Risk of ultrasound-detected neonatal brain abnormalities in intrauterine growth-restricted fetuses born between 28 and 34 weeks' gestation: relationship with gestational age at birth and fetal Doppler parameters

Intracranial ultrasound abnormalities and mortality in preterm infants with and without fetal growth restriction stratified by fetal Doppler study results

OBJECTIVE

To evaluate whether fetal growth restriction (FGR) with or without abnormal Dopplers is associated with intracranial abnormalities and death in premature infants.

STUDY DESIGN

Premature infants with and without FGR born between 2016 and 2019 were included. Primary outcome was death, severe intraventricular hemorrhage (IVH) or periventricular leukomalacia (PVL). Groups were compared using standard bivariate testing and multivariable regression.

RESULTS

Among 168 FGR and 560 non-FGR infants, FGR infants with abnormal Dopplers had an increased incidence of death, severe IVH or PVL compared to non-FGR infants (13% (16/123) vs. 7% (41/560); p = 0.03) while FGR infants with normal Dopplers had a nonsignificant decrease. In a logistic regression model, FGR with abnormal Dopplers was associated with more than three times higher odds of death, severe IVH or PVL (OR 3.2, 95% CI 1.54,6.49; p < 0.001).

CONCLUSIONS

Growth-restricted infants with abnormal Dopplers had an increased risk of death, intracranial abnormalities, and prematurity-related morbidities.

Risk Factors for Periventricular Leukomalacia in Preterm Infants: A Systematic Review, Meta-analysis, and GRADE-Based Assessment of Certainty of Evidence

BACKGROUND

We analyzed the certainty of evidence (CoE) for risk factors of periventricular leukomalacia (PVL) in preterm neonates, a common morbidity of prematurity.

METHODS

Medline, CENTRAL, Embase, and CINAHL were searched. Cohort and case-control studies and randomised randomized controlled trials were included. Data extraction was performed in duplicate. A random random-effects meta-analysis was utilizedused. CoE was evaluated as per Grading of Recommendations Assessment, Development and Evaluation (GRADE) guidelines.

RESULTS

One hundred eighty-six studies evaluating 95 risk factors for PVL were included. Of the 2,509,507 neonates assessed, 16,569 were diagnosed with PVL. Intraventricular hemorrhage [adjusted odds ratio: 3.22 (2.52-4.12)] had moderate CoE for its association with PVL. Other factors such as hypocarbia, chorioamnionitis, PPROM >48 hour, multifetal pregnancy reduction, antenatal indomethacin, lack of antenatal steroids, perinatal asphyxia, ventilation, shock/hypotension, patent ductus arteriosus requiring surgical ligation, late-onset circulatory collapse, sepsis, necrotizing enterocolitis, and neonatal surgery showed significant association with PVL after adjustment for confounders (CoE: very low to low). Amongst the risk factors associated with mother placental fetal (MPF) triad, there was paucity of literature related to genetic predisposition and defective placentation. Sensitivity analysis revealed that the strength of association between invasive ventilation and PVL decreased over time (P < 0.01), suggesting progress in ventilation strategies. Limited studies had evaluated diffuse PVL.

CONCLUSION

Despite decades of research, our findings indicate that the CoE is low to very low for most of the commonly attributed risk factors of PVL. Future studies should evaluate genetic predisposition and defective placentation in the MPF triad contributing to PVL. Studies evaluating exclusively diffuse PVL are warranted.

Cerebroplacental ratio and aortic isthmus Doppler in early fetal growth restriction

PURPOSE

To assess the utility of cerebroplacental ratio (CPR) and fetal aortic isthmus (AoI) Doppler in the prediction of perinatal outcome in early fetal growth restriction (FGR).

METHODS

A prospective observational cohort study of 70 early FGR cases was conducted through serial Doppler examinations and findings of the last examination were correlated with perinatal outcome. Doppler blood flow measurements of AoI included end diastolic velocity (EDV), peak systolic velocity (PSV), pulsatility index (PI), resistance index (RI), and isthmic flow index (IFI).

RESULTS

Significant association of CPR and all Doppler indices of AoI with the overall adverse perinatal outcome was seen. The sensitivity of CPR was moderate (63.64%) but higher than most AoI indices. Most AoI Doppler indices (PI, RI, IFI) had higher specificities (100%). AoI PSV and EDV had higher sensitivities than CPR for the prediction of overall adverse perinatal outcome, with AoI PSV having the highest sensitivity (100%).

