Relationship between arterial and venous Doppler and perinatal outcome in fetal growth restriction

Maternal PlGF and umbilical Dopplers predict pregnancy outcomes at diagnosis of early-onset fetal growth restriction

BACKGROUNDSevere, early-onset fetal growth restriction (FGR) causes significant fetal and neonatal mortality and morbidity. Predicting the outcome of affected pregnancies at the time of diagnosis is difficult, thus preventing accurate patient counseling. We investigated the use of maternal serum protein and ultrasound measurements at diagnosis to predict fetal or neonatal death and 3 secondary outcomes: fetal death or delivery at or before 28+0 weeks, development of abnormal umbilical artery (UmA) Doppler velocimetry, and slow fetal growth.METHODSWomen with singleton pregnancies (n = 142, estimated fetal weights [EFWs] below the third centile, less than 600 g, 20+0 to 26+6 weeks of gestation, no known chromosomal, genetic, or major structural abnormalities) were recruited from 4 European centers. Maternal serum from the discovery set (n = 63) was analyzed for 7 proteins linked to angiogenesis, 90 additional proteins associated with cardiovascular disease, and 5 proteins identified through pooled liquid chromatography and tandem mass spectrometry. Patient and clinician stakeholder priorities were used to select models tested in the validation set (n = 60), with final models calculated from combined data.RESULTSThe most discriminative model for fetal or neonatal death included the EFW z score (Hadlock 3 formula/Marsal chart), gestational age, and UmA Doppler category (AUC, 0.91; 95% CI, 0.86-0.97) but was less well calibrated than the model containing only the EFW z score (Hadlock 3/Marsal). The most discriminative model for fetal death or delivery at or before 28+0 weeks included maternal serum placental growth factor (PlGF) concentration and UmA Doppler category (AUC, 0.89; 95% CI, 0.83-0.94).CONCLUSIONUltrasound measurements and maternal serum PlGF concentration at diagnosis of severe, early-onset FGR predicted pregnancy outcomes of importance to patients and clinicians.TRIAL REGISTRATIONClinicalTrials.gov NCT02097667.FUNDINGThe European Union, Rosetrees Trust, Mitchell Charitable Trust.

Clinical significance of intermittent absent end-diastolic flow of the umbilical artery in fetal growth restriction

BACKGROUND

Fetal growth restriction can result from a variety of maternal, fetal, and placental conditions. Umbilical artery Doppler assesses the impedance to blood flow along the fetal component of the placental unit. An abnormal umbilical artery waveform reflects the presence of placental insufficiency and can help differentiate a growth-restricted fetus from the constitutionally small, thus guiding further management. The presence of persistently absent end-diastolic flow and reversed end-diastolic flow is an indication for inpatient antenatal surveillance and preterm delivery. There is no consensus on the optimal management of intermittent absent end-diastolic flow owing to a lack of data to support the ideal delivery timing for growth-restricted fetuses with this finding.

OBJECTIVE

This study aimed to estimate the risks of adverse perinatal outcomes among growth-restricted pregnancies with persistently elevated, intermittently absent, and persistently absent end-diastolic flow. Fetal growth restriction is a common condition that is associated with an increased risk of fetal morbidity and mortality. Intermittently absent umbilical artery end-diastolic flow may be identified among pregnancies with fetal growth restriction. The fetal risks associated with persistently absent end-diastolic flow have been described. However, the risks associated with intermittent absent end-diastolic flow are not as well-known.

STUDY DESIGN

We performed a retrospective cohort study including nonanomalous, singleton, growth-restricted pregnancies that received umbilical artery Doppler assessment at our institution from 2009 to 2020. Fetuses were classified into the following 3 categories: elevated umbilical artery Doppler, intermittent absent end-diastolic flow, and persistently absent end-diastolic flow. The Doppler categories were classified by the most severe in the pregnancy. The primary outcome was a composite of neonatal morbidity.

