Abnormal fetal heart rate associated with congenital abnormalities

Non-reassuring foetal status and neonatal irritability in the Japan Environment and Children's Study: A cohort study

The aim of this study was to investigate whether non-reassuring foetal status (NRFS) affected an infant's temperament, or if the temperament formed prenatally resulted in an excessive heart rate reaction that was diagnosed as NRFS. We examined the correlation between NRFS and difficulty in holding a baby, and the amount of crying in the one month after birth, which was considered an indicator of the newborn's temperament. We divided the cases with NRFS into positive NRFS and false positive NRFS. NRFS was associated with bad mood, frequent crying for a long duration, and intense crying. After adjustment for other covariates, NRFS was associated with bad mood (odds ratio, OR = 1.15, 95% confidence interval, CI = 1.00-1.33), and intense crying (1.12, 1.02-1.24). In the multi-variable model, positive and false positive NRFS were not clearly associated with neonatal irritability. When stratified by parity, NRFS and false positive NRFS were likely to be positively associated with neonatal irritability in parous women. The clear association between NRFS and intense crying was observed in parous women (multi-variable adjusted OR = 1.46, 95% CI = 1.16-1.83), but not in nulliparae (1.01, 0.91-1.12) (p for effect modification <0.01). Similarly, increased odds of intense crying associated with false positive NRFS were only found in parous women (multi-variable adjusted OR = 1.40, 95% CI = 1.09-1.81) (p for effect modification = 0.03). There was no association observed between positive NRFS and irritability; therefore, NRFS has no effect on an infant's temperament.

Association between exposure to air pollution during pregnancy and false positives in fetal heart rate monitoring

Fetal heart rate (FHR) monitoring is essential for fetal management during pregnancy and delivery but results in many false-positive diagnoses. Air pollution affects the uterine environment; thus, air pollution may change FHR reactivity. This study assessed the association between exposure to air pollution during pregnancy and FHR monitoring abnormalities using 2005-2010 data from the Japan Perinatal Registry Network database. Participants were 23,782 singleton pregnant women with FHR monitoring, without acidemia or fetal asphyxia. We assessed exposure to air pollutants, including particulate matter (PM), ozone, nitrogen dioxide (NO2), and sulfur dioxide (SO2). In a multi-trimester model, first-trimester PM exposure was associated with false positives in FHR monitoring (odds ratio [OR] per interquartile range (10.7 μg/m3) increase = 1.20; 95% CI: 1.05-1.37), but not second-trimester exposure (OR = 1.05; 95% CI: 0.91-1.21) and third-trimester exposure (OR = 1.06; 95% CI: 0.96-1.17). The association with first-trimester PM exposure persisted after adjustment for exposure to ozone, NO2, and SO2; however, ozone, NO2, and SO2 exposure was not associated with false positives in FHR monitoring. First-trimester PM exposure may alter fetal cardiac response and lead to false positives in FHR monitoring.

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.

Nonstress testing and contraction stress testing

Antepartum fetal heart rate (FHR) testing, including the nonstress test and contraction stress test, has evolved in clinical usage over the past 3 decades. Although the nonstress test has become a standard of care in high-risk pregnancy, it has been modified by the use of fetal stimulation (vibroacoustic stimulation) and the addition of automated fetal movement recording (actocardiotocography). In all of its formats, antepartum FHR testing has been associated with reduction of preventable fetal loss. More recently, there have been attempts to improve test efficacy by computer-enhanced approaches.

Perinatal asphyxia: assessing its causal role and timing

Perinatal asphyxia, whether prenatal, intrapartum, or neonatal is thought to be a significant contributor to newborn morbidity and mortality as well as long-term neurological deficits. Development of an intrapartum tool/test that can reliably identify and discriminate between varying degrees of fetal acidemia and suggest whether it is respiratory or metabolic in nature would be highly desirable. This article critically reviews the available experience with the currently available monitoring techniques and the significance of abnormalities of fetal and intrapartum measurements with respect to the predictive value of the observations available to the clinician.

