Intrauterine Pressure Measurements Research Articles

Feasibility of continuous intra-uterine pressure measurements during amnioreduction in twin-to-twin transfusion syndrome therapy

IntroductionThis work explores the feasibility of simultaneous and continuous intra-abdominal, intra-uterine, and arterial blood pressure measurements to examine the hemodynamic perturbation expected during therapeutic amnioreduction and to better understand the protective role of the placenta during that treatment. MethodsPatients with twin-to-twin transfusion syndrome were treated with fetoscopic laser ablation followed by amnioreduction. Intra-abdominal, intra-uterine, and mean arterial pressures were simultaneously recorded during amnioreduction performed in steps of 200 mL. Placental thickness and uterine dimensions were measured before and after amnioreduction by ultrasonography. ResultsUseful pressure recordings were obtained between volume reduction steps and short hands-off periods in four studies. Median amnioreduction volume was 1400 mL corresponding to a median uterine volume reduction of 1121 mL. Mean intra-uterine pressure significantly fell from 24.8 to 13.6 mmHg (p = 0.011) and intra-abdominal pressure significantly decreased from 13.4 to 9.2 mmHg after amnioreduction (p = 0.015). Uterine pressure recordings revealed transient contractions (A, in mmHg) following individual amnioreduction steps, which increased with fractional amnioreduction (F, no dimension) (A = 17.23*F + 11.81; r = 0.50, p = 0.001). DiscussionSimultaneous and continuous measurement of intra-abdominal, intra-uterine, and arterial blood pressures during amnioreduction is feasible. The dynamics reveal transient uterine contractions reaching levels comparable to those seen during childbirth which seem to oppose impending maternal hypovolemia by placental steal at the expense of temporarily reducing placental perfusion pressure and underline the importance of uterine and placental interaction.

Clinical value of four-dimensional hysterosalpingo-contrast sonography assisted by intrauterine pressure measurement for tubal patency evaluation

We aimed to explore the clinical value of four-dimensional hys-terosalpingo-contrast sonography (4D-HyCoSy) assisted by intrauterine pres-sure measurement for evaluating tubal patency. One hundred and thirty-two patients diagnosed with tubal factor infertility from February 2018 to February 2021 were selected as subjects. With hysterosalpingography diagnosis results as the gold standard, 4D-HyCoSy was conducted for all patients, and the status of the fallopian tubes was classified into patency, occlusion, and partial occlusion. Based on the function of fallopian tubes, 4D-HyCoSy diagnosis results revealed that fallopian tubes showed bilateral patency, incomplete patency (including bilateral partial occlusion, unilateral patency, and unilateral partial occlusion, unilateral patency and unilateral occlusion), unilateral partial occlusion and unilateral occlusion, and bilateral occlusion. Thecutoff value of peak intra-uterine pressure was determined using the receiver operating characteristic curve (ROC), specificity, and the area under the ROC curve (AUC) between 4D-HyCoSy alone and 4D-HyCoSy assisted by intrauterine pressure measure-ments. There were significant differences in the peak intrauterine pressure among patients with bilateral patency, incomplete patency, unilateral partial occlusion, and unilateral and bilateral occlusions (p<0.05). The corresponding cutoff values of peak intrauterine pressure were 24.42, 36.34, and 47.68 kPa; AUC values were 0.812, 0.836, and 0.827, respectively. The FSM model showed that the AUC of 4D-HyCoSy alone, assisted by peak intrauterine pressure was 0.85, with a higher sensitivity (88.13%) than that of 4D-HyCoSy (p<0.05). 4D-HyCoSy, assisted by intrauterine pressure measurement, has an excellent value for evaluating tubal patency.

