Unselected low-risk pregnancies and the effect of continuous intrapartum fetal heart rate monitoring on umbilical blood gases and cerebral palsy

Comparison and verification of detection accuracy for late deceleration with and without uterine contractions signals using convolutional neural networks

Introduction

Cardiotocography (CTG) is used to monitor and evaluate fetal health by recording the fetal heart rate (FHR) and uterine contractions (UC) over time. Among these, the detection of late deceleration (LD), the early marker of fetal mild hypoxemia, is important, and the temporal relationship between FHR and UC is an essential factor in deciphering it. However, there is a problem with UC signals generally tending to have poor signal quality due to defects in installation or obesity in pregnant women. Since obstetricians evaluate potential LD signals only from the FHR signal when the UC signal quality is poor, we hypothesized that LD could be detected by capturing the morphological features of the FHR signal using Artificial Intelligence (AI). Therefore, this study compares models using FHR only (FHR-only model) and FHR with UC (FHR + UC model) constructed using a Convolutional Neural Network (CNN) to examine whether LD could be detected using only the FHR signal.

Methods

The data used to construct the CNN model were obtained from the publicly available CTU-UHB database. We used 86 cases with LDs and 440 cases without LDs from the database, confirmed by expert obstetricians.

Results

The results showed high accuracy with an area under the curve (AUC) of 0.896 for the FHR-only model and 0.928 for the FHR + UC model. Furthermore, in a validation using 23 cases in which obstetricians judged that the UC signals were poor and the FHR signal had an LD-like morphology, the FHR-only model achieved an AUC of 0.867.

Conclusion

This indicates that using only the FHR signal as input to the CNN could detect LDs and potential LDs with high accuracy. These results are expected to improve fetal outcomes by promptly alerting obstetric healthcare providers to signs of nonreassuring fetal status, even when the UC signal quality is poor, and encouraging them to monitor closely and prepare for emergency delivery.

Review of optical methods for fetal monitoring in utero

The current technology for monitoring fetal wellbeing during child birth is cardiotocography. However, CTG has high false positive rates that lead to unnecessary emergency Cesarean deliveries and false negatives that result in birth injuries. To curtail these issues, fetal pulse oximetery has been a topic of interest for many decades. Fetal pulse oximetry would yield the oxygen saturation of the fetus in utero and provide a more robust marker for clinicians to make decisions about performing emergency Cesarean deliveries. Here, we present a review of biomedical optical developments related to transabdominal fetal pulse oximetery in the biophotonics field and the challenges that must be overcome to make transabdominal pulse oximetry a clinical reality.

Deep neural network-based classification of cardiotocograms outperformed conventional algorithms

Cardiotocography records fetal heart rates and their temporal relationship to uterine contractions. To identify high risk fetuses, obstetricians inspect cardiotocograms (CTGs) by eye. Therefore, CTG traces are often interpreted differently among obstetricians, resulting in inappropriate interventions. However, few studies have focused on quantitative and nonbiased algorithms for CTG evaluation. In this study, we propose a newly constructed deep neural network model (CTG-net) to detect compromised fetal status. CTG-net consists of three convolutional layers that extract temporal patterns and interrelationships between fetal heart rate and uterine contraction signals. We aimed to classify the abnormal group (umbilical artery pH < 7.20 or Apgar score at 1 min < 7) and the normal group from CTG data. We evaluated the performance of the CTG-net with the F1 score and compared it with conventional algorithms, namely, support vector machine and k-means clustering, and another deep neural network model, long short-term memory. CTG-net showed the area under the receiver operating characteristic curve of 0.73 ± 0.04, which was significantly higher than that of long short-term memory. CTG-net, a quantitative and automated diagnostic aid system, enables early intervention for putatively abnormal fetuses, resulting in a reduction in the number of cases of hypoxic injury.

Intrapartum fetal heart rate patterns and perinatal outcome in chorioamnionitis at or beyond 34 weeks of gestation

AIM

To investigate intrapartum fetal heart rate (FHR) patterns in women with chorioamnionitis at or beyond 34 weeks of gestation in relation to neonatal outcome and to compare clinical and subclinical chorioamnionitis.

METHODS

A retrospective questionnaire survey on deliveries during 2015 was conducted by the Perinatology Committee of the Japan Society of Obstetrics and Gynecology from 2016 to 2018. A total of 498 singleton births complicated by chorioamnionitis delivered at ≥34 weeks of gestation without major congenital malformations were included. The subjects were divided into clinical and subclinical chorioamnionitis groups based on Lencki's criteria. Poor perinatal outcome was defined as death or brain damage. We analyzed clinical features, FHR patterns in the last 2 h before delivery, gestational age, birthweight, Apgar score, umbilical arterial blood gas analysis, and infant's outcome.

RESULTS

Incidence of chorioamnionitis at ≥34 weeks of gestation was 0.59% (522/87827). Clinical and subclinical chorioamnionitis comprised 240 and 258 cases, respectively. Abnormal FHR patterns (late deceleration or decreased baseline variability) were significantly associated with poor perinatal outcome. Combined late deceleration and decreased variability showed low positive predictive value (12.8%) and high negative predictive value (99.5%), and was significantly associated with long-term poor outcome in clinical chorioamnionitis only (odds ratio: 29.4, p < 0.01). Poor perinatal outcome showed no significant difference between the clinical and subclinical chorioamnionitis groups.

CONCLUSIONS

Combined late deceleration and decreased variability could predict poor perinatal outcome in clinical chorioamnionitis. Poor perinatal outcome occurred in infants born to mothers with clinical and subclinical chorioamnionitis.

Fetal heart rate pattern in term or near-term cerebral palsy: a nationwide cohort study

BACKGROUND

It is crucial to interpret fetal heart rate patterns with a focus on the pattern evolution during labor to estimate the relationship between cerebral palsy and delivery. However, nationwide data are not available.

OBJECTIVE

The aim of our study was to demonstrate the features of fetal heart rate pattern evolution and estimate the timing of fetal brain injury during labor in cerebral palsy cases.

STUDY DESIGN

In this longitudinal study, 1069 consecutive intrapartum fetal heart rate strips from infants with severe cerebral palsy at or beyond 34 weeks of gestation, were analyzed. They were categorized as follows: (1) continuous bradycardia (Bradycardia), (2) persistently nonreassuring, (3) reassuring-prolonged deceleration, (4) Hon's pattern, and (5) persistently reassuring. The clinical factors underlying cerebral palsy in each group were assessed.

RESULTS

Hypoxic brain injury during labor (those in the reassuring-prolonged deceleration and Hon's pattern groups) accounted for 31.5% of severe cerebral palsy cases and at least 30% of those developed during the antenatal period. Of the 1069 cases, 7.86% were classified as continuous bradycardia (n=84), 21.7% as persistently nonreassuring (n=232), 15.6% as reassuring-prolonged deceleration (n=167), 15.9% as Hon's pattern (n=170), 19.8% as persistently reassuring (n=212), and 19.1% were unclassified (n=204). The overall interobserver agreement was moderate (kappa 0.59). Placental abruption was the most common cause (31.9%) of cerebral palsy, accounting for almost 90% of cases in the continuous bradycardia group (64 of 73). Among the cases in the Hon's pattern group (n=67), umbilical cord abnormalities were the most common clinical factor for cerebral palsy development (29.9%), followed by placental abruption (20.9%), and inappropriate operative vaginal delivery (13.4%).

