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

Placental Changes and Neuropsychological Development in Children-A Systematic Review

Placental dysfunction may increase the offspring's later-life disease risk. The objective of this systematic review was to describe associations between pathological placental changes and neuropsychological outcomes in children after the neonatal period. The inclusion criteria were human studies; original research; direct placental variables; neuropsychological outcomes; and analysis between their associations. The exclusion criterion was the offspring's age-0-28 days or >19 years. The MEDLINE and EMBASE databases were last searched in May 2022. We utilized the ROBINS-I for the risk of bias assessment and performed a narrative synthesis. In total, 3252 studies were identified, out of which 16 were included (i.e., a total of 15,862 participants). Half of the studies were performed on children with neonatal complications, and 75% of the studies reported an association between a placental change and an outcome; however, following the completion of the funnel plots, a risk of publication bias was indicated. The largest study described a small association between placental size and a risk of psychiatric symptoms in boys only. Inconsistency between the studies limited the evidence in this review. In general, no strong evidence was found for an association between pathological placental changes and childhood neuropsychological outcomes after the neonatal period. However, the association between placental size and mental health in boys indicates a placental sexual dimorphism, thereby suggesting an increased vulnerability for male fetuses.

VEGF Expression in Umbilical Cord MSC Depends on the Patient's Health, the Week of Pregnancy in Which the Delivery Took Place, and the Body Weight of the Newborn - Preliminary Report

Introduction

Cells collected from Wharton's jelly are a rich source of mesenchymal stem cells. They can be easily obtained and grown using the adhesive method. They produce many types of proteins, including VEGF. Their role is to participate in angiogenesis, vasodilation, stimulation of cells to migrate, and chemotactic activity. The aim of this study was to evaluate expression of genes from the vascular endothelial growth factor family: VEGFA, VEGFB and VEGFC in MSC and the analysis of dependence of the expression of the studied genes on clinical factors related to the course of pregnancy and childbirth, and health of mother and child.

Material and Methods

The research material was an umbilical cord obtained from 40 patients hospitalized in the Department of Obstetrics and Pathology of Pregnancy of the Independent Public Clinical Hospital No.1 in Lublin. The age of the women was 21-46, all gave birth by cesarean section. Some of the patients suffered from hypertension and hypothyroidism. Material collected from patients immediately after delivery was subjected to enzymatic digestion with type I collagenase. The isolated cells were then cultured in adherent conditions, and then gene expression was assessed using qPCR and the immunophenotype of the cells was assessed cytometrically.

Results

Conducted studies have shown significant differences in expression of VEGF family genes depending on clinical condition of mother and child. Significant differences in VEGF-family gene expression level in umbilical cord MSC collected from women with hypothyroidism, hypertension, time of labor and birth weight of the baby were shown.

Conclusion

Probably due to hypoxia (caused, for example, by hypothyroidism or hypertension), the MSCs found in the umbilical cord may react with an increased expression of VEGF and a compensatory increase in the amount of secreted factor, the aim of which is, i.a., vasodilation and increase of blood supply to the fetus through the umbilical vessels.

Antenatal hemodynamic findings and heart rate variability in early school-age children born with fetal growth restriction

BACKGROUND

According to epidemiological studies, impaired intrauterine growth increases the risk for cardiovascular morbidity and mortality in adulthood. Heart rate variability (HRV), which reflects the autonomic nervous system function, has been used for risk assessment in adults while its dysfunction has been linked to poor cardiovascular outcome.

OBJECTIVE

We hypothesized that children who were born with fetal growth restriction (FGR) and antenatal blood flow redistribution have decreased HRV at early school age compared to their gestational age matched peers with normal intrauterine growth.

STUDY DESIGN

A prospectively collected cohort of children born with FGR (birth weight <10th percentile and/or abnormal umbilical artery flow, n = 28) underwent a 24-hour Holter monitoring at the mean age of 9 years and gestational age matched children with birth weight appropriate for gestational age (AGA, n = 19) served as controls. Time- and frequency domain HRV indices were measured and their associations with antenatal hemodynamic changes were analyzed.

