Fetal Heart Rate Decelerations Research Articles

Holy consent – a dilemma for medical staff when maternal consent is withheld for emergency caesarean section

A parturient (grand multipara) developed arrested labour complicated by severe fetal heart rate decelerations. Senior physicians explained the need for a caesarean section, but she chose to deliver vaginally since rabbinical blessing could not be obtained. Forcing the mother to have a cesarean section without consent is considered "civil battery." The dilemma faced by medical staff and the implications of her refusal for the treating medical staff are described.

Catastrophe Theory Model for Decelerations of Fetal Heart Rate

Background: Decelerations of fetal heart rate (FHR) are the results of many pathophysiological factors that modulate the intrinsic rate of the heart. FHR change is a complex phenomenon and can be viewed as a type of nonlinear dynamic system. This paper presents a qualitative model of FHR decelerations based on catastrophe theory, especially to account for abrupt heart rate changes seen in variable decelerations. Methods: One of the elementary catastrophes, the cusp catastrophe, was used to model FHR changes seen in variable, late, and early decelerations. Results: Catastrophe theory describes typical variable decelerations as an abrupt response to a slowly changing force of attack (uterine contraction) and physiological defense. Because of its three-dimensionality and topological features, the cusp catastrophe model provides a qualitatively satisfying description of FHR decelerations. Conclusion: The organized complexity of living systems offers the best hope for the application of catastrophe theory. The nature of the elementary catastrophes will be essential knowledge in the mathematical analysis of biology.

Amnioinfusion for the Prevention of the Meconium Aspiration Syndrome

Meconium-stained amniotic fluid is reported in up to 22% of term deliveries, and varying proportions of infants delivered through meconium-stained fluid develop meconium aspiration syndrome, a condition with reported casefatality rates ranging from 5% to 40%. Randomized trials suggest that amnioinfusion of saline is associated with a reduced risk of meconium aspiration syndrome and operative delivery. This international, randomized, controlled study enrolled 2003 women from 13 countries who had thick meconium staining of amniotic fluid during labor and a singleton fetus with a gestational age of 36 weeks or more. A total of 1998 women were randomly assigned to amnioinfusion or standard care after being stratified according to the presence or absence of variable fetal heart rate decelerations. Amnioinfusion was done by infusing 800 mL of sterile saline transcervically over 40 minutes and continuing until a maximum of 1500 mL was delivered. A total of 1975 women were available for analysis. The study groups were comparable sociodemographically and in baseline obstetric characteristics. More than 90% of women in both groups underwent continuous fetal heart rate monitoring. A composite primary outcome, including perinatal death, moderate or severe meconium aspiration syndrome, or both, occurred in 4.5% of infants in the amnioinfusion group and 3.5% of the control group, for a relative risk (RR) of 1.26 (95% confidence interval [CI], 0.82-1.95). The respective rates of moderate or severe meconium aspiration syndrome were 4.4% and 3.1 %, yielding a RR of 1.39 (95% CI, 0.88-2.19). There were 5 perinatal deaths in each group (0.5%). Mild respiratory distress occurred in approximately 3% of each group. Stratified analysis showed no significant effect of amnioinfusion on the frequency of the primary outcome whether or not fetal heart decelerations were present. Rates of oropharyngeal suctioning, laryngoscopy, and intubation in the delivery room were comparable, as were the proportions of infants having meconium below the vocal cords. Fetal heart rate monitoring demonstrated abnormalities that justified clinical intervention in 14.1% of the amnioinfusion group and 13.9% of the control group (RR, 1.02; 95% CI, 0.79-1.30). No significant group differences were found in rates of cesarean delivery, maternal fever in the peripartum period, maternal death, or serious morbidity. Amnioinfusion for thick meconium staining of amniotic fluid did not lower the risk of perinatal death, moderate or severe meconium aspiration syndrome, or other serious neonatal disorders in this study, and it should not be recommended for this indication when standard peripartum surveillance is assured.

