Intrauterine Pressure Catheter Research Articles

Uterine contractile activity and neonatal outcome - A blind analysis of a randomized controlled trial cohort.

Sufficient contractions are necessary for a successful delivery but each contraction temporarily constricts the oxygenated blood flow to the fetus. Individual fetal or placental characteristics determine how the fetus can withstand this temporary low oxygen saturation. However, only a few studies have examined the impact of uterine activity on neonatal outcome and even less attention has been paid to parturients' individual characteristics. Our objective was therefore to find out whether fetuses compromised by maternal or intrapartum risk factors are more vulnerable to excessive uterine activity. Uterine contractile activity was assessed by intrauterine pressure catheters. Women (n = 625) with term singleton pregnancies and fetus in cephalic presentation were included in this secondary, blind analysis of a randomized controlled trial cohort. Intrauterine pressure as Montevideo units (MVU), contraction frequency/10 min and uterine baseline tone were calculated for 4 h prior to birth or the decision to perform cesarean section. Uterine activity in relation to umbilical artery pH linearly or ≤7.10 was used as the primary outcome. Need for operative delivery (either cesarean section or vacuum-assisted delivery) due to fetal distress was analyzed as a secondary outcome. In addition, belonging to vulnerable subgroups with, for example, chorioamnionitis, hypertensive or diabetic disorders, maternal smoking or neonatal birthweight <10th percentile were investigated as additional risk factors. A linear decline in umbilical artery pH was seen with increasing intrauterine pressure in all deliveries (p < 0.001). Among parturients with suspected chorioamnionitis, every increasing 10 MVUs increased the likelihood of umbilical artery pH ≤7.10 (odds ratio [OR] 1.17, 95% confidence interval [CI] 1.02-1.34, p = 0.023). The need for operative delivery due to fetal distress was increased among all laboring women by every increasing 10 MVUs (OR 1.05, 95% CI 1.01-1.09, p = 0.015). This association with operative deliveries was further increased among parturients with hypertensive disorders (OR 1.23, 95% CI 1.05-1.43, p = 0.009) and among those with diabetic disorders (OR 1.13, 95% CI 1.04-1.28, p = 0.003). Increasing intrauterine pressure impairs umbilical artery pH especially among parturients with suspected chorioamnionitis. Fetuses in pregnancies affected by chorioamnionitis, hypertensive or diabetic disorders are more vulnerable to high intrauterine pressure.

A prospective observational study comparing intrauterine pressure during the second stage of labor: Does body mass index affect pressure generated during pushing?

AbstractObjectiveTo compare intrauterine pressure generated during pushing as measured by an intrauterine pressure catheter in the first and second stages of labor in obese patients (body mass index [BMI] ≥ 35 kg/m2) and nonobese (BMI &lt; 35 kg/m2).MethodsThis was a prospective observational study of patients in labor at term. Peak intrauterine pressure was measured during a Valsalva maneuver in the first and second stages of labor, both during a contraction and at rest and compared between obese and nonobese patients. Pushing pressure, defined as the mean of the highest three out of five peak pressures attained minus the intrauterine resting pressure were also compared for the two groups.ResultsA total of 115 patients were enrolled: 50 (43.5%) obese and 65 (56.5%) nonobese. We found pushing pressures were significantly less in obese patients both with risk difference (RD) = 13.71 (95% confidence interval [CI]: 5.53, 21.90) and without RD = 12.19 (95% CI: 4.46, 19.91) a uterine contraction compared to the nonobese patients in the second stage of labor. This effect persisted after controlling for confounding variables.ConclusionObese patients with BMI ≥ 35 kg/m2 generated lower intrauterine pressures during pushing than compared to nonobese (BMI &lt; 35 kg/m2). This suggests that obese patients may need a longer second stage of labor or a longer duration of pushing to achieve vaginal birth.

The impact of body mass index on labour management and mode of delivery: A retrospective matched cohort study.