The Influence of Uterine Abnormalities on Uterine Peristalsis in the Non-Pregnant Uterus: A Systematic Review

Study Objective The aim of this systematic review is to explain the effect of uterine abnormalities, categorized in leiomyomas, adenomyosis and congenital uterine anomalies, on uterine peristalsis in the non-pregnant uterus. Design Systematic review. Setting N/A. Patients or Participants Non-pregnant women with uterine abnormalities such as adenomyosis, leiomyomas or congenital uterine anomalies. Interventions Measurement of uterine peristalsis. Measurements and Main Results Fourteen eligible studies were included; eight case-control studies and six controlled prospective studies. The sample sizes ranged from twelve to 205 participants. Various methods of analyzing uterine contractions were used, including transvaginal ultrasound, hysterosalpingo-radionuclide scintigraphy, cine MR and intrauterine pressure measurement. The researched types of uterine abnormalities seem to have an influence on uterine peristalsis, majorly reflected in the presence and frequency of uterine contractions. The included studies suggest that the presence of uterine abnormalities leads to a decreased presence of uterine peristalsis. An increment of frequency of uterine contractions was noted in presence of uterine abnormalities as well. Furthermore, dysperistalsis was observed in patients with leiomyomas, endometriosis and adenomyosis. The included studies were difficult to compare due to heterogeneity, a result of differences in e.g., used methods, analysis and definition of uterine peristalsis and the report of the phases of the menstrual cycle. Conclusion It can be concluded that uterine abnormalities have a clear adverse effect on uterine peristalsis. Further research is needed on objective measurement tools, treatment and clinical consequences of abnormal uterine peristalsis in patients with uterine abnormalities. The aim of this systematic review is to explain the effect of uterine abnormalities, categorized in leiomyomas, adenomyosis and congenital uterine anomalies, on uterine peristalsis in the non-pregnant uterus. Systematic review. N/A. Non-pregnant women with uterine abnormalities such as adenomyosis, leiomyomas or congenital uterine anomalies. Measurement of uterine peristalsis. Fourteen eligible studies were included; eight case-control studies and six controlled prospective studies. The sample sizes ranged from twelve to 205 participants. Various methods of analyzing uterine contractions were used, including transvaginal ultrasound, hysterosalpingo-radionuclide scintigraphy, cine MR and intrauterine pressure measurement. The researched types of uterine abnormalities seem to have an influence on uterine peristalsis, majorly reflected in the presence and frequency of uterine contractions. The included studies suggest that the presence of uterine abnormalities leads to a decreased presence of uterine peristalsis. An increment of frequency of uterine contractions was noted in presence of uterine abnormalities as well. Furthermore, dysperistalsis was observed in patients with leiomyomas, endometriosis and adenomyosis. The included studies were difficult to compare due to heterogeneity, a result of differences in e.g., used methods, analysis and definition of uterine peristalsis and the report of the phases of the menstrual cycle. It can be concluded that uterine abnormalities have a clear adverse effect on uterine peristalsis. Further research is needed on objective measurement tools, treatment and clinical consequences of abnormal uterine peristalsis in patients with uterine abnormalities.

Clinical Use of Electrohysterography During Term Labor: A Systematic Review on Diagnostic Value, Advantages, and Limitations.

Real-time electrohysterography (EHG)-based technologies have recently become available for uterine monitoring during term labor. Therefore, obstetricians need to be familiar with the diagnostic value, advantages, and limitations of using EHG. The aims of this study were to determine the diagnostic value of EHG in comparison to (1) the intrauterine pressure catheter (IUPC), (2) the external tocodynamometer (TOCO), and (3) in case of maternal obesity; (4) to evaluate EHG from users' and patients' perspectives; and (5) to assess whether EHG can predict labor outcome. A systematic review was performed in the MEDLINE, EMBASE, and Cochrane library in October 2017 resulting in 209 eligible records, of which 20 were included. A high sensitivity for contraction detection was achieved by EHG (range, 86.0%-98.0%), which was significantly better than TOCO (range, 46.0%-73.6%). Electrohysterography also enhanced external monitoring in case of maternal obesity. The contraction frequency detected by EHG was on average 0.3 to 0.9 per 10 minutes higher compared with IUPC, which resulted in a positive predictive value of 78.7% to 92.0%. When comparing EHG tocograms with IUPC traces, an underestimation of the amplitude existed despite that patient-specific EHG amplitudes have been mitigated by amplitude normalization. Obstetricians evaluated EHG tocograms as better interpretable and more adequate than TOCO. Finally, potential EHG parameters that could predict a vaginal delivery were a predominant fundal direction and a lower peak frequency. Electrohysterography enhances external uterine monitoring of both nonobese and obese women. Obstetricians consider EHG as better interpretable; however, they need to be aware of the higher contraction frequency detected by EHG and of the amplitude mismatch with intrauterine pressure measurements.