Predicting Prolonged Fetal Heart Rate Deceleration following Intrathecal Fentanyl/Bupivacaine

Predicting Prolonged Fetal Heart Rate Deceleration following Intrathecal Fentanyl/Bupivacaine

Massive Pulmonary Embolism in Pregnancy Treated With Catheter Fragmentation and Local Thrombolysis

Catheter-directed thromboembolus fragmentation and thrombolysis is used with success for treatment of pulmonary embolism with hemodynamic decompensation in nonpregnant patients, but information on its use during pregnancy is limited. We report successful treatment of massive bilateral pulmonary emboli in the third trimester of pregnancy. A 29-year-old multigravida at 30 weeks of gestation presented with dyspnea, chest pain, heart palpitations, and syncope. A computed tomographic angiogram demonstrated massive bilateral central pulmonary emboli. Despite heparin and oxygen therapy, aggressive fluid resuscitation and pressor treatment, hypotension persisted, and there were prolonged, deep fetal heart rate decelerations. Emergency percutaneous pulmonary artery catheter thrombus fragmentation, followed by local infusion of tissue plasminogen activator, was performed. The patient recovered rapidly and was discharged from the hospital on subcutaneous low-molecular-weight heparin. She was delivered of a normal, healthy infant at term. Catheter-directed mechanical fragmentation and local thrombolytic infusion therapy is a treatment option for pulmonary embolism with hemodynamic decompensation in pregnancy. Advantages are rapid clot lysis with consequent return of normal hemodynamics and uterine perfusion and avoidance of systemic thrombolytics and associated risk of bleeding complications.

Amnioinfusion for the Prevention of the Meconium Aspiration Syndrome

It is uncertain whether amnioinfusion (infusion of saline into the amniotic cavity) in women who have thick meconium staining of the amniotic fluid reduces the risk of perinatal death, moderate or severe meconium aspiration syndrome, or both. We performed a multicenter trial in which 1998 pregnant women in labor at 36 or more weeks of gestation who had thick meconium staining of the amniotic fluid were stratified according to the presence or absence of variable decelerations in fetal heart rate and then randomly assigned to amnioinfusion or to standard care. The composite primary outcome measure was perinatal death, moderate or severe meconium aspiration syndrome, or both. Perinatal death, moderate or severe meconium aspiration syndrome, or both occurred in 44 infants (4.5 percent) of women in the amnioinfusion group and 35 infants (3.5 percent) of women in the control group (relative risk, 1.26; 95 percent confidence interval, 0.82 to 1.95). Five perinatal deaths occurred in the amnioinfusion group and five in the control group. The rate of cesarean delivery was 31.8 percent in the amnioinfusion group and 29.0 percent in the control group (relative risk, 1.10; 95 percent confidence interval, 0.96 to 1.25). For women in labor who have thick meconium staining of the amniotic fluid, amnioinfusion did not reduce the risk of moderate or severe meconium aspiration syndrome, perinatal death, or other major maternal or neonatal disorders.

Telemetric antenatal fetal monitoring.

Extracted from text ... September 2005, Vol. 11, No. 3 71 SAJOG The origin of antenatal fetal heart rate monitoring (AFM) appears lost in the mists of time. Odendaal, 1 in his signal thesis on cardiotocography, mentions that Legumeau de Kegadarek had first observed the occurrence of fetal heart rate decelerations in 1822, after which Von Winckel, in 1893, observed that bradycardia may be associated with poor fetal outcome. Electronic AFM has remained an integral part of obstetric practice since the early 1970s, when continuous monitoring became established and the true significance of decelerations was appreciated. Developing communities often have inordinately high perinatal mortality ..

Antepartum rupture of the intertwin‐dividing membrane in monochorionic diamniotic twins: a case report and review of the literature

