8 mm Hg within 5 min. These changes were associated with a rapid increase in the concentration of ACTH in fetal plasma. There was a significant (P<0.05) increase in the percentage change (+40 to +47%) over basal ACTH levels in fetal plasma at +5, +15 and +20 min after oxytocin. Administration of saline had no significant effect on intrauterine pressure, fetal PaO2 or fetal plasma ACTH levels. We speculate that increases in uterine activity and/or transient decreases in fetal PaO2 may contribute to short-term fluctuations in plasma ACTH in fetal sheep.

The Use of Mersilene Tape in Transabdominal Cerclage

2017 ◽  
Vol 752 ◽  
pp. 64-70
Author(s):  
Claudia Mehedințu ◽  
Ana Maria Rotaru ◽  
Marina Antonovici ◽  
Mihaela Plotogea ◽  
Elvira Brătilă ◽  
...  
Keyword(s):  
Biomechanical Properties ◽  
Uterine Wall ◽  
Medical Procedures ◽  
Genital Tract Infection ◽  
Uterine Contractions ◽  
Cervical Incompetence ◽  
Intrauterine Pressure ◽  
Uterine Growth ◽  
Mersilene Tape ◽  
Lower Genital Tract Infection

Aim: The purpose of this article is to show the use and utility of mersilene tape in medical procedures, such as transabdominal cerclage (TAC). Material and methods: Based on their biomechanical properties, we present our experience with mersilene tape used as treatment for cervical incompetence. Cervical insufficiency or cervical incompetence is defined as asymptomatic cervical shortening and dilatation with the absence of detectable uterine contractions. The mechanical properties of cervical tissue are derived from its extracellular matrix and its most important constituent the fibrillar collagen, alongside other constituents such as proteoglycans, hyaluronic acid, elastin, and water. In the absence of the uterine contractions, the cervix is loaded by intrauterine pressure (including the weight of the growing fetus and amniotic sac), the gravity as well as passive pressure from the uterine wall. These forces also depend on the support action of pelvic floor structures and abdominal wall. The static load resulting from the combination of uterine growth, hydrostatic pressure and gravity seems to be the dominant determinants that cause cervical shortening. The placement of the mersilene tape acts as a barrier between the intrauterine pressure and the cervix. The main advantage of the TAC procedure is the placement of the nonabsorbable suture (mersilene tape at the level of the internal os, avoiding the placement of a vaginal foreign body and subsequently increasing the risk of ascending lower genital tract infection, decreased incidence of slippage, and the ability to leave the stitch in place between pregnancies. Results: The follow-up was without complications regarding the pregnancies treated with transabdominal cerclage. None of the pregnancies terminated prematurely as related to the presence of the tape, but it necessitates to be performed a caesarean section for delivery. Conclusions: Mersilene tape is safe and useful in different medical procedures, including transabdominal cerclage during pregnancy.

An optimized algorithm for the detection of uterine contractions in intrauterine pressure recordings

1975 ◽  
Vol 8 (3) ◽  
pp. 294-301 ◽  
Author(s):  
Lawrence Chik ◽  
Victor J. Hirsch ◽  
Robert J. Sokol ◽  
Mortimer G. Rosen
Keyword(s):  
Uterine Contractions ◽  
Intrauterine Pressure

scholarly journals A myofibre model for the study of uterine excitation-contraction dynamics

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Uri Goldsztejn ◽  
Arye Nehorai
Keyword(s):  
Uterine Contraction ◽  
Muscle Layer ◽  
Tissue Level ◽  
Intercellular Coupling ◽  
Force Development ◽  
Uterine Contractions ◽  
Cellular Excitability ◽  
Slow Progress ◽  
Contraction Dynamics ◽  
Electrical Propagation

