Computerised analysis of unstimulated and stimulated behaviour in fetuses with intrauterine growth restriction

The role of the fetal biophysical profile in the management of fetal growth restriction

Growth-restricted fetuses are at risk of hypoxemia, acidemia, and stillbirth because of progressive placental dysfunction. Current fetal well-being, neonatal risks following delivery, and the anticipated rate of fetal deterioration are the major management considerations in fetal growth restriction. Surveillance has to quantify the fetal risks accurately to determine the delivery threshold and identify the testing frequency most likely to capture future deterioration and prevent stillbirth. From the second trimester onward, the biophysical profile score correlates over 90% with the current fetal pH, and a normal score predicts a pH >7.25 with a 100% positive predictive value; an abnormal score on the other hand predicts current fetal acidemia with similar certainty. Between 30% and 70% of growth-restricted fetuses with a nonreactive heart rate require biophysical profile scoring to verify fetal well-being, and an abnormal score in 8% to 27% identifies the need for delivery, which is not suspected by Doppler findings. Future fetal well-being is not predicted by the biophysical profile score, which emphasizes the importance of umbilical artery Doppler and amniotic fluid volume to determine surveillance frequency. Studies with integrated surveillance strategies that combine frequent heart rate monitoring with biophysical profile scoring and Doppler report better outcomes and stillbirth rates of between 0% and 4%, compared with those between 8% and 11% with empirically determined surveillance frequency. The variations in clinical behavior and management challenges across gestational age are better addressed when biophysical profile scoring is integrated into the surveillance of fetal growth restriction. This review aims to provide guidance on biophysical profile scoring in the in- and outpatient management of fetal growth restriction.

Fetal Heart Rate Variability Is Affected by Fetal Movements: A Systematic Review

Introduction: Fetal heart rate variability (FHRV) evaluates the fetal neurological state, which is poorly assessed by conventional prenatal surveillance including cardiotocography (CTG). Accurate FHRV on a beat-to-beat basis, assessed by time domain and spectral domain analyses, has shown promising results in the scope of fetal surveillance. However, accepted standards for these techniques are lacking, and the influence of fetal breathing movements and gross movements may be especially challenging. Thus, current standards for equivalent assessments in adults prescribe rest and controlled respiration. The aim of this review is to clarify the importance of fetal movements on FHRV. Methods: A systematic review in accordance with the PRISMA guidelines based on publications in the EMBASE, the MEDLINE, and the Cochrane Library databases was performed. Studies describing the impact of fetal movements on time domain, spectral domain and entropy analyses in healthy human fetuses were reviewed. Only studies based on fetal electrocardiography or fetal magnetocardiography were included. PROSPERO registration number: CRD42018068806. Results: In total, 14 observational studies were included. Fetal movement detection, signal processing, length, and selection of appropriate time series varied across studies. Despite these divergences, all studies showed an increase in overall FHRV in the moving fetus compared to the resting fetus. Especially short-term, vagal mediated indexes showed an increase during fetal breathing movements including an increase in Root Mean Square of the Successive Differences (RMSSD) and High Frequency power (HF) and a decrease in Low Frequency power/High Frequency power (LF/HF). These findings were present even in analyses restricted to one specific fetal behavioral state defined by Nijhuis. On the other hand, fetal body movements seemed to increase parameters supposed to represent the sympathetic response [LF and Standard Deviation of RR-intervals from normal sinus beats (SDNN)] proportionally more than parameters representing the parasympathetic response (RMSSD, HF). Results regarding entropy analyses were inconclusive. Conclusion: Time domain analyses as well as spectral domain analyses are affected by fetal movements. Fetal movements and especially breathing movements should be considered in these analyses of FHRV.

Increased labor induction and women presenting with decreased or altered fetal movements - a population-based survey

Introduction

Women’s awareness of fetal movements is important as perception of decreased fetal movements can be a sign of a compromised fetus. We aimed to study rate of labor induction in relation to number of times women seek care due to decreased or altered fetal movements during their pregnancy compared to women not seeking such care. Further, we investigated the indication of induction.

Material and methods

A prospective population-based cohort study including all obstetric clinics in Stockholm, Sweden. Questionnaires were distributed to women who sought care due to decreased or altered fetal movements ≥ 28 week’s gestation in 2014, women for whom an examination did not indicate a compromised fetus that required induction of labor or cesarean section when they sought care. Women who gave birth at ≥ 28 weeks’ gestation in 2014 in Stockholm comprises the reference group.

