Electronic Fetal Monitoring Patterns Research Articles

Intrapartum electronic fetal monitoring features associated with a clinical diagnosis of nonreassuring fetal status

Nonreassuring fetal status detected by continuous electronic fetal monitoring accounts for almost 1 in 4 primary cesarean deliveries. However, given the subjective nature of the diagnosis, there is a need to identify the electronic fetal monitoring patterns that are clinically considered nonreassuring. This study aimed to describe which electronic fetal monitoring features are most commonly associated with first-stage cesarean delivery for nonreassuring fetal status, and to evaluate the risk of neonatal acidemia following cesarean delivery for nonreassuring fetal status. This was a nested case-control study in a prospectively collected cohort of patients with singleton pregnancies at ≥37 weeks' gestation, admitted in spontaneous labor or for induction of labor from 2010 to 2014 at a single tertiary care center. Patients with preterm pregnancies, multiple gestations, planned cesarean delivery, or nonreassuring fetal status in the second stage of labor were excluded. Cases were identified as having nonreassuring fetal status on the basis of what was documented in the operative note by the delivering physician. Controls were patients without nonreassuring fetal status within 1 hour of delivery. Cases were matched to controls in a 1:2 ratio by parity, obesity, and history of cesarean delivery. Electronic fetal monitoring data were abstracted by credentialed obstetrical research nurses for the 60 minutes before delivery. The primary exposure of interest was the incidence of high-risk category II electronic fetal monitoring features in the 60 minutes before delivery; in particular, the incidence of minimal variability, recurrent late decelerations, recurrent variable decelerations, tachycardia, and >1 prolonged deceleration were compared between groups. We also compared neonatal outcomes between cases and controls, including fetal acidemia (umbilical artery pH <7.1), other umbilical artery gas analytes, and neonatal and maternal outcomes. Of the 8580 patients in the parent study, 714 (8.3%) underwent cesarean delivery for nonreassuring fetal status in the first stage of labor. Patients diagnosed with nonreassuring fetal status requiring cesarean delivery were more likely to have recurrent late decelerations, >1 prolonged deceleration, and recurrent variable decelerations compared with controls. More than 1 prolonged deceleration was associated with 6 times increased rate of nonreassuring fetal status diagnosis resulting in cesarean delivery (adjusted odds ratio, 6.73 [95% confidence interval, 2.47-8.33]). Rates of fetal tachycardia were similar between groups. Minimal variability was less common in the nonreassuring fetal status group compared with controls (adjusted odds ratio, 0.36 [95% confidence interval, 0.25-0.54]). Compared with control deliveries, cesarean delivery for nonreassuring fetal status was associated with nearly 7 times higher risk of neonatal acidemia (7.2% vs 1.1%; adjusted odds ratio, 6.93 [95% confidence interval, 3.83-12.54]). Composite neonatal morbidity and composite maternal morbidity were more likely among patients delivered for nonreassuring fetal status in the first stage (3.9% vs 1.1%; adjusted odds ratio, 5.70 [2.60-12.49]; and 13.3% vs 8.0%; adjusted odds ratio, 1.99 [1.41-2.80]). Although multiple category II electronic fetal monitoring features have been traditionally linked to acidemia, the presence of recurrent late decelerations, recurrent variable decelerations, and prolonged decelerations seemed to concern obstetricians enough to surgically intervene for nonreassuring fetal status. A clinical intrapartum diagnosis of nonreassuring fetal status in the setting of these electronic fetal monitoring features is also associated with increased risk of acidemia, suggesting clinical validity to the diagnosis of nonreassuring fetal status.

The relationship between maternal anemia and electronic fetal monitoring patterns

