Abnormal fetal aortic velocity waveform and minor neurological dysfunction at 7 years of age

Excitatory and inhibitory neuron imbalance in the intrauterine growth restricted fetal guinea pig brain: Relevance to the developmental origins of schizophrenia and autism

Neurodevelopmental disorders such as schizophrenia and autism are thought to involve an imbalance of excitatory and inhibitory signaling in the brain. Intrauterine growth restriction (IUGR) is a risk factor for these disorders, with IUGR onset occurring during critical periods of neurodevelopment. The aim of this study was to determine the impact of IUGR on excitatory and inhibitory neurons of the fetal neocortex and hippocampus. Fetal brains (n = 2) were first collected from an unoperated pregnant guinea pig at mid-gestation (32 days of gestation [dg]; term ∼67 dg) to visualize excitatory (Ctip2) and inhibitory (calretinin [CR] and somatostatin [SST]) neurons via immunohistochemistry. Chronic placental insufficiency (CPI) was then induced via radial artery ablation at 30 dg in another cohort of pregnant guinea pigs (n = 8) to generate IUGR fetuses (52 dg; n = 8); control fetuses (52 dg; n = 7) were from sham surgeries with no radial artery ablation. At 32 dg, Ctip2- and CR-immunoreactive (IR) cells had populated the cerebral cortex, whereas SST-IR cells had not, suggesting these neurons were yet to complete migration. At 52 dg, in IUGR versus control fetuses, there was a reduction in SST-IR cell density in the cerebral cortex (p = .0175) and hilus of the dentate gyrus (p = .0035) but not the striatum (p > .05). There was no difference between groups in the density of Ctip2-IR (cortex) or CR-IR (cortex, hippocampus) neurons (p > 0.05). Thus, we propose that an imbalance in inhibitory (SST-IR) and excitatory (Ctip2-IR) neurons in the IUGR fetal guinea pig brain could lead to excitatory/inhibitory dysfunction commonly seen in neurodevelopmental disorders such as autism and schizophrenia.

Detection and clinical outcome of small-for-gestational-age fetuses in the third trimester-A comparison between routine ultrasound examination and examination on indication

INTRODUCTION

Fetal growth restriction is a major risk factor for adverse perinatal outcome. As most of the growth-restricted fetuses are small for gestational age (SGA), an efficient antenatal screening method for SGA fetuses would have a major impact on perinatal health. The aim of this study was to compare the SGA prediction rate achieved with third-trimester routine ultrasound estimation of fetal weight (EFW) with that obtained using ultrasound examination on indication. The secondary aim was to evaluate the clinical outcome in relation to the SGA screening method.

MATERIAL AND METHODS

During 1995-2009, two perinatal centers in southern Sweden offered routine ultrasound examination at 32-34 gestational weeks to 99 265 women with singleton pregnancies. Of these, 59 452 (60%) underwent the ultrasound examination. The other population, comprising 24 868 pregnancies, was cared for in another three centers that used a risk-based method with ultrasound examinations on indication only. Of them, 5792 (23%) underwent ultrasound examination at 32-36 gestational weeks. The deviation in the EFW from the expected one was expressed as the EFW z-score, SGA EFW being defined as the EFW z-score less than -2. SGA prediction ability was assessed by receiver operating characteristic (ROC) curves. Crude and adjusted risk ratios were calculated for selected variables of perinatal outcome when comparing the populations.

RESULTS

The SGA prediction ability for routine ultrasound was high, area under the ROC curve was 0.90 (95% CI 0.89-0.91). For an EFW z-score of -1, the sensitivity was 67.3% and specificity was 90.5% among routinely screened pregnancies; corresponding numbers in the ultrasound on indication population were 34.3% and 96.6%. The screened population had a lower risk of preterm birth, birthweight z-score less than -3, and Apgar score less than 7 at 5 min with adjusted risk ratios 0.87 (95% CI 0.82-0.92), 0.75 (95% CI 0.61-0.92), and 0.77 (95% CI 0.68-0.87), respectively. No difference in perinatal mortality was detected. There were no differences in perinatal outcome between the two subcohorts of infants born SGA.

CONCLUSIONS

Third-trimester routine ultrasound improves the detection of SGA antenatally compared with ultrasound performed on indication, but no convincing improvement in perinatal outcome was identified.

Associations between preterm birth, small-for-gestational age, and neonatal morbidity and cognitive function among school-age children in Nepal

Background

The long term consequences of low birth weight (LBW), preterm birth, small-for-gestational age (SGA, defined as birth weight for given gestational age less than the 10th percentile of the reference), and early newborn morbidity on functional outcomes are not well described in low income settings.

Methods

In rural Nepal, we conducted neurocognitive assessment of children (n = 1927) at 7–9 y of age, for whom birth condition exposures were available. At follow-up they were tested on aspects of intellectual, executive, and motor function.

Results

The prevalence of LBW (39.6%), preterm birth (21.2%), and SGA (55.4%) was high, whereas symptoms of birth asphyxia and sepsis were reported in 6.7% and 9.1% of children. In multivariable regression analyses, adjusted for confounders, LBW was strongly associated with scores on the Universal Nonverbal Intelligence Test (UNIT), tests of executive function, and the Movement Assessment Battery for Children (MABC). Preterm was not associated with any of the test scores. Conversely, SGA was significantly (all p < 0.005) associated with lower UNIT scores (−2.04 SE = 0.39); higher proportion failure on Stroop test (0.06, SE = 0.02); and lower scores on the backward digit span test (−0.16, SE = 0.04), MABC (0.98, SE = 0.25), and finger tapping test (−0.66, SE = 0.22) after adjusting for confounders. Head circumference at birth was strongly and significantly associated with all test scores. Neither birth asphyxia nor sepsis symptoms were significantly associated with scores on cognitive or motor tests.

Conclusion

In this rural South Asian setting, intrauterine growth restriction is high and, may have a negative impact on long term cognitive, executive and motor function.

Cardiovascular function in adulthood following intrauterine growth restriction with abnormal fetal blood flow

OBJECTIVES

To examine whether intrauterine growth restriction (IUGR) is associated with increased cardiovascular risk later in life.

METHODS

We examined 19 young adults (aged 22-25 years) who were born at term after IUGR, along with 18 controls. All had been examined previously with fetal Doppler, and in the present follow-up with echocardiography, carotid echo-tracking ultrasound, applanation tonometry, blood pressure and laser Doppler, in order to characterize their cardiac and vascular geometry and/or function.

RESULTS

The diameter of the ascending aorta and the left ventricular diameter were smaller in the IUGR group, but only ascending aortic diameter remained significantly smaller after adjustment for body surface area (P < 0.05). The aortic pressure augmentation index was higher in the IUGR group (P < 0.05). The common carotid artery diameter, intima-media thickness and distensibility as well as left ventricular mass and function were similar in the two groups. IUGR status was found to be an independent predictor of ascending aortic diameter.

CONCLUSIONS

IUGR due to placental dysfunction seems to contribute to the higher systolic blood pressure augmentation and the smaller aortic dimensions that are observed in adults more than 20 years later, with possible negative consequences for future left ventricular performance due to increased aortic impedance.

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.

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.

Cognitive function after intrauterine growth restriction and very preterm birth

OBJECTIVE

To evaluate the effects of intrauterine growth restriction (IUGR) with absent or reversed end-diastolic blood flow in the umbilical artery and very preterm birth on cognitive outcome at 5 to 8 years of age.

METHODS

We studied 34 children with IUGR born at a median of 26.9 gestational weeks (GWs) (range: 24-29 GWs) (PT-IUGR), 34 matched preterm appropriate-for-gestational age (PT-AGA) children, and 34 term AGA children (T-AGA) by using the Wechsler Preschool and Primary Scale of Intelligence, Wechsler Intelligence Scale for Children, Strengths and Difficulties Questionnaire, and Brown's attention-deficit disorder (ADD) scales.

