Fetal Heart Rate Patterns Research Articles

Predicting umbilical artery pH during labour: Development and validation of a nomogram using fetal heart rate patterns

ObjectiveNomograms are statistical models that combine variables to obtain the most accurate and reliable prediction for a particular risk. Fetal heart rate (FHR) interpretation alone has been found to be poorly predictive for fetal acidosis while other clinical risk factors exist. The aim of this study was to create and validate a nomogram based on FHR patterns and relevant clinical parameters to provide a non-invasive individualized prediction of umbilical artery pH during labour. Study designA retrospective observational study was conducted on 4071 patients in labour presenting singleton pregnancies at >34 gestational weeks and delivering vaginally. Clinical characteristics, FHR patterns and umbilical cord gas of 1913 patients were used to construct a nomogram predicting an umbilical artery (Ua) pH <7.18 (10th centile of the study population) after an univariate and multivariate stepwise logistic regression analysis. External validation was obtained from an independent cohort of 2158 patients. Area under the receiver operating characteristics (ROC) curve, sensitivity, specificity, positive and negative predictive values of the nomogram were determined. ResultsUpon multivariate analysis, parity (p < 0.01), induction of labour (p = 0.01), a prior uterine scar (p = 0.02), maternal fever (p = 0.02) and the type of FHR (p < 0.01) were significantly associated with an Ua pH <7.18 (p < 0.05). Apgar score at 1, 5 and 10 min were significantly lower in the group with an Ua pH <7.18 (p < 0.01). The nomogram constructed had a Concordance Index of 0.75 (area under the curve) with a sensitivity of 57%, a specificity of 91%, a negative predictive value of 5% and a positive predictive value of 99%. Calibration found no difference between the predicted probabilities and the observed rate of Ua pH <7.18 (p = 0.63). The validation set had a Concordance Index of 0.72 and calibration with a p < 0.77. ConclusionWe successfully developed and validated a nomogram to predict Ua pH by combining easily available clinical variables and FHR. Discrimination and calibration of the model were statistically good. This mathematical tool can help clinicians in the management of labour by predicting umbilical artery pH based on FHR tracings.

Correlation between umbilical arterial pH values and fetal vertebral artery Doppler waveforms at the beginning of the second stage of labor: a pilot prospective study

Objective: The aim of this study was to evaluate the association between umbilical arterial pH and fetal vertebral artery Doppler velocimetry waveforms measured at the beginning of the second stage of labor in physiological term pregnancies.Methods: This was a prospective cohort study of 250 pregnancies. The resistance index, pulsatility index, and peak systolic velocity were measured. The relationship between the fetal Doppler and the umbilical arterial pH was evaluated. A simple linear regression and a general linear model were used to explore possible correlations of Doppler parameters with fetal and neonatal outcome adjusted for confundents.Results: Umbilical arterial pH values were directly associated with vertebral artery pulsatility index. Fetuses with lower pulsatility index values were at increased risk of a subsequent diagnosis of pathological fetal heart rate tracing patterns (presence of decelerations or reduced variability according to FIGO criteria during the second stage of labor). We estimated a decrease in pulsatility index of 10% in those fetuses destined to show a pathological fetal heart rate tracing.Conclusion: Vertebral artery Doppler waveforms correlates with umbilical pH in normal pregnancies and is also a function of fetal heart rate patterns. If this proportional association would be demonstrated also for abnormal pH values, vertebral artery pulsatility index might be useful to evaluate fetal wellbeing in those cases of suspected hypoxia/academia.

A Sinusoidal FHR Pattern observed in a Case of Congenital Leukemia Diagnosed after Emergent Cesarean Delivery

A Sinusoidal FHR Pattern observed in a Case of Congenital Leukemia Diagnosed after Emergent Cesarean Delivery

Intrauterine resuscitation during the second stage of term labour by maternal hyperoxygenation versus conventional care: study protocol for a randomised controlled trial (INTEREST O2)