Anemia is a commonly diagnosed comorbidity in pregnancy that is associated with increased risk of maternal and neonatal complications. Recent data demonstrate that maternal anemia is associated with higher umbilical artery and umbilical vein O2 content at the time of delivery. This study aimed to examine the relationship between maternal anemia and electronic fetal monitoring patterns associated with fetal hypoxia. This is a secondary analysis of a prospective cohort study of singleton term deliveries with cord gases and universal complete blood count collected on admission between 2010 and 2014. Maternal anemia was defined as hemoglobin ≤11.0 g/dL on admission. The primary outcome was a composite of high-risk category 2 electronic fetal monitoring features in the last 60 minutes before delivery (recurrent late and/or variable decelerations, minimal variability, tachycardia, or >1 prolonged deceleration); secondary outcomes were total deceleration area and total deceleration area >90th percentile. Of the 8580 patients in the original study, 8196 were included in the analysis. Outcomes were compared between patients with and without anemia. Multivariable logistic regression was used to adjust for potentially confounding factors, including hypertensive disorders of pregnancy and induction of labor. Of the 8196 patients with complete blood count on admission and fetal monitoring data, 2672 (32.6%; 2672/8196) were anemic and 5524 (67.4%; 5524/8196) were not. Patients with anemia were significantly less likely to have composite high-risk category 2 features on electronic fetal monitoring (34.2% vs 32.0%; adjusted risk ratio, 0.93; 95% confidence interval, 0.86-0.99). Women with anemia also had decreased total deceleration area and were less likely to have total deceleration area >90th percentile (18.7% vs 16.2%; adjusted risk ratio, 0.85; 95% confidence interval, 0.77-0.94). Patients with anemia are less likely to have high-risk category 2 electronic fetal monitoring features associated with fetal hypoxia. This finding is consistent with the association between maternal anemia and increased umbilical cord O2 content, and suggests that maternal anemia may be protective against intrapartum fetal hypoxia.

Correlation between total deceleration area and fetal cord blood pH in neonates complicated with meconium-stained amniotic fluid at term.

To assess the correlation between total area under the Curve (AUC) of decelerations and accelerations and neonatal acidemia in pregnancies complicated with meconium-stained amniotic fluid (MSAF). A retrospective cohort study was conducted among women who delivered with a diagnosis of MSAF. Electronic fetal monitoring (EFM) patterns 120 min before delivery were interpreted by a researcher blinded to fetal outcomes. The primary outcome was fetal acidemia, defined as umbilical artery pH below 7.10. The correlation was tested using the Spearman correlation coefficient. A total of 102 women were included; 24 delivered infants with cord blood pH < 7.20, and only five delivered infants with cord blood pH < 7.10. A significant correlation was demonstrated between total AUC of decelerations and accelerations and cord blood pH (P= 0.02). A sub-analysis according to gestational age at delivery (up to and beyond 40 weeks) was conducted. A significant correlation was demonstrated (P= 0.02) only in the term group(n= 37). A correlation was demonstrated between total AUC of decelerations and accelerations and cord blood pH in neonates with MSAF. This correlation was significant for neonates delivered before 40 weeks of gestation, but not for those delivered after 40 weeks of gestation.

Electronic fetal monitoring changes in the setting of maternal anemia

Anemia is a commonly diagnosed comorbidity in pregnancy that is associated with an increased risk of fetal complications. However, recent work from our group demonstrated that maternal anemia was associated with higher umbilical artery O2 content at the time of delivery. Given this, we aimed to examine the relationship between maternal anemia and electronic fetal monitoring (EFM) patterns associated with fetal hypoxia.

The Effect of Intrapartum Oxygen Supplementation on Category II Fetal Monitoring

(Am J Obstet Gynecol. 2020;223:905.e1–905.e7) While oxygen is routinely administered in response to category II electronic fetal monitoring (EFM) patterns, there is not currently any evidence that this practice is beneficial for the neonate. Maternal oxygen supplementation in this context is meant to reduce fetal hypoxia, but a recent study suggests umbilical artery lactate was not improved with oxygen supplementation compared with therapy using room air (RA). This was a secondary analysis of that study, aimed at investigating how oxygen supplementation affects other markers of category II EFM.

The Effect of Intrapartum Oxygen Supplementation on Category II Fetal Monitoring

(Abstracted from Am J Obstet Gynecol 2020;223:905.e1–905.e7) The administration of maternal oxygenation (O2) is a commonly used resuscitation technique for fetuses with category II electronic fetal monitoring (EFM) patterns. In cases of recurrent fetal decelerations, the goal of maternal O2 supplementation is to increase fetal oxygenation.