RESULTS

The PT-IUGR group had mean (SD) scores on the verbal IQ (VIQ) and full-scale IQ (FSIQ) of 83.8 (17.3) and 78.9 (16.6), respectively, compared with the PT-AGA group, which had scores of 96.0 (14.5) and 90.1 (14.2) (P = .003 and P < .007), and the T-AGA group, which had scores of 101.3 (12) and 102.9 (13.2) (P < .001 and P < 001), respectively. The VIQ difference remained significant after adjustment for parental level of education, gestational age at birth, and neonatal morbidity. Performance IQ (PIQ) did not differ between the PT-IUGR and PT-AGA groups; their mean PIQs were lower than that of the T-AGA group (P < .001). Boys in the PT-IUGR group scored lower than girls in VIQ and FSIQ (P = .005 and .007, respectively). Behavior and ADD scores did not differ between the preterm groups.

CONCLUSIONS

Children born very preterm after IUGR have an increased risk for cognitive impairment at early school age compared with children delivered very preterm for other reasons. Differences in cognitive outcome were restricted to boys who may have been especially vulnerable to the influence of IUGR and very preterm birth.

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.

Obstetric management of intrauterine growth restriction

The aim of obstetric management is to identify growth-restricted foetuses at risk of severe intrauterine hypoxia, to monitor their health and to deliver when the adverse outcome is imminent. After 30-32 gestational weeks, a Doppler finding of absent or reverse end-diastolic flow in the umbilical artery of a small-for-gestational age foetus is in itself an indication for delivery. In very preterm foetuses, the intrauterine risks have to be balanced against the risk of prematurity. All available diagnostic information (e.g., Doppler velocimetry of umbilical artery, foetal central arteries and veins and of maternal uterine arteries; foetal heart rate with computerised analysis of short-term variability; amniotic fluid amount; and foetal gestational age-related weight) should be collected to support the timing of delivery. If possible, the delivery should optimally take place before the onset of late signs of foetal hypoxia (pathological foetal heart rate pattern, severely abnormal ductus venosus blood velocity waveform, pulsations in the umbilical vein).

Cerebellum of the premature infant: rapidly developing, vulnerable, clinically important

Brain abnormality in surviving premature infants is associated with an enormous amount of neurodevelopmental disability, manifested principally by cognitive, behavioral, attentional, and socialization deficits, most commonly with only relatively modest motor deficits. The most recognized contributing neuropathology is cerebral white matter injury. The thesis of this review is that acquired cerebellar abnormality is a relatively less recognized but likely important cause of neurodevelopmental disability in small premature infants. The cerebellar disease may be primarily destructive (eg, hemorrhage, infarction) or primarily underdevelopment. The latter appears to be especially common and relates to a particular vulnerability of the cerebellum of the small premature infant. Central to this vulnerability are the extraordinarily rapid and complex developmental events occurring in the cerebellum. The disturbance of development can be caused either by direct adverse effects on the cerebellum, especially the distinctive transient external granular layer, or by indirect remote trans-synaptic effects. This review describes the fascinating details of cerebellar development, with an emphasis on events in the premature period, the major types of cerebellar abnormality acquired during the premature period, their likely mechanisms of occurrence, and new insights into the relation of cerebellar disease in early life to subsequent cognitive/behavioral/attentional/socialization deficits.

Signs of fetal brain sparing are not related to umbilical cord blood gases at birth

BACKGROUND

Fetal chronic hypoxia leads to centralization of circulation in order to spare the vital organs brain, adrenals and the heart. This can be documented by Doppler ultrasound. Increased blood velocity in the fetal middle cerebral artery (MCA) is an acknowledged sign of centralization of circulation in chronic hypoxia, and is called brain sparing.

AIM

Our aim was to assess the relationship between signs of brain sparing in the MCA and umbilical cord blood gases at birth.

STUDY DESIGN

A prospective study.

SUBJECTS

Singleton 57 high-risk pregnancies (outcome was compared with 21 normal pregnancies).

METHODS

MCA Doppler was performed within 24 h of elective caesarean section in high-risk pregnancies. Umbilical cord blood gases were analysed at birth.

MAIN OUTCOME MEASURES

Cord blood gases were related to signs of centralization of fetal circulation in the MCA.

RESULTS

No correlation between signs of brain sparing in the MCA and cord blood gases. Apgar score at 5'<7 was seen in three newborns, but only one of these had antenatal signs of brain sparing. Newborns with antenatal brain sparing were admitted more often (p<0.04) and had a longer duration of stay in NICU (p<0.03) compared to newborns without brain sparing.

CONCLUSION

Decreased pulsatility index in MCA is an acknowledged sign of fetal centralization of circulation during chronic hypoxia. However, signs of brain sparing are not related to cord blood gases at birth, which might suggest that redistribution of fetal circulation can maintain normal blood gases for a long time during chronic hypoxia.

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

OBJECTIVE

To assess the neurodevelopmental outcome at 2 years of age of children who had been small-for-gestational-age (SGA) term babies with cerebral blood flow redistribution.

METHODS

Perinatal outcome was assessed in a cohort of 97 term singleton appropriate-for-gestational-age and 125 term singleton SGA fetuses with normal umbilical artery Doppler, stratified according to the presence of cerebral blood flow redistribution. Neurodevelopmental outcome was assessed prospectively at 2 years of age by means of the 24-month Age & Stage Questionnaire (ASQ).

RESULTS

Of the 125 SGA fetuses, 25 had redistribution of the cerebral blood flow, and 100 did not. There were no significant differences in perinatal outcome between these two SGA groups. At 2 years of age, children who had been SGA fetuses with middle cerebral artery (MCA) pulsatility index (PI) < 5(th) centile had a higher incidence of suboptimal neurodevelopmental outcome compared with those with normal MCA-PI (52% vs. 31%; P = 0.049) and a lower mean centile in communication (53.1 vs. 67.4; P = 0.006) and problem-solving (39.7 vs. 47.4; P = 0.04) areas.

CONCLUSION

SGA fetuses with cerebral blood flow redistribution have a higher risk of subtle neurodevelopmental deficits at 2 years of age. This challenges the concept that fetal cerebral redistribution is an entirely protective mechanism and suggests MCA-PI as a risk stratifying factor for adverse neurodevelopmental outcome.

Pathological prenatal Doppler sonography findings and their association with neonatal cranial ultrasound abnormalities in a high risk collective

The aim of this study was to evaluate whether prenatal Doppler ultrasound plays a role in the risk assessment of neonatal abnormal cranial ultrasound findings (NACU). Doppler examinations of blood flow velocities in the umbilical artery (n = 132), the fetal middle cerebral artery (n = 96) and the ductus venosus (n = 46) were conducted in 132 consecutive high-risk cases. The cases were divided into three groups: normal (I), pathological (II) and highly pathological Doppler (III) results, according to the resistance index calculated and were assessed for any association between the Doppler groups and the short-term outcome of the neonate, especially NACU. A significant association was found between Doppler groups and gestational age at delivery, birth weight, length and head circumference, growth restriction, cesarean section rate, Apgar score and pH values. NACU was diagnosed significantly more often in the pathological (12.1%) and highly pathological (38.5%) Doppler groups than in the group with normal Doppler (1.7%; p < 0.001). Multivariate analysis showed that the Doppler groups (odds ratio 1.67, 95% confidence interval [CI] 1.14-2.84, p < 0.001) and gestational age at delivery (odds ratio 1.37, 95% CI 1.08-2.74; p < 0.001) were independent variables that could be used to predict NACU. The present study showed that a pathological prenatal Doppler result is highly predictive for NACU in addition to gestational age and can therefore be used for risk assessment.