This study aims to examine the association between body mass index (BMI) and mode of delivery, progression of labour, and intrapartum interventions. This was a retrospective matched cohort study including Class III obese (BMI ≥40 kg/m2 ) and normal BMI (BMI <25 kg/m2 ) women planning a vaginal birth who had a live, singleton delivery from January 2015 to December 2018. Patients were matched (1:1) based on age, gestational age, parity, onset of labour and birth weight. The primary outcome was caesarean delivery (CD). Secondary outcomes were delivery outcomes, intrapartum management and interventions. Rates of each outcome were compared with matched analysis, and duration of labour with time-to-event analysis. We studied two groups of 300 pregnant women. The CD rate was significantly higher for obese women than the normal BMI cohort (19.3% vs 13.3%; risk ratio (RR) 1.43, 95% CI 1.02-1.98, P = 0.035). Cervical dilation prior to CD for failure to progress was slower in obese than normal BMI (0.04 vs 0.16 cm/h). The obese cohort had a longer duration of labour in those who underwent induction (13.70 vs 11.48 h, P = 0.024). Intrapartum intervention rates were higher for obese women, with significant differences in rates of fetal scalp electrodes (72.7% vs 22.7%, RR 3.20, 95% CI 2.58-3.99, P < 0.001), intrauterine pressure catheters (18.3% vs 0%, P < 0.001), epidural analgesia (44.0% vs 37.0%, RR 1.20, 95% CI 1.01-1.44, P = 0.040) and fetal scalp lactate sampling (8.0% vs 3.0%, RR = 2.67, 95% CI 1.33-5.33, P = 0.004). Class III obesity is associated with an increased risk of CD and intrapartum interventions.

Use of External Uterine Electromyography Across Stage I Labor.

Highly sensitive, external uterine electromyography (EMG) measures myometrial electrical activity and is noninvasive compared with the clinical intrauterine pressure catheter. Most experimental studies have measured EMG in 30-minute epochs, limiting the utility of this instrumentation in intrapartum clinical practice. To test proof of concept, surface uterine EMG contraction activity was continuously collected throughout the first stage of labor from healthy women at term gestation with (n = 3) and without (n = 1) epidural or combined spinal-epidural analgesia for a maximal length of 11 hours and 24 minutes. EMG activity was recorded concurrently with tocodynamometer (toco) signals, using a pair of electrodes on the left and right sides of the maternal umbilicus with grounds attached to both hips of the reclining woman in labor. The preamplifier cutoff frequency settings were appropriate to monitor smooth muscle contraction in labor, with the analog high-pass filter set at 0.05 Hz and the low-pass filter at 1.50 Hz. Signals were sampled at 100 Hz, transmitted to a computer, and visualized by Chart 4.2 software. EMG data from epochs at baseline, during the pre-epidural fluid bolus and at the 60-minute post-epidural test dose, and at 3, 5, 6, and 8 cm dilatation were analyzed for burst power spectrum peak frequency (Hz), burst power spectrum amplitude (mV2 ), and burst duration (seconds). Uterine EMG contractile bursts were preceded and followed by a stable baseline and coincided with toco contractions. Movement artifacts were negligible, and large movement artifacts were easily distinguishable. The EMG bursts and toco contractions remained clearly identifiable, even when one woman without epidural analgesia stood beside the bed laboring for approximately 10 minutes. Burst spectral components fell within the expected 0.34-to-1.00 Hz range for term labor. High-quality data demonstrate that EMG instrumentation effectively and accurately measures uterine contraction parameters across the first stage of term labor.

Association between Elevated Intrauterine Resting Tone during Labor and Neonatal Morbidity.