BackgroundPerinatal asphyxia is, even in developed countries, one the major causes of neonatal morbidity and mortality. Therefore, if foetal distress during labour is suspected, one should try to restore foetal oxygen levels or aim for immediate delivery. However, studies on the effect of intrauterine resuscitation during labour are scarce. We designed a randomised controlled trial to investigate the effect of maternal hyperoxygenation on the foetal condition. In this study, maternal hyperoxygenation is induced for the treatment of foetal distress during the second stage of term labour.Methods/designThis study is a single-centre randomised controlled trial being performed in a tertiary hospital in The Netherlands. From among cases of a suboptimal or abnormal foetal heart rate pattern during the second stage of term labour, a total of 116 patients will be randomised to the control group, where normal care is provided, or to the intervention group, where before normal care 100% oxygen is supplied to the mother by a non-rebreathing mask until delivery. The primary outcome is change in foetal heart rate pattern. Secondary outcomes are Apgar score, mode of delivery, admission to the neonatal intensive care unit and maternal side effects. In addition, blood gas values and malondialdehyde are determined in umbilical cord blood.DiscussionThis study will be the first randomised controlled trial to investigate the effect of maternal hyperoxygenation for foetal distress during labour. This intervention should be recommended only as a treatment for intrapartum foetal distress, when improvement of the foetal condition is likely and outweighs maternal and neonatal side effects.Trial registrationEudraCT, 2015-001654-15; registered on 3 April 2015. Dutch Trial Register, NTR5461; registered on 20 October 2015.

Intrapartum and perinatal results associated with different degrees of staining of meconium stained amniotic fluid

ObjectiveTo determine the intrapartum and perinatal results associated with different degrees of staining of meconium stained amniotic fluid (MSAF). Study designIn a retrospective cohort study of all singleton deliveries over a period of one year (2015) in a tertiary hospital, we compared different degrees of MSAF (yellow, green and thick) to clear amniotic fluids, and analysed in each group maternal, intrapartum and neonatal variables as well as umbilical cord blood gas analysis. ResultsOf the 3590 deliveries included, 503 (14%) had MSAF. The incidence of MSAF rises with gestational age at delivery, reaching 20.7% in gestations above 41 weeks compared to 4.3% below 37 weeks. As the amniotic fluid staining progresses we found a higher proportion of intrapartum fevers (p < 0.001), pathological fetal heart rate patterns (p < 0.05), operative vaginal deliveries and cesarean sections (p < 0.001), as well as the need for advanced neonatal resuscitation (p < 0.001). There was also a correlation between MSAF and low Apgar scores at five minutes (p < 0.001) and fetal-neonatal mortality (p < 0.001) but there was not a higher proportion of neonatal intensive care admissions (p > 0.05). We have observed a similar distribution of umbilical artery pH ranges in all groups (p > 0.05). ConclusionsMSAF was associated with an increase in the rate of pathological fetal heart rate patterns, intrapartum fevers, operative vaginal and cesarean section deliveries, need for neonatal resuscitation, low Apgar scores and higher fetal-neonatal mortality. Moreover, we found that the risks increase as the staining and consistency of the amniotic fluid evolves so it should alert the obstetrician and paediatrician to the potential adverse outcomes.

Intrapartum and perinatal results associated with different degrees of staining of meconium stained amniotic fluid

ObjectiveTo determine the intrapartum and perinatal results associated with different degrees of staining of meconium stained amniotic fluid (MSAF). Study designIn a retrospective cohort study of all singleton deliveries over a period of one year (2015) in a tertiary hospital, we compared different degrees of MSAF (yellow, green and thick) to clear amniotic fluids, and analysed in each group maternal, intrapartum and neonatal variables as well as umbilical cord blood gas analysis. ResultsOf the 3590 deliveries included, 503 (14%) had MSAF. The incidence of MSAF rises with gestational age at delivery, reaching 20.7% in gestations above 41 weeks compared to 4.3% below 37 weeks. As the amniotic fluid staining progresses we found a higher proportion of intrapartum fevers (p < 0.001), pathological fetal heart rate patterns (p < 0.05), operative vaginal deliveries and cesarean sections (p < 0.001), as well as the need for advanced neonatal resuscitation (p < 0.001). There was also a correlation between MSAF and low Apgar scores at five minutes (p < 0.001) and fetal-neonatal mortality (p < 0.001) but there was not a higher proportion of neonatal intensive care admissions (p > 0.05). We have observed a similar distribution of umbilical artery pH ranges in all groups (p > 0.05). ConclusionsMSAF was associated with an increase in the rate of pathological fetal heart rate patterns, intrapartum fevers, operative vaginal and cesarean section deliveries, need for neonatal resuscitation, low Apgar scores and higher fetal-neonatal mortality. Moreover, we found that the risks increase as the staining and consistency of the amniotic fluid evolves so it should alert the obstetrician and paediatrician to the potential adverse outcomes.