RESULTS

Total 233 fetuses met the criteria. Of which 78 (33.0%) had elevated umbilical artery Doppler waveforms, 37 (16.0%) had intermittent absent end-diastolic flow, and 119 (51.0%) had absent end-diastolic flow. The composite outcome was statistically different between the groups, occurring in 16.9% with elevated umbilical artery Doppler waveforms (13/77), 35.1% (12/39) with intermittent absent end-diastolic flow, and 56.3% (65/127) with absent end-diastolic flow (P<.001). The odds ratio for the composite outcome was significantly increased in absent end-diastolic flow (odds ratio, 6.15; 95% confidence interval, 3.14-12.80) and was not significantly increased for intermittently absent end-diastolic flow (odds ratio, 2.46; 95% confidence interval, 0.98-6.19) when compared with elevated umbilical artery Doppler waveforms. When adjusted for gestational age at delivery and antenatal steroids, no difference was seen in the primary outcome for intermittent absent end-diastolic flow (adjusted odds ratio, 0.73; 95% confidence interval, 0.20-2.68) and absent end-diastolic flow (adjusted odds ratio, 1.44; 95% confidence interval, 0.51-4.07).

CONCLUSION

Among growth-restricted pregnancies, intermittent absent end-diastolic flow is associated with a similar rate of composite neonatal morbidity as persistently elevated Doppler waveforms. In addition, there is no difference in composite neonatal morbidity between the 3 groups when corrected for gestational age at delivery and antenatal steroid administration. These similar outcomes should be considered when creating an antenatal surveillance plan and discussing the potential for outpatient management.

T2* weighted fetal MRI and the correlation with placental dysfunction

INTRODUCTION

Transverse relaxation time (T2*) is related to tissue oxygenation and morphology. We aimed to describe T2* weighted MRI in selected fetal organs in normal pregnancies, and to investigate the correlation between fetal organ T2* and placental T2*, birthweight (BW) deviation, and redistribution of fetal blood flow.

METHODS

T2*-weighted MRI was performed in 126 singleton pregnancies between 23+6- and 41+3-weeks' gestation. The T2* value was obtained from the placenta and fetal organs (brain, lungs, heart, liver, kidneys, and spleen). In normal BW pregnancies (BW > 10th centile), the correlation between the T2* value and gestational age (GA) at MRI was estimated by linear regression. The correlation between fetal organ Z-score and BW group was demonstrated by boxplots and investigated by analysis of variance (ANOVA) for each organ.

RESULTS

In normal BW pregnancies fetal organ T2* was negatively correlated with GA. We found a significant correlation between BW group and fetal organ T2* z-score in the fetal heart, kidney, lung and spleen. A positive linear correlation was demonstrated between fetal organ T2* and outcomes related to placental function such as BW deviation and placenta T2* in all investigated fetal organs except for the fetal liver. In the fetal heart, kidneys, and spleen the T2* value showed a significant correlation with fetal redistribution of blood flow (Middle cerebral artery Pulsatility Index) before delivery.

DISCUSSION

Fetal T2* is correlated with BW, placental function, and redistribution of fetal blood flow, suggesting that fetal organ T2* reflects fetal oxygenation and morphological changes related to placental dysfunction.

Association between Abnormal Antenatal Doppler Characteristics and Gastrointestinal Outcomes in Preterm Infants

Antenatal Doppler disturbances are associated with fetal hypoxia and may induce a brain-sparing vascular redistribution at the expense of splanchnic circulation, possibly predisposing to gut complications. We aimed to compare several gastrointestinal outcomes among very-low-birthweight (VLBW) preterm infants with different antenatal Doppler features. VLBW infants born between 2010-2022 were retrospectively included and stratified into the following clusters based on antenatal Doppler characteristics: normal Doppler (controls); absent or reversed end-diastolic flow in the umbilical artery (UA-AREDF) alone or also in the ductus venosus (UA+DV-AREDF); and abnormal Doppler with or without brain-sparing redistribution. The following outcomes were evaluated: time to reach full enteral feeds (FEF), feeding intolerance (FI), necrotizing enterocolitis (NEC), and spontaneous intestinal perforation (SIP). Overall, 570 infants were included. Infants born following UA+DV-AREDF had significantly higher FI, NEC, and SIP rates and achieved FEF later compared to controls. Increased FI prevalence and a longer time to FEF compared to controls were also observed among UA-AREDF infants and in the presence of brain-sparing redistribution, which also increased NEC rates. Antenatal Doppler abnormalities exacerbate the gastrointestinal risks of preterm infants. Detailed knowledge of Doppler features can aid in identifying those at highest risk of intestinal complications who may benefit from tailored enteral feeding management.