Internal contraction monitoring provides a quantitative assessment of intrauterine resting tone. During the course of labor, elevated intrauterine resting tone may be identified. We hypothesized that elevated intrauterine resting tone could lead to compression of the spiral arteries, thus limiting uterine blood flow and resulting in neonatal compromise. Therefore, our objective was to assess the association between elevated resting tone during labor and neonatal morbidity. This was a secondary analysis of a prospective cohort study of singleton deliveries at ≥37 weeks of gestation. Patients with ruptured membranes and an intrauterine pressure catheter in place for at least 30 minutes prior to delivery were included. Intrauterine resting tone was calculated as the average baseline pressure between contractions during the 30 minutes prior to delivery. The study group had elevated intrauterine resting tone, defined as intrauterine resting tone ≥75th percentile (≥12.3 mm Hg). Primary outcome was composite neonatal morbidity: hypoxic-ischemic encephalopathy, hypothermia treatment, intubation, seizures, umbilical arterial pH ≤7.1, oxygen requirement, or death. Secondary outcomes included umbilical artery pH <7.2, lactate ≥4 mmol/L, and rates of neonatal intensive care unit admission. Of the 8,580 patients in the cohort, 2,210 (25.8%) met the inclusion criteria. The median intrauterine resting tone was 9.7 mm Hg (interquartile range: 7.3-12.3 mm Hg). Elevated resting tone was associated with a shorter median duration of the first stage of labor (10.0 vs. 11.0 hours, p < 0.01) and lower rates of labor induction and oxytocin augmentation (p < 0.01). Neonatal composite morbidity was higher among patients with elevated intrauterine resting tone (5.1 vs. 2.9%, p = 0.01). After adjusting for chorioamnionitis and amnioinfusion, elevated intrauterine resting tone was associated with increased risk of neonatal morbidity (adjusted odds ratio: 1.70, 95% confidence interval: 1.06-2.74). Our findings suggest that elevated intrauterine resting tone is associated with increased risk of neonatal composite morbidity. · Higher intrauterine resting tone is associated with increased risk of neonatal morbidity.. · Elevated intrauterine tone can negatively impact umbilical artery pH and lactate levels.. · If elevated intrauterine pressure is noted, we recommend close monitoring of fetal status..

The Relationship Between Uterine Activity, Oxytocin Dosing, Labor Progress, and Mode of Birth in Nulliparas with Obesity: Minimal Usefulness of Montevideo Unit Measurement.

Maternal obesity and cesarean birth disproportionately affect Black parturients; thus, prevention of cesarean birth is a key modifiable factor to improve pregnancy outcomes and reduce disparities. The primary driver of unplanned cesarean birth among people with higher body mass index is prolonged labor duration. However, strategies to optimize outcomes in these situations have not been established. We aimed to evaluate the influence of oxytocin augmentation on uterine activity and labor progression in nulliparas with obesity. This secondary analysis involved nulliparas with obesity (BMI ≥30kg/m2) who had spontaneous labor onset followed by oxytocin augmentation and an intrauterine pressure catheter. Using Linear Mixed Models, we evaluated relationships between uterine activity measured in Montevideo units (MVU), oxytocin dose, and rate of cervical dilation normalized by labor duration. In this diverse sample (35.6% Caucasian, 16.11% African American, 40.2% Hispanic) of nulliparas with obesity (n = 87; BMI 35.54 ± 4.38kg/m2), 31% ended labor with cesarean birth. Among those with vaginal birth, only 13% had MVU ≥200 prior to the final 2hours of labor. MVUs were only minimally responsive to oxytocin dose and were not associated with labor progression nor birth route. MVU measurements may not be useful to diagnose labor arrest in nulliparas with obesity. Optimizing care for birthing people with obesity is essential for improving perinatal outcomes and for reducing racial health disparities.