Universal characteristics of evolution and development are inherent in fetal autonomic brain maturation.

Adverse prenatal environmental influences to the developing fetus are associated with mental and cardiovascular disease in later life. Universal developmental characteristics such as self-organization, pattern formation, and adaptation in the growing information processing system have not yet been sufficiently analyzed with respect to description of normal fetal development and identification of developmental disturbances. Fetal heart rate patterns are the only non-invasive order parameter of the developing autonomic brain available with respect to the developing complex organ system. The objective of the present study was to investigate whether universal indices, known from evolution and phylogeny, describe the ontogenetic fetal development from 20 weeks of gestation onwards. By means of a 10-fold cross-validated data-driven multivariate regression modeling procedure, relevant indices of heart rate variability (HRV) were explored using 552 fetal heart rate recordings, each lasting over 30 min. We found that models which included HRV indices of increasing fluctuation amplitude, complexity and fractal long-range dependencies largely estimated the maturation age (coefficients of determination 0.61-0.66). Consideration of these characteristics in prenatal care may not only have implications for early identification of developmental disturbances, but also for the development of system-theory-based therapeutic strategies.

Relevant obstetric factors associated with fetal heart rate monitoring for cerebral palsy in pregnant women with hypertensive disorder of pregnancy.

AimThe study identifies the relevant obstetric factors associated with fetal heart rate (FHR) monitoring for cerebral palsy (CP) in pregnant women with hypertensive disorders of pregnancy (HDP).MethodsThe subjects were neonates with CP (birth weight ≥ 2000 g, gestational age ≥ 33 weeks) who were approved for compensation for CP by the Operating Organization of the Japan Obstetric Compensation System between 2009 and 2012. After selection of women with antepartum HDP, obstetric characteristics associated with FHR monitoring were analyzed.ResultsThe subjects included 33 neonates with CP whose mothers suffered from HDP during pregnancy and 450 neonates whose mothers did not develop HDP. The rates of placental abruption (48.5% vs. 20%; P < 0.001) and light‐for‐gestational age (12.1% vs. 2.2%; P = 0.011) were significantly higher in women with HDP than in those without HDP. Regarding FHR pattern analysis, fetal bradycardia was observed on admission to hospital in 94% of women with placental abruption. In women without placental abruption, FHR was likely to indicate a favorable pattern on admission, but became worse with the progression of labor.ConclusionThis is first study to clinically demonstrate FHR patterns in CP cases in association with HDP. Although antepartum CP is undetectable, pregnant women with HDP should be placed under strict observation and management to minimize fetal hypoxic conditions during labor.

Effect of Structured Bed Exercise on Uterine Contractions, Fetal Heart Rate Patterns, and Maternal Psychophysical Symptoms of Hospitalized High-Risk Pregnant Women: A Randomized Control Trial

PurposeThis study examined the effect on uterine contraction frequency (UCF), blood pressure (BP), heart rate (HR), fetal heart rate (FHR) patterns and psychophysical symptoms (physical discomfort, anxiety, and depression) of structured bed exercise (SBE) in hospitalized high-risk pregnant women prescribed bed rest. MethodsForty-five hospitalized high risk pregnant women at >24 weeks of pregnancy prescribed bed rest were randomly assigned to the experimental or control group. From January to May 2014, data were collected using electronic fetal monitoring and patient monitoring of UCF, BP, HR and FHR patterns, and psychophysical symptoms were measured using the antenatal physical discomfort scale, state-trait anxiety scale, and Edinburgh postnatal depression scale. ResultsUCF, BP, HR, and FHR patterns (rate, variability, acceleration, and deceleration) did not differ significantly between the experimental and control groups. The experimental group showed a significant increase in baseline FHR after SBE within the normal range, and after SBE, it reduced to the FHR before SBE. The variability, acceleration and deceleration of FHR before and after SBE did not differ significantly between two groups. Moreover, there was no statistically significant difference before and after SBE in the experimental group. Also, the experimental group showed statistically significant decreases in physical discomfort score. However, there were no significant differences in depression and anxiety score between two groups. ConclusionsSBE in hospitalized high-risk pregnant women under bed rest did not increase the risk to the fetus, and relieved physical discomfort and anxiety. Therefore, SBE should be considered as a nursing intervention in hospitalized high-risk pregnant women.