Results

Labor was induced more often among the 2683 women who had sought care due to decreased or altered fetal movements (RR 1.4, 95% CI 1.3–1.5). In women who presented with decreased or altered fetal movements induction of labor occurred more frequently for fetal indication than those with induction of labor and no prior fetal movement presentation (RR 1.6, 95% CI 1.4–1.8). The rate of induction increased with number of times a woman sought care, RR 1.3 for single presentation to 3.2 for five or more.

Conclusions

We studied women seeking care for decreased or altered fetal movements and for whom pregnancy was not terminated with induction or caesarean section. Subsequent (median 20 days), induction of labor and induction for fetal indications were more frequent in this group compared to the group of women with no fetal movement presentations. Among women seeking care for altered or decreased fetal movements, the likelihood of induction of labor increased with frequency of presentation.

The prognostic accuracy of short term variation of fetal heart rate in early-onset fetal growth restriction: A systematic review

OBJECTIVE

Cardiotocography (CTG) is an important tool for fetal surveillance in severe early-onset fetal growth restriction (FGR). Assessment of the CTG is usually performed visually (vCTG). However, it is suggested that computerized analysis of the CTG (cCTG) including short term variability (STV) could more accurately detect fetal compromise. The objective of this study was to systematically review the literature on the association between cCTG and perinatal outcome and the comparison of cCTG with vCTG.

STUDY DESIGN

A systematic search was performed in MEDLINE, EMBASE and Google Scholar. Studies were included that assessed prognostic accuracy of STV or compared STV to vCTG in patients with FGR. Risk of bias and concerns about applicability were assessed with the QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies-2) instrument.

RESULTS

Of the 885 records identified in the search, five cohort studies (387 patients) were included. We found no randomized studies comparing STV with visual CTG in patients with FGR. The risk of bias of all studies was generally judged as 'low'. One small study found an association of low STV with neonatal acidosis. One study observed no association of STV with long-term outcome. Composite analysis of all five studies showed a non-significant relative risk for acidosis after a low STV of 1.4 (95% CI 0.6-3.2, N = 387). Further meta-analysis was hampered due to heterogeneity in outcome reporting and use of different thresholds.

CONCLUSION

The evidence from the included studies did not support an association of STV and short or long term outcome. However, available data are limited and heterogeneous, and influenced by management based on STV. Solid evidence from a randomized controlled trial comparing STV with vCTG including long term infant outcome is needed before STV can be used clinically for timing of delivery in patients with FGR.

Is there a relationship between fetal brain function and the fetal behavioral state? A fetal MEG-study

AIM

Fetal magnetography enables the recording of biomagnetic fetal signals, including fetal heart and fetal brain signals. These signals allow the determination of fetal behavioral states and functional brain signals with auditory evoked responses (AER). In the current study, we investigated how the behavioral state influences the AER and how stimulation affects fetal state.

METHODS

One hundred and four fetuses in three age groups (28-31 weeks, 32-35 weeks and 36-41 weeks) were recorded with and without auditory stimulation. Both sessions were scored for fetal states. The AER latency was determined for each state separately. Forty-five additional subjects were recorded with two sessions of 10 min without stimulation to investigate a possible time effect on state changes.

RESULTS

The state distribution was significantly different between stimulation and no stimulation conditions. The AER latencies were significantly shorter in active sleep (P=0.013) and active wakefulness (P=0.004) compared to quiet sleep.

CONCLUSION

Auditory stimulation has an effect on fetal states. The state information should be taken into account for the analysis of AER latencies.

Neurodevelopment after fetal growth restriction

Fetal growth restriction (FGR) can emerge as a complication of placental dysfunction and increases the risk for neurodevelopmental delay. Marked elevations of umbilical artery (UA) Doppler resistance that set the stage for cardiovascular and biophysical deterioration with subsequent preterm birth characterize early-onset FGR. Minimal, or absent UA Doppler abnormalities and isolated cerebral Doppler changes with subtle deterioration and a high risk for unanticipated term stillbirth are characteristic for late-onset FGR. Nutritional deficiency manifested in lagging head growth is the most powerful predictor of developmental delay in all forms of FGR. Extremes of blood flow resistance and cardiovascular deterioration, prematurity and intracranial hemorrhage increase the risks for psychomotor delay and cerebral palsy. In late-onset FGR, regional cerebral vascular redistribution correlates with abnormal behavioral domains. Irrespective of the phenotype of FGR, prenatal tests that provide precise and independent stratification of risks for adverse neurodevelopment have yet to be determined.