CONCLUSION

CPR shows significant association and moderate sensitivity for prediction of overall adverse perinatal outcome in early FGR; hence recommended in all cases of early FGR. AoI Doppler also appears to have a role in assessment and decision making in FGR in view of high sensitivity and high specificity of AoI indices in the prediction of perinatal outcome. However, larger studies are required to confirm its utility in the management of early FGR.

Fetal Doppler Assessment in Neonatal Care: Analysis of Fetal Doppler Abnormalities and Neonatal Outcomes

Fetal Doppler ultrasonography provides an effective and noninvasive approach to identify circulatory abnormalities in the maternal-fetal circulation. It is invaluable to assess the hemodynamic status of the fetus under a wide range of physiologic, infectious, and abnormal anatomic conditions. Findings from these studies are often used to make clinical decisions, including whether to proceed with urgent delivery of the fetus. In this review, we focus on key literature describing the main uses of Doppler ultrasonography in neonatal medicine, including how abnormal findings may be implicated in immediate and long-term outcomes. Our review highlights the importance of fetal Doppler examination as an effective intrauterine management strategy, and its full potential is more likely to be realized when considered in context with other available clinical information.

Aortic Isthmus Doppler Velocimetry in Fetuses with Intrauterine Growth Restriction: A Literature Review

Intrauterine growth restriction (IUGR) is associated with poor perinatal prognosis and a higher risk of stillbirth, neonatal death, and cerebral palsy. Its detection and the evaluation of its severity by new Doppler velocimetric parameters, such as aortic isthmus (AoI), are of great relevance for obstetrical practice. The AoI is a vascular segment that represents a point of communication between the right and left fetal circulations. It is considered to be a functional arterial shunt that reflects the relationship between the systemic and cerebral impedances, and has recently been proposed as a tool to detect the status of hemodynamic balance and prognosis of IUGR in fetuses. In the present review, we noticed that in healthy fetuses, the AoI net flow is always antegrade, but in fetuses with IUGR the deterioration of placental function leads to progressive reduction in its flow until it becomes mostly retrograde; this point is associated with a drastic reduction in oxygen delivery to the brain. The more impaired the AoI flow is, the greater is the risk of impairment in the Doppler velocimetry of other vessels; and the alterations of the AoI Doppler seem to precede other indicators of severe hypoxemia. Although there seems to be an association between the presence of retrograde flow in the AoI and the risk of long-term neurologic disability, its role in the prediction of perinatal morbi-mortality remains unclear. The AoI Doppler seems to be a promising tool in the management of fetuses with IUGR, but more studies are needed to investigate its employment in clinical practice.

Obstetric management, tests, and technologies that impact childhood development

Childhood brain development begins before birth, and obstetric management, tests, and technologies designed to diagnose and treat fetal conditions can have an impact on development. Preconception counseling for maternal diabetes and hypertension affect the risk of fetal congenital anomalies and growth restriction. Patients with risk factors for pre-existing maternal diabetes are offered early diabetic screening because earlier diagnosis and treatment can decrease the risk of fetal and neonatal complications. Screening for chromosomal abnormalities in the first or second trimester is offered to all females regardless of age. Cell-free fetal DNA screening can be used to test for fetal genetic abnormalities as early as 9 weeks of gestation with results available in 10 days. Ultrasound performed around 20 weeks' gestation can identify the 3% of fetuses that have a major congenital malformation. Fetal magnetic resonance imaging can be used to better assess fetal central nervous system abnormalities when neurosonography is inconclusive. Doppler ultrasound can be used to assess blood flow in the umbilical artery and fetal middle cerebral artery to aid in the management of the growth-restricted fetus. In summary, diagnosis and treatment of maternal and fetal conditions from the preconception period throughout pregnancy are important for optimizing fetal health and provide the best opportunity for optimal child development. WHAT THIS PAPER ADDS: Cell-free fetal DNA screening can identify fetal genetic abnormalities as early as 9 weeks' gestation. Ultrasound performed around 20 weeks' gestation can detect major fetal congenital malformations. Fetal magnetic resonance imaging can aid neurosonography in the assessment of fetal central nervous system abnormalities. Doppler ultrasound to assess fetal blood flow is used to successfully manage the growth-restricted fetus.