OXIDATIVE STRESS AND REPRODUCTIVE FUNCTION: Reactive oxygen species in the mammalian pre-implantation embryo

In brief

Reactive oxygen species are generated throughout the pre-implantation period and are necessary for normal embryo formation. However, at pathological levels, they result in reduced embryo viability which can be mediated through factors delivered by sperm and eggs at conception or from the external environment.

Abstract

Reactive oxygen species (ROS) occur naturally in pre-implantation embryos as a by-product of ATP generation through oxidative phosphorylation and enzymes such as NADPH oxidase and xanthine oxidase. Biological concentrations of ROS are required for crucial embryonic events such as pronuclear formation, first cleavage and cell proliferation. However, high concentrations of ROS are detrimental to embryo development, resulting in embryo arrest, increased DNA damage and modification of gene expression leading to aberrant fetal growth and health. In vivo embryos are protected against oxidative stress by oxygen scavengers present in follicular and oviductal fluids, while in vitro, embryos rely on their own antioxidant defence mechanisms to protect against oxidative damage, including superoxide dismutase, catalase, glutathione and glutamylcysteine synthestase. Pre-implantation embryonic ROS originate from eggs, sperm and embryos themselves or from the external environment (i.e. in vitro culture system, obesity and ageing). This review examines the biological and pathological roles of ROS in the pre-implantation embryo, maternal and paternal origins of embryonic ROS, and from a clinical perspective, we comment on the growing interest in combating increased oxidative damage in the pre-implantation embryo through the addition of antioxidants.

Dysregulation of integrin αvβ3 and α5β1 impedes migration of placental endothelial cells in fetal growth restriction

Placentas from pregnancies complicated by severe early-onset fetal growth restriction (FGR) exhibit diminished vascular development mediated by impaired angiogenesis, but underlying mechanisms remain unknown. In this study, we show that FGR endothelial cells demonstrate inherently reduced migratory capacity despite the presence of fibronectin, a matrix protein abundant in placental stroma that displays abnormal organization in FGR placentas. Thus, we hypothesized that aberrant endothelial-fibronectin interactions in FGR are a key mechanism underlying impaired FGR endothelial migration. Using human fetoplacental endothelial cells isolated from uncomplicated term control and FGR pregnancies, we assessed integrin α5β1 and αvβ3 regulation during cell migration. We show that endothelial integrin α5β1 and αvβ3 interactions with fibronectin are required for migration and that FGR endothelial cells responded differentially to integrin inhibition, indicating integrin dysregulation in FGR. Whole-cell expression was not different between groups. However, there were significantly more integrins in focal adhesions and reduced intracellular trafficking in FGR. These newly identified changes in FGR endothelial cellular processes represent previously unidentified mechanisms contributing to persistent angiogenic deficiencies in FGR.