Intrauterine pressure catheter use and risk of placental abruption and postpartum hemorrhage

Intrauterine pressure catheter use and risk of placental abruption and postpartum hemorrhage

Experiences with intrapartum fetal monitoring in the Netherlands: A survey study

IntroductionWorldwide, cardiotocography is used for continuous monitoring of fetal heart rate (FHR) and uterine contractions during labour. Different methods for FHR registration and registration of contractions are available. Literature about the frequency of use of different fetal monitoring methods is lacking. ObjectiveTo evaluate the use of and preferences for fetal monitoring methods for intrapartum fetal monitoring among Dutch obstetric care providers. Study designBetween October and November 2020 the Dutch Society of Obstetrics and Gynaecology sent an email invitation to all secondary care midwives and gynaecologists (in training) in the Netherlands to complete an online survey regarding the use and personal experience with fetal monitoring methods. The survey mainly consisted of multiple choice questions. Descriptive statistics are reported. Continuous variables were presented as median with interquartile ranges (IQR). Categorical variables were expressed as numbers with percentages. ResultsThe response rate was 29 % (n/N = 510/1748). All Dutch hospitals were represented. The respondents estimated the use of fetal scalp electrode (FSE) at 71 % (IQR 58–85 %) of deliveries. The most common indication for use of the FSE was inadequate external FHR registration (94 %). More than half (54 %) of the respondents reported to use intrauterine pressure catheter with an estimated use of 5 % (IQR 2–8 %) of deliveries. The most common indication for use of intrauterine pressure catheter was inadequate external contraction registration (75 %). The use of ST-analysis was reported in 25 % of the respondents with an estimated use of 60 % (IQR 30–72 %) of deliveries. Almost all respondents (99 %) reported to use fetal blood sampling with an estimated use of 15 % (IQR 10–23 %) of deliveries. Ninety percent of respondents would prefer a valid and reliable external monitoring technique during labour. Thirty-one percent of respondents assume that external fetal monitoring with non-invasive fetal electrocardiography and electrohysterography will become standard care within the next 5 years. ConclusionsCurrently, the FSE is the most used technique for FHR monitoring during labour in the Netherlands. The most common indication for use of FSE is inadequate external FHR registration. Obstetric care providers would prefer a non-invasive external registration method that provides reliable data.

A Novel, Cardiac-Derived Algorithm for Uterine Activity Monitoring in a Wearable Remote Device.

Background: Uterine activity (UA) monitoring is an essential element of pregnancy management. The gold-standard intrauterine pressure catheter (IUPC) is invasive and requires ruptured membranes, while the standard-of-care, external tocodynamometry (TOCO)’s accuracy is hampered by obesity, maternal movements, and belt positioning. There is an urgent need to develop telehealth tools enabling patients to remotely access care. Here, we describe and demonstrate a novel algorithm enabling remote, non-invasive detection and monitoring of UA by analyzing the modulation of the maternal electrocardiographic and phonocardiographic signals. The algorithm was designed and implemented as part of a wireless, FDA-cleared device designed for remote pregnancy monitoring. Two separate prospective, comparative, open-label, multi-center studies were conducted to test this algorithm. Methods: In the intrapartum study, 41 laboring women were simultaneously monitored with IUPC and the remote pregnancy monitoring device. Ten patients were also monitored with TOCO. In the antepartum study, 147 pregnant women were simultaneously monitored with TOCO and the remote pregnancy monitoring device. Results: In the intrapartum study, the remote pregnancy monitoring device and TOCO had sensitivities of 89.8 and 38.5%, respectively, and false discovery rates (FDRs) of 8.6 and 1.9%, respectively. In the antepartum study, a direct comparison of the remote pregnancy monitoring device to TOCO yielded a sensitivity of 94% and FDR of 31.1%. This high FDR is likely related to the low sensitivity of TOCO. Conclusion: UA monitoring via the new algorithm embedded in the remote pregnancy monitoring device is accurate and reliable and more precise than TOCO standard of care. Together with the previously reported remote fetal heart rate monitoring capabilities, this novel method for UA detection expands the remote pregnancy monitoring device’s capabilities to include surveillance, such as non-stress tests, greatly benefiting women and providers seeking telehealth solutions for pregnancy care.