Expected day of delivery from ultrasound dating versus last menstrual period--obstetric outcome when dates mismatch

OBJECTIVE

To analyse the association between fetal size at time of dating ultrasound and risk for preterm delivery and small-for-gestational-age (SGA) birth and to evaluate if timing of ultrasound, that is before 14 weeks of gestation or after 16 weeks affects this association.

DESIGN

Retrospective cohort study.

SETTING

Ultrasound departments of Ultragyn, Stockholm, Sweden.

POPULATION

A total of 28,776 singleton pregnancies dated between 1998 and 2004.

METHODS

Obstetric outcome was assessed through linkage of the cohort to the Swedish Medical Birth Register.

MAIN OUTCOME MEASURES

Risks of preterm delivery, low birthweight for gestational age, pre-eclampsia, asphyxia, respiratory distress, instrumental delivery, caesarean section, and postterm birth were calculated for the groups dated early and late.

RESULTS

When the expected date of delivery was postponed after ultrasound dating by 7 days or more, there was an increased risk for preterm delivery and pre-eclampsia in the late dating group (OR 1.49, 95% CI 1.27-1.73 and OR 1.27, 95% CI 1.02-1.60, respectively) but not in the early dating group. In both dating groups, there was an increased risk for SGA birth (OR 1.77, 95% CI 1.13-2.78 and OR 2.09, 95% CI 1.59-2.73, respectively) There was no increased risk for any of the other diagnoses.

CONCLUSION

Our study gives further support to the notion that intrauterine growth restriction may be present as early as the first trimester. Accordingly, our study also suggests that surveillance of pregnancies with postponed estimated date of delivery may provide means for increased detection of fetal growth restriction.

Prediction and perinatal outcomes of fetal growth restriction

Assessment of fetal growth and wellbeing is one of the major purposes of antenatal care. Some fetuses have smaller than expected growth in utero and while some of these fetuses are constitutionally small, others have failed to meet their growth potential, that is they are growth restricted. While severe growth restriction is uncommon, the consequences of it being undetected may include perinatal death or severe morbidity. It is, therefore, important to have strategies in place to detect the fetus at risk of growth restriction. These would include an assessment of 'prior risk' from maternal history and examination combined with the results of biochemical and ultrasound investigations, the most promising of which are uterine artery Doppler and biochemistry. We discuss some of the factors to consider when stratifying the obstetric population into degrees of likelihood for growth restriction, and discuss aspects of the management and outcome of pregnancies complicated by growth restriction.

Doppler changes in the main fetal brain arteries at different stages of hemodynamic adaptation in severe intrauterine growth restriction

OBJECTIVE

To evaluate changes in the temporal evolution and regional distribution of arterial brain Doppler parameters in relation to different stages of hemodynamic adaptation in fetuses with severe intrauterine growth restriction (IUGR).

METHODS

Thirty-six fetuses with severe IUGR (<or= 32 weeks of gestation) and abnormal umbilical artery (UA) pulsatility index (PI) (mean > 2 SD) were evaluated longitudinally with pulsed Doppler ultrasound at four different hemodynamic stages: Stage 1 (n = 36), mean UA-PI > 2 SD or absent UA end-diastolic flow; Stage 2 (n = 34), abnormal middle cerebral artery (MCA) PI (mean < 2 SD); Stage 3 (n = 30), reversed UA end-diastolic flow; Stage 4 (n = 12), absent or reversed atrial flow in the ductus venosus. In addition, 36 normally grown fetuses were studied for comparison. PI and time-averaged maximum velocity (TAMXV) in the MCA and the anterior cerebral (ACA), pericallosal (PER) and posterior cerebral (PCA) arteries were measured.

RESULTS

In IUGR fetuses, PI values from all arteries were significantly reduced at Stage 2. At Stages 3 and 4, ACA-PI and PCA-PI did not change further, whereas MCA-PI and PER-PI showed a slight increase. In the ACA, MCA and PER, TAMXV in Stage 2 increased significantly. In Stages 3 and 4, ACA and PER-TAMXV remained unchanged, whereas MCA-TAMXV showed a slight decrease, mirroring the PI values. PCA-TAMXV values were similar to controls at all stages.

CONCLUSION

In IUGR fetuses, the brain arteries differ in the magnitude and time sequence of Doppler parameters in relation to systemic hemodynamic adaptation, suggesting the existence of regional brain redistribution processes.

Cognitive function in young adults following intrauterine growth restriction with abnormal fetal aortic blood flow

OBJECTIVE

Intrauterine growth restriction (IUGR) is a recognized risk factor for neurological deficits later in life. Abnormal fetal blood flow in the presence of IUGR helps to distinguish fetuses with true growth impairment from those that are small but normally grown. This study aimed to evaluate the influence of IUGR with abnormal fetal blood flow on cognitive function and psychological development in young adults.

METHODS

Cognitive capacity (Wechsler adult intelligence scale-III (WAIS-III)) and psychological development (symptom check-list and Wender Utah rating scale) were evaluated at 18 years of age in 19 subjects who had had IUGR (abnormal fetal blood flow in the descending aorta and birth weight small-for-gestational age) and in 23 control subjects who had had normal fetal aortic blood flow and birth weight appropriate-for-gestational age (AGA). School grades at 16 years of age were also recorded.

RESULTS

The IUGR subjects had significantly lower results at 18 years of age in the combined subtests of the WAIS-III measuring executive cognitive functions (P = 0.03) and lower school grades at 16 years of age (P = 0.03) compared with the AGA group. IUGR subjects did not exhibit significantly more psychological distress symptoms.

CONCLUSION

IUGR with abnormal fetal blood flow is associated with impaired executive cognitive function in young adults.

Small-for-gestational-age fetuses with normal umbilical artery Doppler have suboptimal perinatal and neurodevelopmental outcome

OBJECTIVE

To evaluate the perinatal and neurodevelopmental outcome of small-for-gestational-age fetuses with normal umbilical artery Doppler managed expectantly during pregnancy and delivery.

STUDY DESIGN

Perinatal and neurodevelopmental outcome was assessed from a cohort of singleton small-for-gestational-age fetuses with normal umbilical artery Doppler and normally grown controls matched by gestational age at delivery, parity and parental socio-economic level. Neurodevelopmental outcome was prospectively evaluated by means of the 24-month Age&Stage Questionnaire (ASQ).

RESULTS

A total of 129 small-for-gestational-age fetuses and 259 controls were included. Small-for-gestational-age fetuses had a higher risk for neonatal intensive care unit admission (15.5% versus 3.9%; p<0.001) and significant neonatal morbidity (2.3% versus 0%; p=0.04) than controls. At 24-months, these fetuses showed significantly lower neurodevelopmental centile in the problem solving (42.8 versus 52.1; p=0.001) and personal-social (44.4 versus 54.6; p<0.001) areas than controls.

CONCLUSION

Perinatal and neurodevelopmental outcome in small-for-gestational-age fetuses with normal umbilical artery Doppler is suboptimal, which may challenge the role of umbilical artery Doppler to discriminate between normal-SGA and growth-restricted fetuses.

Fetal brain sparing is strongly related to the degree of increased placental vascular impedance

BACKGROUND

Doppler ultrasound examination has become an established method of clinical surveillance in high-risk pregnancies. Doppler indication of fetal brain sparing (BS) is an acknowledged sign of circulation redistribution during chronic hypoxia.

OBJECTIVES

To evaluate the relationship between placental vascular resistance and signs of BS in middle cerebral artery (MCA) blood flow velocity.