RESULTS

Time- and frequency domain HRV parameters (standard deviation of R-R intervals, SDNN; low frequency, LF; high frequency, HF; LF/HF; very low frequency, VLF) did not differ significantly between FGR and AGA groups born between 24 and 40 weeks. Neither did they differ between children born with FGR and normal umbilical artery pulsatility or increased umbilical artery pulsatility. In total, 56% of the FGR children demonstrated blood flow redistribution (cerebroplacental ratio, CPR < -2 SD) during fetal life and their SDNN (p = .01), HF (p = .03) and VLF (p = .03) values were significantly lower than in FGR children with CPR ≥ -2SD.

CONCLUSIONS

Early school age children born with FGR and intrauterine blood flow redistribution demonstrated altered heart rate variability. These prenatal and postnatal findings may be helpful in targeting preventive cardiovascular measures in FGR.

Dysregulation of inflammatory cytokines and inhibition of VEGFA in the human umbilical cord are associated with negative pregnancy outcomes

INTRODUCTION

Cytokines and vascular endothelial growth factors (VEGF) are involved in all aspects of pregnancy: from placentation, through fetal development, parturition and neonatal well-being. Umbilical cord inflammatory cytokines and/or VEGF have not been well studied with respect to dysregulation associated with disorders of pregnancy or maternal/neonatal outcomes.

METHODS

Here we have used multiplex ELISA to screen umbilical cord lysates (comprising cord blood, endothelia and Wharton's jelly, n = 380), for levels of IFN-γ, IL1-β, IL-6, IL-8, IL-10, TNF-α and VEGFs A, C and D and associations with 46 ICD9/10 codes encompassing obstetric, maternal and neonatal variables.

RESULTS

No significant differences were observed for IFNγ, VEGFC or VEGFD with any clinical outcomes. The cytokines IL1-β, IL-6, IL-8, IL-10, and TNF-α showed varying levels of induction and suppression with primarily fetal-placental and neonatal complications. The largest number of significant differences between umbilical cytokines and clinical outcomes were observed for chorioamnionitis (IL1-β, IL-6, IL-8, TNF-α), and meconium passage during birth (IL1-β, IL-6, IL-8) where significant pro-inflammatory responses occurred and sex differences in IL-8 expression were noted. In contrast, gonococcal infection showed suppressed immune response significantly lowering IL1-β, IL-6, IL-8, IL-10 and TNF-α. For 12/46 negative pregnancy outcomes, strong suppression of VEGFA occurred.

DISCUSSION

Angiogenic and inflammatory changes in the umbilical cord could be detrimental by increasing vascular permeability in the umbilical artery or vein and/or altering vascular tone, either of which would alter blood flow affecting delivery and removal of compounds. Further elucidation of inflammatory responses in the umbilical cord may provide mechanistic understanding of adverse pregnancy outcomes.

Perinatal Micro-Bleeds and Neuroinflammation in E19 Rat Fetuses Exposed to Utero-Placental Ischemia

Offspring of preeclampsia patients have an increased risk of developing neurological deficits and cognitive impairment. While low placental perfusion, common in preeclampsia and growth restriction, has been linked to neurological deficits, a causative link is not fully established. The goal of this study was to test the hypothesis that placental ischemia induces neuroinflammation and micro-hemorrhages in utero. Timed-pregnant Sprague Dawley rats were weight-matched for sham surgery (abdominal incision only) or induced placental ischemia (surgical reduction of utero-placental perfusion (RUPP)); n = 5/group on gestational day 14. Fetal brains (n = 1–2/dam/endpoint) were collected at embryonic day (E19). Placental ischemia resulted in fewer live fetuses, increased fetal demise, increased hematocrit, and no difference in brain water content in exposed fetuses. Additionally, increased cerebral micro-bleeds (identified with H&E staining), pro-inflammatory cytokines: IL-1β, IL-6, and IL-18, eotaxin (CCL11), LIX (CXCL5), and MIP-2 (CXCL2) were observed in RUPP-exposed fetuses. Microglial density in the sub-ventricular zone decreased in RUPP-exposed fetuses, with no change in cortical thickness. Our findings support the hypothesis that exposure to placental ischemia contributes to microvascular dysfunction (increased micro-bleeds), fetal brain inflammation, and reduced microglial density in proliferative brain areas. Future studies will determine whether in utero abnormalities contribute to long-term behavioral deficits in preeclampsia offspring through impaired neurogenesis regulation.