An EHG-based Preterm Delivery Prediction Algorithm via Convolution Neural Network

Premature delivery is one of the direct factors that affect the early development and safety of infants. Its direct clinical manifestation is the change of uterine contraction intensity and frequency. Uterine Electrohysterography(EHG) signal collected from the abdomen of pregnant women can accurately and effectively reflect the uterine contraction, which has higher clinical application value than invasive monitoring technology such as intrauterine pressure catheter. Therefore, the research of fetal preterm birth recognition algorithm based on EHG is particularly important for perinatal fetal monitoring. We proposed a convolution neural network(CNN) based on EHG fetal preterm birth recognition algorithm, and a deep CNN model was constructed by combining the Gramian angular difference field(GADF) with the transfer learning technology. The structure of the model was optimized using the clinical measured term-preterm EHG database. The classification accuracy of 94.38% and F1 value of 97.11% were achieved. The experimental results showed that the model constructed in this paper has a certain auxiliary diagnostic value for clinical prediction of premature delivery.

Association of Body Mass Index With the Use of Health Care Resources in Low-Risk Nulliparous Pregnancies After 39 Weeks of Gestation.

To compare health care medical resource utilization in low-risk nulliparous pregnancies according to body mass index (BMI, calculated as weight in kilograms divided by height in meters squared) categories. This is a secondary analysis of a multicenter randomized controlled trial of induction of labor between 39 0/7 39 and 4/7 weeks of gestation compared with expectant management in low-risk nulliparous pregnant people, defined as those without standard obstetric indications for delivery at 39 weeks. Body mass index at randomization was categorized into four groups (lower than 25, 25-29, 30-39, and 40 or higher). The primary outcome of this analysis was time spent in the labor and delivery department from admission to delivery. Secondary outcomes included length of stay (LOS) postdelivery, total hospital LOS, and antepartum, intrapartum, and postpartum resource utilization, which were defined a priori. Multivariable generalized linear modeling and logistic regressions were performed, and 99% CIs were calculated. A total of 6,058 pregnant people were included in the analysis; 640 (10.6%) had BMIs of lower than 25, 2,222 (36.7%) had BMIs between 25 and 29, 2,577 (42.5%) had BMIs of 30-39, and 619 (10.2%) had BMIs of 40 or higher. Time spent in the labor and delivery department increased from 15.1±9.2 hours for people with BMIs of lower than 25 to 23.5±13.6 hours for people with BMIs of 40 or higher, and every 5-unit increase in BMI was associated with an average 9.8% increase in time spent in the labor and delivery department (adjusted estimate per 5-unit increase in BMI 1.10, 99% CI 1.08-1.11). Increasing BMI was not associated with an increase in antepartum resource utilization, except for blood tests and urinalysis. However, increasing BMI was associated with higher odds of intrapartum resource utilization, longer total hospital LOS, and postpartum resource utilization. For example, every 5-unit increase in BMI was associated with an increase of 26.1% in the odds of antibiotic administration, 57.6% in placement of intrauterine pressure catheter, 5.1% in total inpatient LOS, 31.0 in postpartum emergency department visit, and 23.9% in postpartum hospital admission. Among low-risk nulliparous people, higher BMI was associated with longer time from admission to delivery, total hospital LOS, and more frequent utilization of intrapartum and postpartum resources. ClinicalTrials.gov, NCT01990612.

Induction of labour in pregnant individuals with obesity.