Prognostic value of the aortic isthmus Doppler assessment on late onset fetal growth restriction

Background As conflicting results have been reported about the association of reversed flow on the aortic isthmus (AoI) and adverse perinatal results in fetal growth restriction (FGR), we aim to compare perinatal outcomes (including tolerance to labor induction) of late-onset FGR between those with anterograde and reversed AoI flow. Methods This was an observational retrospective cohort study on 148 singleton gestations diagnosed with late-onset FGR (diagnosis ≥32+0 weeks), with an estimated fetal weight (EFW) <10th centile and mild fetal Doppler alteration: umbilical artery (UA) pulsatility index (PI) >95th centile, middle cerebral artery (MCA)-PI <5th centile or cerebral-placental ratio <5th centile. Anterograde AoI flow was present in n=79 and reversed AoI flow in n=69. Delivery was recommended from 37 weeks in both groups. Perinatal results were compared between the groups. Results The global percentage of vaginal delivery of fetuses with anterograde and reversed blood flow was 55.7% vs. 66.7% (P=0.18) and the percentage of cesarean section (C-section) for non-reassuring fetal status was 12.7% vs. 15.9% (P=0.29), respectively. When evaluating those that underwent labor induction, the vaginal delivery rate was 67.9% vs. 77.2% (P=0.17), respectively. There were no significant differences regarding any other perinatal variables and there were no cases of severe morbidity or mortality. Conclusion We observed that the presence of reversed AoI flow does not worsen perinatal outcomes on fetuses with late-onset growth restriction with mild Doppler alterations. Attempt of labor induction is feasible in these fetuses regardless of the direction of AoI flow.

Neonatal Morbidities of Fetal Growth Restriction: Pathophysiology and Impact

Being born small lays the foundation for short-term and long-term implications for life. Intrauterine or fetal growth restriction describes the pregnancy complication of pathological reduced fetal growth, leading to significant perinatal mortality and morbidity, and subsequent long-term deficits. Placental insufficiency is the principal cause of FGR, which in turn underlies a chronic undersupply of oxygen and nutrients to the fetus. The neonatal morbidities associated with FGR depend on the timing of onset of placental dysfunction and growth restriction, its severity, and the gestation at birth of the infant. In this review, we explore the pathophysiological mechanisms involved in the development of major neonatal morbidities in FGR, and their impact on the health of the infant. Fetal cardiovascular adaptation and altered organ development during gestation are principal contributors to postnatal consequences of FGR. Clinical presentation, diagnostic tools and management strategies of neonatal morbidities are presented. We also present information on the current status of targeted therapies. A better understanding of neonatal morbidities associated with FGR will enable early neonatal detection, monitoring and management of potential adverse outcomes in the newborn period and beyond.

Three-dimensional ultrasound cranial imaging and early neurodevelopment in preterm growth-restricted infants

AIM

Fetal growth restriction (FGR) is associated with increased perinatal morbidity, mortality and long-term neurodevelopmental sequelae. The objective of this study was to examine whether information about early neurodevelopmental deficits was evident using three-dimensional head ultrasound and developmental assessments in preterm infants with FGR, compared with appropriate for gestational age (AGA) infants in the early post-natal period.

METHODS

Twenty preterm FGR infants weighing <10th centile and born between 28 and 32 weeks were compared with age-matched AGA infants. In the second post-natal week after birth, we used three-dimensional ultrasound to assess cerebral ventricular volumes. Prechtl General Movement Assessments were performed at 4-6 weeks after birth. Test of Infant Motor Performance (TIMP) to measure functional motor behaviour was performed at 4-6 and 12-14 weeks corrected age.

RESULTS

There was no statistically significant difference in the combined cerebral ventricular volume between the two groups (FGR, 0.81 ± 0.42 vs. AGA 0.72 ± 0.38 cm³ , P = 0.4). The TIMP assessment at 12-14 week term corrected demonstrated lower scores (worse performance) in FGR infants compared with the AGA cohort (regression coefficient: -7.74 (95% CI -16.06, 0.57); P = 0.07). We observed a significant correlation between greater ventricular volume and lower TIMP scores in the cohorts separately and also overall (FGR, r = -0.5, P = 0.06 vs. AGA, r = -0.62, P = 0.007 and overall, r = -0.53, P = 0.001).

CONCLUSION

Ultrasound in the early weeks may be useful to detect the neuropathology which could then mediate functional consequences.