Clinical assessment of uterine contractions.

The assessment of uterine contractions is important in clinical decision-making, but the precise role for appraising contractions remains controversial. Four clinical approaches to assessing contractions are available: manual palpation; intrauterine pressure determination; external tocodynamometry; and electrohysterography. Palpation is inexpensive and harmless but requires the constant bedside presence of a trained observer. Intrauterine pressure measurement is considered the most sensitive and specific technique, and has become the standard by which other methods are judged; however, its quantitative measurements are not always precise or reproducible. Moreover, the availability of intrauterine pressure measurements does not seem to improve maternal or neonatal outcomes in most situations. External tocodynamometry is the most widely used technique. It is easy to apply and provides reasonably accurate information about the frequency and duration of contractions, but not their amplitude. It can require frequent adjustment during labor and might not work well in patients who are obese. Electrohysterography is a recently available noninvasive technology that detects uterine electrical activity using electrodes placed on the mother's abdominal wall. This approach is at least as reliable and accurate as tocodynamometry.

Electrohysterography for uterine monitoring during term labour compared to external tocodynamometry and intra-uterine pressure catheter

ObjectiveCurrent uterine monitoring techniques have major drawbacks that could be avoided when using electrohysterography for uterine monitoring. Recently, a new electrohysterography method has been developed, providing a real-time tocogram on standard cardiotocography monitors. The diagnostic characteristics of this novel method need to be determined and compared to conventional methods We hypothesised that electrohysterography can perform better than external tocodynamometry due to the adhesive properties of the contact electrodes (less motion sensitive), and the improved signal acquisition through subcutaneous tissue (less obesity sensitive). Study designIn this prospective diagnostic accuracy study, uterine contractions of labouring women were simultaneously monitored by three different monitoring techniques: electrohysterography, external tocodynamometry, and intra-uterine pressure catheter as method of reference. We performed a two-hour measurement during first and/or second stage of term labour. The contractions of each method were automatically detected by a computer-based algorithm. As the applied method had not been described in literature before, an interim analysis was performed to minimise exposure to the invasive pressure catheter. The main outcome parameter was the sensitivity of electrohysterography in comparison to external tocodynamometry for uterine contraction detection, tested by the Wilcoxon signed rank test. ResultsUterine contractions of 48 term labouring women were simultaneously monitored by electrohysterography, external tocodynamometry, and intra-uterine pressure catheter. The study was terminated after the interim analysis as the sensitivity of electrohysterography was significantly higher compared to external tocodynamometry: median 89.5% (interquartile range (IQR); 82–93) and 65.3% (IQR; 53–81) respectively, p<0.001. In a subgroup analysis of obese women (n=15), the sensitivity of electrohysterography was significantly higher than external tocodynamometry (median 88.4% (IQR; 79–95) and 45.8% (IQR; 38–61) respectively, p<0.001). Whereas in a subanalysis of second stage of labour (n=8), electrohysterography did not perform better than external tocodynamometry (median 72.8% (IQR; 61–87) and 66.4% (IQR; 46–75) respectively, p=0.225). Electrohysterography registered 0.4 more contractions per 10min than the intra-uterine pressure measurement (p<0.001) and 0.5 more contractions per 10min than external tocodynamometry (p<0.001). ConclusionElectrohysterography has a higher sensitivity for uterine contraction detection than external tocodynamometry during first stage of labour, in non-obese and obese women. Electrohysterography identifies more contractions than conventional techniques.