Prenatal Risk Factors for Adverse Developmental Outcome in Preterm Infants-Systematic Review

Background: Preterm infants are still at an increased risk for suboptimal neurodevelopmental outcomes when compared with term born infants. The development of a child born preterm can be jeopardized by suboptimal conditions during pregnancy, in addition to the suboptimal growth environment postnatally compared to the normal in utero environment. This review summarizes the literature on the role of chorioamnionitis, placental insufficiency, and maternal smoking on the developmental outcomes of preterm infants. Methods: A systematic database search was performed to identify all original articles published on or before September 12, 2018 that evaluated the impact of clinical or histological chorioamnionitis, abnormal prenatal fetal and placental blood flow, and prenatal smoking exposure on the neuropsychological and cognitive outcomes of preterm infants. We identified a total of 54 studies. Thirty five original articles evaluated the effects of clinical or histological chorioamnionitis; 15 studies evaluated the effects of abnormal blood flow patterns; and four studies evaluated the effects of maternal smoking during pregnancy. Results: The studies on prenatal risk factors showed conflicting results about the impact on the neurodevelopment of preterm infants. The majority of the studies did not show that chorioamnionitis poses a direct risk to the development of preterm infants. The role of abnormal prenatal placental and fetal blood flow on the development of preterm infants remained inconclusive because the sample sizes were often small and methodological problems complicated the interpretation of the data. Maternal smoking during pregnancy was assessed only in one cohort which showed that maternal smoking is a risk for suboptimal cognitive and neuropsychological development in preterm infants. Conclusions: This review summarizes the data on several prenatal risk factors which play a role in the developmental outcomes of preterm infants. To optimize the developmental outcomes, we need to first optimize the fetal wellbeing before birth. More research that extends from the fetal life to long-term developmental outcomes is needed.

Variation in hospital mortality in an Australian neonatal intensive care unit network

BACKGROUND

Studying centre-to-centre (CTC) variation in mortality rates is important because inferences about quality of care can be made permitting changes in practice to improve outcomes. However, comparisons between hospitals can be misleading unless there is adjustment for population characteristics and severity of illness.

OBJECTIVE

We sought to report the risk-adjusted CTC variation in mortality among preterm infants born <32 weeks and admitted to all eight tertiary neonatal intensive care units (NICUs) in the New South Wales and the Australian Capital Territory Neonatal Network (NICUS), Australia.

METHODS

We analysed routinely collected prospective data for births between 2007 and 2014. Adjusted mortality rates for each NICU were produced using a multiple logistic regression model. Output from this model was used to construct funnel plots.

RESULTS

A total of 7212 live born infants <32 weeks gestation were admitted consecutively to network NICUs during the study period. NICUs differed in their patient populations and severity of illness.The overall unadjusted hospital mortality rate for the network was 7.9% (n=572 deaths). This varied from 5.3% in hospital E to 10.4% in hospital C. Adjusted mortality rates showed little CTC variation. No hospital reached the +99.8% control limit level on adjusted funnel plots.

CONCLUSION

Characteristics of infants admitted to NICUs differ, and comparing unadjusted mortality rates should be avoided. Logistic regression-derived risk-adjusted mortality rates plotted on funnel plots provide a powerful visual graphical tool for presenting quality performance data. CTC variation is readily identified, permitting hospitals to appraise their practices and start timely intervention.

Fetal ventricular interactions and wall mechanics during ductus arteriosus occlusion in a sheep model

We investigated the effect of fetal sheep ductus arteriosus occlusion (DO) on the distribution of cardiac output and left and right ventricular function by tissue and pulsed Doppler at baseline; after 15 and 60 min of DO induced with a vascular occluder; and 15 min after release of DO. Ductal occlusion decreased fetal pO2. Mean left ventricular output increased (p < 0.001) from 725 to 1013 mL/min, and right ventricular (1185 mL/min vs. 552 mL/min) and systemic (1757 mL/min vs. 1013 mL/min) cardiac outputs fell (p < 0.001) after 15 min of DO, compared with baseline. Pulmonary vascular impedance decreased and volume blood flow increased more than threefold during DO, whereas foramen ovale volume blood flow remained unchanged. Left ventricular systolic function was unaffected, whereas isovolumic relaxation velocity deceleration decreased. Right ventricular functional indices remained unchanged. We conclude that DO increased pulmonary volume blood flow, not foramen ovale volume blood flow. Left ventricular output increased, although not as much as right ventricular output fell, resulting in decreased systemic cardiac output. During DO, left ventricular function exhibited diminished relaxation.