Abstract As the uterus remodels in preparation for delivery, the excitability and contractility of the uterine smooth muscle layer, the myometrium, increase drastically. But when remodelling proceeds abnormally it can contribute to preterm birth, slow progress of labour, and failure to initiate labour. Remodelling increases intercellular coupling and cellular excitability, which are the main targets of pharmaceutical treatments for uterine contraction disorders. However, the way in which electrical propagation and force development depend on intercellular coupling and cellular excitability is not fully understood. Using a computational myofibre model we study the dependency of electrical propagation and force development on intercellular coupling and cellular excitability. This model reveals that intercellular coupling determines the conduction velocity. Moreover, our model shows that intercellular coupling alone does not regulate force development. Further, cellular excitability controls whether conduction across the cells is blocked. Lastly, our model describes how cellular excitability regulates force development. Our results bridge cellular factors, targeted by drugs to regulate uterine contractions, and tissue level electromechanical properties, which are responsible for delivery. They are a step forward towards understanding uterine excitation-contraction dynamics and developing safer and more efficient pharmaceutical treatments for uterine contraction disorders.

Relation between fetal arterial and oxytocin-induced uterine contractions in pregnant sheep

1984 ◽  
Vol 62 (10) ◽  
pp. 1337-1340 ◽  
Author(s):  
Stephen J. Lye ◽  
Mary E. Wlodek ◽  
John R. G. Challis
Keyword(s):  
Positive Relationship ◽  
Late Pregnancy ◽  
Oxygen Electrode ◽  
Experimental Paradigm ◽  
Uterine Activity ◽  
Significant Positive Relationship ◽  
Uterine Contractions ◽  
Intrauterine Pressure ◽  
Pregnant Sheep ◽  
Maximum Decrease

The relation between oxytocin-induced type A uterine contractions and fetal arterial [Formula: see text], measured continuously with an intravascular oxygen electrode, was studied in nine chronically catheterized sheep during late pregnancy. Oxytocin provoked dose-related increases in intrauterine pressure (IUP) and decreases in fetal [Formula: see text]. There was a significant positive relationship between changes in IUP and the maximum decrease in fetal [Formula: see text] (average r = 0.696, df = 92; P < 0.001). We conclude that changes in uterine activity contribute to transient fetal hypoxemia, and that administration of exogenous oxytocin provides an experimental paradigm to examine the consequences of this relationship.

ESTIMATION OF INTRAUTERINE PRESSURE FROM ELECTROHYSTEROGRAPHY USING HILBERT PHASE SLIPS AND STATISTICS METHOD

2017 ◽  
Vol 17 (06) ◽  
pp. 1750089 ◽  
Author(s):  
ZIDUO YANG ◽  
RENHUAN YANG ◽  
YAOSHENG LU
Keyword(s):  
Median Filter ◽  
Motion Artifacts ◽  
Detection Accuracy ◽  
Prognostic Information ◽  
Uterine Activity ◽  
Uterine Contractions ◽  
Intrauterine Pressure ◽  
Signal Segment ◽  
Low Sensitivity ◽  
Phase Slips

Prognostic information during pregnancy can be obtained by monitoring maternal uterine activity. Tocodynamometry (TOCO) is widely used to assess the uterine activity today but it has been found that it has very low sensitivity. Another method to assess the uterine activity is intrauterine pressure catheter (IUPC) which is accurate but highly invasive. Electrohysterogram (EHG) measured from abdominal surface is a noninvasive method to detect uterine contractions. To reduce motion artifacts of intrauterine pressure (IUP) estimated from EHG signal and further improve the accuracy of contractions detected by IUP estimation, we propose a method to divide the EHG signal into segments by using Hilbert phase slips. Standard deviation (STD) was used to estimate IUP from each EHG signal segment and median filter was used to remove the motion artifacts. The method we proposed was compared with other four methods from literatures. The proposed method results in a higher contractions detection accuracy of EHG-based IUP estimation and a higher correlation coefficient with the IUPC signals compared to other methods which demonstrated the capabilities of the proposed method in reducing motion artifacts of IUP estimation based on abdominal EHG.

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