CONCLUSION

Intrapartum hypoxic brain injury accounted for approximately 30% of severe cerebral palsy cases, whereas a substantial proportion of the cases were suspected to have either a prenatal or postnatal onset. Up to 16% of cerebral palsy cases may be preventable by placing a greater focus on the earlier changes seen in the Hon's fetal heart rate progression.

Umbilical cord arterial blood gas analysis in term singleton pregnancies: a retrospective analysis over 11 years

Objective

Given that the large volume of data on cord arterial blood gas analysis (ABGA) have been rarely addressed in Korean population, we aimed to examine the incidence, associated factors, and neonatal outcomes in cases of low cord pH, and investigate the incidence of cerebral palsy (CP).

Methods

From data of all consecutive term singleton pregnancies delivered in our institution from 2006 to 2016 (n=15,701), cases with cord ABGA (n=14,221) available were included. We collected information on maternal clinical characteristics and delivery outcomes and also examined neonatal and infant outcomes, including neonatal intensive care unit (NICU) admission and CP, in cases with low cord pH, defined as a pH <7.1.

Results

Rates of low Apgar scores at 1 minute (<4) and 5 minutes (<7) were 0.6% (n=79) and 0.4% (n=58), respectively. Rates of cord pH <7.2, <7.1, and <7.0 were 7.1% (n=1,011), 1.1% (n=163), and 0.3% (n=38), respectively. Among cases with low cord pH, 30.1% (n=49/163) were admitted to the NICU and 11.0% (n=18/163) required ventilator support. Ultrasonography of the brain was performed in 28.8% (n=47/163), with abnormal findings observed in 27.7% (n=13/47). Among cases with low cord pH, 1.8% (n=3/163) were subsequently diagnosed with CP, including 2 cases of spastic CP and 1 of ataxic CP.

Conclusion

Although low cord pH was a relatively frequent finding observed in 1 out of every 87 cases, hypoxic-ischemic encephalopathy-related CP was found in only 1 out of 7,111 term singleton deliveries over 11 years in our institution.

Evaluation of 3-tier and 5-tier FHR pattern classifications using umbilical blood pH and base excess at delivery

OBJECTIVE

The relevance between time-series fetal heart rate (FHR) pattern changes during labor and outcomes such as arterial blood gas data at delivery has not been studied. Using 3-tier and 5-tier classification systems, we studied the relationship between time-series FHR pattern changes before delivery and umbilical artery blood gas data at delivery.

METHODS

The subjects were 1,909 low-risk women with vaginal delivery (age: 29.1 ± 4.4 years, parity: 1.7 ± 0.8). FHR patterns were classified by a skilled obstetrician based on each 10 min-segment of the last 60 min before delivery from continuous CTG records in an obstetric clinic.

RESULTS

The relationship between each 10 min-segment FHR pattern classification from 60 minutes before delivery and umbilical artery blood pH and base excess (BE) values at delivery changed with time. In the 3-tier classification, mean pH of Category I group in each 10 min-segment was significantly higher than that of Category II group. For Category I groups in each 10-minute segment, its number decreased and its average pH increased as the delivery time approached. In the 5-tier classification, there was the same tendency. About each level group in 10 min-segment, the higher the level, the lower the blood gas values, and mean pH of higher level groups decreased as the delivery time approached.

CONCLUSIONS

The relationship between classifications and outcomes was clear at any time from 60 min before delivery in 3- and 5-tier classifications, and the 5-tier classification was more relevant.

Cumulative deceleration area: a simplified predictor of metabolic acidemia

OBJECTIVE

Fetal monitoring, ubiquitous in obstetrics is used to predict and prevent intrapartum fetal injury. Despite decades of education and nomenclature revision, clinicians show low agreement on key elements, including the types of deceleration and hence their presumed etiology. Cumulative deceleration area is not dependent on deceleration type and could potentially mitigate this problem. Although deceleration area has shown promise as a marker of acidemia, no reports have shown how deceleration area evolves in late labor. Advances in computerization allow for direct measurement of deceleration area and standard fetal heart rate (FHR) patterns. The objective of this study was to compare the evolution and discrimination performance of deceleration area and other FHR patterns in late labor in term neonates with metabolic acidemia (MA) and in those with normal cord gases.

METHODS

This retrospective cohort study included women with a term singleton (≥37 weeks) in cephalic presentation with cord gas data and FHR tracings available for analysis. MA included neonates with an umbilical artery base deficit >12 mmol/L (n = 132). Controls included those with normal cord gases (base deficit <8 mmol/L) and a 5-minute Apgar score of >6 (n = 1498). Deceleration area and other FHR patterns were summarized and compared in 30-minute segments over the last five hours. Receiver-operating characteristic curves were constructed and AUCs compared.

RESULTS

Deceleration area had the highest AUC (0.702, 95% CI 0.655-0.749) and was a superior marker of MA compared to baseline (AUC 0.588, 95% CI 0.530-0.645), baseline variability (AUC 0.611, 95% CI 0.558-0.663), and number of late decelerations (AUC 0.582, 95% CI 0.527-0.637).

CONCLUSION

Cumulative deceleration area reduces the necessity to determine deceleration type. In a single number, it objectively quantifies three important aspects of decelerations; frequency, depth and duration and was a superior marker of MA compared to baseline level, baseline variability and number of late decelerations. The acidemia group had higher deceleration area over the last two hours prior to delivery. This result indicates that the cumulative area and persistence of repetitive decelerations is important clinically.

Obstetric factors associated with uterine rupture in mothers who deliver infants with cerebral palsy

Objective: The aim of the present study was to clarify the obstetric factors associated with uterine rupture in mothers who deliver infants with cerebral palsy (CP) in Japan.Methods: This retrospective case-cohort study reviewed the obstetric characteristics and clinical courses of mothers who experienced uterine rupture and compared those who delivered an infant with CP (cases) with those who delivered an infant without CP (cohort). Data were obtained from the Japan Obstetric Compensation System for CP database (27 cases) and the perinatal database of the Japan Society of Obstetrics and Gynecology (312 cohorts). The subjects included live singleton infants delivered between 2009 and 2014 with a birth weight ≥2000 g and gestation ≥33 weeks.Results: Augmentation was performed 33% in cases and 8% in cohorts (p < .001). The amount of bleeding during surgery was 1819 g in cases and 1096 g in cohorts (p < .001). Length of gestational weeks and neonatal birth weight were significantly higher and Apgar scores and umbilical arterial pH were lower in cases compared to cohorts (p < .001). In cases with CP, 11 cases of uterine rupture involved scarred uteruses. Seven were trial of labor after a previous cesarean. On one hand, 16 cases occurred in unscarred uteruses. Five of the uterine fundal pressure maneuvers and four of tachysystole due to excessive augmentation were reported in association with uterine rupture.Conclusion: Two-third of the relevant obstetric factors for CP associated with uterine rupture were iatrogenic. At least, to reduce CP resulting from delivery-related uterine rupture, reckless delivery management should be avoided.