METHODS

The MCA, uterine artery, and umbilical artery (UA) were located by color Doppler ultrasound in 103 high-risk pregnancies at risk for intrauterine fetal hypoxia. The blood velocity spectrum was analyzed for the following parameters: pulsatility index (PI) and signs of notching in the uterine arteries. Z-score was calculated for the MCA PI.

RESULTS

Signs of BS in the MCA were correlated to increased placental vascular impedance. The degree of BS in the MCA expressed as Z-scores was correlated to increasing vascular impedance, both in the umbilical and uterine arteries, and to adverse outcome of pregnancy. The greatest deviation in MCA PI Z-scores was seen in preterm pregnancies.

CONCLUSION

A clear correlation exists between increasing placental vascular impedance and BS in the MCA. Preterm pregnancies express the greatest deviation from the mean MCA PI.

Antenatal Doppler measurements and early brain injury in very low birth weight infants

OBJECTIVE

To determine the correlation between fetoplacental blood flow and brain injury and volumes in very low birth weight (VLBW) infants.

STUDY DESIGN

Antenatal blood flow from the umbilical artery (UA), middle cerebral artery (MCA), and descending aorta was determined in 70 VLBW infants. The directions of the total diastolic flow of the aortic isthmus and the end-diastolic flow of ductus venosus also were measured. Serial brain ultrasound examinations and MRI at term were performed to assess brain abnormalities. On the basis of brain imaging findings, the newborn infants were classified as normal (n = 14), intermediate brain pathology (n = 31), and major pathology (n = 25) groups.

RESULTS

Abnormalities in fetoplacental blood flow were not related to anatomic brain lesions. However, an abnormal UA/MCA pulsatility index ratio was associated with reduced total brain volume (mean, 360 mL; SD, 32.5 mL) and reduced cerebral volume (344 mL; SD, 28.4 mL) compared with infants with normal UA/MCA pulsatility index ratio (mean, 405 mL; SD, 51.3 mL, P = .01, and mean, 368 mL; SD, 52.3 mL, P = .012), respectively.

CONCLUSIONS

Redistribution of fetal blood flow in VLBW infants is associated with reduced brain volume at term age. Neurodevelopmental follow-up of this cohort will clarify the significance of these blood flow changes on development.

Fetal middle cerebral to uterine artery pulsatility index ratios in normal and pre-eclamptic pregnancies

OBJECTIVES

To calculate the normal range for the fetal middle cerebral artery (MCA)/uterine artery pulsatility index (PI) ratio in the third trimester of pregnancy and to assess its value, compared with that of the MCA/umbilical artery PI ratio, in predicting an unfavorable outcome of pregnancies complicated by pre-eclampsia.

METHODS

Doppler blood flow velocimetry of the uterine and umbilical arteries and fetal MCA was performed. We calculated the ratios between 1) the PI of the MCA and the mean PI value of both uterine arteries and 2) the PI of the MCA and the PI of the umbilical artery. All women were examined at or beyond 26 weeks of gestation. A cross-sectional study of 231 normal pregnancies was conducted to construct the reference range. Values below the 5th percentile or an MCA/umbilical artery PI ratio lower than 1.08 were defined as brain-sparing. A further 115 pregnancies with pre-eclampsia (50 mild and 65 severe) were assessed prospectively and the results were related to perinatal outcome. The accuracy of MCA/uterine artery and MCA/umbilical artery PI ratios for prediction of unfavorable pregnancy outcome was compared.

RESULTS

Normal MCA/uterine artery PI ratios decreased with advancing gestational age. Redistribution of the fetal circulation indicated by a low MCA/uterine artery PI ratio was seen in 30% of the mild (n=15) and 46% of the severe (n=30) pre-eclamptic cases. There was a significant difference between those without and those with signs of brain-sparing, respectively, in mean birth weight (2456.0 vs. 1424.5 g), gestational age at delivery (35.6 vs. 31.3 weeks) and gestational age at the time of examination (34.9 vs. 30.9 weeks). Furthermore, there was a significantly higher rate of small-for-gestational-age (SGA) neonates (57.8% vs. 25.7%), preterm delivery (100% vs. 81.8%) and Cesarean section (90.7% vs. 66.7%) in cases with an MCA/uterine artery PI ratio below the 5th percentile. However, there was no difference between the groups in the rate of low 5-min Apgar scores, admission to the neonatal intensive care unit, or deliveries before 34 weeks. The MCA/uterine artery and MCA/umbilical artery PI ratios were similar in the prediction of adverse perinatal outcome. Both ratios were better at predicting the outcome of pregnancy than were signs of increased vascular impedance in either the umbilical or uterine arteries.

CONCLUSIONS

Normal MCA/uterine artery PI ratio decreases with gestational age. Abnormally low MCA/ uterine artery PI ratios are related to unfavorable pregnancy outcome. The predictive value of the MCA/uterine artery PI ratio is similar to that of the MCA/umbilical artery PI ratio.

Ultrasound Markers of Fetal Infection, Part 2

Up to 1% of all pregnancies have clinically overt intra-amniotic bacterial infections, and an even larger percentage of pregnant women may be affected by silent infections. Although most pregnant women with overt intra-amniotic bacterial infection have experienced prolonged rupture of membranes (PROM), symptomatic and most silent nonviral intra-amniotic infections may occur with intact membranes. The etiology of intra-amniotic infection after PROM is almost always polymicrobial and consists of genital tract pathogens, such as group B streptococci, Chlamydia trachomatis, Neisseria gonorrhoeae, mycoplasmas, aerobic Gram-negative bacilli, such as the coliforms, and facultative and anaerobic endogenous organisms, such as peptococci, peptostreptococci, and Bacteroides species. These organisms gain access to the uterine cavity by the ascending route. Organisms such as Treponema pallidum, Listeria monocytogenes, Toxoplasma gondii, trypanosomes, and plasmodia are capable of gaining access to the amniotic cavity by transplacental hematogenous spread, and cause devastating fetal infections. Symptomatic intra-amniotic infection is usually a diagnosis of exclusion. Diagnostic criteria based on both clinical and laboratory findings lack sensitivity and are nonspecific. It is difficult to obtain uncontaminated intra-amniotic samples, especially when there is PROM. The problem is even greater with silent infections. In most cases, fetal infection is suspected after an unexplained and unexpected adverse outcome. Maternal morbidity is increased with intra-amniotic infection; although maternal mortality is extremely rare in developed countries, this is not the case in societies where pregnant women have limited or no access to medical care. Although infected women who are treated early and aggressively with wide-spectrum antibiotics do well, more than 10% of these women develop bacteremia and up to half of them will require cesarean delivery because of poor uterine contractions and arrest of labor. The overwhelming majority of term neonates exposed to intrauterine infection after PROM do well, but up to 30% of these neonates require treatment of neonatal pneumonia or bacteremia. Outcomes for preterm neonates or for neonates who experienced silent fetal infections are more severe. Morbidity and mortality rates in these cases are high, and survivors may have long-term devastating sequelae. The ability to identify ultrasound markers of fetal infection will help clinicians identify etiologic agents with greater accuracy and correlate these infections with specific antepartum and postpartum syndromes. The recognition of markers of intrauterine infection will also reduce unexpected adverse outcomes that result from undiagnosed fetal infections.

Suboptimal neurodevelopment in very preterm infants is related to fetal cardiovascular compromise in placental insufficiency

OBJECTIVE

The purpose of this study was to determine the relationship between fetal cardiovascular hemodynamics and neurodevelopmental outcome in infants born before 32 gestational weeks with placental insufficiency.