Maternal heart rate patterns under resting conditions in late pregnancy.

Objectives:To describe maternal heart rate patterns observed during antenatal monitoring under resting conditions between the gestational ages of 34 to 38 weeks and to demonstrate its associations with uterine activity.Methods:Each participant had five high quality ECG electrodes attached to her anterior abdominal wall which were connected to the Monica AN24 device to collect raw electrical signals from the maternal and fetal ECG and signals of uterine activity. Proprietary software was then used to download the raw data and extract the maternal and fetal heart rate patterns and uterine activity.Results:Several distinct maternal heart rate patterns were observed. These included unusually high or low levels of variability, tachycardia, bradycardia, regular and irregular periodic changes and sporadic changes where the heart rate suddenly decreased or increased. Some of the fluctuations, especially decelerations of maternal heart rate, seemed to be associated with uterine activity.Conclusion:The clinical implications of these different patterns, for both the mother and fetus, needs to be explored further. There is a need for computerized analyses of the different maternal patterns during different gestational ages to determine its relevance.SynopsisVarious maternal heart rate patterns under resting conditions in late pregnancy are described.

416: Does tachysystole influence maternal and neonatal outcomes during induction of labor?

To evaluate the rate of tachysystole during induction of labor and to estimate its impact on obstetrical and neonatal outcomes A retrospective cohort study of all women, at 37+0 to 41+6 gestational weeks, who underwent induction of labor, from 2015 to 2016 in a university-affiliated tertiary medical center. Induction of labor was done with prostaglandin E2 vaginal insert. Women were routinely followed at 12 and 24 hours post initiation of cervical ripening and at any time point if contractions or ruptured membranes were reported by the women. Electronic fetal heart rate tracings and medical records were carefully inspected and documented, to evaluate contraction frequency and fetal heart rate patterns. Obstetrical and neonatal outcomes were analyzed and compared between two groups - women with tachysystole (defined as > 5 contractions in 10 minutes) and those without. 414 met eligibility criteria, of whom 118 (28.5%) had tachysystole and 296 (71.5%) did not. Women in the tachysystole group had a shorter time to vaginal delivery: 18.5 vs. 25 hours (P<0.05). Other obstetrical and neonatal outcomes did not differ between two groups, including rates of operative vaginal delivery or cesarean delivery, as well as Apgar score and umbilical cord pH. In women undergoing induction of labor, tachysystole rate was higher than previously reported. However, our data suggests that tahcysytole does not influence maternal and neonatal outcomes, and is associated with a shorter time to delivery.

293: Term appropriate for gestational age infants with Neonatal Encephalopathy: Is there a characteristic intrapartum fetal heart rate pattern?

Neonatal encephalopathy (NE) of the term AGA newborn is source of severe neurological morbidity. Strict criteria for therapeutic Hypothermia (Hth) eligibility enables consistency in diagnosis of NE. We aimed to evaluate intrapartum fetal heart rate patterns in NE eligible for Hth. A retrospective cohort of clinical data and FHR of term AGA infants treated by Hth; computerized records in a tertiary center, 2009 - 2017. Entry criteria for Hth: GA ≥ 36+0w and two obligatory conditions: Bundle (1) 10’ Apgar ≤ 5, CPR > 10’, pH<7.0, BE>16 mEq/ml in cord blood. Bundle (2): altered consciousness and one of the following: hypotonia, decreased reflexes, clinical seizures. FHR 1h prior to delivery was assessed by trained obstetrician. We characterized the pattern of the FHR: Category system (1-3), FHR-NICHD criteria, mean total deceleration area (area = Half of depth x Duration of deceleration, added over given time), mean deceleration duration 50 infants filled the criteria, 30 had recorded antenatal FHR for at least an hour prior to delivery. Overall, group characteristics were: mean maternal age 28.4y±6.04, GA 39w±1.77, parity 2.94±2.44, BW 3136gr±480.34, cord pH 6.9±0.227. Groups with vs without recorded FHR were similar, including the rate of sentinel events such as uterine rupture, placental abruption, heavy meconium (Table). Notably, two third of cases (58%) in both groups were preceded by such a sentinel event. FHR characteristics were: reduced variability 43.3%, terminal bradycardia 50%, tachycardia 40%. Mean area of deceleration 29.06±24.30 and mean duration of deceleration 1.736±1.105. 21 (70%) infants with FHR Category 2 and 9 (30%) Category 3. We compared FHR characteristics of Category 2 vs 3 (not inherent to definitions), respectively: baseline and total number of variable decelerations were significantly different between the groups mean baseline 147bpm±12.18 and 157.77bpm±12.01, p=0.038, total number of variable decelerations 17.23±11.67 and 6.22±4.29, p=0.012. FHR patterns between these two categories were similar for bradycardia, number of severe variable or late decelerations, mean area and mean duration of deceleration Term AGA infants affected by NE have no preceding pathognomonic intrapartum FHR tracing. The majority of NE are determined by unforeseen sentinel events