Diagnostic accuracy of fetal scalp lactate for intrapartum acidosis compared with scalp pH

OBJECTIVE

To determine the diagnostic accuracy of fetal scalp lactate sampling (FSLS) and to establish an optimal cut-off value for intrapartum acidosis compared with fetal scalp pH.

METHODS

A 20-month retrospective cohort study was conducted of all neonates delivered in our institution for whom fetal scalp blood sampling (FSBS) was performed, matching their intrapartum gasometry to their cord gasometry at delivery (n=243). The time taken from the performance of scalp blood sampling to arterial umbilical cord gas acquisition was 45 min at most. Five arterial cord gasometry patterns were set for assessing the predictive ability of both techniques. Subsequent obstetric management for a pathological value was analysed considering the use of both techniques.

RESULTS

The optimal cut-off value for FSLS was 4.8 mmol/L: this value has 100% sensitivity and 63% specificity for umbilical arterial cord gas pH≤7.0 and base deficit (BD)≥12 detection, and 100% sensitivity and 64% specificity for umbilical arterial cord gas pH≤7.10 and BD≥12 detection, with a false negative rate of <1.3%, improving fetal scalp pH performance. FSLS showed the best area under the curve (AUC) of 0.86 and 0.84 for both arterial cord gasometry patterns, respectively. Expedite birth following lactate criteria would have been the same as following pH criteria (92 obstetric interventions) with no cases of missed metabolic acidosis. In the cohort, 19.8% of cases were discordant, but no cases of metabolic acidosis were in this group.

CONCLUSIONS

FSLS improves the detection of metabolic acidosis via fetal scalp pH with an optimal cut-off value of 4.8 mmol/L. FSLS can be used without increasing obstetrical interventions or missing metabolic acidosis.

Elevated C-reactive protein levels in histological chorioamnionitis at term: impact of funisitis on term neonates

OBJECTIVE

To compare clinical features and inflammatory effects for mothers and newborns between cases with or without funisitis among histlogical chorioamnionitis (HCA) at term.

METHODS

We recruited 42 patients who were diagnosed with HCA at term. The women were classified into group HCA1/2 (HCA without funisitis, n = 22) and group HCA3 (HCA with funisitis, n = 20). Medical records and cardiotocograms were retrospectively reviewed to analyze predelivery maternal signs, abnormal FHR patterns, and neonatal outcomes. Differences between the two groups were evaluated using the Mann-Whitney U-test.

RESULTS

The maternal CRP and WBC level of group HCA3 was observed to be significantly greater than that of group HCA1/2. Moreover, neonatal CRP levels at days 0, 1 and 2 of group HCA3 were significantly greater than of group HCA1/2. The ratios of abnormal FHR patterns of the two groups for recurrent late deceleration and prolonged deceleration were 26% and 43%, respectively, which was not statistically significant between the two groups.

CONCLUSION

We showed that HCA at term, particularly for funisitis, elevates the levels of maternal and neonatal CRP. Neonatal inflammatory signs, including elevated CRP levels, should be considered when managing cases of abnormal elevated CRP levels during labor at term.

The Regional Centralization of Electronic Fetal Heart Rate Monitoring and Its Impact on Neonatal Acidemia and the Cesarean Birth Rate

Objective. The improvement of the accuracy of fetal heart rate (FHR) pattern interpretation to improve perinatal outcomes remains an elusive challenge. We examined the impact of an FHR centralization system on the incidence of neonatal acidemia and cesarean births. Methods. We performed a regional, population-based, before-and-after study of 9,139 deliveries over a 3-year period. The chi-squared test was used for the statistical analysis. Results. The before-and-after study showed no difference in the rates of acidemia, cesarean births, or perinatal death in the whole population. A subgroup analysis using the 4 hospitals in which an FHR centralization system was continuously connected (compliant group) and 3 hospitals in which the FHR centralization system was connected on demand (noncompliant group) showed that the incidence acidemia was significantly decreased (from 0.47% to 0.11%) without a corresponding increase in the cesarean birth rate due to nonreassuring FHR patterns in the compliant group. Although there was no difference in the incidence of nonreassuring FHR patterns in the noncompliant group, the total cesarean birth rate was significantly higher than that in the compliant group. Conclusion. The continuous FHR centralization system, in which specialists help to interpret results and decide clinical actions, was beneficial in reducing the incidence of neonatal acidemia (pH < 7.1) without increasing the cesarean birth rate due to nonreassuring FHR patterns.

Relevant Obstetric Factors for Cerebral Palsy: From the Nationwide Obstetric Compensation System in Japan

Objective

The aim of this study was to identify the relevant obstetric factors for cerebral palsy (CP) after 33 weeks’ gestation in Japan.

Study design

This retrospective case cohort study (1:100 cases and controls) used a Japanese national CP registry. Obstetric characteristics and clinical course were compared between CP cases in the Japan Obstetric Compensation System for Cerebral Palsy database and controls in the perinatal database of the Japan Society of Obstetrics and Gynecology born as live singleton infants between 2009 and 2011 with a birth weight ≥ 2,000 g and gestation ≥ 33 weeks.

Results

One hundred and seventy-five CP cases and 17,475 controls were assessed. Major relevant single factors for CP were placental abnormalities (31%), umbilical cord abnormalities (15%), maternal complications (10%), and neonatal complications (1%). A multivariate regression model demonstrated that obstetric variables associated with CP were acute delivery due to non-reassuring fetal status (relative risk [RR]: 37.182, 95% confidence interval [CI]: 20.028–69.032), uterine rupture (RR: 24.770, 95% CI: 6.006–102.160), placental abruption (RR: 20.891, 95% CI: 11.817–36.934), and preterm labor (RR: 3.153, 95% CI: 2.024–4.911), whereas protective factors were head presentation (RR: 0.199, 95% CI: 0.088–0.450) and elective cesarean section (RR: 0.236, 95% CI: 0.067–0.828).

Conclusion

CP after 33 weeks’ gestation in the recently reported cases in Japan was strongly associated with acute delivery due to non-reassuring fetal status, uterine rupture, and placental abruption.

Intrapartum fetal heart rate patterns preceding terminal bradycardia in infants (>34 weeks) with poor neurological outcome: A regional population-based study in Japan

AIM

Intrapartum fetal bradycardia necessitates immediate operative delivery. Our aim was to investigate the hypothesis that some non-reassuring fetal heart rate (FHR) patterns were present before the onset of terminal bradycardia in infants who developed subsequent brain damage.

MATERIAL AND METHODS

From a population-based study of 65,197 deliveries, 190 stillbirths, 115 neonatal deaths, and 136 neurologically high-risk infants were registered by the Miyazaki Perinatal Conference. There were 15 cases of neurologically high-risk infants born at >34 weeks of gestation exhibiting intrapartum terminal bradycardia. Focusing on the brain-damaged infants, we retrospectively analyzed FHR patterns for at least 1 h prior to the bradycardia.