Identification of the mechanical parameters for the human uterus in vivo using intrauterine pressure measurements.

There are limited experimental data to characterize the mechanical response of human myometrium. A method is presented in this work to identify mechanical parameters describing the active response of human myometrium from the in vivo intrauterine pressure measurements. The human uterine contraction during labor is simulated by implementing a coupled model in a finite element scheme, and the intrauterine pressure is evaluated as the outcome. A meta-model is developed to approximate the finite element simulation response with a lower computational cost and used to identify model parameters through fitting its prediction to the in vivo measurements. Copyright © 2016 John Wiley & Sons, Ltd.

Does measurement of intrauterine pressure have predictive value during oxytocin-augmented labor?

Objective: In a previous randomized trial that compared monitoring uterine contractions with an intrauterine pressure catheter (IUPC) versus external monitoring, we demonstrated that use of an IUPC did not improve the outcome of labor. To provide insight in the lack of a positive effect, we evaluated level of IUP in Montevideo units (MU) in correlation with dysfunctional labor and adverse neonatal outcome.Study design: Here, we present two secondary analyses on the 503 women who had IUP measured in the trial. Firstly, we assessed labor outcome in relation to the highest IUP measured at any time during labor. Secondly, we assessed labor outcome to the IUP registered at the last vaginal examination during the first stage of labor in two study groups (above and below 200 MU).Results: Women with lower IUP were statistically significant older, had pregnancies with a longer gestational age, longer labors and neonates with a higher birth weight. The risk of a cesarean section was higher in women who had low IUP during labor (Likelihood Ratio 1.6 for IUP < 100 MU, 0.41 for IUP > 300 MU). IUP was not associated with neonatal outcome.Conclusion: IUP is associated with mode of delivery. However, use of internal tocodynamometry does not improve birth outcomes.

The use and abuse of oxytocin

Key content Oxytocin is a well‐established drug with a long history of use. The generation of intrauterine pressure is a result of myometrial activity, but is attenuated by a softening cervix. The introduction of active management regimens have not changed the outcome of labour as we envisaged. Too many babies suffer asphyxia as a result of misuse of oxytocin. Some form of education programme must be developed to warn of the dangers of this very useful drug. Better training and education programmes must be in place for midwives and obstetricians for labour management and cardiotography interpretation. Learning objectives To outline the history of the development of oxytocin. To understand the mechanism of intrauterine pressure development. To understand the methods of intrauterine pressure measurement and assessment. To understand the development of principles of active management with a discussion of the subsequent studies analysing the results of such labour management. To outline the medicolegal aspects of labour augmentation, with particular reference to oxytocin use. To discuss possible implications for the future. Ethical issues Should all women be given the information that oxytocin augmentation of slow labour may reduce the duration of labour by several hours but does not change the mode of delivery, whilst carrying a risk of causing fetal asphyxia? Should women sign informed consent before their labours are augmented? Should augmentation of labour only be undertaken under the direct supervision of a senior clinician?

Electrohysterographic detection of uterine contractions in term pregnancy.

Uterine-contraction detection is a fundamental component of pregnancy monitoring. Electrohysterography (EHG) provides a non-invasive and accurate alternative to intrauterine pressure (IUP) measurements, and several techniques provide an estimated IUP (eIUP) based on the EHG alone. Commonly, EHG contraction detection is based on amplitude thresholding of the eIUP. We aim at improving the reliability of contraction detection, such that automatic contraction detection can be realized. An algorithm for template-matching of the eIUP signal is proposed. This method is based on Bayesian evidence using a Gaussian likelihood function to classify uterine activity. Gaussian templates are matched to the input signal, with weights obtained empirically from manually-annotated contraction events in a training data-set. The results show an improvement in contraction detection accuracy compared to threshold-based methods. The template-matching method is adaptable to relevant features in the input training data, and is thus less sensitive to differences in eIUP derivation or measurement variability. The method allows for improved automatic uterine contraction detection in labor EHG data, while being extensible to e.g. preterm contraction detection.