We report a case of monochorionic diamniotic twin gestation confirmed by ultrasound visualization of the thin intertwin-dividing membrane at 32 weeks' gestation. Ultrasound at 36 weeks failed to demonstrate the thin dividing membrane. The pregnancy ended a few days later with spontaneous vaginal delivery of the first twin. The second twin was in transverse lie with no membranes that could be felt around. Severe fetal heart rate deceleration developed, prompting delivery by emergency caesarean section. Cord entanglement was noted at the time of delivery, which resulted in severe perinatal morbidity of the second twin. The antepartum rupture of the dividing membrane must have happened some time between 32 and 36 weeks. The etiology for this intrauterine disruption is unknown. A review of the literature about the antepartum rupture of the intertwin-dividing membrane is described, along with its possible causes and complications. In addition, we discuss possible causes of incorrect amnionicity determination, and thus how to minimize these pitfalls. We conclude that antepartum disruption of the intertwin-dividing membrane is more common than previously thought. Moreover, prenatal ultrasonographic visualization of a dividing membrane in a diamniotic twin pregnancy does not rule out future change in this environment to a monoamniotic one, with all its perinatal morbidity and mortality complications, which result mainly from cord entanglement. This suggests a modification in the method and frequency of the prenatal fetal well-being follow-up, as well as the time and mode of delivery.

Maternal Complex Partial Seizure Associated With Fetal Distress

We describe a 43-year-old woman who had a complex partial seizure in the seventh month of pregnancy with simultaneous fetal heart rate monitoring. The seizure was accompanied by fetal heart rate decelerations, indicating fetal distress. Maternal partial seizures can be associated with fetal distress.

Maternal Position During Non-stress Test and Fetal Heart Rate Patterns

Monitoring of pregnant women before delivery routinely includes the nonstress test (NST), which often is used in early pregnancy. The investigators sought to determine whether maternal position during the NST at different stages of pregnancy influences fetal heart rate (FHR) patterns. The 368 women included in the study, who had a total of 1055 NSTs, each lasting 30 minutes, were in a reclining or sitting position or walked during the NST. Telemetry was used to record the test in those who walked. Parameters considered were minutes of reactive NST with minimum length, number of fetal movements, baseline FHR, number of large accelerations, number of dubious NST, and number of variable decelerations. The reclining position did not substantially influence the duration of NST, but in the sitting position or during walking, the time needed to record three large accelerations of a reactive tracing decreased significantly as pregnancy progressed. Mothers perceived more fetal movements when reclining. Baseline FHR did not vary significantly with maternal position but declined as pregnancy progressed. Gestational age and maternal position did not significantly influence the number of large accelerations. Dubious NST results became less frequent in all groups as pregnancy continued. The highest rates, observed before 37 weeks gestation, were 7.6% while walking, 6.1% while reclining, and 5% while sitting. After 39 weeks, variable decelerations of FHR were most numerous in the reclining position followed by the sitting position and least numerous while walking. These observations suggest that two factors influence the NST: gestational age and maternal position during the test. Testing in the sitting position or during walking should be encouraged because FHR reactivity is observed most rapidly under these circumstances.

Ultrasound Detection of Nuchal Cord Prior to Labor Induction and the Risk of Cesarean Section

The term for an umbilical cord that passes around the fetal neck is nuchal cord. Reported prevalence rates at delivery range from 6% to 37%. Up to half of nuchal cords resolve before delivery. Although the diagnosis is not routinely made before delivery, it may be suspected if there are variable fetal heart rate decelerations on cardiotocography during labor. This study evaluated transabdominal ultrasonography for detecting a nuchal cord just before induction of labor. Another goal was to learn whether a nuchal cord during labor predicts an increased need for cesarean delivery. Scans using gray-scale and color Doppler imaging were done in a prospective series of 289 women having labor induced after 36 weeks gestation. Transverse and sagittal views of the neck were obtained, and nuchal cord was diagnosed if the cord lay around at least three of the four sides of the neck. Postmaturity was by far the most common reason for inducing labor in this series. A nuchal cord was found in 18% of deliveries. Most often there was a single loop of cord. More than one loop of cord lay along the neck in 10 of 52 deliveries in which nuchal cord had been diagnosed. Ultrasonography was 60% sensitive with more than one loop present but only 37% sensitive with a single loop; the difference, however, was not statistically significant. Nuchal cord could not be related to reduced fetal movement before induction, parity, an occipitoposterior position, or a reduced amniotic fluid index. No significant increase in cesarean deliveries was associated with nuchal cord, and the condition did not predict low Apgar sores, admission to a neonatal intensive care unit, or the cord arterial pH. Neither of the two neonatal deaths was associated with nuchal cord. In this series, the presence of a nuchal cord did not increase the risk of cesarean delivery and did not compromise the neonatal outcome. Ultrasonography does not reliably detect nuchal cord before induction of labor, limiting its value in high-risk pregnancies.