738 Sex-specific differences in electronic fetal monitoring patterns

Fetal male sex is associated with worse neonatal outcomes, but etiology of this phenomenon is not well elucidated. It has been hypothesized that males have an increased cytokine response and decreased catecholamine response to traumatic events, which could suggest a decreased tolerance of labor and therefore be detected in electronic fetal monitoring (EFM) patterns. We sought to determine if there were differences in EFM features in the 60 minutes prior to delivery. We performed a secondary analysis of a prospective cohort study of low risk women (excluding those with hypertensive disorder or diabetes) with a singleton fetus admitted for labor at term between 2010 to 2014 in a single institution. Baseline characteristics were compared between mothers of male and female infants. The primary outcome was EFM characteristics in the 60 minutes before delivery. Multivariable logistic regression was performed to determine the relationship between fetal sex and EFM characteristic while adjusting for confounders. Of the 4,055 low risk patients, 2,074 (51%) delivered a male infant. Mothers of male fetuses were more likely to go into spontaneous labor (p=0.02), but rates of operative vaginal (5.6 vs 4.1%, p=0.04) and cesarean delivery (CD) (18.1 vs 14.0%, p<0.01) and non-reassuring fetal status as indication for delivery (18.1vs 14.0%, p<0.01) were higher among males. Males were more likely to have bradycardia, recurrent variable decelerations, and higher total deceleration area and were less likely to have tachycardia compared to females. Males had higher odds of decelerations and bradycardia, but females had higher odds of tachycardia, possibly due to improved ability to generate a catecholamine response. Cesarean deliveries for non-reassuring fetal status are more common in pregnancies with male fetuses. These data suggest males are less likely to tolerate stresses of labor, which may drive the difference in mode of delivery and at least partially explain the increased morbidity male neonates experience.

The effect of intrapartum oxygen supplementation on category II fetal monitoring

Maternal oxygen administration is a widely used intrauterine resuscitation technique for fetuses with category II electronic fetal monitoring patterns, despite a paucity of evidence on its ability to improve electronic fetal monitoring patterns. This study investigated the effect of intrapartum oxygen administration on Category II electronic fetal monitoring patterns. This is a secondary analysis of a randomized trial conducted in 2016-2017, in which patients with fetuses at ≥37 weeks' gestation in active labor with category II electronic fetal monitoring patterns were assigned to 10 L/min of oxygen by face mask or room air until delivery. Trained obstetrical research nurses blinded to allocation extracted electronic fetal monitoring data. The primary outcome was a composite of high-risk category II features including recurrent variable decelerations, recurrent late decelerations, prolonged decelerations, tachycardia, or minimal variability 60 minutes after randomization to room air or oxygen. Secondary outcomes included individual components of the composite high-risk category II features, resolution of recurrent decelerations within 60 minutes of randomization, and total deceleration area. The outcomes between the room air and oxygen groups were compared using univariable statistics. Time-to-event analysis was used to compare time to resolution of recurrent decelerations between the groups. Paired analysis was used to compare the pre- and postrandomization outcomes within each group. All 114 randomized patients (57 room air and 57 oxygen) were included in this analysis. There was no difference in resolution of recurrent decelerations within 60 minutes between the oxygen and room air groups (75.4% vs 86.0%; P=.15). The room air and oxygen groups had similar rates of composite high-risk category II features including recurrent variable decelerations, recurrent late decelerations, prolonged decelerations, tachycardia, and minimal variability 60 minutes after randomization. Time to resolution of recurrent decelerations and total deceleration area were similar between the room air and oxygen groups. Among patients who received oxygen, there was no difference in the electronic fetal monitoring patterns pre- and postrandomization. Similar findings were observed in the electronic fetal monitoring patterns pre- and postrandomization in room air patients. Intrapartum maternal oxygen administration for category II electronic fetal monitoring patterns did not resolve high-risk category II features or hasten the resolution of recurrent decelerations. These results suggest that oxygen administration has no impact on improving category II electronic fetal monitoring patterns.