Neurodevelopmental outcomes of preterm singletons, twins and higher-order gestations: a population-based cohort study

OBJECTIVE

To study the neurodevelopmental outcomes of multiple (twins, triplets, quads) compared with singleton extremely preterm infants <29 weeks gestation.

DESIGN

Population-based retrospective cohort study.

SETTING

A network of 10 neonatal intensive care units in a geographically defined area of New South Wales and the Australian Capital territory.

PATIENTS

1473 infants <29 weeks gestation born between 1 January 1998 and 31 December 2004.

INTERVENTION

At 2-3 years of corrected age, a neurodevelopmental assessment was conducted using either the Griffiths Mental Developmental Scales or the Bayley Scales of Infant Development II.

MAIN OUTCOME MEASURE

Moderate-severe functional disability was defined as developmental delay (Griffiths Mental Developmental Scales General Quotient or Bayley Scales of Infant Development-II Mental Development Index >2 SDs below the mean), moderate cerebral palsy (unable to walk without aids), sensorineural or conductive deafness (requiring amplification) or bilateral blindness (visual acuity <6/60 in the better eye).

RESULTS

Of the 1081 singletons and 392 multiples followed-up, singletons demonstrated higher rates of systemic infections, steroid treatment for chronic lung disease and birth weight <10th percentile. Moderate-severe functional disability did not differ significantly between singletons and multiples (15.8% vs 17.6%, OR 1.14; 95% CI 0.84 to 1.54; p=0.464). Further subgroup analysis of twins, higher-order gestations, 1st-born multiples, 2nd or higher-born multiples, same and unlike gender multiples, did not demonstrate statistically higher rates of functional disability compared with singletons.

CONCLUSIONS

Premature infants from multiple gestation pregnancies appear to have comparable neurodevelopmental outcomes to singletons.

Population study of neurodevelopmental outcomes of extremely premature infants admitted after office hours

AIM

The aim of the study was to compare neurodevelopmental outcomes of extremely preterm infants admitted during (OH) and after (AH) office hours.

METHODS

A retrospective review of the New South Wales and Australian Capital Territory Neonatal Intensive Care Units' (NICUs) Data Collection of all infants <29 weeks gestation admitted to New South Wales and Australian Capital Territory NICUs between January 1998 and December 2004 was conducted. The primary outcome was moderate/severe functional disability (FD) at 2-3 years follow-up defined as developmental delay (Griffiths Mental Developmental Scales general quotient or Bayley Scales of Infant Development-II mental developmental index >2 standard deviations below the mean), cerebral palsy (unable to walk without aids), deafness (requiring bilateral hearing aids) or blindness (visual acuity <6/60 in the better eye).

RESULTS

Mortality and age at follow-up were comparable between the AH and OH groups. Developmental outcome was evaluated in 972 (74.9%) infants admitted during AH and 501 (74.6%) admitted during OH. FD was not significantly different between the AH and OH groups (17.1% vs. 14.8%, adjusted odds ratio 1.131, 95% confidence interval 1.131 (0.839-1.523), P = 0.420). There were no significant differences between AH and OH infants with cerebral palsy (9.6% vs. 7.6%), developmental delay (5.4% vs. 5.0%) or any other component of FD.

CONCLUSION

There is little circadian variation in mortality and adverse neurodevelopmental outcomes in an NICU network with the current model of after hours staffing and support, and sharing of NICU workload within a network.

Environmental origins of congenital heart disease: the heart-placenta connection

Although the mammalian embryo is well protected in the uterus, environmental chemicals, drugs, and maternal nutritional imbalances can interfere with regulatory pathways directing placental and embryonic development early in gestation. Embryonic cells are most susceptible to environmental influences during cellular specification and differentiation stages. Because biochemical differentiation precedes morphological outcome often by days, the period of susceptibility to environmental chemicals expectedly precedes visible morphogenic effects. The cellular mechanisms by which drugs and other environmental factors disrupt embryonic development and induce cardiac abnormalities have remained undefined.