RESULTS

Brain damage (cerebral palsy [n = 11] and mental retardation [n = 2]) was diagnosed at 2 years old in 13 out of 15 neurologically high-risk infants. Two infants had bradycardia on admission. In the remaining 11 infants, FHR patterns were reassuring in six (55%) and non-reassuring in five (45%), including late decelerations (n = 4) and variable decelerations (n = 2). Clinically relevant factors in the non-reassuring group included intrauterine infection (n = 3), malpresentation with umbilical cord coiling (n = 1), and unknown causes (n = 1). Clinically relevant features in the reassuring group included cord prolapse (n = 1), vaginal breech delivery (n = 1), shoulder dystocia (n = 1), rupture of membranes (n = 1), and unknown causes (n = 2).

CONCLUSION

More than half of the brain-damaged infants born at >34 weeks of gestation who exhibited intrapartum terminal bradycardia had unremarkable FHR patterns before abrupt-onset bradycardia. For those with non-reassuring patterns preceding bradycardia, intrauterine infection was the major sentinel event.

Obstetric care consensus no. 1: safe prevention of the primary cesarean delivery

In 2011, one in three women who gave birth in the United States did so by cesarean delivery. Cesarean birth can be life-saving for the fetus, the mother, or both in certain cases. However, the rapid increase in cesarean birth rates from 1996 to 2011 without clear evidence of concomitant decreases in maternal or neonatal morbidity or mortality raises significant concern that cesarean delivery is overused. Variation in the rates of nulliparous, term, singleton, vertex cesarean births also indicates that clinical practice patterns affect the number of cesarean births performed. The most common indications for primary cesarean delivery include, in order of frequency, labor dystocia, abnormal or indeterminate (formerly, nonreassuring) fetal heart rate tracing, fetal malpresentation, multiple gestation, and suspected fetal macrosomia. Safe reduction of the rate of primary cesarean deliveries will require different approaches for each of these, as well as other, indications. For example, it may be necessary to revisit the definition of labor dystocia because recent data show that contemporary labor progresses at a rate substantially slower than what was historically taught. Additionally, improved and standardized fetal heart rate interpretation and management may have an effect. Increasing women's access to nonmedical interventions during labor, such as continuous labor and delivery support, also has been shown to reduce cesarean birth rates. External cephalic version for breech presentation and a trial of labor for women with twin gestations when the first twin is in cephalic presentation are other of several examples of interventions that can contribute to the safe lowering of the primary cesarean delivery rate.

Safe prevention of the primary cesarean delivery

In 2011, 1 in 3 women who gave birth in the United States did so by cesarean delivery. Cesarean birth can be lifesaving for the fetus, the mother, or both in certain cases. However, the rapid increase in cesarean birth rates from 1996 through 2011 without clear evidence of concomitant decreases in maternal or neonatal morbidity or mortality raises significant concern that cesarean delivery is overused. Variation in the rates of nulliparous, term, singleton, vertex cesarean births also indicates that clinical practice patterns affect the number of cesarean births performed. The most common indications for primary cesarean delivery include, in order of frequency, labor dystocia, abnormal or indeterminate (formerly, nonreassuring) fetal heart rate tracing, fetal malpresentation, multiple gestation, and suspected fetal macrosomia. Safe reduction of the rate of primary cesarean deliveries will require different approaches for each of these, as well as other, indications. For example, it may be necessary to revisit the definition of labor dystocia because recent data show that contemporary labor progresses at a rate substantially slower than what was historically taught. Additionally, improved and standardized fetal heart rate interpretation and management may have an effect. Increasing women's access to nonmedical interventions during labor, such as continuous labor and delivery support, also has been shown to reduce cesarean birth rates. External cephalic version for breech presentation and a trial of labor for women with twin gestations when the first twin is in cephalic presentation are other of several examples of interventions that can contribute to the safe lowering of the primary cesarean delivery rate.

Fault and blame, insults to the perinatal brain may be remote from time of birth

There is a certainty in malpractice cases that neurodevelopmental deficits are caused by preventable events at birth when the onset, nature, and timing of the insult in the antenatal and natal period are unknown. The biggest problem is determining timing. Electronic fetal monitoring is given excessive importance in legal cases. Before assigning fault on events at birth, a better understanding of developmental neurobiology and limitations of the present clinical biomarkers is warranted. The issues of single versus repeated episodes, timing of antenatal insults, pros and cons of legal arguments, interaction of various etiologic and anatomic factors are discussed.

Cardiotocography in the prognosis of perinatal outcome

AIM

The objective of the study was to examine whether cardiotocography can (CTG) predict asphyxia of the embryo, manifested as hypoxic-ischemic encephalopathy (HIE), and to what extent one can rely on CTG record.

MATERIAL AND METHODS

Retrospective research was carried out at the Clinic for Gynecology and Obstetrics UKC Tuzla and medical documentation from the history of mothers and newborns was used. The study group consisted of 68 pregnancies and newborns who developed HIE. The control group consisted of 40 pregnancies, which resulted in birth of healthy newborns--without signs of asphyxia. CTG records were analyzed, Apgar score, the ways of finishing delivery.

RESULTS

Pathological CTG records (bradycardia 100, tachycardia 180, silent type of curve, late decelerations) were found in 45 (66.17%) cases of the study group in comparison to 11 (27.5%) in the control group. In the study group Apgar score in 5th minute lower than 7 had 17.46% newborns and the highest incidence of the normally finished deliveries. We conclude that cardiotocography is one of the reliable methods of fetal monitoring in pregnancy and delivery, and that pathological CTG record very likely indicates the possible presence of perinatal asphyxia.

CONCLUSION

Achieving a low degree of correlation between pathological intrapartum cardiotocography findings and long-term outcome of children can be achieved by rapid and adequate obstetric intervention and the relatively short duration of fetal acidosis, and optimal procedures during intensive care of newborns.

Fetal heart rate classification proposed by the perinatology committee of the Japan Society of Obstetrics and Gynecology: reproducibility and clinical usefulness

AIM

Intrapartum management guidelines based on fetal heart rate classification comprising a 5-tier system (Levels 1-5) was proposed by the Perinatology Committee of the Japan Society of Obstetrics and Gynecology (JSOG). This study aimed to assess the reproducibility and clinical usefulness of this classification.

METHODS

For assessing intraobserver and interobserver reproducibility in the interpretation of fetal heart rate tracing, 2 obstetricians reviewed 247 fetal heart rate tracings using the JSOG classification (Level 1, normal; Level 2, benign variant; Level 3, mild variant; Level 4, moderate variant; and Level 5, severe variant) and a subjective 3-tier classification (normal, equivocal, and ominous). In a separate series, we investigated whether the JSOG classification is related to early neonatal outcome and the delivery mode in 96 deliveries.

RESULTS

Weighted kappa coefficients of intraobserver and interobserver reproducibility in the interpretation of fetal heart rate tracings based on the JSOG classification were 0.73 to 0.77 and 0.70, respectively. In the subjective classification, these values were 0.69 to 0.72 and 0.59. There was a progressive increase in the rate of instrumental or cesarean deliveries across the 5 levels of the JSOG classification (P<0.001). Although, level 5 of the JSOG classification had a lower Apgar score and umbilical artery pH than did the other 4 levels (p<0.05), there were no significant differences among the other levels in regard to early neonatal outcome.

