Neurodevelopmental outcome in 2-year-old infants who were small-for-gestational age term fetuses with cerebral blood flow redistribution

Longitudinal study of aortic isthmus Doppler in appropriately grown and small-for-gestational-age fetuses with normal and abnormal umbilical artery Doppler

OBJECTIVE

To establish reference ranges using longitudinal data for aortic isthmus (AoI) Doppler indices in appropriate-for-gestational-age (AGA) fetuses and to document the longitudinal trends in a cohort of small-for-gestational-age (SGA) fetuses with normal umbilical artery Doppler and in fetuses with intrauterine growth restriction (IUGR) and abnormal umbilical artery Doppler.

METHODS

AoI Doppler reference ranges were established from longitudinal data on 72 AGA singleton fetuses. Reliability of AoI Doppler flow measurements at two different sites and reproducibility between two operators was reviewed. A prospective longitudinal study of AoI Doppler indices in 48 SGA fetuses with normal umbilical artery Doppler and 10 IUGR fetuses was performed.

RESULTS

The AoI pulsatility index (PI) and peak systolic velocity (PSV) in AGA fetuses showed a significant increase with gestational age. Analysis of intra- and interoperator variability revealed no significant mean difference in measurements of AoI-PI or AoI-PSV. Observations of AoI-PI and AoI-PSV from SGA fetuses did not differ significantly from those of AGA or IUGR fetuses. Retrograde flow in the AoI did not predate changes in the ductus venosus in IUGR fetuses.

CONCLUSIONS

Reference ranges for fetal AoI Doppler parameters in AGA fetuses constructed using longitudinal data are consistent with those obtained from cross-sectional data. The AoI Doppler parameters in SGA fetuses did not differ from those in AGA fetuses. Preterm IUGR fetuses did not manifest alterations in AoI-PI or AoI-PSV prior to changes in biophysical profile or ductus venosus Doppler. Further large-scale prospective studies are needed to determine whether AoI Doppler parameters are of any value in timing delivery or reducing adverse neurodevelopmental outcome.

Neonatal neurobehavior and diffusion MRI changes in brain reorganization due to intrauterine growth restriction in a rabbit model

Background

Intrauterine growth restriction (IUGR) affects 5–10% of all newborns and is associated with a high risk of abnormal neurodevelopment. The timing and patterns of brain reorganization underlying IUGR are poorly documented. We developed a rabbit model of IUGR allowing neonatal neurobehavioral assessment and high resolution brain diffusion magnetic resonance imaging (MRI). The aim of the study was to describe the pattern and functional correlates of fetal brain reorganization induced by IUGR.

Methodology/Principal Findings

IUGR was induced in 10 New Zealand fetal rabbits by ligation of 40–50% of uteroplacental vessels in one horn at 25 days of gestation. Ten contralateral horn fetuses were used as controls. Cesarean section was performed at 30 days (term 31 days). At postnatal day +1, neonates were assessed by validated neurobehavioral tests including evaluation of tone, spontaneous locomotion, reflex motor activity, motor responses to olfactory stimuli, and coordination of suck and swallow. Subsequently, brains were collected and fixed and MRI was performed using a high resolution acquisition scheme. Global and regional (manual delineation and voxel based analysis) diffusion tensor imaging parameters were analyzed. IUGR was associated with significantly poorer neurobehavioral performance in most domains. Voxel based analysis revealed fractional anisotropy (FA) differences in multiple brain regions of gray and white matter, including frontal, insular, occipital and temporal cortex, hippocampus, putamen, thalamus, claustrum, medial septal nucleus, anterior commissure, internal capsule, fimbria of hippocampus, medial lemniscus and olfactory tract. Regional FA changes were correlated with poorer outcome in neurobehavioral tests.

Conclusions

IUGR is associated with a complex pattern of brain reorganization already at birth, which may open opportunities for early intervention. Diffusion MRI can offer suitable imaging biomarkers to characterize and monitor brain reorganization due to fetal diseases.