Neurodevelopment after fetal growth restriction

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

The heart-placenta axis in the first month of pregnancy: induction and prevention of cardiovascular birth defects

Extrapolating from animal studies to human pregnancy, our studies showed that folate (FA) deficiency as well as one-time exposure to environmental factors in the first two to three weeks of human gestation can result in severe congenital heart defects (CHDs). Considering that approximately 49% of pregnancies are unplanned, this period of pregnancy can be considered high-risk for cardiac, as well as for neural, birth defects, as the woman usually is not aware of her pregnancy and may not yet be taking precautionary actions to protect the developing embryo. Using avian and mouse vertebrate models, we demonstrated that FA supplementation prevents CHD induced by alcohol, lithium, or elevation of the metabolite homocysteine, a marker for FA deficiency. All three factors affected the important Wnt signaling pathway by suppressing Wnt-mediated gene expression in the heart fields, resulting in a delay of cardiomyocyte migration, cardiomyogenesis, and CHD. Optimal protection of cardiogenesis was observed to occur with FA supplementation provided upon morning after conception and at higher doses than the presently available in prenatal vitamin supplementation. Our studies demonstrate pathways and cell processes that are involved with protection of one-carbon metabolism during heart development.

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

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

Fetal 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.

Right ventricular performance in the fetus with hypoplastic left heart syndrome

BACKGROUND

In the fetus with hypoplastic left heart syndrome (HLHS), the single right ventricle (RV) pumps the entire cardiac output in utero. By investigating RV performance in utero, we sought to determine the inherent capabilities of a single RV before the increased metabolic demands of postnatal life and surgical palliation. In addition, we sought to determine whether the presence or absence of a left ventricular cavity impacts on RV performance in fetal life.

METHODS

Between November 2004 and December 2006, Doppler flow-derived measures of ventricular performance were obtained with echocardiography in 76 fetuses with normal cardiovascular system and in 48 age-matched fetuses with HLHS from 17 weeks until 40 weeks of gestation. The myocardial performance index, ventricular ejection force, and cardiac output were determined for both groups and compared using unpaired Student's t tests and regression analysis.

RESULTS

In fetuses with HLHS, cardiac output was diminished by 20%, RV ejection force was elevated, and RV myocardial performance index was elevated compared with those of normal fetuses. The presence of a left ventricular cavity did not impact on RV performance in utero.

CONCLUSIONS

Fetuses with HLHS have preserved systolic performance but impaired diastolic performance compared with normal fetuses. The heart of a fetus with HLHS is less efficient than the normal heart in that ejection force of the RV is increased, but overall delivery of cardiac output is lower than normal. We conclude that patients with HLHS have inherent limitations in cardiac performance even before birth.

Infant neurodevelopment following fetal growth restriction: relationship with antepartum surveillance parameters

OBJECTIVES

To evaluate the relationship between fetal Doppler parameters, biophysical profile score (BPP) and neurodevelopmental delay at 2 years of corrected age in infants who had been growth-restricted in utero.

METHODS

This was a prospective observational study including 113 pregnancies complicated by intrauterine growth restriction (IUGR) (abdominal circumference<5th percentile and elevated umbilical artery (UA) pulsatility index). The relationships of UA, middle cerebral artery and ductus venosus (DV) Doppler features, BPP, birth acidemia (artery pH<7.0+/or base deficit>12), gestational age at delivery, birth weight and neonatal morbidity (i.e. bronchopulmonary dysplasia, >Grade 2 intraventricular hemorrhage, or necrotizing enterocolitis) with a 2-year neurodevelopmental delay were evaluated. Best Beginnings Developmental Screen, Bayley Scale of Infant Development II (BSID) and Clinical Adaptive/Clinical Linguistic Auditory Milestone Stage were used. BSID<70, cerebral palsy, abnormal tone, hearing loss and/or blindness defined neurodevelopmental delay.