Intrapartum Hypoxic Damage is detected by Hypoxia Index to Prevent Cerebral Palsy

Aims: To prevent fetal brain damage and cerebral palsy (CP). Methods: The hypoxia index was studied to solve the vague late deceleration (LD). Hypoxic fetal brain damage was known by the loss of variability. Early delivery before the loss of variability will prevent cerebral palsy, however, no numeric sign of the loss of variability was present, which was seeked by the author in the summing hypoxic effect in repeated FHR deceleration, where the sum of durations of FHR deceleration (min) was divided by the lowest FHR (bpm) and multiplied by 100, in the hypoxia index (HI), in the full FHR monitoring course, possibly using a computer. Results: The Hi was 25 & 26 in CP and severe brain damage, while 20-24 in abnormal FHR but neither brain damage nor cerebral palsy with significant differences. Thus, a numeric threshold in HI to develop cerebral palsy was 25, and the safe HI is 24 or less. The CP will be prevented by the early delivery when the HI is less than 25. Discussion: As HI was 6 in 3 connected LD while HI was 26 after 50 min’s LD repetition, the outcome depends on the repetition, but not to the LD pattern, and all of early, late, variable decelerations and continuous fetal bradycardia are evaluated by HI, namely, HI decides outcome, instead of deceleration pattern, where outcome is digitally diagnosed using numeric HI. Conclusion: HI covers the role of all decelerations, while FHR pattern was discarded in computerized FHR diagnosis.

43: Contraction associated maternal heart rate decelerations: a pragmatic marker of intrapartum volume status

Echocardiography has demonstrated uterine contractions increase cardiac preload and stroke volume through auto-transfusion. These hemodynamic changes may be associated with a compensatory decrease in maternal heart rate. Our objective was to evaluate a visual maternal Contraction-Associated Heart Rate Deceleration (CAHD) pattern as a potential marker of relative hypovolemia. We performed a pre-specified secondary analysis of a prospectively collected cohort from a RCT of maternal admission pulse pressure (PP), epidural coload volume, and post-epidural complications. Participants were healthy laboring women with non-anomalous singleton gestations ≥35 weeks and a category 1 FHR pattern from admission to epidural placement. Those without continuous maternal pulse oximetry data were excluded. Maternal heart rate tracings were evaluated for the presence of CAHD (Figure 1) in the hour prior to epidural placement. Women with and without CAHD were compared. Evaluated study outcomes were: post-epidural category 2/3 FHR abnormalities, maternal hypotension, and obstetric interventions. Of 414 participants, 388 (93.7%) met inclusion criteria; of these 124 (32.0%) had CAHD before epidural placement. On admission, women with CAHD had lower systolic (116.6 vs 119.5, p=.002) and higher diastolic (75.3 vs 73.6, p=.03) blood pressures and a narrower PP (41.3 vs 46.0, p<.001) than women without CAHD. Demographic and clinical characteristics were otherwise similar between groups. CAHD was associated with more frequent post-epidural FHR abnormalities, diastolic hypotension, and obstetric interventions (Table 1). Among women with CAHD, a larger initial epidural bolus (1500 vs 500 mL) was associated with less frequent systolic hypotension (9.8 vs 32.8%, p=.003) and obstetric interventions (21.6 vs 42.5%, p=.02). Among women with CAHD and narrow PP, post-epidural FHR abnormalities were less frequent with a 1500 mL bolus (37.3 vs 58.2%, p=.03), but this finding was not significant for those without CAHD. Maternal CAHD pattern is a pragmatic visual marker of intrapartum maternal volume status. CAHD is associated with more frequent post-epidural FHR abnormalities and need for obstetric interventions. Additional maternal volume loading with epidural placement should be considered for women with CAHD.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Strip of the Month: Marked Variability: To Worry or Not?