Altered small-world topology of structural brain networks in infants with intrauterine growth restriction and its association with later neurodevelopmental outcome

Intrauterine growth restriction (IUGR) due to placental insufficiency affects 5-10% of all pregnancies and it is associated with a wide range of short- and long-term neurodevelopmental disorders. Prediction of neurodevelopmental outcomes in IUGR is among the clinical challenges of modern fetal medicine and pediatrics. In recent years several studies have used magnetic resonance imaging (MRI) to demonstrate differences in brain structure in IUGR subjects, but the ability to use MRI for individual predictive purposes in IUGR is limited. Recent research suggests that MRI in vivo access to brain connectivity might have the potential to help understanding cognitive and neurodevelopment processes. Specifically, MRI based connectomics is an emerging approach to extract information from MRI data that exhaustively maps inter-regional connectivity within the brain to build a graph model of its neural circuitry known as brain network. In the present study we used diffusion MRI based connectomics to obtain structural brain networks of a prospective cohort of one year old infants (32 controls and 24 IUGR) and analyze the existence of quantifiable brain reorganization of white matter circuitry in IUGR group by means of global and regional graph theory features of brain networks. Based on global and regional analyses of the brain network topology we demonstrated brain reorganization in IUGR infants at one year of age. Specifically, IUGR infants presented decreased global and local weighted efficiency, and a pattern of altered regional graph theory features. By means of binomial logistic regression, we also demonstrated that connectivity measures were associated with abnormal performance in later neurodevelopmental outcome as measured by Bayley Scale for Infant and Toddler Development, Third edition (BSID-III) at two years of age. These findings show the potential of diffusion MRI based connectomics and graph theory based network characteristics for estimating differences in the architecture of neural circuitry and developing imaging biomarkers of poor neurodevelopment outcome in infants with prenatal diseases.

Postnatal neuro-development of fetuses with absent end-diastolic flow in the umbilical artery and/or fetal descending aorta

OBJECTIVE

To determine whether absence of end-diastolic flow in the umbilical artery and/or fetal aorta impacts postnatal neuro-development in preterm-born children.

METHODS

The study group, consisting of 43 fetuses with absent end-diastolic flow in the umbilical artery and/or fetal aorta, was compared with a control group, consisting of 30 fetuses, matching for gestational age but with normal doppler-flow results. The children's neuro-developmental status was assessed using the 'Munich functional developmental diagnostics' (MFDD), between the 2nd and 3rd year of life.

RESULTS

Gestational age at birth was 33 + 6 weeks in the study group and 34 + 4 weeks in the control group. A brain-sparing effect was observed in 37.3% of fetuses in the study group compared with 10.0% in the control group (p = 0.014). For all seven MFDD domains, the number of children with deficiencies was higher in the study group. For the domains perception, active speech and comprehension this effect was statistically significant (p < 0.05). Overall, 30.2% of children in the study group and 16.7% of the control group had pathologic test results (p < 0.013).

CONCLUSION

Pathological doppler-flow in the umbilical artery and/or fetal descending aorta in preterm born children is associated with neuro-developmental deficiencies. Intensive pediatric care is recommended to mitigate these deficiencies during early childhood.

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.

Tissue Doppler echocardiographic markers of cardiac dysfunction in small-for-gestational age fetuses

OBJECTIVE

The objective of the study was to evaluate echocardiographic markers of cardiac dysfunction in small-for-gestational age (SGA) fetuses with normal umbilical artery Doppler.

STUDY DESIGN

Cardiac function was evaluated in 58 SGA (mean gestational age, 38 weeks) and 58 gestational-age matched normally grown fetuses by conventional echocardiography (peak early [E] and late [A] ratios and myocardial performance index [MPI]), and tissue Doppler imaging (TDI) (annular peak velocities and MPI').

RESULTS

With conventional echocardiography, SGA fetuses had a nonsignificant trend to increased E/A ratios and left MPI compared with controls. TDI demonstrated that SGA fetuses had significantly lower right E' and A' peak velocities and higher MPI' values.

CONCLUSION

These findings further support that a proportion of SGA fetuses have true late-onset intrauterine growth restriction, which is associated with subclinical cardiac dysfunction, as previously described for early-onset intrauterine growth restriction.