CONCLUSIONS

This study demonstrated that both intraobserver reproducibility and interobserver reproducibility of the JSOG classification for interpreting FHR tracings were clinically acceptable. The results also suggest that the intervention according to the JSOG classification is useful for avoiding worsening early neonatal outcomes.

Electronic fetal monitoring in the United States: temporal trends and adverse perinatal outcomes

OBJECTIVE

To examine trends in electronic fetal monitoring (EFM) use and quantify the extent to which such trends are associated with changes in rates of primary cesarean delivery and neonatal morbidity and mortality.

METHODS

We carried out a retrospective study of more than 55 million nonanomalous singleton live births (24-44 weeks of gestation) delivered in the United States between 1990 and 2004. Changes in the risks of neonatal mortality, cesarean delivery, and operative vaginal delivery for fetal distress, 5-minute Apgar score lower than 4, and neonatal seizures (at 34 weeks of gestation or after) were examined in relation to changes in EFM use.

RESULTS

Electronic fetal monitoring use increased from 73.4% in 1990 to 85.7% in 2004, a relative increase of 17% (95% confidence interval 16-18%). This increase was associated with an additional 5% and 2% decline in early and late neonatal deaths, respectively, at 24-33 weeks of gestation as well as a 4-7% additional decline in the 5-minute Apgar score lower than 4 at 24-33, 34-36, and 37-44 weeks of gestation. Increasing EFM use was associated with a 2-4% incremental increased rate of both cesarean delivery and operative vaginal delivery for fetal distress at 24-33, 34-36, and 37-44 weeks of gestation. Increasing EFM was not associated with any temporal changes in the rate of neonatal seizures.

CONCLUSIONS

The temporal increase in EFM use in the United States appears to be modestly associated with the recent declines in neonatal mortality, especially at preterm gestations.

LEVEL OF EVIDENCE

II.

Applying the ecology model to perinatal medicine: from a regional population-based study

Objective. Ecology model is useful to provide a framework for organizing medical care. We aimed to see if the ecology model is applicable to perinatal care in Japan. Methods. On a population-based approach, we had 53,461 deliveries in Miyazaki from 2001 to 2005. In comparison, we used all of the 106,613 deliveries in Tokyo in 2009. Women were divided into 4 grades by risk-allocation criteria and their proportion was expressed per 1,000 women to apply to the model and to delineate the ecology curve. The perinatal mortality was compared by Chi-square test. Results. We found remarkable similarity in ecology curves between the original ecology models and that representing Miyazaki perinatal data. However, the curve representing Tokyo was different from the original one. Besides, the perinatal mortality was significantly lower in Miyazaki (4.40/1,000) than in Tokyo (5.06/1,000). Conclusion. Applying the ecology model to perinatal care is useful with improvement of perinatal outcome and it would provide an appropriate framework for organizing perinatal care.

Perinatal death and neurological damage as a sequential chain of poor outcome

OBJECTIVE

We investigated the risk factors of perinatal death and neurological damage.

METHODS

Perinatal death and neurological damage were retrospectively investigated using a population-based study of 108 024 deliveries from 1998 to 2007. Main factors studied were asphyxia, growth restriction and preterm delivery < 34 weeks of gestation, since these three factors were most often associated with poor prognosis. The impact of each factor was identified by multiple regression analyses.

RESULTS

There were 459 perinatal deaths (4.3/1000) and 220 neurological damages (2.0/1000). Preterm delivery accounted for 50% of perinatal deaths and neurological damage, whereas it constituted 2.6% of total births. Multiple regression analyses showed that prematurity < 34 weeks (10-fold), asphyxia (10-fold) and growth restriction (2-fold) were independent and significant risk factors associated with poor outcomes, and that the magnitude was similar throughout the three consecutive critical events of fetal death, neonatal death and neurological damage.

CONCLUSIONS

Prematurity < 34 weeks, asphyxia and growth restriction are independent and persistent risk factors from perinatal death to neurological damage.

Electronic fetal heart rate monitoring and its relationship to neonatal and infant mortality in the United States

OBJECTIVE

To examine the association between electronic fetal heart rate monitoring and neonatal and infant mortality, as well as neonatal morbidity.

STUDY DESIGN

We used the United States 2004 linked birth and infant death data. Multivariable log-binomial regression models were fitted to estimate risk ratio for association between electronic fetal heart rate monitoring and mortality, while adjusting for potential confounders.

RESULTS

In 2004, 89% of singleton pregnancies had electronic fetal heart rate monitoring. Electronic fetal heart rate monitoring was associated with significantly lower infant mortality (adjusted relative risk, 0.75); this was mainly driven by the lower risk of early neonatal mortality (adjusted relative risk, 0.50). In low-risk pregnancies, electronic fetal heart rate monitoring was associated with decreased risk for Apgar scores <4 at 5 minutes (relative risk, 0.54); in high-risk pregnancies, with decreased risk of neonatal seizures (relative risk, 0.65).

CONCLUSION

In the United States, the use of electronic fetal heart rate monitoring was associated with a substantial decrease in early neonatal mortality and morbidity that lowered infant mortality.

Is the perinatal outcome of placental abruption modified by clinical presentation?

Objective. The purpose of this study was to elucidate the impact of the clinical presentation on perinatal outcome in placental abruption. Study Design. A retrospective study was performed in 97 placental abruptions. Placental abruptions were classified according to clinical presentation: pregnancy-induced hypertension (HT, n = 22), threatened premature labor and/or premature rupture of membranes (TPL/ROM, n = 35), clinically low risk (LR, n = 27), and others (n = 13). Perinatal outcomes were compared among the HT, TPL/ROM, and LR groups. Results. The HT had significantly higher incidence of IUGR, IFUD, and low fibrinogen. The TPL/ROM had less severe disease. However, the LR had significantly higher incidence of IUFD, low UA pH < 7.1, low Apgar score of <7 at 5 min, and low fibrinogen. Conclusion. Disease severity in placental abruption is likely to depend on the clinical presentation.

The impact of non-significant variable decelerations appearing in the latent phase on delivery mode: a prospective cohort study

BACKGROUND

Variable decelerations are the most frequent fetal heart rate changes that are related to labor. The objective of the study was to estimate the impact of non-significant variable decelerations (NSV) appearing during the latent phase of labor on delivery mode and neonatal outcome.

METHODS

Women at term, who were in the latent phase of labor and had a singleton pregnancy, were prospectively included. Women were divided into three groups. All had a fetal heart rate tracing with normal baseline and variability. The study group was composed of women who had in addition NSV, Category II, according to the National Institute of Child Health and Human Development categorization system. Women who had Category I tracings composed the control group. Women who had non-repetitive severe variables (SV) composed a second control group (Category II-SV). Main outcome compared was mode of delivery. Secondary outcome was cord pH. One-way analysis of variance was used to compare the continuous demographic and clinical variables of the three groups. Backwards stepwise logistic regression using significant univariables was performed to determine which predicted operative delivery. P < 0.05 was considered significant.