People with obesity may require induction of labour (IoL) due to a higher incidence of pre-existing comorbidities and pregnancy complications, as well as to prevent post-term pregnancies and late-term stillbirths. IoL at 39-40 weeks is associated with fewer caesarean births and lower morbidity for the pregnant person and neonate when compared with expectant management. Ensuring the success and safety of IoL in people with obesity requires adherence to evidence-based protocols for the management of labour induction and augmentation. Cervical ripening as well as the latent and active phases of labour in people with obesity may be considerably prolonged, requiring higher cumulative doses of oxytocin. This should be guided by intrauterine pressure catheters and early provision of neuraxial analgesia, where possible. There is insufficient evidence to recommend one method of IoL over another. The need for higher doses of prostaglandins and concurrent agents for cervical ripening should be studied in prospective studies.

An Unexpected Cause of Recurrent Fetal Decelerations

An Unexpected Cause of Recurrent Fetal Decelerations

Novel uterine contraction monitoring to enable remote, self-administered nonstress testing

The serial fetal monitoring recommended for women with high-risk pregnancies places a substantial burden on the patient, often disproportionately affecting underprivileged and rural populations. A telehealth solution that can empower pregnant women to obtain recommended fetal surveillance from the comfort of their own home has the potential to promote health equity and improve outcomes. We have previously validated a novel, wireless pregnancy monitor that can remotely capture fetal and maternal heart rates. However, such a device must also detect uterine contractions if it is to be used to robustly conduct remote nonstress tests. This study aimed to describe and validate a novel algorithm that uses biopotential and acoustic signals to noninvasively detect uterine contractions via a wireless pregnancy monitor. A prospective, open-label, 2-center study evaluated simultaneous detection of uterine contractions by the wireless pregnancy monitor and an intrauterine pressure catheter in women carrying singleton pregnancies at ≥32 0/7 weeks' gestation who were in the first stage of labor (ClinicalTrials.gov Identifier: NCT03889405). The study consisted of a training phase and a validation phase. Simultaneous recordings from each device were passively acquired for 30 to 60 minutes. In a subset of the monitoring sessions in the validation phase, tocodynamometry was also deployed. Three maternal-fetal medicine specialists, blinded to the data source, identified and marked contractions in all modalities. The positive agreement and false-positive rates of both the wireless monitor and tocodynamometry were calculated and compared with that of the intrauterine pressure catheter. A total of 118 participants were included, 40 in the training phase and 78 in the validation phase (of which 39 of 78 participants were monitored simultaneously by all 3 devices) at a mean gestational age of 38.6 weeks. In the training phase, the positive agreement for the wireless monitor was 88.4% (1440 of 1692 contractions), with a false-positive rate of 15.3% (260/1700). In the validation phase, using the refined and finalized algorithm, the positive agreement for the wireless pregnancy monitor was 84.8% (2722/3210), with a false-positive rate of 24.8% (897/3619). For the subgroup who were monitored only with the wireless monitor and intrauterine pressure catheter, the positive agreement was 89.0% (1191/1338), with a similar false-positive rate of 25.4% (406/1597). For the subgroup monitored by all 3 devices, the positive agreement for the wireless monitor was significantly better than for tocodynamometry (P<.0001), whereas the false-positive rate was significantly higher (P<.0001). Unlike tocodynamometry, whose positive agreement was significantly reduced in the group with obesity compared with the group with normal weight (P=.024), the positive agreement of the wireless monitor did not vary across the body mass index groups. This novel method to noninvasively monitor uterine activity, via a wireless pregnancy monitoring device designed for self-administration at home, was more accurate than the commonly used tocodynamometry and unaffected by body mass index. Together with the previously reported remote fetal heart rate monitoring capabilities, this added ability to detect uterine contractions has created a complete telehealth solution for remote administration of nonstress tests.

Use of Methadone Maintenance Therapy for Opioid Use Disorder in Pregnancy.

Use of Methadone Maintenance Therapy for Opioid Use Disorder in Pregnancy.

Maternal Hypotension and Tachysystole Following Neuraxial Anesthesia: Effect on Fetus in Labor.

Maternal Hypotension and Tachysystole Following Neuraxial Anesthesia: Effect on Fetus in Labor.