A placenta clinic approach to the diagnosis and management of fetal growth restriction

Effective detection and management of fetal growth restriction is relevant to all obstetric care providers. Models of best practice to care for these patients and their families continue to evolve. Since much of the disease burden in fetal growth restriction originates in the placenta, the concept of a multidisciplinary placenta clinic program, managed primarily within a maternal-fetal medicine division, has gained popularity. In this context, fetal growth restriction is merely one of many placenta-related disorders that can benefit from an interdisciplinary approach, incorporating expertise from specialist perinatal ultrasound and magnetic resonance imaging, reproductive genetics, neonatal pediatrics, internal medicine subspecialties, perinatal pathology, and nursing. The accurate diagnosis and prognosis for women with fetal growth restriction is established by comprehensive clinical review and detailed sonographic evaluation of the fetus, combined with uterine artery Doppler and morphologic assessment of the placenta. Diagnostic accuracy for placenta-mediated fetal growth restriction may be enhanced by quantification of maternal serum biomarkers including placenta growth factor alone or combined with soluble fms-like tyrosine kinase-1. Uterine artery Doppler is typically abnormal in most instances of early-onset fetal growth restriction and is associated with coexistent preeclampsia and underlying maternal vascular malperfusion pathology of the placenta. By contrast, rare but potentially more serious underlying placental diagnoses, such as massive perivillous fibrinoid deposition, chronic histiocytic intervillositis, or fetal thrombotic vasculopathy, may be associated with normal uterine artery Doppler waveforms. Despite minor variations in placental size, shape, and cord insertion, placental function remains, largely normal in the general population. Consequently, morphologic assessment of the placenta is not currently incorporated into current screening programs for placental complications. However, placental ultrasound can be diagnostic in the context of fetal growth restriction, for example in Breus' mole and triploidy, which in turn may enhance diagnosis and management. Several examples are illustrated in our figures and supplementary videos. Recent advances in the ability of multiparameter screening and intervention programs to reduce the risk of severe preeclampsia will likely increase efforts to deliver similar improvements for women at risk of fetal growth restriction. Placental pathology is important because the underlying pathologies associated with fetal growth restriction have a wide range of recurrence risks. Rare conditions such as massive perivillous fibrinoid deposition or chronic histolytic intervillositis may recur in >50% of subsequent pregnancies. Postpartum care in a placenta-focused program can provide effective counseling for modifiable maternal risk factors, and can assist in planning future pregnancy care based on the pathologic basis of fetal growth restriction.

Antenatal glucocorticoids, magnesium sulfate, and mode of birth in preterm fetal small for gestational age

A diagnosis of fetal growth restriction and subsequent preterm birth is associated with increased risks of adverse perinatal and neurodevelopmental outcomes and potentially long-lasting effects to adulthood. Most such cases are associated with placental insufficiency and the fetal response to chronic intrauterine hypoxemia and nutrient deprivation leads to substantial physiological and metabolic adaptations. The management of such pregnancies, especially with respect to perinatal interventions and birth mode, remains an unresolved dilemma. The benefits from standard interventions for threatened preterm birth may not be necessarily translated to pregnancies with small-for-gestational-age fetuses. Clinical trials or retrospective studies on outcomes following administration of antenatal glucocorticoids and magnesium sulfate for neuroprotection when preterm birth is imminent either have yielded conflicting results for small-for-gestational-age fetuses, or did not include this subgroup of patients. Experimental models highlight potential harmful effects of administration of antenatal glucocorticoids and magnesium sulfate in the pregnancies with fetal small for gestational age although clinical data do not substantiate these concerns. In addition, heterogeneity in definitions of fetal small for gestational age, variations in the inclusion criteria, and the glucocorticoid regime contribute to inconsistent results. In this review, we discuss the physiologic adaptions of the small-for-gestational-age fetus to its abnormal in utero environment in relation to antenatal glucocorticoids; the impact of antenatal glucocorticoids and intrapartum magnesium sulfate in pregnancies with fetal small for gestational age; the current literature on birth mode for pregnancies with fetal small for gestational age; and the knowledge gaps in the existing literature.