Fetal acidosis and hypotension during repeated umbilical cord occlusions are associated with enhanced chemoreflex responses in near-term fetal sheep

This study examined the hypothesis that repeated episodes of brief but severe hypoxia would not attenuate the chemoreflex-mediated rapid initial fall in fetal heart rate (FHR) and, further, that greater hypoxic stress, as shown by hypotension and metabolic acidosis, would be associated with an enhanced chemoreflex response. Chronically instrumented, near-term fetal sheep received 1 min total umbilical cord occlusion either every 5 min for 4 h (1:5 group; n = 8) or every 2.5 min (1:2.5 group; n = 8) until mean arterial blood pressure fell to <20 mmHg on two successive occlusions. Umbilical cord occlusion caused variable decelerations, with sustained hypertension in the 1:5 group and little change in acid-base status (pH 7.34 +/- 0.03 after 4 h). In contrast, the 1:2.5 group showed progressive hypotension and metabolic acidemia (pH 6.92 +/- 0.04 after the last occlusion). The 1:2.5 group showed a significant increase in the rate of initial fall in FHR during the occlusion series, which was greater than the 1:5 group in the last 30 min of the occlusion series (9.4 +/- 1.4 vs. 3.5 +/- 0.3 beats.min(-1).s(-1); P < 0.01), with a greater fall in FHR (71.9 +/- 6.5 vs. 47.0 +/- 8.7 beats/min; P < 0.05). In summary, this study demonstrated that repetitive laborlike cord occlusions, which led to severe fetal compromise, were associated with an increase in the slope and magnitude of the initial FHR deceleration. These findings support the concept of the chemoreflex as a central, robust component of fetal adaptation to severe hypoxia.

Predicting prolonged fetal heart rate deceleration following intrathecal fentanyl/bupivacaine

Intrathecal opioids for labor analgesia are occasionally associated with fetal heart rate abnormalities. We wanted to identify risk factors for this occurrence. The fetal tracings of 151 consecutive patients were reviewed for the period including 30 min before and 60 min after combined spinal-epidural analgesia using intrathecal bupivacaine with fentanyl. Their progress of labor at injection was also recorded. Lack of fetal head engagement (odds ratio 5.5, 95% CI 2.1-14.2) and the presence of variable fetal heart rate decelerations (odds ratio 3.6, 95% CI 1.6-8.4) were associated with prolonged fetal heart rate deceleration after combined spinal-epidural analgesia. This case-control study suggests that if the fetal head is not engaged or if the fetus is experiencing variable decelerations, there is an increased risk of prolonged fetal heart rate deceleration following intrathecal fentanyl/bupivacaine. This finding must now be confirmed in a cohort study.

Association of Nonreassuring Fetal Heart Rate Patterns and Subsequent Cerebral Palsy in Pregnancies with Intrauterine Bacterial Infection

We evaluated an association of nonreassuring fetal heart rate (FHR) patterns and subsequent cerebral palsy (CP) in pregnancies with intrauterine bacterial infection. Among 10,030 infants born during 1995 to 2000, 139 were complicated with acute intrauterine bacterial infection in labor. The FHR patterns 2 hours immediately before delivery were interpreted according to the guidelines of the National Institute of Child Health and Human Development. The correlations between the FHR patterns and umbilical blood gases, as well as FHR patterns and CP were studied. Statistics included unpaired t test, contingency table with chi (2) and Fisher test, and one-way analysis of variance with Bonferroni/Dunn test. Fifteen infants (11%) developed CP at 2 years or older. Nonreassuring FHR patterns including recurrent late deceleration, severe variable deceleration, and prolonged deceleration occurred in 24% of pregnancies with intrauterine infection. Incidence of CP was not different according to the FHR deceleration patterns or umbilical pH values. Multiple logistic regression analysis revealed that fetal tachycardia (OR, 11; 95% CI, 1.8 to 67) and lower gestational age (< 34 weeks; OR, 9.4; 95% CI, 0.96 to 93) was associated with CP in intrauterine infection. Nonreassuring FHR patterns were increased in intrauterine infection. CP occurred more frequently and was associated with tachycardia and lower gestational age, but not with FHR deceleration patterns or acidemia, suggesting different pathophysiology from acute hypoxia-ischemia.