STUDY DESIGN

Seventeen fetuses that underwent Doppler ultrasonography within 24 hours before delivery were included in this prospective cross-sectional study. Placental histology was examined. Multiple inflammatory markers and vascular endothelial growth factor (VEGF) and its receptor were analyzed from umbilical cord serum. Neurodevelopmental outcome was assessed by Griffiths scales at 1 year of corrected age.

RESULTS

Infants with suboptimal outcome (n = 7) had higher umbilical artery, ductus venosus, and inferior vena cava pulsatility index values (P < .05) and lower weight-indexed cardiac outputs (P < .05) than infants with normal outcome (n = 10). Placental histology and serum revealed no inflammation. VEGF values were similar among all infants.

CONCLUSION

In placental insufficiency with delivery before 32 gestational weeks, suboptimal neurodevelopment was related to decreased fetal weight-indexed cardiac output and increased systemic venous pressure.

Impaired vascular growth in late adolescence after intrauterine growth restriction

BACKGROUND

Abnormal blood flow in a fetus small for gestational age indicates true fetal intrauterine growth restriction (IUGR). We tested the hypothesis that IUGR with abnormal fetal blood flow is associated with long-term abnormal vascular morphology and function in adolescence.

METHODS AND RESULTS

In a prospective study, vascular mechanical properties of the common carotid artery (CCA), abdominal aorta, and popliteal artery (PA) were assessed by echo-tracking sonography in 21 adolescents with IUGR and abnormal fetal aortic blood flow and in 23 adolescents with normal fetal growth and normal fetal aortic blood flow. Endothelium-dependent and -independent vasodilatation of the brachial artery was measured by high-resolution ultrasound. After adjustment for body surface area and sex, the IUGR group had significantly smaller end-diastolic vessel diameters than the referents in the abdominal aorta and PA (mean difference, 1.7 mm [95% CI, 0.62 to 2.74] and 0.6 mm [95% CI, 0.25 to 1.02], respectively) (P=0.003 and P=0.002, respectively), with a similar trend in the CCA (P=0.09). A higher resting heart rate was observed in the IUGR group (P=0.01). No differences were found in stiffness or in endothelium-dependent and -independent vasodilatation between the 2 groups.

CONCLUSIONS

IUGR caused by placental insufficiency appears to be associated with impaired vascular growth persisting into young adulthood in both men and women. The smaller aortic dimensions and the higher resting heart rate seen in adolescents with previous IUGR may be of importance for future cardiovascular health.

Does antenatal identification of small-for-gestational age fetuses significantly improve their outcome?

OBJECTIVES

Most obstetric clinics have a program for the identification of small-for-gestational age (SGA) fetuses because of the increased risk of fetal complications that they present. We have a structured model for the identification and follow-up of SGA pregnancies. We aimed to determine whether the recognition of SGA antepartum improves fetal outcome.

METHODS

All pregnancies at Malmö University Hospital from 1990 to 1998 (n = 26 968) were reviewed. SGA fetuses identified prior to delivery (n = 681) were compared with those not identified (n = 573). Also, all pregnancies with SGA fetuses were compared with those appropriate-for-gestational age (AGA) (n = 24 585). The risk of serious fetal complications (hypoxic encephalopathy grade 2 or 3, intracranial hemorrhage, Apgar score <4 at 5 min, neonatal convulsions, umbilical pH <7.0, cerebral palsy, mental retardation, stillbirth, intrapartum or infant death) was assessed with cross-tabulation and logistic regression analysis, adjusted for gestational age and degree of SGA.

RESULTS

When compared with SGA fetuses identified before delivery (54%), SGA fetuses not identified before delivery were characterized by a four-fold increased risk of adverse fetal outcome (odds ratio, 4.1; 95% CI, 2.5-6.8). Similarly, compared with AGA fetuses, SGA fetuses were associated with a four-fold increased risk of serious fetal complications.

CONCLUSIONS

A structured antenatal surveillance program for fetuses identified as SGA results in a lower risk of adverse fetal outcome, compared with cases of SGA fetuses not identified antepartum.

Current concepts in intrauterine growth restriction

Regulation of fetal growth is multifactorial and complex. Diverse factors, including intrinsic fetal conditions as well as maternal and environmental factors, can lead to intrauterine growth restriction (IUGR). The interaction of these factors governs the partitioning of nutrients and rate of fetal cellular proliferation and maturation. Although IUGR is probably a physiologic adaptive response to various stimuli, it is associated with distinct short- and long-term morbidities. Immediate morbidities include those associated with prematurity and inadequate nutrient reserve, while childhood morbidities relate to impaired maturation and disrupted organ development. Potential long-term effects of IUGR are debated and explained by the fetal programming hypothesis. In formulating a comprehensive approach to the management and follow-up of the growth-restricted fetus and infant, physicians should take into consideration the etiology, timing, and severity of IUGR. In addition, they should be cognizant of the immediate perinatal response of the growth-restricted infant as well as the childhood and long-term associated morbidities. A multi disciplinary approach is imperative, including early recognition and obstetrical management of IUGR, assessment of the growth-restricted newborn in the delivery room, possible monitoring in the neonatal intensive care unit, and appropriate pediatric follow-up. Future research is necessary to establish effective preventive, diagnostic, and therapeutic strategies for IUGR, perhaps affecting the health of future generations.

Paediatric consequences of fetal growth restriction

The evidence for outcome following fetal growth restriction (FGR) has previously been inferred from studies, based on babies who were born small for gestational age (SGA). Great care is required when evaluating studies in this area due to a number of potential confounders. It does appear, however, that FGR is associated with an increased risk of poor neurological outcome. This includes an increased risk of cerebral palsy in babies greater than 32 weeks' gestation. Below 32 weeks, the effects of prematurity appear to negate the effects of FGR. FGR is also associated with cognitive deficit and behaviour problems. Babies with poor prenatal head growth appear to have a worse cognitive outcome. However, the role of 'fetal brain sparing' remains unclear, as impaired cognitive outcome is still evident in babies with appropriate head growth. Recent studies, which have identified FGR more accurately using fetal growth standards, have found an increased incidence of major intracranial injury and other adverse neonatal outcomes, which had previously been thought to occur less frequently in FGR babies. FGR is also associated with poor postnatal growth. The majority of children with FGR demonstrate catch-up growth in the first 2 years of life. Children who fail to demonstrate catch-up growth have a high risk of long-term growth problems. There is evidence of impaired growth hormone activity in some children with FGR who have persistent poor growth in the postnatal period.

Abnormal retinal optic nerve morphology in young adults after intrauterine growth restriction

Intrauterine growth restriction (IUGR) is a recognized risk factor for neurologic deficits later in life. Abnormal fetal blood flow in the presence of fetal growth retardation helps to distinguish true fetal growth impairment from small but normally grown infants. The present study aimed to investigate the influence of IUGR with abnormal fetal blood flow on retinal optic nerve morphology at 18 y of age. A prospective study was performed in 19 subjects with IUGR [abnormal fetal aortic blood flow velocity; median birth weight deviation of -31% (-22 to -42%; median (range)] and in 23 subjects with a normal birth weight for gestational age [normal fetal aortic blood flow velocity; median birth weight deviation of -2% (-10 to 22%)]. All subjects were previously examined concerning minor neurologic dysfunction (MND) at 7 y of age. The ocular fundus was examined by ophthalmoscopy, and the optic nerve morphology was evaluated by digital image analysis. Decrease in neuroretinal rim area at 18 y of age was associated with increasing negative birth weight deviation (r = 0.71, p < 0.0001). The subjects with severe MND at 7 y had a reduced neuroretinal rim area [median (range), 1.57 mm(2) (1.37-1.78 mm(2))] compared with those with less severe MND [1.94 mm(2) (1.33-2.71 mm(2))] and with those with normal neurologic function [2.18 mm(2) (1.75-2.70 mm(2)); p < 0.05 and p < 0.0001, respectively]. A decrease in neuroretinal rim area reflects either a reduction in axonal volume or a decrease in the number of axons in the optic nerve. It is yet unclear whether this finding represents neuronal changes within other cerebral regions in subjects with IUGR.