RESULTS

Of 1005 women who delivered during the study period 186 had Category II- NSV tracings (study group), 76 had Category II-SV and 251 had Category I tracings. Mode of delivery and indications for operative delivery were similar between women in Category II-NSV compared to Category I. In addition mean cord pH did not differ between the two groups. Conversely, women in Category II-SV, had a higher rate of cesarean or vacuum deliveries compared to the other groups (p = 0.0001). Beside, they had a significantly higher number of neonates born with cord pH between 7.0 to 7.1 (p = 0.03).

CONCLUSIONS

Non-significant variable decelerations in early stages of labor are probably a non-ominous sign for neonatal outcome and have no impact on delivery mode.

[Cerebral palsy and perinatal asphyxia (I--diagnosis)]

Cerebral palsy (CP) is a group of disorders of the development of movement and posture, causing activity limitations, that are attributed to nonprogressing disturbances that occurred in the developing fetal or infant brain. The motor abnormalies are often accompanied by disturbances of sensation, perception, cognition, behavior and/or by a seizure disorder. The prevalence of CP has not decreased in developed countries over the past 30 years, despite the widespread use of electronic fetal heart rate monitoring and a 5- to 6-fold increase in the cesarean delivery rate. In the term newborn, CP may be attributed to perinatal asphyxia in case of metabolic acidosis in the cord blood (pH<7,00 and base deficit>12 mmol/L), followed by a moderate or severe neonatal encephalopathy within 24 hours and a further neurological impairement characterized by spastic quadriplegia and dyskinesia/dystonia. Dating the time of fetal asphyxia during delivery is possible when there are acute catastrophic complications during labor and unexpected acute or progressive fetal heart rate anomalies after a normal admission test, when there is a need for intensive neonatal resuscitation, a multi-organ failure within 72 hours of birth and visualization of acute non focal cerebral abnormalities, mainly by early magnetic resonance imaging (MRI). MRI sequences show either a brain-damaged pattern of the central basal ganglia, thalami and posterior limbs of internal capsules with relative cortical sparing, in acute, near-total asphyxial insults manifested by a continuous bradycardia or a pattern of cortical injury in the watershed zones and relative sparing of the central grey matter, in prolonged partial asphyxia, manifested by late or atypical variable decelerations with progressive fetal tachycardia, loss of reactivity and absent fluctuation. Prolongation of either type of asphyxial insult results in more global brain damage. In order to differentiate a CP occurring after perinatal asphyxia from other neurological sequelae in relation with infection, hemorrhage, stroke, malformations, genetic or metabolic diseases, it is essential that a definitive information from the brain by MRI and an extensive histological examination of the placenta are at disposal.

Probing the fetal cardiac signal for antecedents of brain injury

Obstetric care providers and researchers have long relied on analysis of the fetal heart rate tracing for insight into the fetal neurologic status. Although a normal fetal heart rate tracing does provide reassurance of intact neurologic function, an abnormal pattern is a very poor predictor of newborn brain injury. Indeed, if the clinical end point of interest is cerebral palsy, a non-reassuring fetal heart rate tracing has a 99% false positive rate. More recent analyses of fetal heart rate variability and fetal ECG waveforms, however, hold promise for improved diagnostic accuracy.

The fetal heart rate response to hypoxia: insights from animal models

This article examines recent studies that have systematically dissected features of fetal heart rate responses to labor that may help identify developing fetal compromise, such as the slope of the deceleration, overshoot, and variability. Although repeated deep decelerations are never necessarily benign, fetuses with normal placental reserve can fully compensate even for frequent deep but brief decelerations for surprisingly prolonged intervals before developing profound acidosis and hypotension.

Development and significance of a fetal electrocardiogram recorded by signal-averaged high-amplification electrocardiography

Although ultrasonic diagnostic imaging and fetal heart monitors have undergone great technological improvements, the development and use of fetal electrocardiograms to evaluate fetal arrhythmias and autonomic nervous activity have not been fully established. We verified the clinical significance of the novel signal-averaged vector-projected high amplification ECG (SAVP-ECG) method in fetuses from 48 gravidas at 32-41 weeks of gestation and in 34 neonates. SAVP-ECGs from fetuses and newborns were recorded using a modified XYZ-leads system. Once noise and maternal QRS waves were removed, the P, QRS, and T wave intervals were measured from the signal-averaged fetal ECGs. We also compared fetal and neonatal heart rates (HRs), coefficients of variation of heart rate variability (CV) as a parasympathetic nervous activity, and the ratio of low to high frequency (LF/HF ratio) as a sympathetic nervous activity. The rate of detection of a fetal ECG by SAVP-ECG was 72.9%, and the fetal and neonatal QRS and QTc intervals were not significantly different. The neonatal CVs and LF/HF ratios were significantly increased compared with those in the fetus. In conclusion, we have developed a fetal ECG recording method using the SAVP-ECG system, which we used to evaluate autonomic nervous system development.

Intrapartum fetal heart rate patterns in infants (> or =34 weeks) with poor neurological outcome

BACKGROUND

Cases suggestive of non-acidemia related cerebral palsy (CP) are likely misdiagnosed as acidemia related CP because of the presence of nonreasuring fetal heart rate (FHR) patterns.

AIMS

Our purpose was to compare intrapartum FHR patterns between the cases of neurological damage and the cases without disability after severe metabolic acidemia and neonatal encephalopathy, and also to compare the FHR patterns between cases with CP due to asphyxia and cases with CP of other etiology in infants born after 34 weeks.

STUDY DESIGN

From 1998 to 2003, our peer review conferences determined 136 infants with high-risk factors for neurological impairment in the unselected 65,197 live births. High-risk infants were chosen according to our criteria. Among them 58 were eligible infants because they were born at > or =34 weeks of gestation and also had legible FHR traces.

OUTCOME MEASURES

Incidence of nonreassuring FHR patterns.

RESULTS

Fifteen infants were acidemia related and 43 were non-acidemia related high-risk infants. Ten of the 15 acidemia infants developed CP and all had shown bradycardia > or =13 min with a nadir <80 bpm. In the 43 non-acidemia infants, 35 had CP, mental retardation, epilepsy, or hearing loss and 74% (26/35) of them had shown nonreassuring FHR patterns. Incidence of severe bradycardia was significantly elevated in the acidemia related CP compared with acidotic infants without disability, and those with non-acidemia related CP.

CONCLUSIONS

Even in infants with non-acidemia related CNS impairments, who were born at > or =34 weeks of gestation, 74% had shown intrapartum nonreassuring FHR patterns.

Clinical importance of cytomegalovirus antigenemia for intrauterine cytomegalovirus infection

BACKGROUND

Little is known about the clinical importance of cytomegalovirus (CMV) antigenemia for intrauterine-CMV-infected newborns. The aims of the present study were to evaluate the diagnostic accuracy of CMV antigenemia during the neonatal period and its association with clinical manifestations.