Category II Fetal Monitoring in Fetuses With Congenital Heart Defects: Are They Any Different? [06O

INTRODUCTION: The majority of literature investigating continuous electronic fetal monitoring (EFM) excludes anomalous fetuses. The objective of this study was to determine if Category II EFM characteristics differed between fetuses with and without congenital heart defects (CHD). METHODS: This was a retrospective IRB-approved cohort study of singleton, term pregnancies admitted for induction or labor with an antenatal diagnosis of fetal CHD between 2017–2019. We excluded fetuses with genetic abnormalities. Cases were matched by race and obesity in a 1:2 ratio to a historic control of term pregnancies with structurally normal fetuses. EFM characteristics in the 1 hour before delivery were extracted. The primary outcome was incidence of Category II EFM features; secondary outcome was total deceleration area (TDA). RESULTS: 47 cases of fetal CHD were matched to 94 controls. There was no difference in advanced maternal age, other baseline demographics, or mode of delivery between groups. Fetuses with CHD were less likely to have prolonged decelerations (6.4 vs 25.5%, P&lt;.01) or any periods of tachycardia (4.3 vs 17.0, p 0.03) compared to normal fetuses. Other Category II features were similar between groups including incidence of recurrent late and variable decelerations and minimal variability. There was no difference in TDA between groups. CONCLUSION: Prolonged decelerations and tachycardia were less common in CHD fetuses. The incidence of other Category II features were similar to nonanomalous fetuses. These results suggest that structural heart defects do not increase the risk of concerning EFM patterns. Future studies should evaluate the risk of acidemia with Category II EFM and CHD.

Elevated umbilical cord arterial lactate at birth and electronic fetal monitoring characteristics on admission and in the active phase.

Objective:To investigate the association between elevated umbilical arterial lactate at birth and electronic fetal monitoring (EFM) characteristics at admission and in the beginning of the active phase of labor.Study Design:Nested case-control study within a prospective cohort of laboring patients at term who achieved active labor. Neonates with umbilical arterial lactate ≥ 4 mmol/L (cases, n=119), were matched 1:1 to controls with lactate <4mmol/L. EFM patterns were compared with multivariable logistic regression.Result:There were no differences in EFM parameters in the first 60 minutes after admission. At the beginning of active labor, 13.5% of cases and 26.1% of controls had always category I tracings, adjusted odds ratio 0.48, 95% confidence interval 0.24-0.94). Cases were less likely to have an always category I tracing from admission into the active phase.Conclusion:Elevated umbilical arterial lactate at birth is associated with distinct EFM patterns early in the labor course.

758: Marked variability-cause for concern?

Continuous electronic fetal monitoring (EFM) is widely used to assess intrapartum fetal well-being during labor. However, little guidance is available regarding the frequency and interpretation of marked variability. We investigated the incidence of marked variability before delivery and its association with neonatal morbidity. This is a secondary analysis of a prospective cohort of 8,580 singleton deliveries from 2010-2015 at 37 weeks or beyond. EFM patterns during the 120 minutes prior to delivery were interpreted in 10-minute epochs. The primary outcomes were 1) a composite neonatal morbidity (death, respiratory distress, mechanical ventilation, suspected sepsis, meconium aspiration syndrome, therapeutic hypothermia, hypoxic-ischemic encephalopathy, & seizure) and 2) a composite adverse acid-base status (umbilical artery acidemia pH<7.10, elevated lactate ≥4 mmol/L, elevated base excess < -12). Outcomes were compared between women with and without marked variability defined as fluctuations in EFM amplitude of greater than 25 beats per minute ever in last 120 minutes. Adjusted risk ratios were estimated using multivariable logistic regression. Of the 8,580 women, 390 (4.5%) had marked variability before delivery. 757 (8.8%) of neonates had composite neonatal morbidity and 2,212 (26%) had composite adverse acid-base status. After adjusting for maternal age & obesity, women who had marked variability did not have increased risk of the composite neonatal morbidity 11% vs 8.7% aRR, [95% CI] 1.22 [0.91 1.63], though there was an increase in the risk of respiratory distress 7.2% vs 3.7% 1.85 [1.25, 2.70]. In contrast, there was an increased risk of composite adverse acid-base status 41.5% vs 25% 1.66 [1.47, 1.88]. This finding was driven by an increased risk of elevated lactate 42% vs 25% 1.66 [1.47, 1.88]. Marked variability occurred rarely before delivery and was not associated with increased risk of composite neonatal morbidity. However, marked variability was significantly associated with an increased risk of respiratory distress and elevated cord blood lactate.

A Prospective Cohort Study of Fetal Heart Rate Monitoring: Deceleration Area is Predictive of Fetal Acidemia

(Am J Obstet Gynecol. 2018;218:523.e1–523.e12) While intrapartum electronic fetal monitoring (EFM) is commonly used and promises to reduce adverse neonatal outcomes by predicting acidemia, there is a lack of data regarding an association between EFM patterns and acidemia. This study aimed to assess EFM patterns and their association with acidemia and neonatal morbidity and determine which visually interpreted EFM patterns were associated with acidemia and neonatal morbidity.