Maternal Low Volume Circulation Relates to Normotensive and Preeclamptic Fetal Growth Restriction

This narrative review summarizes current evidence on the association between maternal low volume circulation and poor fetal growth. Though much work has been devoted to the study of cardiac output and peripheral vascular resistance, a low intravascular volume may explain why high vascular resistance causes hypertension in women with preeclampsia (PE) that is associated with fetal growth restriction (FGR) and, at the same time, presents with normotension in FGR itself. Normotensive women with small for gestational age babies show normal gestational blood volume expansion superimposed upon a constitutionally low intravascular volume. Early onset preeclampsia (EPE; occurring before 32 weeks) is commonly associated with FGR, and poor plasma volume expandability may already be present before conception, thus preceding gestational volume expansion. Experimentally induced low plasma volume in rodents predisposes to poor fetal growth and interventions that enhance plasma volume expansion in FGR have shown beneficial effects on intrauterine fetal condition, prolongation of gestation and birth weight. This review makes the case for elevating the maternal intravascular volume with physical exercise with or without Nitric Oxide Donors in FGR and EPE, and evaluating its role as a potential target for prevention and/or management of these conditions.

Fetal Doppler Evaluation to Predict NEC Development

Antenatal factors play a role in NEC pathogenesis. This study aimed to investigate the predictive value of fetal ductus venosus doppler (DV) for NEC in fetal growth restriction fetuses (FGRF) and to assess the predictive accuracy of IG21 and Fenton curves in NEC development. Data from FGRF, postnatal findings, and Doppler characteristics were collected between 2010 and 2020 at a single center. Patients were then divided into two groups (i.e., with and without NEC). Bivariate and multivariate analyses were performed. We identified 24 cases and 30 controls. Absent or reversed end-diastolic flow (AREDF) and increased resistance in the DV were more impaired in cases (p < 0.05). Although the median birthweight was not different, the Fenton z-score was lower in NEC (p < 0.05). Fetal cardiopulmonary resuscitation, synchronized intermittent mandatory ventilation, neonatal respiratory distress, persistent patent ductus arteriosus (PDA), and inotropic support were more frequent in the NEC group. Furthermore, NEC patients had lower white blood cells (WBC) (p < 0.05). The predictive model for NEC (model 4), including Fenton z-score, WBC, PDA, and DV had an AUC of 84%. Fetal Doppler findings proved effective in predicting NEC in FGR. The Fenton z-score was the most predictive factor considering the fetal growth assessment showing high sensitivity.

Clinical Opinion: The diagnosis and management of suspected fetal growth restriction: an evidence-based approach

This study reviewed the literature about the diagnosis, antepartum surveillance, and time of delivery of fetuses suspected to be small for gestational age or growth restricted. Several guidelines have been issued by major professional organizations, including the International Society of Ultrasound in Obstetrics and Gynecology and the Society for Maternal-Fetal Medicine. The differences in recommendations, in particular about Doppler velocimetry of the ductus venosus and middle cerebral artery, have created confusion among clinicians, and this review has intended to clarify and highlight the available evidence that is pertinent to clinical management. A fetus who is small for gestational age is frequently defined as one with an estimated fetal weight of <10th percentile. This condition has been considered syndromic and has been frequently attributed to fetal growth restriction, a constitutionally small fetus, congenital infections, chromosomal abnormalities, or genetic conditions. Small for gestational age is not synonymous with fetal growth restriction, which is defined by deceleration of fetal growth determined by a change in fetal growth velocity. An abnormal umbilical artery Doppler pulsatility index reflects an increased impedance to flow in the umbilical circulation and is considered to be an indicator of placental disease. The combined finding of an estimated fetal weight of <10th percentile and abnormal umbilical artery Doppler velocimetry has been widely accepted as indicative of fetal growth restriction. Clinical studies have shown that the gestational age at diagnosis can be used to subclassify suspected fetal growth restriction into early and late, depending on whether the condition is diagnosed before or after 32 weeks of gestation. The early type is associated with umbilical artery Doppler abnormalities, whereas the late type is often associated with a low pulsatility index in the middle cerebral artery. A large randomized clinical trial indicated that in the context of early suspected fetal growth restriction, the combination of computerized cardiotocography and fetal ductus venosus Doppler improves outcomes, such that 95% of surviving infants have a normal neurodevelopmental outcome at 2 years of age. A low middle cerebral artery pulsatility index is associated with an adverse perinatal outcome in late fetal growth restriction; however, there is no evidence supporting its use to determine the time of delivery. Nonetheless, an abnormality in middle cerebral artery Doppler could be valuable to increase the surveillance of the fetus at risk. We propose that fetal size, growth rate, uteroplacental Doppler indices, cardiotocography, and maternal conditions (ie, hypertension) according to gestational age are important factors in optimizing the outcome of suspected fetal growth restriction.