Adenosine A₂a receptors and O₂ sensing in development

Reduced mitochondrial oxidative phosphorylation, via activation of adenylate kinase and the resulting exponential rise in the cellular AMP/ATP ratio, appears to be a critical factor underlying O₂ sensing in many chemoreceptive tissues in mammals. The elevated AMP/ATP ratio, in turn, activates key enzymes that are involved in physiologic adjustments that tend to balance ATP supply and demand. An example is the conversion of AMP to adenosine via 5'-nucleotidase and the resulting activation of adenosine A(₂A) receptors, which are involved in acute oxygen sensing by both carotid bodies and the brain. In fetal sheep, A(₂A) receptors associated with carotid bodies trigger hypoxic cardiovascular chemoreflexes, while central A(₂A) receptors mediate hypoxic inhibition of breathing and rapid eye movements. A(₂A) receptors are also involved in hypoxic regulation of fetal endocrine systems, metabolism, and vascular tone. In developing lambs, A(₂A) receptors play virtually no role in O₂ sensing by the carotid bodies, but brain A(₂A) receptors remain critically involved in the roll-off ventilatory response to hypoxia. In adult mammals, A(₂A) receptors have been implicated in O₂ sensing by carotid glomus cells, while central A(₂A) receptors likely blunt hypoxic hyperventilation. In conclusion, A(₂A) receptors are crucially involved in the transduction mechanisms of O₂ sensing in fetal carotid bodies and brains. Postnatally, central A(₂A) receptors remain key mediators of hypoxic respiratory depression, but they are less critical for O₂ sensing in carotid chemoreceptors, particularly in developing lambs.

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.

Intrauterine growth restriction: new concepts in antenatal surveillance, diagnosis, and management

Intrauterine growth restriction (IUGR) remains one of the main challenges in maternity care. Improvements have to start from a better definition of IUGR, applying the concept of the fetal growth potential. Customized standards for fetal growth and birthweight improve the detection of IUGR by better distinction between physiological and pathological smallness and have led to internationally applicable norms. Such developments have resulted in new insights in the assessment of risk and surveillance during pregnancy. Serial fundal height measurement plotted on customized charts is a useful screening tool, whereas fetal biometry and Doppler flow are the mainstay for investigation and diagnosis of IUGR. Appropriate protocols based on available evidence as well as individualized clinical assessment are essential to ensure good management and timely delivery.

Cerebral maturation in IUGR and appropriate for gestational age preterm babies

Intrauterine growth restriction (IUGR) is associated with increased risk of perinatal morbidity and mortality, as well as long-term neurological deficits. However, neurostructural correlations with observed developmental disabilities have not yet been established. Magnetic resonance imaging (MRI) could prove useful for assessing brain development in the early neonatal period. We evaluated cerebral lesions and morphological maturation by MRIs in 59 preterm neonates, in order to verify the hypothesis that IUGR interferes on human brain development. A total of 26 pregnancies were complicated by IUGR and 33 pregnancies delivered preterm at a comparable gestational age with appropriate for gestational age (AGA). Magnetic resonance examination was performed at the completion of 41 weeks' gestation. White matter disease studied with MR included periventricular cavitations and punctuate lesions characterized by increased signal on T1-weighted and decreased signal on T2-weighted images. Cerebral maturation was defined by the total maturation score, on the basis of 4 morphological parameters of cerebral maturation: myelination (M), cortical infolding (C), germinal matrix distribution (GM), and glial cell migration pattern (G). No difference in brain lesions and in the level of cerebral maturation was found between preterm AGA and IUGR neonates. However, myelination was significantly reduced in IUGR neonates with brain sparing compared to IUGR neonates with normal Doppler of middle cerebral artery. Our study could not demonstrate any major significant difference between preterm AGA and IUGR neonates in terms of lesion occurrence and cerebral maturation. We observed, however, a mild delay in myelination in IUGR with brain sparing in utero. The relevance of this finding needs to be investigated with long-term follow-up.