Electronic fetal monitoring is a popular technology used to establish fetal well-being. Despite its widespread use, the terminology used to describe patterns seen on the monitor has not been consistent until recently. In 1997, the National Institute of Child Health and Human Development (NICHD) Research Planning Workshop published guidelines for interpretation of fetal tracings. This publication was the culmination of 2 years of work by a panel of experts in the field of fetal monitoring and was endorsed in 2005 by both the American College of Obstetricians and Gynecologists (ACOG) and the Association of Women’s Health, Obstetric and Neonatal Nurses (AWHONN). In 2008, ACOG, NICHD, and the Society for Maternal-Fetal Medicine reviewed and updated the definitions for fetal heart rate (FHR) patterns, interpretation, and research recommendations. Following is a summary of the terminology definitions and assumptions found in the 2008 NICHD workshop report. Normal values for arterial umbilical cord gas values and indications of acidosis are defined in Table 1. View this table: Table 1. Arterial Umbilical Cord Gas Values ### Assumptions from the NICHD Workshop ### Baseline FHR

Oxytocin Use in Labor: Legal Implications.

Oxytocin is one of the most commonly used medications in obstetrics and has been associated with claims of negligence in cases of adverse outcomes. Errors involving intravenous oxytocin administration for induction or augmentation of labor are most commonly dose related and include failure to avoid or treat tachysystole or failure to asses or treat a fetal heart rate pattern indicative of disruption in oxygenation. Clinicians should be knowledgeable regarding pharmacokinetics of oxytocin and the effect of uterine contractions on fetal oxygenation as well as safe titration of oxytocin to achieve the desired effect while minimizing harm.

Hypoxic Fetal Brain Damage Followed by Cerebral Palsy will be Prevented by Computerized Fetal Monitoring

Diagnostic tool to detect fetal risk in the birth process, instead of listening to fetal heart sound, mother’s abdominal fetal ECG, PCG and ultrasound CW Doppler fetal heart detector, while the subjective FHR pattern diagnosis had been widely used in the world since 1968, but it was based on subjective visual pattern recognition, where the diagnosis was disturbed by vague definition and observer difference [1]. The author noticed its controversy nature based on subjective human visual FHR observation, and created objective numeric FHR analysis in 1969 and created objective and numeric FHR analysis to achieve FHR score, which was determined every 5 min, and correlated neonatal Apgar score and umbilical cord blood pH, and precisely predicted neonatal well using and asphyxia using the regression equations to neonatal Apgar score and UApH [2].

Relationship between fetal heart rate patterns and a time course for evaluation of fetal well-being: “the 30 minutes rule” for decision of mechanical delivery

ObjectiveTo predict acidosis in fetus showing deceleration associated with non-reassuring fetal status during delivery, we examined the relationship between duration of the deceleration and umbilical arterial pH. Materials and methodsA total of 19,907 deliveries in eight facilities of the Juntendo Perinatal Care Group, 895 cases of vaginal deliveries with level 3 decelerations were selected for the subjects of this study. The cut-off point of time when the umbilical arterial pH fell below 7.20 in all cases of level 3 and for each deceleration type were examined. The explanatory variables were the pH and pO2 of umbilical arterial gas and the time from onset of the level 3 pattern to delivery. From receiver operating characteristic (ROC) analysis using these variables, the critical point indicating low Apgar score was set at an umbilical arterial pH < 7.20. ResultsThe cut-off point of time when the umbilical arterial pH fell below 7.2 was 33.5 min for all cases of level 3, and 604 cases of severe variable decelerations with normal baseline variability and normal baseline heart rates, the cut-off point was 33.5 min as well. For 108 cases of late decelerations, there was no significant cut-off point for either the mild or severe cases. Mild prolonged deceleration showed the cut-off point of 34.5 min. ConclusionsWe confirmed the time indices for predicting and preventing acidosis in fetuses showing decelerations. To prevent fetal acidosis, the decision related to proper timing for performing assisted delivery by considering the time course is important.

Maternal Pulse Pressure and the Risk of Postepidural Complications: A Randomized Controlled Trial.