Timing delivery of the growth-restricted fetus

Intrauterine growth restriction (IUGR) is commonly defined as an estimated fetal weight of less than the 10th percentile. While 70% of these are small for normal reasons and not at risk, 30% are pathologically small at risk for numerous complications including fetal death. In the late preterm IUGR fetus (>34 weeks), prematurity risks less and the risk of fetal demise becomes the primary concern. Pulsed-wave Doppler interrogation of the umbilical and middle cerebral artery is useful in reducing perinatal mortality, however, Doppler changes in these vessels of the IUGR fetus may not occur after 34 weeks gestation. There are no randomized trials addressing the timing of delivery of the IUGR fetus in the late preterm or early-term period. However, retrospective reports show an increase risk of fetal demise. While timing the delivery of the late preterm/early-term IUGR fetus requires consideration of multiple factors (e.g. degree of growth restriction, etiology, amniotic fluid volume, and biophysical and Doppler testing), available data suggests that delivery should occur by 37 to 38 weeks for singleton IUGR fetuses. In twin pregnancies with a co-twin IUGR fetus, chorionicity also impacts timing of delivery, but delivery should occur by 34-36 weeks.

Neurobehavioral outcomes in preterm, growth-restricted infants with and without prenatal advanced signs of brain-sparing

OBJECTIVE

To evaluate the neurobehavioral outcomes of preterm infants with intrauterine growth restriction (IUGR), with and without prenatal advanced brain-sparing.

METHODS

A cohort of IUGR infants (birth weight < 10(th) percentile with abnormal umbilical artery Doppler) born before 34 weeks of gestation was compared with a control group of appropriate-for-gestational age infants matched for gestational age at delivery. MCA pulsatility index was determined in all cases within 72 hours before delivery. Neonatal neurobehavior was evaluated at 40 weeks' ( ± 1) corrected age using the Neonatal Behavioral Assessment Scale. The effect of abnormal MCA pulsatility index (< 5(th) percentile) on each neurobehavioral area was adjusted for maternal smoking status and socioeconomic level, mode of delivery, gestational age at delivery, pre-eclampsia, newborn illness severity score and infant sex by multiple linear and logistic regression.

RESULTS

A total of 126 preterm newborns (64 controls and 62 IUGR) were included. Among IUGR fetuses, the proportion of abnormal MCA Doppler parameters was 53%. Compared with appropriate-for-gestational age infants, newborns in the IUGR subgroup with abnormal MCA Doppler had significantly lower neurobehavioral scores in the areas of habituation, motor system, social-interactive and attention. Similarly, the proportion of infants with abnormal neurobehavioral scores was significantly higher in the IUGR subgroup with abnormal MCA Doppler parameters in the areas of habituation, social-interactive, motor system and attention.

CONCLUSION

Abnormal MCA Doppler findings are predictive of neurobehavioral impairment among preterm newborns with IUGR, which suggests that this reflects an advanced stage of brain injury with a higher risk of abnormal neurological maturation.

Neurodevelopment following fetal growth restriction and its relationship with antepartum parameters of placental dysfunction

Placental dysfunction leading to fetal growth restriction (FGR) is an important risk factor for neurodevelopmental delay. Recent observations clarify that FGR evolves prenatally from a preclinical phase of abnormal nutrient and endocrine milieu to a clinical phase that differs in characteristics in preterm and term pregnancies. Relating childhood neurodevelopment to these prenatal characteristics offers potential advantages in identifying mechanisms and timing of critical insults. Based on available studies, lagging head circumference, overall degree of FGR, gestational age, and umbilical artery (UA), aortic and cerebral Doppler parameters are the independent prenatal determinants of infant and childhood neurodevelopment. While head circumference is important independent of gestational age, overall growth delay has the greatest impact in early onset FGR. Gestational age has an overriding negative effect on neurodevelopment until 32-34 weeks' gestation. Accordingly, the importance of Doppler status is demonstrated from 27 weeks onward and is greatest when there is reversed end-diastolic velocity in the UA or aorta. While these findings predominate in early-onset FGR, cerebral vascular impedance changes become important in late onset FGR. Abnormal motor and neurological delay occur in preterm FGR, while cognitive effects and abnormalities that can be related to specific brain areas increase in frequency as gestation advances, suggesting different pathophysiology and evolving vulnerability of the fetal brain. Observational and management studies do not suggest that fetal deterioration has an independent impact on neurodevelopment in early-onset FGR. In late-onset FGR further research needs to establish benefits of perinatal intervention, as the pattern of vulnerability and effects of fetal deterioration appear to differ in the third trimester.

Fetal heart rate after vibroacoustic stimulation

OBJECTIVE

To define reference ranges for fetal heart rate (FHR) parameters after vibroacoustic stimulation (VAS) according to gestational age by determining the relationship between FHR and gestational age using a computerized analysis system.