RESULTS

Seventy-two of the 113 pregnancies completed assessment; there were 10 stillbirths, 19 neonatal deaths, three infant deaths and nine pregnancies with no follow-up. Twenty fetuses (27.8%) had UA reversed end-diastolic velocity (REDV), 34 (47.2%) abnormal DV Doppler features and 31 (43.1%) an abnormal BPP. Median gestational age at delivery and birth weight were 30.4 weeks and 933 g, respectively. Twelve infants had acidemia and 28 neonatal morbidity. There were 38 (52.8%) infants with neurodevelopmental delay, including 37 (51.4%) with abnormal tone, 20 (27.8%) with speech delay, 23 (31.9%) with an abnormal neurological examination, eight (11.1%) with a hearing deficit and six (8.3%) with cerebral palsy. Gestational age at delivery was associated with cerebral palsy (r2=0.52, P<0.0001; 92% sensitivity and 83% specificity for delivery at <27 weeks). UA-REDV was associated with global delay (r2=0.31, P=0.006) and birth weight with neurodevelopmental delay (r2=0.54, P<0.0001; 82% sensitivity and 64% specificity for BW<922 g).

CONCLUSIONS

Although UA-REDV is an independent contributor to poor neurodevelopment in IUGR no such effect could be demonstrated for abnormal venous Doppler findings or BPP. Gestational age and birth weight remain the predominant factors for poor neurodevelopment in growth-restricted infants.

Placenta and fetal growth restriction

The placenta, as the vector for all maternal-fetal oxygen and nutrient exchange, is a principal influence on birthweight. Placental weight summarizes laterally expanding growth of the chorionic disc, and villous arborization yielding the nutrient exchange surface. These different growth dimensions alter fetoplacental weight ratio and ponderal index, and thus may modify placental functional efficiency. The placenta may show a range of histopathologies, some of which are also associated with fetal growth restriction. Different fetal intrinsic abilities to compensate for gross and histo-pathology may clarify the imperfect relationships between fetal growth and both intrauterine pathology, and the long-term health risks associated with poor fetal growth.

Doppler assessment of the aortic isthmus and perinatal outcome in preterm fetuses with severe intrauterine growth restriction

OBJECTIVES

To evaluate the characteristics and association with perinatal outcome of the aortic isthmus (AoI) circulation as assessed by Doppler imaging in preterm growth-restricted fetuses with placental insufficiency.

METHODS

This was a prospective cross-sectional study. Fifty-one fetuses with intrauterine growth restriction (IUGR) and either an umbilical artery (UA) pulsatility index (PI) > 95(th) centile or a cerebroplacental ratio < 5(th) centile were examined at 24-36 weeks' gestation. AoI impedance indices (PI and resistance index) and absolute velocities (peak systolic (PSV), end-diastolic and time-averaged maximum (TAMXV) velocities), were measured in all cases and compared with reference ranges by gestational age. Furthermore, fetuses were stratified into two groups according to the direction of the diastolic blood flow in the AoI: those with antegrade flow (n = 41) and those with retrograde flow (n = 10). Clinical surveillance was based on gestational age and Doppler assessment of the UA, middle cerebral artery and ductus venosus (DV). Adverse perinatal outcome was defined as stillbirth, neonatal death and severe morbidity (respiratory distress syndrome, bronchopulmonary dysplasia, Grade III/IV intraventricular hemorrhage, necrotizing enterocolitis and a neonatal intensive care unit stay > 14 days).

RESULTS

Adverse perinatal outcome was significantly associated with an increased AoI-PI (area under the curve 0.77; 95% CI, 0.63-0.92; P < 0.005). A significant correlation (P < 0.001) was found between retrograde blood flow in the AoI and adverse perinatal outcome, the overall perinatal mortality being higher in the retrograde group (70% vs. 4.8%, P < 0.001). In 4/5 (80%) fetuses the reversal of flow in the AoI preceded that in the DV by 24-48 h. AoI-PSV and AoI-TAMXV were < 5(th) centile in 40/51 (78%) and 48/51 (94%) cases, respectively, whereas AoI-PI was > 95(th) centile in 21/51 (41%) cases.

CONCLUSIONS

Retrograde flow in the AoI in growth-restricted fetuses correlates strongly with adverse perinatal outcome. Absolute velocities in the AoI are decreased in growth-restricted fetuses. The data suggest a potential role for Doppler imaging of the AoI in the clinical surveillance of fetuses with severe IUGR, which should be confirmed in larger prospective studies.