Systematic Review of the Risk of Uterine Rupture with the Use of Amnioinfusion After Previous Cesarean Delivery

Amnioinfusion is commonly used for the intrapartum treatment of women with pregnancy complicated by thick meconium or oligohydramnios with deep variable fetal heart rate decelerations. Its benefit in women with previous cesarean deliveries is less known. Theoretically, rapid increases in intrauterine volume would lead to a higher risk of uterine rupture. Searches of the Cochrane Library from inception to the third quarter of 2001 and MEDLINE, 1966 to November 2001, were performed by using keywords "cesarean" and "amnioinfusion." Search terms were expanded to maximize results. All languages were included. Review articles, editorials, and data previously published in other sites were not analyzed. Four studies were retrieved having unduplicated data describing amnioinfusion in women who were attempting a trial of labor after previous cesarean section. As the studies were of disparate types, meta-analysis was not possible. The use of amnioinfusion in women with previous cesarean delivery who are undergoing a trial of labor may be a safe procedure, but confirmatory large, controlled prospective studies are needed before definitive recommendations can be made.

Index of suspicion in the nursery

A 2,216-g baby boy is born at 37 weeks’ gestation to a 34-year-old gravida 2, para 1 female. The pregnancy was uncomplicated until the day prior to delivery, when a biophysical profile score of 4/8 was obtained on assessment. Fetal heart rate decelerations to 80 beats/min and multiple late decelerations were noted the evening of delivery, and an emergent cesarean section is planned. The male infant is delivered precipitously prior to entering the operating room. Placental abruption is evident after delivery. At birth, the baby is limp but has spontaneous respirations, with a respiratory rate of 60 breaths/min. Mild intercostal retractions are evident. Femoral pulses are weak, but the heart rate is detected at 130 beats/min. On auscultation, heart sounds are not audible. Apgar scores are 7, 7, and 8 at 1, 5, and 10 minutes, respectively. Shortly after initial assessment, continuous positive airway pressure (CPAP) is applied at 4 to 5 cm H2O, and the baby is transported to the neonatal intensive care unit where the blood pressure is 44/16 mm Hg (mean, 27 mm Hg) and the oxygen saturation is 98% (with CPAP). Color and tone are poor, and the baby subsequently receives bag-and-mask ventilation and a bolus of 10 mL/kg normal saline via a peripheral intravenous …

The umbilical coiling index, a review of the literature

Our aim was to review the literature on umbilical cord coiling. Relevant articles in English published between 1966 and 2003 were retrieved by a Medline search and cross-referencing. The normal umbilical cord coiling index (UCI) is 0.17 (?± 0.009) spirals completed per cm. Abnormal cord coiling, i.e. UCI <?10th centile (?<?0.07) or >?90th centile (?>?0.30) is associated with adverse pregnancy outcome. Hypocoiling of the cord is associated with increased incidence of fetal demise, intrapartum fetal heart rate decelerations, operative delivery for fetal distress, anatomic-karyotypic abnormalities and chorio-amnionitis. Hypercoiling of the cord is associated with increased incidence of fetal growth restriction, intrapartum fetal heart rate decelerations, vascular thrombosis and cord stenosis. It is not clear whether abnormal coiling is actually a cause of pathology, or merely one of the sequelae, or both. We discuss the theories involving the cause of cord coiling, and the consequences of the degree of cord coiling on blood flow through the umbilical vessels. In the future ultrasonographic evaluation of the umbilical cord and the UCI may become an integral part of fetal assessment in high-risk pregnancies.