METHODS

Data were analyzed from 3453 women using 10-minute observational recordings during nonstress testing (NST) and VAS testing. FHR parameters were analyzed according to gestational age.

RESULTS

All FHR parameters were related to gestational age except for mean baseline FHR, which did not vary significantly with gestational age. All other parameters followed trends similar to the NST results, except for decelerations.

CONCLUSION

FHR parameters after VAS differed significantly according to gestational age. The results suggest that the gestational age of the fetus should be considered when interpreting FHR patterns after VAS.

Low maternal awareness of fetal movement is associated with small for gestational age infants

Our aim was to identify associations between information given to pregnant women about fetal activity, level of maternal awareness of fetal activity, maternal concern about decreased fetal movement, and pregnancy outcomes. This was a population-based cross-sectional study. Mothers with a singleton delivery were invited to answer an anonymous structured questionnaire before discharge from the delivery unit. Six hundred and ninety-one mothers participated (60.4% of eligible women). Women were highly aware of fetal activity. Yet, 25% did not receive any information from care providers about expected normal fetal activity. Receiving information about fetal activity was associated with increased maternal awareness (odds ratio, 2.0; 95% confidence interval [CI], 1.2-3.4). Low maternal awareness of fetal activity was associated with an increased risk of having a small for gestational age infant (odds ratio, 6.5; 95% CI, 3.5-12.3). Expectations about the normal frequency of fetal movements, as reported by the mothers, varied from 25 kicks/hour to 3 kicks/24 hours. Receiving information about expected fetal activity was associated with maternal concerns about decreased fetal movement, but not with improved outcomes. We conclude that receiving information about expected fetal activity was associated with maternal concerns, but not with improved outcomes.

Management of decreased fetal movements

Maternal perception of decreased fetal activity is a common complaint, and one of the most frequent causes of unplanned visits in pregnancy. No proposed definitions of decreased fetal movements have ever been proven to be superior to a subjective maternal perception in terms of identifying a population at risk. Women presenting with decreased fetal movements do have higher risk of stillbirth, fetal growth restriction, fetal distress, preterm birth, and other associated outcomes. Yet, little research has been conducted to identify optimal management, and no randomized controlled trials have been performed. The strong associations with adverse outcome suggest that adequate management should include the exclusion of both acute and chronic conditions associated with decreased fetal movements. We propose guidelines for management of decreased fetal movements that include both a nonstress test and an ultrasound scan and report findings in 3014 cases of decreased fetal movements.

The assessment of fetal behavior of growth restricted fetuses by 4D sonography

AIM

To find out whether the quantity of fetal facial expression and quality of body movements can be used as an additional diagnostic criterion for prenatal brain impairment in fetuses with growth restriction.

SUBJECT AND METHODS

A prospective study was conducted in 50 uncomplicated healthy women as control group with reliably dated pregnancies and 50 pregnant women with a growth restricted fetus as study group in the third trimester of pregnancy. 4D ultrasound observation is specially designed to assess whether functional brain impairment and fetal growth restriction had prenatally occurred by the utilization of several behavioral patterns.

RESULTS

The median value of all movement patterns in the normal fetuses differed from fetuses with intrauterine growth restriction (IUGR). Statistical evaluation revealed significant differences in the distribution of the movements between these groups (P<0.05). We noted a tendency that IUGR fetuses have less behavioral activity than normal fetuses in all observed movement patterns. Correlation reached statistical significance between normal and IUGR fetuses in the third trimester in hand to head, hand to face and head retroflexion. Statistically significant differences could be shown in the distribution of the median values of observation over the five qualitative categories of head and hand movements (P<0.05).

CONCLUSIONS

Recent data on IUGR fetuses obtained by 4D sonography are stimulating and might result in a more effective strategy to assess development before birth. The results of this study may encourage future use of 4D ultrasound for quantitative and qualitative assessment of fetal behavior as possible indicators of the neurological condition in IUGR fetuses.

Neurobehavioral assessment before birth

The complexities of neurobehavioral assessment of the fetus, which can be neither directly viewed nor manipulated, cannot be understated. Impetus to develop methods for measuring fetal neurobehavioral development has been provided by the recognition that individual differences in neurobehavioral functioning do not originate with birth and acceptance of the key contribution of the antenatal period to postnatal life. Research has centered around four aspects of fetal functioning: heart rate, motor activity, behavioral state, and responsivity to stimulation. Longitudinal studies have revealed that the developmental trajectories of these characteristics parallel the developing nervous system, detected a transitional period between 28 and 32 weeks gestation, and established within-fetal stability during the second half of gestation. Despite the promise of fetal stimulation and habituation paradigms as measures of neural functioning, significant safety and ethical concerns exist. Construction of a unified fetal neurobehavioral scale is premature until a sufficient degree of normative data is available and the predictive validity of specific aspects of fetal neurobehavior to child developmental outcomes is better established.