Low-complexity intrauterine pressure estimation using the Teager energy operator on electrohysterographic recordings

Monitoring the progression of maternal uterine activity provides important prognostic information during pregnancy and parturition. Currently used methods for intrauterine pressure (IUP) measurement are unsuitable for long-term observation of uterine activity. The abdominally measured electrohysterogram (EHG) provides a non-invasive alternative to the existing methods for long-term ambulatory uterine contraction monitoring. A new low-complexity method for IUP estimation based on the Teager energy (TE) operator is proposed. The TE operator was used as it mimics the physiologic phenomena underlying the generation of the EHG signals. Several EHG signal analysis methods for IUP estimation from the literature are compared with the new TE method. The comparison is based on correlation and root mean square error of the IUP estimate with the gold standard internally measured IUP as well as their respective computational complexity. The proposed method results in a superior IUP estimation accuracy and complexity compared to state-of-the-art methods from the literature, with a complexity as much as 55 times lower. Therefore, the proposed method offers a valuable new option for long-term ambulatory uterine monitoring.

Accuracy and Reliability of Uterine Contraction Identification Using Abdominal Surface Electrodes

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 &lt; 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 &lt; 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 &lt; 0.001). Conclusion The electrohysterographic technique was more reliable and similar in accuracy to tocodynamometry in detecting intrapartum uterine contractions.

In vivo measurement of intrauterine pressure by telemetry: a new approach for studying parturition in mouse models

Transgenic and knockout mouse models have proven useful in the study of genes necessary for parturition-including genes that affect the timing and/or progression of labor contractions. However, taking full advantage of these models will require a detailed characterization of the contractile patterns in the mouse uterus. Currently the best methodology for this has been measurement of isometric tension in isolated muscle strips in vitro. However, this methodology does not provide a real-time measure of changes in uterine pressure over the course of pregnancy. Recent advances have opened the possibility of using radiotelemetric devices to more accurately and comprehensively study intrauterine pressure in vivo. We tested the effectiveness of this technology in the mouse, in both wild-type (WT) mice and a mouse model of defective parturition (SK3 channel-overexpressing mice), after surgical implant of telemetry transmitters into the uterine horn. Continuous recordings from day 18 of pregnancy through delivery revealed that WT mice typically deliver during the 12-h dark cycle after 19.5 days postcoitum. In these mice, intrauterine pressure gradually increases during this cycle, to threefold greater than that measured during the 12-h cycle before delivery. SK3-overexpressing mice, by contrast, exhibited lower intrauterine pressure over the same period. These results are consistent with the outcome of previous in vitro studies, and they indicate that telemetry is an accurate method for measuring uterine contraction, and hence parturition, in mice. The use of this technology will lead to important novel insights into changes in intrauterine pressure during the course of pregnancy.

Symptoms and signs with scar rupture--value of uterine activity measurements.

To evaluate the symptoms and signs of scar rupture with special reference to intrauterine pressure measurement a retrospective analysis of labour records of those women who had trial of labour with a previous Caesarean scar in the National University Hospital over a period of 6 years (1985-1990) was carried out. Known symptoms and signs associated with scar rupture, cardiotocographic tracings and fetal and maternal outcome in these patients were studied. Of the 1,018 women with previous Caesarean scar (4.2% of our pregnant population at term) 722 (70.9%) had trial of labour; 70% delivered vaginally. There were 4 (0.55%) incomplete and 5 (0.69%) complete scar ruptures. All 9 women had an oxytocin infusion; 3 were diagnosed postdelivery (all 3 had complete ruptures); 3 of the 6 who had rupture prior to delivery had sudden reduction in uterine activity, 1 had scar pain and prolonged bradycardia and 2 had no symptoms or signs. Continuous cardiotocography with intrauterine pressure measurements may help to identify scar rupture early and may be of value especially in those who have an oxytocin infusion.