Altered Doppler velocimetry of fetal middle cerebral artery in singleton pregnancies complicated by mild well-controlled gestational diabetes

Introduction The aim the present study is to evaluate fetal umbilical artery (UA) and middle cerebral artery (MCA) blood flow in patients with gestational diabetes (GD), in order to determine whether minimal anomalies of glucose metabolism may influence fetal placental function. Methods UA and MCA flow were prospectively measured by transabdominal ultrasound in singleton pregnancies between 34 and 37 weeks of gestation. Results The study included 35 women with GD and 217 non-diabetic patients. Middle cerebral pusatility index (PI) was significantly higher in the GD group (mean MCA - PI =1.82±0.27 vs 1.71 ±0.26; p< 0.02). Likewise, MCA peak systolic velocity (MCA-PSV) was higher in the GD group compared to the non-GD group, though the difference was not significant (mean of MCA-PSV =47.14 ±8.45 vs 47.09 ± 11.21; p = 0.98). UA-PI resulted higher in the non-GD group without significant differences (mean of UA-PI =0.88 ±0.14 vs 0.86 ± 0.15; p = 0.32) Conclusions Our study shows that even in cases of minimal metabolic derangements, GD is characterised by a significant variation in fetal Doppler velocimetry, particularly in the brain.

Chronic Hypoxia Inhibits Respiratory Complex IV Activity and Disrupts Mitochondrial Dynamics in the Fetal Guinea Pig Forebrain

Mitochondrial dysfunction is an underlying cause of childhood neurological disease secondary to the crucial role of mitochondria in proper neurodevelopment. We hypothesized that chronic intrauterine hypoxia (HPX) induces mitochondrial deficits by altering mitochondrial biogenesis and dynamics in the fetal brain. Pregnant guinea pigs were exposed to either normoxia (NMX, 21%O2) or HPX (10.5%O2) starting at 28-day (early onset, EO-HPX) or 50-day (late onset, LO-HPX) gestation until term (65 days). Near-term male and female fetuses were extracted from anesthetized sows, and mitochondria were isolated from excised fetal forebrains (n = 6/group). Expression of mitochondrial complex subunits I-V (CI-CV), fission (Drp-1), and fusion (Mfn-2) proteins was measured by Western blot. CI and CIV enzyme activities were measured by colorimetric assays. Chronic HPX reduced fetal body wts and increased (P < 0.05) brain/body wt ratios of both sexes. CV subunit levels were increased in EO-HPX males only and CII levels increased in LO-HPX females only compared to NMX. Both EO- and LO-HPX decreased CIV activity in both sexes but had no effect on CI activity. EO-HPX increased Drp1 and decreased Mfn2 levels in males, while LO-HPX had no effect on either protein levels. In females, both EO-HPX and LO-HPX increased Drp1 but had no effect on Mfn2 levels. Chronic HPX alters abundance and activity of select complex subunits and shifts mitochondrial dynamics toward fission in a sex-dependent manner in the fetal guinea pig brain. This may be an underlying mechanism of reduced respiratory efficiency leading to disrupted metabolism and increased vulnerability to a second neurological injury at the time of birth in HPX fetal brains.

Clinical monitoring of late fetal growth restriction

Late fetal growth restriction (FGR) poses its own challenges in respect of diagnosis, surveillance and delivery timing. Perinatal morbidity is relatively rare, and mortality extremely unusual, but given that late FGR is much more frequent than early FGR, the burden on neonatal services must not be underestimated. Doppler findings are more subtle than in early FGR, and growth rate rather than absolute fetal size may be important in defining the condition. Though umbilical artery Doppler changes form the basis for triggering delivery: reversed end diastolic flow at 32 weeks, absent at 34 weeks and raised PI at 36 weeks, other modalities of monitoring - for example cardiotocography and cerebral Doppler - are important in surveillance and timing follow up of the condition.