Clinician performed ultrasound in fetal growth restriction: fetal, neonatal and pediatric aspects

Fetal growth restriction (FGR) affects 7-10% pregnancies. Conventional and tissue Doppler imaging has noted cardiac compromise during fetal and early neonatal periods in this cohort. In this article, we discuss the use of salient ultrasound parameters across age groups. During fetal life, certain feto-placental sonographic parameters have been linked to adverse perinatal outcomes and are predictive of later life hypertension. During the early postnatal period altered morphometry (hypertrophied and globular hearts) with sub-clinical impairment of cardiac function has been noted in both term and preterm infants with FGR. Vascular imaging has noted thickened and stiffer arteries in association with significantly elevated blood pressure. Similar findings in the pediatric age groups indicate persistence of these alterations, and have formed the basis of intervention studies. Assessment methodology and clinical relevance of these parameters, especially in designing and monitoring of intervention strategies is discussed. Frontline care givers (obstetricians and neonatologists) are increasingly using point of care ultrasound to discern these manifestations of FGR during the sub-clinical phase.

Detection and assessment of brain injury in the growth-restricted fetus and neonate

Fetal growth restriction (FGR) is a common complication of pregnancy and, in severe cases, is associated with elevated rates of perinatal mortality, neonatal morbidity, and poor neurodevelopmental outcomes. The leading cause of FGR is placental insufficiency, with the placenta failing to adequately meet the increasing oxygen and nutritional needs of the growing fetus with advancing gestation. The resultant chronic fetal hypoxia induces a decrease in fetal growth, and a redistribution of blood flow preferentially to the brain. However, this adaptation does not ensure normal brain development. Early detection of brain injury in FGR, allowing for the prediction of short- and long-term neurodevelopmental consequences, remains a significant challenge. Furthermore, in FGR infants the detection and diagnosis of neuropathology is complicated by preterm birth, the etiological heterogeneity of FGR, timing of onset of growth restriction, its severity, and coexisting complications. In this review, we examine existing and emerging diagnostic tools from human and preclinical studies for the detection and assessment of brain injury in FGR fetuses and neonates. Increased detection rates, and early detection of brain injury associated with FGR, will offer opportunities for developing and assessing interventions to improve long-term outcomes.

Aortic isthmus shunt dynamics in normal and complicated monochorionic pregnancies

OBJECTIVE

To study fetal aortic isthmus (AoI) shunt dynamics in monochorionic (MC) twins.

METHODS

Normal and complicated MC pregnancies were prospectively enrolled. The relationship of isthmus flow index (IFI) with Doppler parameters of umbilical artery (UA), descending aorta, middle cerebral artery, and ductus venosus and with left and right ventricular cardiac output and stroke volume was studied.

RESULTS

The IFI was obtained in 180 examinations from 48 pregnancies (24 twin-twin transfusion syndrome, TTTS; 4 selective intrauterine growth restriction, sIUGR; 12 TTTS + sIUGR; and 8 uncomplicated). Median gestational age was 20.9 weeks. AoI diastolic flow was reversed in three cases. UA pulsatility index (PI) and ductus venosus-PI z-scores were negatively correlated with the IFI (r_s -0.40 and -0.26, respectively, p < 0.001). Regression analysis identified only UA-PI as a determinant of the IFI (p < 0.001). The IFI was significantly correlated with left ventricular cardiac output and stroke volume. It did not differ between TTTS donors and recipients. sIUGR fetuses had significantly lower IFI compared with normal-grown counterparts (p < 0.001).

CONCLUSION

In MC gestations, AoI shunting is predominantly determined by placental flow resistance, while cerebral impedance and volume status have no impact. In MC twins, the relationship between AoI flow and outcome deserves further study in the setting of sIUGR. © 2017 John Wiley & Sons, Ltd.

Brain-Sparing in Intrauterine Growth Restriction: Considerations for the Neonatologist

Intrauterine growth restriction (IUGR) is most commonly caused by placental insufficiency, in response to which the fetus adapts its circulation to preserve oxygen and nutrient supply to the brain ('brain-sparing'). Currently, little is known about the postnatal course and consequences of this antenatal adaptation of the cerebral circulation. The altered cerebral haemodynamics may persist after birth, which would imply a different approach with regard to cerebral monitoring and clinical management of IUGR preterm neonates than their appropriately grown peers. Few studies are available with regard to this topic, and the small body of evidence shows controversy. This review discusses the cerebral circulatory adaptations of IUGR fetuses and appraises the available literature on their postnatal cerebral circulation with potential clinical consequences.