Non-invasive transabdominal uterine electromyography correlates with the strength of intrauterine pressure and is predictive of labor and delivery

Objective: The study was conducted to investigate whether the strength of uterine contractions monitored invasively by intrauterine pressure catheter could be determined from transabdominal electromyography (EMG) and to estimate whether EMG is a better predictor of true labor compared to tocodynamometry (TOCO).Study design: Uterine EMG was recorded from the abdominal surface in laboring patients simultaneously monitored with an intrauterine pressure catheter (n = 13) or TOCO (n = 24). Three to five contractions per patient and corresponding electrical bursts were randomly selected and analyzed (integral of intrauterine pressure; integral, frequency, amplitude of contraction curve on TOCO; burst energy for EMG). The Mann–Whitney test, Spearman correlation and receiver operator characteristics (ROC) analysis were used as appropriate (significance was assumed at a value of p < 0.05).Results: EMG correlated strongly with intrauterine pressure (r = 0.764; p = 0.002). EMG burst energy levels were significantly higher in patients who delivered within 48 h compared to those who delivered later (median [25%/75%]: 96 640 [26 520–322 240] vs. 2960 [1560–10 240]; p < 0.001), whereas none of the TOCO parameters were different. In addition, burst energy levels were highly predictive of delivery within 48 h (AUC = 0.9531; p < 0.0001).Conclusion: EMG measurements correlated strongly with the strength of contractions and therefore may be a valuable alternative to invasive measurement of intrauterine pressure. Unlike TOCO, transabdominal uterine EMG can be used reliably to predict labor and delivery.

Uterine contractility and directed sperm transport assessed by hysterosalpingoscintigraphy (HSSG) and intrauterine pressure (IUP) measurement.

Uterine peristalsis sustains sperm transport and can be detected by hysterosalpingoscintigraphy (HSSG). This study is the first to be designed to investigate utero-tubal transport function by HSSG and uterine contractility by intrauterine pressure measurement (IUP) consecutively on the same day in the periovulatory phase. Twenty-one female subjects (mean age 28.4 years) without a gynecologic history were examined sequentially by HSSG and IUP on the same day to evaluate uterine contractility in relation to the utero-tubal transport function. In HSSG, intact transport function was visualized by the rapid uptake of 99m-technetium-marked albumin aggregates through the female genital tract. In IUP, the frequency of uterine contractions (UC/min), amplitude of uterine contractions and basal pressure tone were detected via a intrauterine catheter. HSSG and IUP were embedded in cycle monitoring with measurement of LH and estradiol. In HSSG, a positive transport of inert particles was assessed in 20 of 21 subjects, in 76% to the side of the dominant follicle or on both sides of the oviduct, and in 19% a strict contralateral transport could be observed. In only one subject (5%), no transport was assessed. The mean value of uterine contractions was 3.4 UC/min (SD +/- 0.7), the mean amplitude was 12.0 mmHg (SD +/- 4.25 mmHg). Basal pressure tone was 70.7 mmHg. There was a statistically significant correlation with estradiol levels: none of the subjects with less than 3 UC/min showed an estradiol level higher than 100 pg/mL; nearly every patient (one exception) with more than 3 UC/min had an estradiol level higher than 100 pg/mL (p < 0.0001, Fisher's exact test). Intact periovulatory utero-tubal transport function can be documented by HSSG and is caused by directed uterine contractility, measured consecutively by IUP. Uterine contractility is influenced by rising estradiol levels. Directed uterine contractility and intact utero-tubal transport function are considered necessary for intact sperm transport, mainly to the side bearing the dominant follicle to maximize fertility.