Fetal growth and well-being

Accurate monitoring of fetal growth is one of the most critically important components of prenatal care. Whether too large or too small for gestational age, the ramifications of abnormal fetal growth have both short-term and long-term sequelae for early neonatal life and beyond. Although not perfectly accurate, ultrasound and other monitoring technologies have markedly improved the ability to follow abnormalities of fetal growth and to decide if early intervention or early delivery is necessary. Clearly, perinatal morbidity and mortality are decreased with close surveillance of these at-risk fetuses.

Fetal growth restriction due to placental disease

Normal fetal growth depends on the genetically predetermined growth potential and its modulation by the health of the fetus, placenta and the mother. Fetuses that are small because of intrauterine growth restriction (IUGR) are at higher risk for poor perinatal and long-term outcome than those who are appropriately grown. Of the many potential underlying processes that may result in IUGR, placental disease is clinically the most relevant. Fetal cardiovascular and behavioral responses to placental insufficiency and the metabolic status are interrelated. The concurrent evaluation of fetal biometry, amniotic fluid volume, heart rate patterns, arterial and venous Doppler, and biophysical variables therefore allow the most comprehensive fetal evaluation in IUGR. In the absence of successful intrauterine therapy, the timing of delivery is perhaps the most critical aspect of the antenatal management. A discussion of the fetal responses to placental insufficiency and a management protocol that accounts for multiple Doppler and biophysical parameters as well as gestational age is provided in this review.

Fetal Neurobehavioral Development: A Tale of Two Cities

Longitudinal neurobehavioral development was examined in 237 fetuses of low-risk pregnancies from 2 distinct populations--Baltimore, Maryland, and Lima. Peru--at 20, 24, 28, 32, 36, and 38 weeks gestation. Data were based on digitized Doppler-based fetal heart rate (FHR) and fetal movement (FM). In both groups. FHR declined while variability, episodic accelerations, and FM-FHR coupling increased, with discontinuities evident between 28 and 32 weeks gestation. Fetuses in Lima had higher FHR and lower variability, accelerations, and FM-FHR coupling. Declines in trajectories were typically observed 1 month sooner in Lima, which magnified these disparities. Motor activity differences were less consistent. No sex differences in fetal neurobehaviors were detected. It is concluded that population factors can influence the developmental niche of the fetus.

Fetal learning: a prospective randomized controlled study

OBJECTIVES

To examine whether prenatal exposure to a music stimulus alters fetal behavior and whether this continues into the newborn period.

SUBJECTS AND METHODS

A prospective randomized control trial was conducted using an exposure learning model in 20 normal term pregnancies. Music was played to ten fetuses via a headphone on the maternal abdomen. Ten controls had the headphone without sound. All fetal studies took place within 72 h prior to elective delivery. All 20 newborns were exposed to the same music on days 3-5. Computerized assessment of fetal heart rate and activity was documented and neonatal behavioral states were recorded. Nonparametric statistical analysis was used.

RESULTS

For the first hour of study, exposed fetuses had higher mean heart rates (FHR) and spent more time exhibiting high FHR variation compared to unexposed fetuses, but neither of these differences was statistically significant. However, by the fourth hour the exposed fetuses not only demonstrated these two features but also exhibited more state transitions (P = 0.01) and higher FHR variation (P = 0.04) compared to unexposed fetuses. These effects were carried over into the neonatal period with prenatally exposed newborns manifesting more state transitions (P = 0.01) and spending a higher proportion of time in awake states (P = 0.05) when exposed to the same music stimulus.

CONCLUSION

Prenatal music exposure alters the fetal behavioral state and is carried forward to the newborn period. This suggests that a simple form of fetal programming or learning has occurred.

Antenatal assessment of the growth restricted fetus

Babies who are small due to intrauterine growth restriction are at higher risk for poor perinatal and long-term outcome than those who are appropriately grown. Through multiple antenatal testing modalities a sequence of deteriorating fetal status can be documented in such cases. The nature of this compromise is best reflected by the combination of fetal biometry, biophysical profile scoring and arterial and venous Doppler. This combination accurately defines fetal states and therefore risk of stillbirth or poor transition to extrauterine life. In the preterm neonate, fetal factors, gestational age and neonatal course interact significantly to impact on short- and long-term outcomes. The potential for iatrogenic prematurity is great and ongoing appraisal of peripartum management is critical. An integrated management protocol accounting for these factors is examined in this review.