Noninvasive monitoring of uterine electrical activity among patients with obesity: a new external monitoring device

Tocodynamometry is a common, noninvasive tool used to measure contraction frequency; however, its utility is often limited in patients with obesity. An intrauterine pressure catheter provides a more accurate measurement of uterine contractions but requires ruptured membranes, limiting its utility during early latent labor. Electrical uterine myography has shown promise as a noninvasive contraction monitor with efficacy similar to that of the intrauterine pressure catheter; however, its efficacy has not been widely studied in the obese population. This study aimed to validate the accuracy of electrical uterine myography by comparing it with tocodynamometry and intrauterine pressure catheters among laboring patients with obesity. This was a prospective observational study from February 2017 to April 2018 of patients with obesity, aged 18 years or older, who were admitted to the labor unit with viable singleton pregnancies and no contraindications for electromyography. Patients were monitored simultaneously with electrical myography and tocodynamometry or intrauterine catheter for more than 30 minutes. Two blinded obstetricians reviewed the tracings. The outcomes of interest were continuous and interpretable tracing, number of contractions, and timing and duration of contractions, interpreted as point estimates and associated 95% confidence intervals. A total of 110 patients were enrolled (65 tocodynamometry, 55 intrauterine catheter). Electrical myography was significantly more interpretable during a 30-minute tracing (P=.001) and detected 39% more contractions than tocodynamometry (P<.0001; 95% confidence interval, 23%-57%), whereas there was no difference in the interpretability of tracings or number of contractions between electrical myography and an intrauterine catheter (P=.16; 95% confidence interval, -0.19 to 1.19). Patients who underwent simultaneous monitoring preferred the electrical myography device over tocodynamometry. Electrical uterine myography is superior to tocodynamometry in the detection of intrapartum uterine contraction monitoring and comparable with internal contraction monitoring.

Intrauterine contraction parameters at baseline and following epidural and combined spinal-epidural analgesia: A repeated measures comparison

ObjectiveThe effects of epidural and combined spinal-epidural analgesia on uterine contraction parameters are unclear, although as many as 80% of laboring women use neuraxial analgesia. We explored the effects of epidural and combined spinal-epidural analgesia on all uterine contraction parameters using a retrospective analysis of selected parturients, who required Intrauterine Pressure Catheter (IUPC) instrumentation for clinical management. Additionally, we analyzed the effects of parity, Pitocin dose, and mode of neuraxial anesthesia, i.e. epidural verses combined spinal-epidural on uterine contractility. DesignUsing a retrospective within and between repeated measure design we compared uterine contraction parameters at 4 time points (epochs): (1) baseline, (2) pre-epidural fluid bolus, (3) immediate and (4) secondary post-epidural/combined spinal-epidural analgesia to detect differences in contractility over time comparing two types of epidural interventions. MethodsEighteen healthy parturients at term gestation were admitted to the labor unit for induction, augmentation, or spontaneous labor. Contraction parameters including frequency, duration, peak intensity, resting intensity and duration, and Montevideo Units (MVUs) were collected using fetal monitor strip data with intrauterine pressure catheter (IUPC) instrumentation. FindingsParametric and non-parametric tests showed no significant differences within or between the two Epidural intervention groups for frequency, duration, peak intensity, resting intensity and duration, and MVUs at all epochs at the .05 alpha level. Compared with Nulliparous women, multiparous women had significantly lower contraction intensity and longer contraction duration. Based on multilevel modeling (MLM), neither Pitocin dose nor type of epidural intervention revealed significant differences on any contraction parameters. ConclusionsWhen parity, other demographic variables and Pitocin dose were statistically controlled, no uterine contraction parameter changed from baseline through 90 min following either epidural or combined spinal-epidural analgesia. Obstetrical care providers should consider the preciseness their contraction monitoring instrumentation and their clinical management preferences as well parity as before prescribing Pitocin after neuraxial analgesia intervention.