Early alteration of structural and functional brain development in premature infants born with intrauterine growth restriction

Placental insufficiency with fetal intrauterine growth restriction (IUGR) is an important cause of perinatal mortality and morbidity and is subsequently associated with significant neurodevelopmental impairment in cognitive function, attention capacity, and school performance. The underlying biologic cause for this association is unclear. Twenty-eight preterm infants (gestational age 32.5 +/- 1.9 wk) were studied by early and term magnetic resonance imaging (MRI). An advanced quantitative volumetric three-dimensional MRI technique was used to measure brain tissue volumes in 14 premature infants with placental insufficiency, defined by abnormal antenatal Doppler measurements and mean birth weights <10(th) percentile (1246 +/- 299 g) (IUGR) and in 14 preterm infants matched for gestational age with normal mean birth weights 1843 +/- 246 g (control). Functional outcome was measured at term in all infants by a specialized assessment scale of preterm infant behavior. Premature infants with IUGR had a significant reduction in intracranial volume (mean +/- SD: 253.7 +/- 29.9 versus 300.5 +/- 43.5 mL, p < 0.01) and in cerebral cortical gray matter (mean +/- SD: 77.2 +/- 16.3 versus 106.8 +/- 24.6 mL, p < 0.01) when measured within the first 2 wk of life compared with control premature infants. These findings persisted at term with intracranial volume (mean +/- SD: 429.3 +/- 47.9 versus 475.9 +/- 53.4 mL, p < 0.05) and cerebral cortical gray matter (mean +/- SD: 149.3 +/- 29.2 versus 189 +/- 34.2 mL, p < 0.01). Behavioral assessment at term showed a significantly less mature score in the subsystem of attention-interaction availability in IUGR infants (p < 0.01). Cerebral cortical gray matter volume at term correlated with attention-interaction capacity measured at term (r = 0.45, p < 0.05). These results suggest that placental insufficiency with IUGR have specific structural and functional consequences on cerebral cortical brain development. These findings may provide insight into the structural-functional correlate for the developmental deficits associated with IUGR.

Absent or reverse end-diastolic flow in the umbilical artery: intellectual development at school age

OBJECTIVE

This study was designed to establish whether, in growth-retarded fetuses, absent or reverse end-diastolic (ARED) flow velocity in the umbilical artery can be predictive of an increased incidence of long-term neurological and intellectual impairment.

STUDY DESIGN

A total of 14 children with intra-uterine growth retardation (IUGR) and ARED flow in the umbilical artery and 11 children without this velocimetric pattern were examined by pediatric neuropsychiatrists at a median age of 8.7 years to evaluate and compare their neurological and intellectual development.

RESULTS

The incidence of major neurological sequelae was higher in the children with ARED velocity in the umbilical artery (21%) than in those without this velocimetric pattern (9%), as was the incidence of mild neurological sequelae (35% versus 27%). No differences in mean intelligence quotient (IQ) as evaluated by mean of Intelligence Scale for Children-Revised (WISC-R) scale were found between the two groups of children at school age.

CONCLUSIONS

Our data demonstrate that Doppler velocimetry in the umbilical artery is a reliable predictor for neurological sequelae when ARED flow is present but cannot be considered a good predictor of intellectual performance at school.

Absent or reversed end-diastolic blood flow in the umbilical artery and abnormal Doppler cerebroplacental ratio--cognitive, neurological and somatic development at 3 to 6 years

The objective of this study was to examine the cognitive, neurological and somatic developments of children who had in utero an absent or reversed end-diastolic blood flow (ARED) in the umbilical artery or an abnormal cerebroplacental ratio (ABF).

METHODS

16 children with ARED blood flow and 15 children with ABF were each matched to children with the same gestational age, appropriate for gestational age, the same sex and born within 4 months. Data were assessed at the age of 3-6 years. Children with asphyxia, neonatal infection, malformation or major surgical interventions in the neonatal period were excluded. Each child underwent a neuropediatrical examination; furthermore, a Kaufman Assessment Battery for Children, a Snijders-Oomen Intelligence Scale for Children and a Man-Drawing Test were used to evaluate cognitive development. The socioeconomic status was also assessed.

RESULTS

Children in the ARED group remained lighter and had a higher frequency of microcephaly. In the Kaufman Assessment Battery for Children and the Snijders-Oomen Intelligence Scale for Young Children, cognitive development was impaired in the ARED and the ABF groups compared to the control group. The ARED and the ABF groups, however, showed no differences. The Man-Drawing Test and the Denver Development Test did not show any differences.

DISCUSSION

ARED blood flow and ABF showed impaired cognitive development. The degree of impairment was the same in the ARED and the ABF groups. Long-term follow-up studies until adulthood are necessary to see if impaired cognitive development remains significant in these groups of patients.

Perinatal predictors of neurodevelopmental outcome in small-for-gestational-age children at 18 months of age

OBJECTIVE

Our purpose was to explore the influence of a range of perinatal variables on neurodevelopment at 18 months in a cohort of small-for-gestational-age (SGA) children born in the mid 1990s.

STUDY DESIGN

Two hundred eighty-two SGA children (birth weight <10th centile) were followed up prospectively; 220 (78%) had Bayley Scales of Infant Development II performed at 18 months' corrected age.

RESULTS

The mean (SD) gestation at delivery was 36.5 (2.7) weeks and mean birth weight was 2095 (549) g. The mean Bayley Scales of Infant Development scores were as follows: Mental Developmental Index score, 95.6 (14.5); Psychomotor Developmental Index score, 97.9 (14.8); and Behavioural Rating Scale score, 110.6 (13.5). SGA children whose mothers had pregnancy-induced hypertension were less likely to have low Mental Development Index scores than SGA children whose mothers were normotensive during pregnancy (10 [23%] vs 78 [44%]. P =.01). Low Psychomotor Development Index scores were associated with not being breast-fed at 3 months (odds ratio [OR] 3.5; 95% CI 1.2-10.1) and long neonatal nursery stay (OR 2.8, 95% CI 1.02-7.05). A low Behavioral Rating Scale score was associated with a large z score for head circumference at birth (OR 2.4, 95% CI 1.2-4.8) and cord arterial base deficit (OR 1.2, 95% CI 1.01-1.4).

CONCLUSION

Few of the perinatal variables previously reported are predictive of early childhood outcome in this modern cohort of SGA infants.

Doppler velocimetry in the evaluation of fetal hypoxia

Knowledge of fetal hemodynamic physiology has developed enormously during the last two decades due to Doppler ultrasound. Some of this knowledge has been utilized for routine surveillance of high-risk pregnancies. The prediction of fetal hypoxia before the development of life lasting sequel is of major importance, especially in the very premature case with absent end-diastolic blood flow in the umbilical artery before lung maturity. This review gives an overview of the present knowledge in this field.