Longitudinal changes in uterine, umbilical and fetal cerebral Doppler indices in late-onset small-for-gestational age fetuses

OBJECTIVES

To determine the longitudinal trends and rates of conversion of normal to abnormal uterine (UtA), umbilical (UA) and middle cerebral artery (MCA) Doppler velocimetry throughout the third trimester in late-onset small-for-gestational-age (SGA) fetuses.

METHODS

UtA, UA and MCA Doppler velocimetry was serially performed in a cohort of singleton consecutive late-onset SGA fetuses with normal Doppler values at diagnosis. The rate of conversion of normal to abnormal Doppler values was evaluated by survival analysis. Longitudinal trends were modeled by means of multilevel analysis.

RESULTS

A total of 616 scans were performed on 171 SGA fetuses. Mean gestational age at inclusion and at delivery was 34.1 (SD 1.6) and 38.7 (SD 1.7) weeks, respectively. The proportions of abnormal UtA (2.3 vs. 4.1%) and UA (2.3 vs. 2.9%) pulsatility index (PI) were not significantly different between 37 weeks and before delivery. On the other hand, the proportions of abnormal MCA-PI (4.1 vs. 13.5%) and cerebroplacental ratio (CPR) (7 vs. 22.8%) were significantly different between these two examinations. The remaining proportion of cases with normal UtA-, UA- and MCA-PIs and CPR at 40 weeks were 98.6, 94.5, 85 and 49.6%, respectively. Whereas a slight increasing trend was observed for the UtA-PI (β = 0.002) and UA-PI (β = 0.01), MCA-PI (β = 0.044) and CPR (β = 0.124) showed a progressive decrease until delivery.

CONCLUSIONS

Late-onset SGA fetuses with normal Doppler velocimetry upon diagnosis show progression from 37 weeks' gestation with worsening CPR followed by a decrease in MCA-PI.

The Growth Restriction Intervention Trial: long-term outcomes in a randomized trial of timing of delivery in fetal growth restriction

OBJECTIVE

The Growth Restriction Intervention Trial found little difference in overall mortality or 2-year outcomes associated with immediate or deferred delivery following signs of impaired fetal health in the presence of growth restriction when the obstetrician was unsure whether to deliver. Because early childhood assessments have limited predictive value, we reevaluated them.

STUDY DESIGN

Children were tested with standardized school-based evaluations of cognition, language, motor performance, and behavior. Analysis and interpretation were Bayesian.

RESULTS

Of 376 babies, 302 (80%) had known outcome: either dead or evaluated at age 6-13 years. Numbers of children dead, or with severe disability: 21 (14%) immediate and 25 (17%) deferred groups. Among survivors, the mean (SD) cognition scores were 95 (15) and 96 (14); motor scores were 8·9 (7·0) and 8·7 (6·7); and parent-assessed behavior scores were 10·5 (7·1) and 10·5 (6·9), respectively, for the 2 groups.

CONCLUSION

Clinically significant differences between immediate and deferred delivery were not found.

Abnormal antenatal Doppler velocimetry and cognitive outcome in very-low-birth-weight infants at 2 years of age

OBJECTIVE

To study neurodevelopmental outcome at 2 years of corrected age in very-low-birth-weight (VLBW) (< or = 1500 g) preterm infants with abnormal fetoplacental flow.

METHODS

A total of 258 VLBW infants were born at Turku University Hospital between 2001 and 2006. Of these, 99 had undergone, within 1 week of delivery, antenatal Doppler assessment of blood flow in the umbilical artery (UA), fetal middle cerebral artery (MCA), descending aorta (DAo), aortic isthmus and ductus venosus and were eligible for inclusion in the study. Postnatally brain pathology was assessed by serial ultrasound and magnetic resonance imaging in 86 of the neonates and brain volume was measured in 80. Cognitive development was evaluated at 2 years of corrected age in 83 infants using the Bayley Scales of Infant Development-II. Motor development was assessed using the Hammersmith Infant Neurological Examination.