Uterine contractility and directed sperm transport assessed by hysterosalpingoscintigraphy (HSSG) and intrauterine pressure (IUP) measurement

Background. Uterine peristalsis sustains sperm transport and can be detected by hysterosalpingoscintigraphy (HSSG). This study is the first to be designed to investigate utero-tubal transport function by HSSG and uterine contractility by intrauterine pressure measurement (IUP) consecutively on the same day in the periovulatory phase. Methods. Twenty-one female subjects (mean age 28.4 years) without a gynecologic history were examined sequentially by HSSG and IUP on the same day to evaluate uterine contractility in relation to the utero-tubal transport function. In HSSG, intact transport function was visualized by the rapid uptake of 99m-technetium-marked albumin aggregates through the female genital tract. In IUP, the frequency of uterine contractions (UC/min), amplitude of uterine contractions and basal pressure tone were detected via a intrauterine catheter. HSSG and IUP were embedded in cycle monitoring with measurement of LH and estradiol. Results. In HSSG, a positive transport of inert particles was assessed in 20 of 21 subjects, in 76% to the side of the dominant follicle or on both sides of the oviduct, and in 19% a strict contralateral transport could be observed. In only one subject (5%), no transport was assessed. The mean value of uterine contractions was 3.4 UC/min (SD ± 0.7), the mean amplitude was 12.0 mmHg (SD ± 4.25 mmHg). Basal pressure tone was 70.7 mmHg. There was a statistically significant correlation with estradiol levels: none of the subjects with less than 3 UC/min showed an estradiol level higher than 100 pg/mL; nearly every patient (one exception) with more than 3 UC/min had an estradiol level higher than 100 pg/mL (p < 0.0001, Fisher's exact test). Conclusions. Intact periovulatory utero-tubal transport function can be documented by HSSG and is caused by directed uterine contractility, measured consecutively by IUP. Uterine contractility is influenced by rising estradiol levels. Directed uterine contractility and intact utero-tubal transport function are considered necessary for intact sperm transport, mainly to the side bearing the dominant follicle to maximize fertility.

Uterine contractility in women whose fetus is delivered in the occipitoposterior position

Objective: Most fetuses in the occipitoposterior position rotate spontaneously after striking the pelvic floor. The increased prevalence of prolonged labor, operative delivery, and oxytocin augmentation in women with an occipitoposterior fetal position seems consistent with decreased uterine contractility. We sought to test the hypothesis that women with a persistent occipitoposterior fetal position have inadequate intrauterine pressure. Study Design: Intrauterine pressure was measured prospectively electronically in 94 women whose labor pain was controlled by patient-requested epidural analgesia. Eleven women (12%) were delivered as a persistent occipitoposterior fetal position. In a nested case-control study, these women were compared with 22 women who were delivered as an occipitoanterior fetal position who were matched for age, parity, gestational age, cervical examination at study enrollment, and body mass index. The intrauterine pressure measurements were initiated during the first stage of labor and continued throughout the entire labor process. Women were encouraged in the second stage of labor, after a period of recording baseline contractility, to push using a standardized Valsalva maneuver once the vertex reached the +2 station. The area under the intrauterine pressure curve (integral) was used to estimate uterine contractility and expulsive performances. Results: Five women (45%) in the occipitoposterior group required operative delivery. The average duration of the second stage of labor in the occipitoposterior group was 91.4 ± 23.2 minutes compared with 51.7 ± 6.6 minutes in the occipitoanterior fetal position (P =.04). Ninety percent of women in the occipitoposterior group required oxytocin, compared with 59% of the women in the occipitoanterior group (P =.11). There were no differences in uterine contractility between occipitoposterior and occipitoanterior groups during either the first stage of labor (integral mean ± SEM: occipitoposterior [1685.3 ± 194.6 mm Hg · s] vs occipitoanterior fetal position [1700.8 ± 128.9 mm Hg · s, P =.98]) or second stages of labor (occipitoposterior [1952.6 ± 186.5 mm Hg · s] vs occipitoanterior fetal position [1740.8 ± 104.3 mm Hg · s, P =.46]). Further, there were no significant differences in pushing performances between the occipitoposterior and occipitoanterior groups (Valsalva maneuver: occipitoposterior 2864.9 ± 328.8 mm Hg · s] vs occipitoanterior [2898.6 ± 222.2 mm Hg · s, P =.90]). Conclusion: Women who were delivered as a persistent occipitoposterior fetal position do not have lower intrauterine pressure levels immediately before or during the second stage of labor. (Am J Obstet Gynecol 2003;188:734-9.)