Communicating the significance of the fetal heart rate record to the user

Fetal heart rate (FHR) records should be presented as measurements derived from numerical analysis. Such analysis requires computerized systems. The Oxford system is the longest established and most tested of the systems available. It could provide the basis for a standardized approach to the numerical analysis of antepartum FHR records. Intrapartum FHR monitoring is of uncertain clinical value. It is premature to recommend standards for numerical analysis to upgrade the present methods of data presentation during labour. Once the patterns of abnormality are better defined numerically such standards will be mandatory because intrapartum FHR records cannot be interpreted reliably by eye.

Biophysical fetal assessment--the Rotunda experience

The evaluation of fetal health using ultrasound to establish a biophysical profile in the Rotunda Hospital in 1987 is reported. The corrected perinatal mortality rate fell from 10.0 in 1986 to 6.9 per 1,000 for babies over 500g and from 5.9 in 1986 to 3.4 for babies over 1,000g. This was achieved without significant alteration in induction and caesarean section rates. The results indicate that this type of fetal assessment does lead to a reduction in perinatal mortality.

Does fetal heart rate predict subsequent heart rate in childhood?

An investigation to determine whether there is any relationship between extremes of fetal heart rate during labour and subsequent heart rate at the age of 10 was carried out using data from the 1970 cohort of British Births. In 11,000 nationally representative children it was found that low fetal heart rate (below 120 beats/min) was associated with a heart rate at age 10 which was significantly lower than in those children whose fetal heart rate had remained between 120 and 160 beats/min (P less than 0.01). This relationship could not be explained by fetal asphyxiation, maternal antenatal hypotension or the method of pain relief during labour. There was no equivalent relationship with high fetal heart rate during labour. This could imply that some fetuses with low heart rates are not exhibiting fetal distress but have an inherent tendency to relatively slow heart rates.

Antepartum cardiotocography

Antepartum cardiotocography remains a valuable adjunct in the management of the high-risk gravida. Twice weekly use of NST coupled with real-time ultrasound assessment of amniotic fluid volume appear reasonable approaches to testing. More controversial is the use of testing in all pregnancies. Clearly, if one could reduce the perinatal mortality to 1-2/1000, such universal application of testing could be justified. However, more pragmatic concerns, such as personnel and cost constraints have all but prohibited the adoption of this policy. Secondly, in an attempt to improve the predictive reliability of antenatal testing additional evaluation of patients demonstrating diminished AFV or variable decelerations should be considered. More frequent testing or consideration for delivery are reasonable management plans. Finally, the use of acoustic stimulation to reduce the frequency of persistently non-reactive NSTs offers considerable promise. Investigations in this and other techniques of surveillance are ongoing. The best single method remains to be discovered, but utilization of current techniques offers the obstetrician a reliable technique by which to assess fetal well-being.

Antepartum fetal risk assessment: the role of the fetal biophysical profile score

In the art of medicine we have always known that establishing an accurate diagnosis of health or disease is essential. An active search for the physical signs, both the time honoured and newly discovered, are a crucial step in achieving diagnostic accuracy, in monitoring disease progression, and in assigning prognosis. In extrauterine medicine it is common practice to gather together sets of biophysical data in order to determine immediate health, to monitor condition, and to estimate prognosis: witness the use of vital signs, and, in the newborn, the Apgar score. The providers of perinatal care have known since biblical days that fetal biophysical activities were a reflection of fetal condition (Luke: Chapter 1, Verses 44-45), yet lacked the ability to categorize these activities in an objective and complete manner. The introduction of dynamic ultrasound imaging methods to perinatal medicine at last create the window through which the principles of extrauterine medicine may now be applied to the intrauterine patient--the fetus. Fetal biophysical profile scoring is a method that utilizes this new wealth of information to differentiate the normal fetus from the fetus at risk for death or damage in utero. The method is based on the concept that the discrimination of fetal health and disease improves as more variables are considered. The now extensive clinical experience with the method, in which both overall (gross) and selected (corrected) perinatal death are reduced, while maintaining a remarkably low false negative predictive error, indicate the validity of the concept. Comparative studies lead us to believe that reliance upon single biophysical variables, such as fetal movement counts, or antepartum fetal heart rate monitoring, is no longer of sufficient accuracy to support its use as a sole measure of fetal condition. Looking forward, we anticipate that while the concept on which fetal biophysical profile scoring is based will remain unchanged, inclusion of additional variables is likely to occur. It seems likely that addition of new variables, as may be now measured using high-resolution dynamic ultrasound methods, both B-mode and Doppler, will improve diagnostic accuracy even more. We believe that the application of the current and future modified methods of composite fetal risk assessment will render the occurrence of the tragedy of perinatal loss even more infrequent. While the goal of complete elimination of perinatal deaths remain elusive, this method may be one step towards this goal.