RESULTS

On univariate analysis, abnormal pulsatility index (PI) in the UA and an abnormal UA-PI/MCA-PI ratio (P = 0.04 and P = 0.003, respectively) as well as increases in both the DAo-PI and in the DAo-PI/MCA-PI ratio (P = 0.03 and P = 0.02, respectively), were associated with adverse cognitive outcome at 2 years of age. However, when controlling for cerebral volume using multivariate analysis, the association between abnormal antenatal Doppler characteristics and cognitive outcome became statistically non-significant, which indicated the determinant role of the volume reduction. Motor development was not associated with antenatal Doppler indices.

CONCLUSION

Abnormal antenatal Doppler indices are associated with adverse cognitive outcome at 2 years in VLBW infants. Our findings suggest that this association may be mediated through brain volume.

Abnormal brain microstructure and metabolism in small-for-gestational-age term fetuses with normal umbilical artery Doppler

OBJECTIVES

To assess microstructural and metabolic brain differences between small-for-gestational age (SGA) and appropriate-for-gestational age (AGA) fetuses at 37 weeks' gestation by magnetic resonance imaging (MRI) spectroscopy and diffusion weighted imaging.

METHODS

Eight SGA and five matched AGA singleton fetuses, all with normal umbilical artery Doppler, were evaluated using MRI at 37 weeks to measure markers of brain microstructure and metabolism. The metabolic spectrum of N-acetyl-aspartate/choline, choline/creatine, inositol/choline and creatine/choline ratios in the left frontal lobe and the apparent diffusion coefficient from the right and left basal ganglia and frontal and occipital lobes, pyramidal tract and corpus callosum were analyzed and compared.

RESULTS

As compared with controls, SGA fetuses showed a significant increase in inositol/choline ratio (SGA, 0.57 vs. AGA, 0.25; P = 0.04) and significantly higher ADC values in the pyramidal tract (SGA, 119.87 x 10(-5) mm(2)/s vs. AGA, 105.11 x 10(-5) mm(2)/s; P = 0.04).

CONCLUSIONS

SGA fetuses with normal umbilical artery Doppler present microstructural and metabolic brain changes, suggesting the existence of an abnormal in-utero brain development in fetuses with this condition.

[Is it necessary to induce labor before 37 weeks of gestation in case of small for gestational age fetus?]

The suspicion of small for gestational age fetus before 37 weeks of gestation implies to discriminate those who are physiologically small from those who have an underlying pathology leading to growth retardation. A labor induction can be needed if the risks associated to the prolongation of the pregnancy are estimated to be higher than those of prematurity and cesarean. In this case, labor induction can be discussed if the fetal vitality is normal. A continuous fetal heart monitoring during induction and labor is, in this case, strongly recommended. However, even in these optimal conditions, the risk of cesarean in case of labor induction for small for gestational age fetus before 37 weeks of gestation is of about 50 % in the rare published studies.

Longitudinal brain perfusion changes in near-term small-for-gestational-age fetuses as measured by spectral Doppler indices or by fractional moving blood volume

OBJECTIVE

The objective of this study was to compare the temporal sequence of fetal brain hemodynamic changes in near-term small-for-gestational-age fetuses as measured by spectral Doppler indices or by fractional moving blood volume.

STUDY DESIGN

Cerebral tissue perfusion measured by fractional moving blood volume, cerebroplacental ratio, anterior cerebral artery, and middle cerebral artery pulsatility indices were weekly performed in a cohort of singleton consecutive small-for-gestational-age fetuses with normal umbilical artery delivered after 37 weeks of gestation.

RESULTS

A total of 307 scans were performed on 110 small-for-gestational-age fetuses. Mean gestational age at diagnosis and at delivery was 35.7 and 38.6 weeks, respectively. The proportion of fetuses with abnormal fractional moving blood volume, cerebroplacental ratio, anterior cerebral artery-pulsatility index, and middle cerebral artery-pulsatility index values was 31.3%, 16.8%, 17.2%, and 10.8% at 37 weeks of gestation and 42.7%, 23.6%, 20.9%, and 16.4% before delivery.

CONCLUSION

The presence of brain redistribution in small-for-gestational-age fetuses was detected earlier and in a higher proportion of fetuses using cerebral tissue perfusion rather than spectral Doppler indices.