The umbilical coiling index, a review of the literature

Our aim was to review the literature on umbilical cord coiling. Relevant articles in English published between 1966 and 2003 were retrieved by a Medline search and cross-referencing. The normal umbilical cord coiling index (UCI) is 0.17 (+/- 0.009) spirals completed per cm. Abnormal cord coiling, i.e. UCI <10th centile (<0.07) or >90th centile (>0.30) is associated with adverse pregnancy outcome. Hypocoiling of the cord is associated with increased incidence of fetal demise, intrapartum fetal heart rate decelerations, operative delivery for fetal distress, anatomic-karyotypic abnormalities and chorio-amnionitis. Hypercoiling of the cord is associated with increased incidence of fetal growth restriction, intrapartum fetal heart rate decelerations, vascular thrombosis and cord stenosis. It is not clear whether abnormal coiling is actually a cause of pathology, or merely one of the sequelae, or both. We discuss the theories involving the cause of cord coiling, and the consequences of the degree of cord coiling on blood flow through the umbilical vessels. In the future ultrasonographic evaluation of the umbilical cord and the UCI may become an integral part of fetal assessment in high-risk pregnancies.

Predictive Value of Late Decelerations for Fetal Acidemia in Unselective Low-Risk Pregnancies

We evaluated the clinical significance of late decelerations (LD) of intrapartum fetal heart rate (FHR) monitoring to detect low pH (< 7.1) in low-risk pregnancies. We selected two secondary and two tertiary-level institutions where 10,030 women delivered. Among them, 5522 were low-risk pregnancies. The last 2 hours of FHR patterns before delivery were interpreted according to the guidelines of the National Institute of Child Health and Human Development. The correlation between the incidence of LD (occasional, < 50%; recurrent, > or = 50%) and severity (reduced baseline FHR accelerations and variability) of LD, and low pH (< 7.1) were evaluated. Statistical analyses included a contingency table with chi2 and the Fisher test, and one-way analysis of variance with the Bonferroni/Dunn test. In the 5522 low-risk pregnancies, 301 showed occasional LD and 99 showed recurrent LD. Blood gases and pH values deteriorated as the incidence of LD increased and as baseline accelerations or variability was decreased. Positive predictive value for low pH (< 7.1) was exponentially elevated from 0% at no deceleration, 1% in occasional LD, and > 50% in recurrent LD with no baseline FHR accelerations and reduced variability. In low-risk pregnancies, information on LD combined with acceleration and baseline variability enables us to predict the potential incidence of fetal acidemia.

An international randomized controlled trial of amnioinfusion for thickly meconium stained amniotic fluid

To determine if amnioinfusion (AI) for thickly meconium stained amniotic fluid reduces (1) perinatal death and/or moderate to severe meconium aspiration syndrome (primary outcome measure), (2) cesarean section, (3) other indicators of serious neonatal and maternal morbidity. In 56 centres in 13 countries, 1998 laboring women at ≥36 weeks gestation with thickly meconium stained liquor were stratified according to the presence or absence of variable fetal heart rate decelerations and randomized either to standard care or to AI, consisting of a transcervical bolus of 800 mL saline over 40 minutes, followed by infusion of 2 mL/minute to a maximum of 1500 mL. The composite primary outcome measure included perinatal death and/or severe or moderate meconium aspiration syndrome (MAS) based on clinical respiratory distress (severe: requiring mechanical ventilation; moderate: requiring oxygen supplementation at a FiO2 ≥ 40% or of ≥48 hours duration) as blindly adjudicated by a group of 3 neonatologists. Perinatal death and/or moderate or severe MAS occurred in 44 (4.5%) babies in the amnioinfusion group and 34 (3.4%) babies in the control group (RR = 1.3, 95% CI = 0.8-2.0). There was a trend toward more frequent cesarean delivery in the AI group (32% vs 29%; RR = 1.1; 95% CI 1.0-1.3). The distribution of other indicators of severe neonatal morbidity including arterial cord pH < 7.05 and severe maternal morbidity were similar in the two treatment groups. We found no evidence of heterogeneity of treatment effect, either across stratum as defined above, or across centres. For women in labor with thickly meconium stained amniotic fluid, amnioinfusion does not reduce the risk of meconium aspiration syndrome, cesarean delivery, or other major indicators of maternal or neonatal morbidity.