Effect of Oligohydramnios on Fetal Heart Rate Patterns during Term Labor Induction.

To estimate the effect of oligohydramnios on fetal heart rate (FHR) patterns in patients undergoing induction of labor (IOL) at term. Secondary analysis of a prospective cohort study of consecutive term, singleton deliveries from 2010 to 2015. We included all patients who underwent IOL. Our primary outcomes were electronic fetal monitoring (EFM) characteristics in the 2 hours preceding delivery. Outcomes were compared between those induced with oligohydramnios and those induced without a diagnosis of oligohydramnios. Our secondary outcome was composite neonatal morbidity. Logistic regression was used to control for confounders. Of 3,787 patients who underwent IOL, 147 had a diagnosis of oligohydramnios and 3,640 were included in the no oligohydramnios group. There was no significant difference in EFM characteristics between the two groups. There was no difference in composite neonatal morbidity. In patients with oligohydramnios, EFM patterns with baseline tachycardia for 30 minutes or greater were significantly associated with composite neonatal morbidity (31.3 vs. 5.3% adjusted odds ratio 8.63, 95% confidence interval 2.18, 34.1]). Term patients undergoing IOL with oligohydramnios had EFM patterns that did not differ from their induced peers.

A Prospective Cohort Study of Fetal Heart Rate Monitoring: Deceleration Area Is Predictive of Fetal Acidemia

(Abstracted from Am J Obstet Gynecol 2018;218:523.e1–523.e12) Intrapartum electronic fetal monitoring (EFM) is the most commonly used tool in obstetrics in the United States, used ubiquitously in US hospitals to monitor the fetal heart rate during labor. However, clear categorization of EFM patterns that predict acidemia remains unclear, and there is a lack of evidence supporting EFM's ability to reduce neonatal morbidity and mortality.

A prospective cohort study of fetal heart rate monitoring: deceleration area is predictive of fetal acidemia

Intrapartum electronic fetal monitoring is the most commonly used tool in obstetrics in the United States; however, which electronic fetal monitoring patterns predict acidemia remains unclear. This study was designed to describe the frequency of patterns seen in labor using modern nomenclature, and to test the hypothesis that visually interpreted patterns are associated with acidemia and morbidities in term infants. We further identified patterns prior to delivery, alone or in combination, predictive of acidemia and neonatal morbidity. This was a prospective cohort study of 8580 women from 2010 through 2015. Patients were all consecutive women laboring at ≥37 weeks' gestation with a singleton cephalic fetus. Electronic fetal monitoring patterns during the 120 minutes prior to delivery were interpreted in 10-minute epochs. Interpretation included the category system and individual electronic fetal monitoring patterns per the Eunice Kennedy Shriver National Institute of Child Health and Human Development criteria as well as novel patterns. The primary outcome was fetal acidemia (umbilical artery pH ≤7.10); neonatal morbidities were also assessed. Final regression models for acidemia adjusted for nulliparity, pregestational diabetes, and advanced maternal age. Area under the receiver operating characteristic curves were used to assess the test characteristics of individual models for acidemia and neonatal morbidity. Of 8580 women, 149 (1.7%) delivered acidemic infants. Composite neonatal morbidity was diagnosed in 757 (8.8%) neonates within the total cohort. Persistent category I, and 10-minute period of category III, were significantly associated with normal pH and acidemia, respectively. Total deceleration area was most discriminative of acidemia (area under the receiver operating characteristic curves, 0.76; 95% confidence interval, 0.72-0.80), and deceleration area with any 10minutes of tachycardia had the greatest discriminative ability for neonatal morbidity (area under the receiver operating characteristic curves, 0.77; 95% confidence interval, 0.75-0.79). Once the threshold of deceleration area is reached the number of cesareans needed-to-be performed to potentially prevent 1 case of acidemia and morbidity is 5and 6, respectively. Deceleration area is the most predictive electronic fetal monitoring pattern for acidemia, and combined with tachycardia for significant risk of morbidity, from the electronic fetal monitoring patterns studied. It is important to acknowledge that this study was performed in patients delivering ≥37 weeks, which may limit the generalizability to preterm populations. We also did not use computerized analysis of the electronic fetal monitoring patterns because human visual interpretation was the basis for the Eunice Kennedy Shriver National Institute of Child Health and Human Development categories, and importantly, it is how electronic fetal monitoring is used clinically.