METHODS

CMV antigenemia was analyzed using neonatal blood from 25 patients suspected of having intrauterine infection because of abnormal clinical manifestations in the mother, fetus, and newborn. Neonatal urine samples were collected for diagnosis of intrauterine infection. The diagnostic accuracy of the antigenemia analysis was evaluated by comparing it with the results of urinary CMV analyses. The clinical manifestations of antigenemia-positive and -negative infected newborns were compared in the infected newborns.

RESULTS

Fifteen newborns were congenitally infected and 10 were uninfected as diagnosed on virus isolation from neonatal urine. Six of 15 infected newborns were positive for CMV antigenemia. CMV antigenemia had a positive predictive value of 100%, a negative predictive value of 52.6%, a sensitivity of 40%, and a specificity of 100%. CMV retinitis and pneumonitis were more prevalent among antigenemia-positive newborns (4/6) than antigenemia-negative newborns (0/9; P < 0.05).

CONCLUSIONS

Antigenemia was significantly associated with retinitis and pneumonia, but it was not sensitive enough to diagnose intrauterine CMV infection.

Risk factors for perinatal deaths in Southern Japan: population-based analysis from 1998 to 2005

BACKGROUND

Some of the perinatal deaths are preventable.

AIMS

To examine with accuracy perinatal deaths and their clinically relevant conditions to further reduce perinatal mortality rates.

STUDY DESIGN

Population-based study.

SUBJECTS

356 perinatal deaths in Miyazaki Prefecture from 1998 to 2005.

OUTCOME MEASURES

Causes and clinically associated risk factors of perinatal deaths in infants with congenital abnormalities and those of the non-malformed infants.

METHODS

We performed a population-based study of 87,593 deliveries in Miyazaki from 1998 to 2005, where 356 perinatal deaths were reported. We also held peer-review audit conference twice a year to investigate causes and clinically associated risk factors of the perinatal deaths, where at least 7 obstetricians and 7 neonatologists congregated.

RESULTS

Our perinatal mortality rate was 4.1/1000. 99% of the neonatal deaths and 85% of the stillbirths were examined by the peer-review audit conferences to validate the accuracy of causes. Three fourths were non-malformed perinatal deaths, in which stillbirths represented twice the number of neonatal deaths. Prematurity is the major factor attributable to neonatal deaths. Half of stillbirths were unexplainable but associated with overt or subtle fetal growth restriction. Intrapartum asphyxia after 32 weeks of gestation resulted in 10% of perinatal deaths. The audit conferences concluded that 13% (28/222) of the non-malformed infants had a potential of avoiding death.

CONCLUSION

In the advanced region of perinatal medicine in Japan, we still have room to improve perinatal mortality. Most prevalent factors were fetal growth restriction, intrapartum asphyxia after 32 weeks of gestation, and sudden fetal deaths of undiagnosed diabetes near-term.

[Fetal heart rate during labour: definitions and interpretation]

Continuous fetal heart rate monitoring is widely used during labor even in low risk pregnancies. Consensus is necessary to define and interpret accurately the different FHR patterns. The normal FHR tracing include baseline rate between 110-160 beats per minute (bpm), moderate variability (6-25 bpm), presence of accelerations and no decelerations. Uterine activity is monitored simultaneously: contractions frequency, duration, amplitude and relaxation time must be also normal. Abnormal baseline heart rate during 10 minutes or more is termed tachycardia above 160 bpm (except for FIGO above 150) and bradycardia below 110 bpm. Variability is minimal below 6 bpm and absent when non visible. Decelerations are classified as early, variable, late, and prolonged. Early and late decelerations have an onset gradual decrease of FHR, in contrast variable decelerations have an abrupt onset. Early deceleration is coincident in timing with uterine contraction. Variable deceleration is variable in onset, duration and timing, and may be described as typical or non reassuring. Late deceleration is associated with uterine contraction; the onset, nadir, and recovery occur after onset, peak and end of the contraction. Prolonged deceleration is lasting more than two but less 10 minutes, with almost onset abrupt and no repetition. Electronic fetal monitoring is a method to detect risk of fetal asphyxia; analysis and interpretation of FHR patterns are difficult with a high false positive rate, increasing operative deliveries. The patterns who are predictive of severe fetal acidosis include recurrent late or variable or prolonged decelerations or bradycardia, with absent FHR variability, and sudden severe bradycardia. The other FHR patterns are not conclusive and defined as non reassuring; obstetrical risk factors must be considered and other method (like scalp sampling for pH) utilised to evaluate fetal state.

The intrapartum deceleration in center stage: a physiologic approach to the interpretation of fetal heart rate changes in labor

One of the most distinctive features of fetal heart rate recordings in labor is the deceleration. In clinical practice, there has been much confusion about the types of decelerations and their significance. In the present review, we examined uteroplacental perfusion in labor, describe the pathophysiologic condition of decelerations, and explain some of the reasons behind the confusion about the terminology. We summarize recent studies that systematically have dissected the features of variable decelerations that may help to identify developing fetal compromise, such as the slope of the deceleration, overshoot, and variability changes. Although no pattern of repeated deep decelerations is necessarily benign, fetuses with normal placental reserve can compensate fully, even for frequent deep but brief decelerations, for surprisingly prolonged intervals before the development of profound acidosis and hypotension. This tolerance reflects the remarkable ability of the fetus to adapt to repeated hypoxia. We propose that, rather than focus on descriptive labels, clinicians should be trained to understand the physiologic mechanisms of fetal heart rate decelerations and the patterns of fetal heart rate change that indicate progressive loss of fetal compensation.

Avoidable factors and causes of neonatal deaths from perinatal asphyxia-hypoxia in South Africa: national perinatal survey

BACKGROUND

Fetal or neonatal hypoxia owing to asphyxia can result in death or severe irreversible brain damage. To prevent this, factors contributing to the development of fetal or neonatal hypoxia must be identified.

AIMS

To determine the primary obstetric and neonatal causes or diagnoses and avoidable factors associated with death from asphyxia-hypoxia.

METHODS

Data from a computerised database from 142 hospitals using the Perinatal Problem Identification Program in South Africa from October 1999 to September 2003 were analysed. All records of deaths from asphyxia-hypoxia were retrieved and analysed. Primary obstetric and neonatal causes or diagnoses and factors associated with these deaths were identified. Each case identified as having died from asphyxia-hypoxia was analysed for possible and probable avoidable factors.

RESULTS

Among 4502 neonatal deaths weighing >999 g, 1459 (32.4%) were identified as being related to asphyxia-hypoxia. Intrapartum asphyxia was the most common diagnosis (72% of deaths). Hypoxic-ischaemic encephalopathy was identified as the main neonatal diagnosis in these deaths. The most common category of probable avoidable factors was health worker-related. Inadequate fetal monitoring was the most common health worker-related probable avoidable factor. Substandard care related to resuscitation was recorded infrequently, most likely because of inability to assess neonatal resuscitation.

CONCLUSIONS

Asphyxia-hypoxia is responsible for about one-third of neonatal deaths. Intrapartum asphyxia is the major primary obstetric cause of deaths from hypoxia. A third of the deaths were judged to be preventable.