The effect of fundal pressure manoeuvre on intrauterine pressure in the second stage of labour

Objective To investigate the relationship between intrauterine pressure and the application of a standardised fundal pressure manoeuvre, and to determine the maternal, fetal and labour characteristics that modulate the relationship. Design Prospective measurement of intrauterine pressure during the second stage of labour. Setting North American university hospital. Population Forty full-term women in spontaneous labour were studied during the second stage. Each woman acted as her own control. All women laboured with requested epidural analgesia. Methods A fundal pressure manoeuvre was performed so as to standardise the level of force and the surface area of application. Intrauterine pressure was measured using a sensor–tip catheter. Five interventions were analysed: 1. valsalva during a uterine contraction; 2. fundal pressure and valsalva during a contraction; 3. fundal pressure during a contraction without valsalva; 4. fundal pressure in the absence of uterine contractions; and 5. valsalva in the absence of uterine contractions. Results Women in the second stage of labour transiently increased their expulsive force (as reflected by intrauterine pressure) by 86% of their baseline contraction using valsalva and fundal pressure simultaneously. The efficiency by which both contraction-enhancing manoeuvres increased intrauterine pressure was directly related to gestational age and inversely related to myometrial thickness. Conclusion Fundal pressure applied under controlled conditions significantly increases intrauterine pressure in some, but not all women. Simultaneous measurement of intrauterine pressure, to maintain feedback during application will create a ‘controlled environment’ for the obstetrician and reassurance that this manoeuvre can be applied in a controlled fashion. Future delineation of the group of women that could benefit from fundal pressure, as well as the group that is refractory is essential to avoid unnecessary or delayed operative interventions.

The effect of fundal pressure manoeuvre on intrauterine pressure in the second stage of labour.

To investigate the relationship between intrauterine pressure and the application of a standardised fundal pressure manoeuvre, and to determine the maternal, fetal and labour characteristics that modulate the relationship. Prospective measurement of intrauterine pressure during the second stage of labour. North American university hospital. Forty full-term women in spontaneous labour were studied during the second stage. Each woman acted as her own control. All women laboured with requested epidural analgesia. A fundal pressure manoeuvre was performed so as to standardise the level of force and the surface area of application. Intrauterine pressure was measured using a sensor-tip catheter. Five interventions were analysed: 1. valsalva during a uterine contraction; 2. fundal pressure and valsalva during a contraction; 3. fundal pressure during a contraction without valsalva; 4. fundal pressure in the absence of uterine contractions; and 5. valsalva in the absence of uterine contractions. Women in the second stage of labour transiently increased their expulsive force (as reflected by intrauterine pressure) by 86% of their baseline contraction using valsalva and fundal pressure simultaneously. The efficiency by which both contraction-enhancing manoeuvres increased intrauterine pressure was directly related to gestational age and inversely related to myometrial thickness. Fundal pressure applied under controlled conditions significantly increases intrauterine pressure in some, but not all women. Simultaneous measurement of intrauterine pressure, to maintain feedback during application will create a 'controlled environment' for the obstetrician and reassurance that this manoeuvre can be applied in a controlled fashion. Future delineation of the group of women that could benefit from fundal pressure, as well as the group that is refractory is essential to avoid unnecessary or delayed operative interventions.