Intrauterine growth restriction

Pathophysiological processes underlying intrauterine growth restriction are very complex and poorly understood. Growth restricted fetuses are at risk of hypoxia and, therefore, an early diagnosis of intrauterine growth restriction is important for initiation of fetal surveillance. Application of a three-dimensional ultrasound method for estimation of fetal weight promises better precision. Use of conditional standard deviation scores of fetal biometric variables has been suggested for improved individualized evaluation of intrauterine growth. Application of umbilical artery Doppler velocimetry in the clinical management of growth-restricted fetuses after 32 weeks of gestation leads to decreased perinatal mortality and lower rates of obstetric interventions. Evaluation of fetal state before 32 weeks is difficult and should include Doppler examination of placental circulation and several fetal arterial and venous vessel beds. In addition, recordings of short-term variability of fetal heart rate and biophysical profile have been suggested for fetal surveillance. Important new data on the time sequence of Doppler changes in various vessels of compromised very preterm growth restricted fetuses have been presented, which will enable the establishment of clinical management protocols for evaluation in prospective randomized studies.

Outcome at school age following antenatal detection of absent or reversed end diastolic flow velocity in the umbilical artery

AIM

To determine whether fetal compromise, manifested by abnormalities of Doppler recordings of umbilical artery velocity waveforms in utero, is associated with neurodevelopmental or educational abnormalities at school age.

METHODS

A cohort of neonates born following high risk pregnancies had been previously identified for a study of the perinatal sequelae of absent (AEDFV) and reversed (REDFV) end diastolic flow velocities. Seventy six children were assessed at 5-12 years of age by a developmental paediatrician who was blinded to perinatal course and Doppler assessments. Forty children born following pregnancies with forward end diastolic flow velocities (FEDFV), were compared with 27 with AEDFV and nine with REDFV. Tests of cognitive, neurological, and sensory function were performed, and reports of behavioural and educational progress were obtained from parents and teachers.

RESULTS

There were no significant differences between FEDFV and AEDFV groups, but on tests of mental ability and neuromotor function the REDFV group had worse scores than either FEDFV or AEDFV. Comparing REDFV and FEDFV groups, the British Ability Scales general conceptual ability mean scores were 87.7 versus 101, and the Quick Neurological Screening Test mean scores were 32.8 versus 21.5.

CONCLUSIONS

Absence of EDFV is well recognised as a marker of fetal compromise which is associated with acute perinatal sequelae. This study suggests it is not associated with adverse neurodevelopmental outcome. However, we found reversal of EDFV on antenatal assessment to be associated with a wide range of problems at school age, suggesting that REDFV represents intrauterine decompensation which may have adverse effects on the developing brain.

Can the degree of retrograde diastolic flow in abnormal umbilical artery flow velocity waveforms predict pregnancy outcome?

OBJECTIVE

Reverse end-diastolic flow is the most pathological type of the umbilical artery flow velocity waveform. We aimed to investigate whether additional prognostic information can be obtained from umbilical artery waveforms in cases with reverse end-diastolic flow.

SUBJECTS AND METHODS

Umbilical artery Doppler velocity waveforms from 44 fetuses with reverse end-diastolic flow were analyzed and the following parameters measured: the highest amplitude and the area below the maximum velocity curve of forward and reverse flow (A, B and C, D, respectively) and the duration of forward and reverse flow (Tc and Td, respectively). Ratios A/B, C/D and Tc/Td were calculated. The cut-off values for A/B, C/D and Tc/Td with the best predictive values for perinatal death were established with the help of receiver operating characteristics curves. The three curves were compared with each other.

RESULTS

Of the three ratios, A/B and C/D had the best capacity to predict perinatal death. Both ratios had acceptable sensitivities, specificities and positive predictive values. In this regard, A/B and C/D were comparable. The cut-off values for A/B and C/D were 4.3 and 4.52, respectively. Survivors had I significantly higher A/B and C/D ratios than non-survivors (P = 0.0001 and 0.0003, respectively). Significantly more fetuses with A/B or C/D below the established cut-off values had pulsations in the venous system (P < 0.05). In fetuses with a gestational age < =210 gestational days the survival rate was significantly higher in those with A/B or C/D above the cut-off values (P = 0.03 and 0.003, respectively).

CONCLUSIONS

The A/B or C/D ratio can be used for quantification of the reverse end-diastolic flow waveforms in the umbilical artery and may offer additional information to the evaluation of fetal condition.

A critical appraisal of the use of umbilical artery Doppler ultrasound in high-risk pregnancies: use of meta-analyses in evidence-based obstetrics

OBJECTIVES

To reanalyze randomized controlled trials on the use of umbilical artery Doppler velocimetry in high-risk pregnancies and determine which high-risk pregnancies benefit from the use of Doppler velocimetry.

METHODS

Searching Medline, the Cochrane Library and Embase we found 13 randomized controlled trials on the use of Doppler velocimetry in high-risk pregnancies. Of these, six included pregnancies with strictly defined suspected intrauterine growth restriction and/or hypertensive disease of pregnancy ('well-defined studies'); the rest included a great variety of high-risk pregnancies ('general risk studies'). The studies were analyzed with particular regard to the heterogeneity and to outcome. Audits of the perinatal deaths reported in the randomized controlled trials were performed by a panel of 32 international experts.

RESULTS

The 'well-defined studies' had a more uniform study design as compared to the 'general risk studies' and they showed a significant reduction in antenatal admissions (odds ratio, 0.56; 95% confidence interval, 0.43-0.72), inductions of labor (0.78; 0.63-0.96), elective deliveries (inductions of labor and elective Cesarean sections) (0.73; 0.61-0.88) and Cesarean sections (0.78; 0.65-0.94). By perinatal audit it was found that more perinatal deaths in the 'well-defined studies' were potentially avoidable by use of Doppler velocimetry ( P < 0.0005) and the rate of avoidable perinatal deaths was higher among controls (50%) than cases (20%) in this group.

CONCLUSION

The randomized controlled trials on umbilical artery Doppler velocimetry show major differences regarding study design and technical and clinical issues and, therefore, they should not be pooled in a simple meta-analysis. By stratification it was found that only in pregnancies with suspected intrauterine growth restriction and/or hypertensive disease of pregnancy will the use of umbilical artery Doppler velocimetry reduce the number of perinatal deaths and unnecessary obstetric interventions.

Two types of umbilical venous pulsations and outcome of high-risk pregnancy

Normally, blood flows evenly in the umbilical vein, without fluctuation. A pulsating pattern has been reported during fetal heart failure and asphyxia. Recently we have noticed two types of pulsating pattern; its relationship to adverse outcome is unclear. In a prospective multicenter study, recording of umbilical cord venous blood flow was conducted in high-risk pregnancies admitted for routine artery Doppler. In cases of pulsating flow or signs of vascular resistance in the umbilical artery, the examination was extended to the intra-abdominal part of the umbilical vein. Venous pulsation, single or double, were noted and correlated to perinatal outcome. Venous flow pulsatility was noted in 83 fetuses during 2 years, 26 had a double pulsating pattern, which was closely related to increased vascular resistance in the umbilical artery and perinatal mortality. A single pulsating venous pattern in one location had a good prognosis. In conclusion a double pulsating venous pattern, especially if extending to the cord, is an ominous finding in high-risk pregnancy associated with poor perinatal outcome. A single pulsating pattern predicted a much better outcome and might be an indication for delivery in the high-risk case.

Correlation between prenatal velocity waveforms in the aortic isthmus and neurodevelopmental outcome between the ages of 2 and 4 years

OBJECTIVE

Experimental studies on fetal lambs have shown that during an increase in the resistance to placental flow the delivery of oxygen to the brain is preserved as long as net flow through the aortic isthmus is antegrade. Our purpose was to determine whether the same changes in aortic isthmus flow in human subjects have any impact on neurodevelopmental outcome.

STUDY DESIGN

Forty-four fetuses were retrospectively included in this study on the basis of an abnormal Doppler velocity in the umbilical artery. Mean gestational age at delivery was 33.0 +/- 2.0 weeks and mean birth weight 1386 +/- 435 g. The neurodevelopmental condition was assessed between the ages of 2 and 4 years. The developmental score was analyzed in relation to the flow patterns in the fetal aortic isthmus, which were classified as follows: group A, net isthmic flow antegrade (defined as the ratio of the systolic antegrade to the diastolic retrograde velocity integrals) (n = 39); group B, net isthmic flow retrograde (n = 5).