To test the hypothesis that increasing the intravenous fluid bolus volume at the time of epidural placement in women with narrow pulse pressure would reduce postepidural fetal heart rate (FHR) abnormalities, hypotension, and resuscitative obstetric interventions. We performed a single-center randomized controlled trial. Eligible participants were normotensive with a nonanomalous singleton gestation at or after 35 weeks and with a narrow pulse pressure (less than 45 mm Hg) on admission. Enrolled patients remained eligible for randomization at epidural request if they were within 6 hours of admission and the FHR remained category 1. Patients were allocated to a 500-mL (institutional standard) or 1,500-mL intravenous fluid bolus at epidural placement. A reference group with admission pulse pressure 50 mm Hg or greater was also evaluated. The primary outcome was a category 2 or 3 FHR pattern within 60 minutes after the epidural test dose. Evaluated secondary outcomes included maternal hypotension and composite resuscitative interventions to correct FHR abnormalities or hypotension. We calculated that 276 women (138/group) would provide 80% power to detect a relative 50% reduction in the occurrence of the primary outcome from 27% in the 500-mL group to 13.5% in the 1,500-mL group (two-sided α=0.05). From October 2015 to November 2016, 276 women were allocated to receive a 500-mL (n=139) or 1,500-mL (n=137) fluid bolus. One hundred thirty-eight women were evaluated in the reference group. Demographic, obstetric, and labor characteristics were similar between groups. The 1,500-mL group had significantly fewer postepidural FHR abnormalities (38.0% compared with 51.8%, relative risk 0.73, 95% CI 0.56-0.96, P=.02). Maternal systolic hypotension (10.2% compared with 34.5%, relative risk 0.30, 95% CI 0.17-0.51, P<.001) and composite postepidural interventions (18.3% compared with 44.2%, relative risk 0.42, 95% CI 0.28-0.62, P<.001) were also less frequent in the 1,500-mL group. Fetal heart rate abnormalities remained significantly less frequent in the reference group than among women with a narrow pulse pressure on admission for delivery. A 1,500-mL intravenous fluid bolus in women with a narrow pulse pressure decreases the risk of postepidural FHR abnormalities (number needed to treat=7), results in less frequent postepidural hypotension, and reduces the need for resuscitative interventions. Admission pulse pressure may be used to individualize intrapartum fluid management at the time of initiation of neuraxial labor analgesia. ClinicalTrials.gov, NCT02565485.

An investigation of fetal behavioural states during maternal sleep in healthy late gestation pregnancy: an observational study.

Fetal behavioural state in healthy late gestation pregnancy is significantly affected by maternal position overnight. Maternal left lateral position is the one most frequently adopted at sleep onset. The maternal position at sleep onset is maintained the longest overnight. Fetal state 1F is more common in maternal supine positions overnight. Fetal state 4F is less common in maternal supine sleep positions. Fetal state and maternal sleep position are independently associated with fetal heart rate variability. Maternal sleep position significantly affects fetal heart rate and heart rate variability and affects circadian fetal heart rate patterns. Fetal behavioural states (FBS) are measures of fetal wellbeing. Maternal position affects FBS with supine position being associated with an increased likelihood of fetal quiescence consistent with the human fetus adapting to a lower oxygen consuming state. Several studies have now confirmed the association between sleep position and risk of late intrauterine death. We designed this study to observe the effects of maternal sleep positions overnight in healthy late gestation pregnancy. Twenty-nine healthy women had continuous fetal ECG recordings overnight. Two blinded observers assigned fetal states in 5min blocks. Measures of fetal heart rate variability (FHRV) were calculated from ECG beat to beat data. Maternal position was determined from infrared video recording. Compared to state 2F (active sleep), 4F (active awake-high activity) occurred almost exclusively when the mother was in a left or right lateral position. State 1F (quiet sleep) was more common when the mother was supine [odds ratio (OR) 1.30, 95% confidence interval (CI) 1.11-1.52] and less common on the maternal right side with the left being the referent position (OR 0.81, 95% CI, 0.70-0.93). State 4F was more common between 21.00 and 01.00h than between 01.00 and 07.00h (OR 2.83, 95% CI 2.32-3.47). In each fetal state, maternal position had significant effects on fetal heart rate and measures of FHRV. In healthy late gestation pregnancy, maternal sleep position affects FBS and heart rate variability. These effects are probably fetal adaptations to positions which may produce a mild hypoxic stress.