Abnormal antepartum cardiotocography and major fetal abnormalities

A 10-year experience of antepartum cardiotocography (8,463 pregnancies) was reviewed to examine the associations with major fetal malformations (278 cases or 3.3%). Patients with critical fetal reserve cardiotocography had a 72% Caesarean section rate (91 of 126) and major fetal malformations were present in 19% (24 of 126) of their infants. Although only 10 of the total 278 malformations (3.6%) were lethal, 6 of these 10 (60%) were associated with a critical reserve antepartum cardiotocographic pattern. As delivery by Caesarean section is usual in patients with critical fetal reserve cardiotocography, it is mandatory to perform ultrasonography to exclude identifiable lethal fetal malformations before delivery.

Antepartum fetal monitoring in insulin-dependent diabetic pregnancies

In order to minimize unexplained stillbirths in insulin-dependent diabetic pregnancies, fetal well-being was assessed by antepartum monitoring while development of pulmonary maturity was awaited. Antepartum monitoring consisted of outpatient nonstress tests beginning at 32 weeks' gestation. Fetuses with nonreactive nonstress tests were further evaluated by contraction stress tests and were delivered if tests were positive. With use of this system there were no unexplained stillbirths during management of 119 insulin-dependent diabetic pregnancies. Of 14 infants delivered because of positive contraction stress tests, six were found to have major disorders; the other eight had no major residual neonatal morbidity. Thus this system of antepartum fetal surveillance: eliminated unexplained stillbirths, identified a subgroup of insulin-dependent diabetic pregnancies with a high rate of major fetal abnormalities, and allowed for identification and subsequent timely delivery of the other distressed fetuses that were at a high risk of neonatal morbidity and/or mortality, such that potential long-term adverse outcomes were avoided.

Umbilical and uterine artery flow velocity waveforms in pregnancy associated with major fetal abnormality

Flow velocity waveforms from the umbilical artery and branches of the uterine artery in the placental bed were recorded using continuous wave Doppler ultrasound. The records of 26 patients with pregnancy complicated by major fetal abnormality were reviewed to determine the changes of a primary fetal disturbance. The systolic/diastolic (A/B) ratio was used as an index of blood flow resistance. In 13 of the 26 patients the umbilical artery waveform systolic/diastolic ratio was high. It is postulated that in these patients there is a process of obliteration of small arteries in the placenta that is triggered by the abnormal fetus. In all patients the uterine artery waveform was normal. In seven of these 13 patients the infant had a birthweight greater than 10th centile. Placental weights were examined. A small placenta expressed as either low weight for gestational age or low placental/fetal weight ratio was associated with a normal umbilical artery waveform. It is suggested that fetuses in these groups have a low growth potential. In contrast a high placental/fetal weight ratio was associated with an abnormal umbilical artery waveform pattern.

A randomized trial of weekly cardiotocography in high-risk obstetric patients

A randomized clinical trial of once-weekly antenatal fetal heart rate monitoring in 539 high-risk patients could find no benefit of monitoring in terms of perinatal mortality, morbidity or Apgar score. The previously well-documented association between abnormal antenatal fetal heart rate traces and low Apgar score was confirmed. A detailed case review showed that in this population monitoring was irrelevant to almost all of the 13 perinatal deaths.

Congenital cardiac fibroma associated with fetal arrhythmia

A congenital cardiac fibroma presented itself, antenatally by bursts of extrasystoles which were detected by the cardiotocograph during labor. Congenital cardiac tumors are extremely rare. The symptomatology of such tumors consists mainly of hemodynamic disturbances and various arrhythmias. Most of the reported cases were diagnosed in neonates or infants, usually in autopsies, none were diagnosed in utero. It seems logical to assume that some of the arrhythmias may have been present but not diagnosed antepartum. To the best of our knowledge the association of congenital cardiac tumor and fetal arrhythmia (FA) has not been reported yet.