292: Does intrapartum maternal oxygen supplementation improve category II fetal heart tracings?

Maternal oxygen (O2) administration for Category II electronic fetal monitoring (EFM) is a widely used intrauterine resuscitation technique, despite paucity of evidence on its ability to improve EFM patterns. We investigated the effect of intrapartum O2 administration on Category II EFM patterns. This is a secondary analysis of a randomized trial conducted from 2016-2017, in which patients ≥ 37 weeks in active labor with Category II EFM were assigned to 10L/min O2 by facemask or room air (RA) until delivery. Trained obstetric research nurses, blinded to allocation, extracted EFM data. The primary outcome was resolution of recurrent decelerations (lates and/or variables) within 60 minutes of randomization. Secondary outcomes were presence of recurrent variables, recurrent lates, tachycardia or minimal variability. Outcomes were compared between RA and O2 groups using univariable statistics. Time-to-event analysis was used to compare time to resolution of recurrent decelerations between groups. Paired analysis was used to compare pre- and post- randomization outcomes within each group. All 114 randomized patients (57 RA, 57 O2) were included in this analysis. There was no difference in resolution of recurrent decelerations within 60 minutes between O2 and RA groups (O2 75.4% vs RA 86.0%, p=0.15). Time to resolution of recurrent decelerations was similar between RA and O2 groups (Figure). RA and O2 groups had similar rates of recurrent variables, recurrent lates, tachycardia, and minimal variability 30 and 60 minutes after randomization (Table). There was no difference in EFM features pre- and post- randomization in both groups. Use of additional intrauterine resuscitation measures was similar in the two groups. Intrapartum maternal O2 administration for Category II EFM did not resolve or hasten the resolution of recurrent decelerations. These results suggest that O2 administration has no impact on Category II EFM patterns.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

756: Electronic fetal monitoring patterns on admission and in the active phase associated with elevated umbilical cord arterial lactate at term

756: Electronic fetal monitoring patterns on admission and in the active phase associated with elevated umbilical cord arterial lactate at term

293: Electronic fetal monitoring patterns on admission and in the active phase associated with elevated umbilical cord arterial lactate at term

293: Electronic fetal monitoring patterns on admission and in the active phase associated with elevated umbilical cord arterial lactate at term

Fetal Sex Differences in Intrapartum Electronic Fetal Monitoring.

Objective The article aimed to estimate differences in electronic fetal monitoring (EFM) patterns in term gestations attributable to fetal sex. Study Design We conducted a prospective cohort study of consecutive, singleton, nonanomalous, term gestations that labored during admission. EFM characteristics in the 30 minutes prior to delivery were evaluated. Logistic regression models estimated adjusted risks for EFM features by sex. To further estimate the impact of sex, we limited the analysis to gestations without composite morbidity (morbidity defined as arterial cord pH <7.20, 5-minute Apgar <7, or neonatal intensive care unit admission). Results Of 2,639 deliveries, 1,400 (53%) were male. Male fetuses had a higher number of decelerations (median [interquartile range]: 8 [5, 11] vs. 7 [4, 10], p < 0.003) and increased total deceleration area (adjusted odds ratio [aOR]: 1.11, 95% confidence interval [CI] :1.04, 1.18). Male fetuses were at increased risk for prolonged decelerations (aOR: 1.21, 95% CI: 1.03, 1.42) and repetitive variable decelerations (aOR: 1.24, 95% CI: 1.05, 1.47). Among neonates without composite morbidity (n = 2,446, 92.7%), male sex conferred an increased risk of late decelerations (aOR: 1.21, 95% CI: 1.02, 1.43) and increased total deceleration area (aOR: 1.12, 95% CI: 1.05, 1.20). Conclusion There are significant sex differences in EFM patterns at term among pregnancies without evidence of acidemia. This suggests that interpretation of EFM patterns may need to take into account factors such as fetal sex.

796: Electronic fetal monitoring patterns in patients induced with oligohydramnios

796: Electronic fetal monitoring patterns in patients induced with oligohydramnios