Intrapartum cardiotocography -- the dilemma of interpretational variation

OBJECTIVE

To evaluate and compare interobserver variation in interpretation of intrapartum cardiotocograms.

SUBJECTS

Fifteen senior (experience >4 years) and 16 junior (experience < or =4 years) obstetricians from 10 delivery units.

DESIGN

Thirty-one obstetricians interpreted intrapartum cardiotocographic (CTG) readings from 22 parturients.

METHODS

Inter-observer agreement in CTG interpretation and decision-making was assessed via proportions of agreement (Pa), with 95% confidence intervals (CI).

MAIN OUTCOME MEASURES

The level of inter-observer agreement was analyzed by calculating Pa values for CTG baseline, variability, early, variable and late decelerations, uterine tonus, power of contractions, hypertonus and clinical decision.

RESULTS

In assessments of normal cases the Pa were acceptable or good (0.63-0.82) as regards all CTG interpretation elements except for the power of contractions (0.24), but in assessments of abnormal cases the Pa values were lower (0.18-0.60). As regards clinical decisions, a higher Pa was found in cases without recommendation for intervention (0.63, 95% CI 0.62-0.64) than in cases with such recommendation (0.55, 95% CI 0.54-0.56). The Pa in the abnormal cases was better among senior than among junior obstetricians.

CONCLUSIONS

Inter-observer variation in interpretation of abnormal CTG readings and recommendations for intervention is relatively wide. To improve reliability, uniform classification and standardized training in CTG interpretation are needed, as well as increased use of computerized CTG.

Intrapartum late deceleration develops more frequently in pre-eclamptic women with severe proteinuria

AIM

Our purpose was to investigate the effect of proteinuria associated with pre-eclampsia on intrapartum fetal heart rate patterns.

METHODS

A retrospective study was performed involving 79 pregnant women with pre-eclampsia and 19 pregnant women with gestational hypertension (GH). Pre-eclampsia was then classified into two groups according to the degree of proteinuria (> or = or < 3 + dipstick), which was classified as severe urinary protein (UP; n = 35) and mild UP (n = 44) at delivery. Intrapartum fetal heart rate (FHR) monitoring was classified as either no deceleration, moderate variable deceleration, severe variable deceleration (sVD), prolonged deceleration (PD), occasional deceleration or recurrent late deceleration (rLD). We evaluated the prevalence of non-reassuring FHR (sVD, PD or rLD), the prevalence of intrauterine growth restriction (IUGR), and cord blood gas status in the three groups. The prevalence of non-reassuring FHR and cord blood gas status of these three groups was also compared with their prevalence in 65 women with low-risk pregnancies. Multiple logistic regression analysis was performed to determine the association between rLD and maternal-fetal parameters.

RESULTS

Levels of systolic and diastolic blood pressure were similar among the three groups. Severe UP was diagnosed significantly earlier, was associated with significantly lower gestational age, and infants with lighter birth weight (P < 0.05) compared with GH and mild UP. The prevalence of IUGR in severe UP was higher than in GH (54%v. 21%, P < 0.05); however, no differences were found in the prevalence of IUGR between mild and severe UP (43%v. 54%, P = 0.33). The prevalence of non-reassuring FHR in GH was not statistically significant in the low-risk pregnancies (5%v. 9%, P = 0.58). In mild and severe UP, the non-reassuring FHRs were more predominant (30% and 43%, respectively) than in low-risk pregnancies and GH (P < 0.05). The rLD was more common in the group with severe UP and accounted for 40% of all FHR patterns. There was no difference in the incidence of low pH among the groups. However, fetuses in pregnancies involving severe UP were significantly hypoxemic when compared with others. Multiple logistic regression analysis showed that worsening proteinuria (odds ratio [OR], 5.5; 95% confidence interval [CI], 2.4-12.9) and IUGR (OR, 3.8; 95% CI, 1.2-11.5) increased the risk of rLD. Rates of preterm birth at less than 32 weeks (OR, 0.7; 95% CI, 0.2-2.5) and severe hypertension (OR, 0.5; 95% CI, 0.2-1.3) were not significant.

CONCLUSION

In pre-eclampsia, the presence of severe proteinuria is associated with an increased likelihood of rLD.

Practices and views on fetal heart monitoring: a structured observation and interview study

OBJECTIVE

To assess and explain deviations from recommended practice in National Institute for Clinical Excellence (NICE) guidelines in relation to fetal heart monitoring.

DESIGN

Qualitative study.

SETTING

Large teaching hospital in the UK.

SAMPLE

Sixty-six hours of observation of 25 labours and interviews with 20 midwives of varying grades.

METHODS

Structured observations of labour and semistructured interviews with midwives. Interviews were undertaken using a prompt guide, audiotaped, and transcribed verbatim. Analysis was based on the constant comparative method, assisted by QSR N5 software.

MAIN OUTCOME MEASURES

Deviations from recommended practice in relation to fetal monitoring and insights into why these occur.

RESULTS

All babies involved in the study were safely delivered, but 243 deviations from recommended practice in relation to NICE guidelines on fetal monitoring were identified, with the majority (80%) of these occurring in relation to documentation. Other deviations from recommended practice included indications for use of electronic fetal heart monitoring and conduct of fetal heart monitoring. There is evidence of difficulties with availability and maintenance of equipment, and some deficits in staff knowledge and skill. Differing orientations towards fetal monitoring were reported by midwives, which were likely to have impacts on practice. The initiation, management, and interpretation of fetal heart monitoring is complex and distributed across time, space, and professional boundaries, and practices in relation to fetal heart monitoring need to be understood within an organisational and social context.

CONCLUSION

Some deviations from best practice guidelines may be rectified through straightforward interventions including improved systems for managing equipment and training. Other deviations from recommended practice need to be understood as the outcomes of complex processes that are likely to defy easy resolution.

Toward quantitative fetal heart rate monitoring

Continuous electronic fetal heart rate (FHR) monitoring during labor is motivated by the clinical experience that fetal distress causes loss of FHR variation and the occurrence of decelerations late during uterine contraction. This practice is of uncertain clinical benefit, perhaps because the interpretation is qualitative. We have developed new quantitative measures and analyzed cardiotocograph records from 148 consecutive patients, 44 of whom had at least one "nonreassuring" epoch. In multivariate regression models, measures of deceleration and variability were significantly associated with the obstetrician's diagnosis (receiver operating characteristic area 0.84, p < 0.05). This approach may be useful clinically.

Assessment of the Fetus: Intermittent Auscultation, Electronic Fetal Heart Rate Tracing, and Fetal Pulse Oximetry

Intrapartum assessment of fetal well-being has evolved over the last 40 years, with the primary focus being fetal heart rate assessments. Despite widespread use and initial enthusiasm for the potential for heart rate monitoring to reduce fetal and neonatal mortality and morbidity, conclusive evidence of improvement in long-term outcomes is lacking. Its use is associated with an increase in operative obstetric interventions and may increase morbidity associated with such interventions. Current investigation includes fetal pulse oximetry and further analysis of specific fetal electrocardiographic changes associated with hypoxic stress. Currently it is likely that fetal heart rate monitoring will maintain its role as a common intervention in obstetric units.