RESULTS

Nonoptimal neurodevelopment was observed in 19 (49%) of 39 fetuses in group A and in all 5 fetuses (100%) in group B. This difference is significant and leads to a relative risk of 2.05 (95% confidence interval, 1.49-2.83) for neurodevelopmental deficit when predominantly retrograde flow is observed in the fetal aortic isthmus before birth.

CONCLUSION

Measuring the ratio of antegrade to retrograde velocity integrals in the aortic isthmus could help in the indirect assessment of cerebral oxygenation during placental circulatory insufficiency.

Reduced number of neurons in the hippocampus and the cerebellum in the postnatal guinea-pig following intrauterine growth-restriction

Intrauterine growth restriction is a risk factor for neurological and behavioural deficits in children although the precise underlying biological correlate for this is unclear. The present study shows that animals with intrauterine growth restriction, induced by a period of reduced placental blood flow during the second half of pregnancy, demonstrate reduced numbers of neurons in the hippocampus and the cerebellum in conjunction with retarded dendritic and axonal growth within these structures. Intrauterine growth restriction was induced at 30 days gestational age by unilateral uterine artery ligation in pregnant guinea-pigs. At one week of age, the total number of CA1 pyramidal neurons in the hippocampus and the Purkinje neurons in the cerebellum were determined using the combined fractionator/optical disector technique. The Cavalieri Principle was used to determine the volume of specific regions within the hippocampus and cerebellum. The body weight of animals that were classified as intrauterine growth-restricted was reduced by 42% (n=8) compared with control animals (n=8, P<0.001), while there was a smaller effect on brain weight (16% reduction, P<0.01). Estimates of the total number of neurons showed a reduction in CA1 pyramidal neurons in growth-restricted animals (4.19+/-0.43x10(5)) compared with control (5.20+/-0.44x10(5), P<0.01), and the volume of the stratum oriens layer above the CA1 region, which contains the apical dendrites of the CA1 pyramidal neurons, was reduced by 21% (P<0.01) in growth-restricted animals. In the cerebellum there was a reduction in the number of Purkinje neurons in growth-restricted animals (3.97+/-0.50x10(5)) compared with control (5.13+/-0.52x10(5), P<0.01), and in the volume of the molecular layer (17%, P<0.05), the internal granular layer (22%, P<0.01) and in the volume of the cerebellar white matter (23%, P<0.01). These results show that a period of placental insufficiency during the second half of pregnancy can effect brain development in a way which could lead to neurological and behavioural deficits in the postnatal animal.

Antenatal predictors of the neurologic sequelae at 3 years of age: a multivariate analysis

OBJECTIVE

To study the association between fetal blood flow abnormalities and the occurrence of long-term neurologic sequelae.

STUDY DESIGN

Umbilical, aortic and middle cerebral artery blood flow parameters were obtained by Doppler examination and retrospectively analyzed in 128 high-risk singleton pregnancies, followed by neurologic examination of the surviving children at 3 years of age. Traditional parameters of neurologic outcome (Apgar scores, intrauterine growth retardation (IUGR), umbilical artery pH and base deficit, gestational age, birth weight, newborn encephalopathy, mode of delivery, fetal heart rate, neurosonographic examination) were included as possible confounding factors. Mann-Whitney U-test, Student's t-test, analysis of variance or Fisher's exact test, where applicable, were used for the univariate analysis. A stepwise logistic regression procedure was conducted to test the independent association of selected perinatal risk factors on neurological outcome. Statistical significance was assumed at P<0.05.

RESULTS

Eighteen out of 114 surviving children suffered neurologic illness at 3 years of age. Four children had major neurologic dysfunction and the remaining 14 suffered minor or mild form of the disease. Although blood flow parameters and various perinatal parameters did not differ significantly between the group of children with major neurologic dysfunction and healthy children, aortic resistance index showed an independent association with occurrence of minor or mild neurologic disabilities.

CONCLUSION

Antenatal evaluation of the aortic blood flow might be an important predictive variable for permanent neurologic disturbances.

Umbilical artery Doppler studies in small for gestational age babies reflect disease severity

OBJECTIVES

To determine: 1. whether abnormal umbilical artery Doppler studies were independently associated with newborn morbidity; and 2. whether small for gestational age babies with normal umbilical artery Doppler studies had small mothers and a low rate of newborn malnutrition and morbidity.

DESIGN

Prospective observational study.

SETTING

National Women's Hospital, a tertiary referral centre, Auckland, New Zealand.

POPULATION

One hundred eighty-six women and their small for gestational age babies (birthweight < 10th%) who had been participants in one of two randomised controlled trials of small for gestational age pregnancies between 1993 and 1997.

METHODS

Newborn morbidity and morphometry were compared between small for gestational age babies with normal and abnormal umbilical artery Doppler studies (resistance index > 95th%). Maternal demographic characteristics and morbidity were also compared.

RESULTS

Compared with small for gestational age babies with normal umbilical artery Doppler studies (n = 109), small for gestational age babies with abnormal umbilical artery Doppler studies (n = 77) were diagnosed earlier in pregnancy as being small for gestational age (30.3 vs 32.9 weeks, P < 0.001), were smaller in all body proportions at birth (median Z score birthweight -1.82 vs -1.70, P = 0.004, Z score length -1.86 vs -1.36, P < 0.0001, Z score head circumference -1.31 vs -0.89, P < 0.0001) and were more likely to experience newborn morbidity. When birthweight and gestation were entered into a logistic regression model, an abnormal umbilical artery Doppler study was not an independent predictor of prolonged newborn nursery admission or hypoglycaemia. Of small for gestational age babies with normal umbilical artery Doppler studies, 53 (49%) had low ponderal indices, 26/98 (26%) were hypoglycaemic and 38 (35%) required admission to the newborn nursery. There was no difference in maternal height, weight and ethnicity between the abnormal and normal umbilical artery Doppler groups.

CONCLUSIONS

Abnormal umbilical artery Doppler studies reflect earlier onset and more severe growth restriction and are not independently associated with newborn morbidity. Small for gestational age babies with normal Doppler studies have a high rate of newborn nursery admission and malnutrition at birth and are not all just normal small babies.

Foetal nutrition, foetal growth restriction and health later in life

Retarded intrauterine growth has been linked to increased risk of perinatal mortality and morbidity, sudden infant death and poorer health later in life. The independent variables used in these studies are mainly neonatal size parameters, such as weight, ponderal index and ratios of head and abdominal measures. These are, in terms of foetal development and growth, crude parameters. This paper discusses the concepts of growth retardation used in most clinical and epidemiological studies. It is again emphasized that small for gestational age (SGA) and intrauterine growth retardation (IUGR) are different concepts. SGA is a size parameter that may or may not reflect restricted foetal growth and is therefore of limited value. Even IUGR, defined as retarded foetal growth rate, may be a too crude a criterion to select foetuses with short- and long-term health risks. Other biophysical measurements, such as foetal blood flow patterns and biochemical parameters, may be helpful in a better selection of these foetuses and infants. Furthermore, different causes of IUGR, e.g. poor maternal nutrition versus insufficient placental function, may not have the same effects on the foetus. The discrepancies in the results of studies on the relationship between IUGR or foetal malnutrition and short- and long-term health risks may be explained by the crudeness of the independent variables used. In the future, research on the biology of the developing human foetus should be more focused in the studies of the relationship between the intrauterine environment and nutrition and risk of poor health later in life.