Fetal growth restriction - from observation to intervention

Fetal growth restriction (FGR) due to placental dysfunction has important short- and long-term impacts that may reach into adulthood. Early-onset FGR before 34 weeks' gestation shows a characteristic sequence of responses to placental dysfunction that evolves from the arterial circulation to the venous system and finally to biophysical abnormalities. In this form of FGR safe prolongation of pregnancy is a primary management goal, as gestational age at delivery, birth weight and iatrogenic premature delivery have an important impact on short-term outcome and neurodevelopment. Surveillance intervals should be adjusted based on umbilical artery and venous Doppler studies. Intervention thresholds need to be based on the balance of fetal vs. neonatal risks and therefore critically depend on gestational age. Late-onset FGR presents with subtle Doppler and biophysical abnormalities and therefore poses a diagnostic dilemma. Often unrecognized, term FGR contributes to a large proportion of adverse perinatal outcome. Monitoring intervals should be adjusted based on middle cerebral artery Doppler and fetal heart rate parameters. Delivery timing thresholds can be low. In both forms of FGR neurodevelopmental impacts of placental disease occur before clinical decisions regarding delivery timing arise. This places special emphasis on future preventative studies.

Middle versus anterior cerebral artery Doppler for the prediction of perinatal outcome and neonatal neurobehavior in term small-for-gestational-age fetuses with normal umbilical artery Doppler

OBJECTIVE

To evaluate whether anterior cerebral artery (ACA) Doppler ultrasonography is superior to middle cerebral artery (MCA) Doppler in the prediction of perinatal outcome and neonatal neurobehavior in term small-for-gestational-age (SGA) fetuses with normal umbilical artery (UA) Doppler.

METHODS

MCA and ACA Doppler ultrasonography was performed in a cohort of SGA term fetuses with normal UA Doppler. Perinatal outcome and neonatal neurobehavioral performance were compared with a group of term appropriate-for-gestational age (AGA) infants. Neurobehavior was evaluated at 40 ( +/- 1) weeks of corrected age with the Neonatal Behavioral Assessment Scale. Differences between the study groups were adjusted for potential confounding variables by multiple linear or logistic regression analyis.

RESULTS

A total of 199 newborns (98 SGA and 101 AGA) were included. Among the SGA fetuses, 28.6 and 17% had MCA and ACA redistribution, respectively. Cases with either type of redistribution had an increased risk for adverse outcome, with no differences in predictive performance between the two parameters. SGA fetuses with MCA redistribution compared with controls had an increased risk for abnormal neurobehavioral performance in motor (36 vs. 20%; adjusted P = 0.02) and state organization (25 vs. 17.5%; adjusted P = 0.03) areas. SGA fetuses with ACA redistribution had only an increased risk for abnormal neurobehavioral performance area in state organization compared with controls (30 vs. 17.5%; adjusted P = 0.021).

CONCLUSION

In term SGA newborns with no signs of brain-sparing, ACA Doppler investigation does not provide any benefit over MCA in terms of the prediction of adverse perinatal outcome.

Cerebral blood perfusion and neurobehavioral performance in full-term small-for-gestational-age fetuses

OBJECTIVE

The purpose of this study was to evaluate changes in cerebral blood perfusion and middle cerebral artery (MCA) Doppler in full-term small-for-gestational-age fetuses (SGA) and to explore their association with neonatal neurobehavioral performance.

STUDY DESIGN

Frontal brain perfusion that was measured by fractional moving blood volume (FMBV) and MCA Doppler pulsatility index were assessed in 60 SGA fetuses with normal umbilical artery Doppler results that were matched with adequate-for-gestational-age fetuses. Neonates were evaluated with the Neonatal-Behavioral-Assessment-Scale (NBAS).

RESULTS

The proportion of SGA fetuses with increased FMBV (35% vs 5%; P < .001) and decreased MCA Doppler pulsatility index (15% vs 1.7%; P < .01) was significantly higher. SGA fetuses showed poorer NBAS scores in all areas. Increased FMBV identified SGA fetuses with the highest risks of abnormal NBAS in social-interactive (odds ratio, 7.8), attention (odds ratio, 22.8), and state-organization (odds ratio, 25.0). Abnormal MCA Doppler identified SGA with abnormal scores in motor area (odds ratio, 10.7).