Hemodynamic changes in the fetal arteries during the second half of pregnancy assessed by Doppler velocimetry

The applicability of Doppler velocimetry has been well established regarding intrauterine growth restriction and fetal hypoxia. This method can also be used to determine fetal anemia and cardiac malformations. The main fetal arteries evaluated by Doppler velocimetry are the middle cerebral artery and the umbilical artery. However, the fetal aorta is responsible for the distribution of blood flow to the upper and lower extremities of the human body and should also be properly valued. In order to characterize abnormalities in the arteries of high-risk fetuses, it is necessary to know the hemodynamic modifications of normal fetuses. On this basis, the authors performed a review of fetal hemodynamics evaluated by Doppler velocimetry in the fetal aorta and middle cerebral and umbilical arteries during the second half of pregnancy. The study of fetal vessels by Doppler velocimetry indirectly evaluates the hemodynamic changes occurring in fetuses at risk. In this respect, we emphasize the changes in Doppler velocimetry occurring in fetal anemia, in restricted intrauterine growth, and in normal fetuses.

Severe early onset pre-eclampsia: prognostic value of ultrasound and Doppler assessment

OBJECTIVE

Assess the prognostic value of ultrasound and Doppler parameters in severe preterm pre-eclampsia.

STUDY DESIGN

Prospective cohort study in Cape Town, South Africa, involving 113 women with severe pre-eclampsia between 24 and 34 weeks of gestation and managed expectantly when suitable. Serial ultrasound and multivessel Doppler assessments were performed 2 to 3 times weekly. Observations included fetal weight estimation, growth pattern, amniotic fluid volume, appearance of the heart and bowel, pulsatility index of the uterine, umbilical and middle cerebral arteries and ductus venosus. Perinatal outcome (death or neurological compromise, n=12) and major morbidity (n=62) were related to findings at recruitment and on the last assessment preceding delivery.

RESULTS

In univariate analysis, fetal growth asymmetry and waveform analysis of all three fetal vessels significantly correlated with both end points. The initial fetal weight estimation with a cutoff weight of 1080 g had the highest sensitivity (83.3%) and negative predictive value (97.5%) for poor outcome (P<0.001) while the final ductus venosus pulsatility index had the highest specificity (92%) and positive predictive value (33%). The combination of a raised placentocerebral ratio and ductus venosus pulsatility index close to delivery had the highest (57.1%) positive predictive value. Logistic regression showed the best overall predictive model for poor outcome to be a combination of initial fetal weight estimation and final ductus venosus pulsatility index (overall accuracy 94.6%, RR 20.20 (7.36, 55.41)). The initial fetal weight estimation with a cutoff weight of 1283 g provided the best correct prediction of major morbidity (83.2% overall accuracy, sensitivity 79.0%, specificity 88.2%, positive and negative predictive values of 89.1 and 77.6% respectively). This was better than using the gestational age at recruitment or delivery, birth weight or any of the Doppler results. The prediction of morbidity was not improved by the addition of any other variable in logistic regression analysis.

CONCLUSION

For the short-term outcome measures assessed in this study, the estimated fetal weight at the time of diagnosis is the most important prognostic factor in severe pre-eclampsia with some additional value of ductus venosus assessment.

Reference ranges for Doppler parameters of the fetal aortic isthmus during the second half of pregnancy

OBJECTIVE

To establish reference ranges for blood flow velocity waveforms (FVW) of the fetal aortic isthmus (AoI) during the second and third trimesters of pregnancy.

METHODS

This was a prospective cross-sectional observational study involving 458 uncomplicated singleton pregnancies between 19 and 37 weeks of gestation. Fetal AoI Doppler parameters were assessed in either the longitudinal aortic arch view or the three vessels and trachea view. Regression analysis was used to determine gestational-age-specific reference ranges and to construct nomograms for the following Doppler parameters: pulsatility index (PI), resistance index (RI) and peak systolic (PSV), end-diastolic (EDV) and time-averaged maximum (TAMXV) velocities. Intra- and interobserver reproducibility were evaluated by calculating intraclass correlation coefficients (ICCs) and limits of agreement.

RESULTS

Reliable FVW in the AoI were obtained in all cases. Acceptable intra- and interobserver reproducibility was obtained. With advancing gestation, there was a significant increase in PSV, TAMXV and PI, whereas RI and EDV remained constant during the second half of pregnancy. No cases of absent or reversed flow during diastole were detected.

CONCLUSION

Normal data of the fetal AoI blood FVW throughout the second and third trimesters of pregnancy are provided. The reported Doppler profiles may be of clinical use in the assessment of hemodynamically compromised growth-restricted fetuses.