830 Risk of chorioamnionitis following intrauterine pressure catheter placement in laboring patients

Intrauterine Pressure Catheters (IUPC) are thought to create a pathway for contamination and ascending infections. We sought to estimate the risk of chorioamnionitis associated with IUPC use in term labor. This is a retrospective cohort study of term (≥37 weeks), singleton pregnancies who labored at our tertiary care center from 2005 to 2018. The primary outcome of chorioamnionitis was defined as maternal intrapartum fever (single oral temperature of >39°C or 38–38.9°C for 30 minutes) and one or more of the following: maternal leukocytosis, purulent cervical drainage, or fetal tachycardia. The primary exposure was the presence of an IUPC documented in the medical record. Cox proportional hazard regression was used to model the effect of cervical examinations on the risk of chorioamnionitis while adjusting for adjusted for number of cervical exams, epidural use, meconium, smoking, GBS, parity, BMI, duration of rupture, labor induction and cesarean section. 20,579 women met inclusion criteria and1,039 (5%) women were diagnosed with chorioamnionitis. Of the subjects diagnosed with chorioamnionitis, 185 (17.8%) had IUPCs compared to 22.5% in women not diagnosed with infection (p<0.001). IUPCs were not associated with increased rate of chorioamnionitis after adjusting for potential confounders (hazard ratio [HR] 0.6, 95% confidence interval [CI] 0.5-0.7; p=<0.001). Presence of IUPCs was higher in women undergoing unplanned cesarean delivery (30.6% versus 21.1% in women undergoing vaginal delivery, p=<0.001). Meconium rates were not higher in women with IUPCs (IUPC 20.0% versus no IUPC18.8 p=0.06) In contrast to prior work, routine use of internal monitoring in laboring patient did not increase the risk of chorioamnionitis. Internal monitors should not be avoided during term labor management.

401 Amplitude-modulation of maternal electrocardiography and phonocardiography as a novel method for wireless non-invasive uterine monitoring

Uterine activity (UA) monitoring is an essential element of pregnancy management. The gold standard intrauterine pressure catheter (IUPC), is invasive and requires ruptured membranes. Conventional, external tocodynamometry (TOCO) is hampered by obesity, maternal movements, and belt positioning, with positive agreement rates (PA) as low as 54-73% and false detection rates (FDR) as high as 15-32%. We prospectively tested a novel algorithm that enables non-invasive and reliable detection of UA. A prospective, comparative, open label, multicenter study was conducted, in which 40 laboring women (≥32 weeks; BMI<50) were simultaneously monitored for 30-60 minutes with IUPC and INVU (Nuvo Group), a wireless device FDA-cleared for remote fetal and maternal heart rate monitoring. Ten subjects were monitored with TOCO as well. UA detection by INVU was based on the modulation of the maternal electrocardiographic and phonocardiographic signals. 3 blinded assessors marked the contractions for each modality. PA and FDR of INVU and TOCO compared to IUPC were calculated. Overall, INVU correctly identified 87.7% of the IUPC contractions. Sub-analysis based on BMI categories (normal: <25, overweight: 25-30, obese: ≥30) showed that UA detection was not affected by BMI (PA: 88.5%, 85.9% and 90.0%, respectively; p=0.42). Overall, INVU FDR was 15.2%. In the subset of sessions recorded with TOCO, TOCO PA and FDR were 46% and 7.1% respectively. UA monitoring via INVU is accurate and reliable, even in obese women, and more precise than TOCO. There is a pressing need for telehealth solutions in pregnancy monitoring, underscored by the current COVID-19 pandemic. INVU (Nuvo Group) is a self-administered device, FDA-cleared for wireless, remote monitoring of fetal and maternal heart rate. This novel method for UA detection via INVU expands its remote pregnancy monitoring capabilities to include surveillance such as non-stress tests, which would be of great benefit to women and providers seeking telehealth solutions for high risk pregnancy care.