CONCLUSION

Increased brain blood perfusion discriminates SGA fetuses that are at risk for abnormal neurobehavior.

Neurobehavior in term, small-for-gestational age infants with normal placental function

OBJECTIVE

The goal was to evaluate the neurobehavioral outcomes of term, small-for-gestational age (SGA) newborns with normal placental function.

METHODS

A cohort of consecutive term SGA newborns with normal prenatal umbilical artery Doppler ultrasound findings was created and compared with a group of term infants with size appropriate for gestational age, who were sampled from our general neonatal population. Neonatal behavior was evaluated at corrected age of 40 +/- 1 weeks with the Neonatal Behavioral Assessment Scale. The effect of the study group on each Neonatal Behavioral Assessment Scale area was adjusted, through multivariate analysis of covariance, for smoking during pregnancy, maternal BMI, socioeconomic level, onset of labor, mode of delivery, use of epidural anesthetic medication, gestational age at delivery, postnatal age (in days) at evaluation, and gender.

RESULTS

A total of 202 newborns (102 SGA and 100 appropriate for gestational age) were included. All of the neurobehavioral areas studied were poorer in the SGA group, with significance for attention, habituation, motor, social-interactive, and regulation of state. The average mean differences in scores between the study groups were 0.77 (95% confidence interval: 0.38-1. 14) for attention, 0.64 (95% confidence interval: 0.13-1.14) for habituation, 0.52 (95% confidence interval: 0.31-0.74) for motor, 0.95 (95% confidence interval: 0.54-1.37) for social-interactive, and 0.68 (95% confidence interval: 0.23-1.13) for regulation of state. These differences remained significant after adjustment for potential confounders.

CONCLUSION

Term SGA newborns with no signs of placental insufficiency had poorer neurobehavioral competencies, which suggests delayed neurologic maturation.

The role of Doppler and placental screening

Placental-associated diseases account for most cases of adverse perinatal outcome in developing countries. Uterine Doppler evaluation predicts most instances of early-onset preeclampsia and intrauterine growth restriction, but there is no evidence in favour of any prophylactic strategy in cases of an abnormal screening result. Umbilical artery Doppler investigation allows identifying those small-for-gestational-age foetuses at higher risk, and its use in these pregnancies improves a number of perinatal outcomes. Middle cerebral artery Doppler investigation reflects brain redistribution, and its use in combination with the umbilical artery in a cerebroplacental ratio seems to improve prediction of adverse outcome, mainly in near-term pregnancies, where most instances of adverse outcome occur in foetuses with normal umbilical artery. Ductus venosus Doppler waveform is a surrogate parameter of the foetal acid-base status. However, the benefits of its use in the management of early-onset growth restriction needs further evidence.

Fetal growth restriction is associated with prioritization of umbilical blood flow to the left hepatic lobe at the expense of the right lobe

Eighty to 85% of the venous perfusion to the fetal liver is from the umbilical vein, the rest from the portal vein. Umbilical venous flow to the liver is essential for intrauterine growth, and is impaired in placental insufficiency. We hypothesized that in growth-restricted fetuses portal blood flow compensates for insufficient umbilical blood flow to the liver. In 29 fetuses with fetal growth restriction (estimated fetal weight < or =5th percentile), we used ultrasound to measure blood flows in the umbilical vein, ductus venosus, left portal vein, and main portal stem. Compared with normal fetuses, both absolute and normalized total venous liver blood flows were reduced in growth-restricted fetuses, related to the degree of placental compromise and equally affecting both liver lobes. However, portal replaced umbilical flow to the right lobe, in a manner graded according to placental vascular resistance; in extreme cases, the right lobe received no umbilical perfusion. In fetal growth restriction, the liver suffers from venous hypoperfusion, and portal blood partially replaces umbilical flow to the right lobe; this will result in right liver lobe hypoxemia. This striking prioritization in nutrient delivery of left over right lobes suggests an adaptive response to poor placental perfusion that may have functional consequences.