Perinatal outcomes after intrauterine growth restriction and umbilical artery Doppler pulsatility index of less than the fifth percentile

Objective: To analyze perinatal morbidity and stillbirth after intrauterine growth restriction (IUGR) with an umbilical artery Doppler pulsatility index (UA PI) less than the fifth centile.Study design: This retrospective cohort study included nonanomalous singleton, IUGR pregnancies receiving UA PI testing at a tertiary-care prenatal diagnostic center. Women with persistently elevated UA PI, absent or reversed end-diastolic flow on UA PI, or who had only one UA PI result were excluded. Low UA PI was defined as having ≥1 UA PI <5%. Women with low UA PI were matched by gestational age at IUGR diagnosis in a random 1 case: 4 control computer-generated algorithm to those with normal UA PI (≤95% and ≥5%). The primary outcome was composite neonatal morbidity and mortality (stillbirth, mechanical ventilation, sepsis, intraventricular hemorrhage, and necrotizing enterocolitis). Secondary outcomes included 5-minute Apgar, umbilical artery pH, delivery type, and interval from IUGR diagnosis to delivery. We compared outcomes after low UA PI to those after normal UA PI with multivariable logistic regression, adjusting for gestational age at delivery, betamethasone use, infant gender, and maternal factors.Results: Of the 1893 IUGR pregnancies, 25 (1.3%) had low UA PI <5% and were randomly matched via computer algorithm to 100 controls. There were no stillbirths in either group; the odds of composite neonatal morbidity was similar among IUGR pregnancies with UA PI <5% versus normal (adjusted odds ratio 0.89 (95% confidence interval 0.27-2.75)). There was no difference in 5-minute Apgars, umbilical artery pH, rate of cesarean delivery for fetal distress, or interval from IUGR diagnosis to delivery between the two groups.Conclusion: Among IUGR pregnancies, UA PI <5% is uncommon and not associated with improved neonatal outcomes compared to normal UA PI. These findings suggest low UA PI can continue to be managed as normal UA PI.

Reference ranges of fetal superior vena cava blood flow velocities and pulsatility index in the second half of pregnancy: a longitudinal study

Background

Fetal superior vena cava (SVC) is essentially the single vessel returning blood from the upper body to the heart. With approximately 80-85% of SVC blood flow representing cerebral venous return, its interrogation may provide clinically relevant information about fetal brain circulation. However, normal reference values for fetal SVC Doppler velocities and pulsatility index are lacking. Our aim was to establish longitudinal reference intervals for blood flow velocities and pulsatility index of the SVC during the second half of pregnancy.

Methods

This was a prospective study of low-risk singleton pregnancies. Serial Doppler examinations were performed approximately every 4 weeks to obtain fetal SVC blood velocity waveforms during 20–41 weeks. Peak systolic (S) velocity, diastolic (D) velocity, time-averaged maximum velocity (TAMxV), time-averaged intensity-weighted mean velocity (TAMeanV), and end-diastolic velocity during atrial contraction (A-velocity) were measured. Pulsatility index for vein (PIV) was calculated.

Results

SVC blood flow velocities were successfully recorded in the 134 fetuses yielding 510 sets of observations. The velocities increased significantly with advancing gestation: mean S-velocity increased from 24.0 to 39.8 cm/s, D-velocity from 13.0 to 19.0 cm/s, and A-velocity from 4.8 to 7.1 cm/s. Mean TAMxV increased from 12.7 to 23.1 cm/s, and TAMeanV from 6.9 to 11.2 cm/s. The PIV remained stable at 1.5 throughout the second half of pregnancy.

Conclusions

Longitudinal reference intervals of SVC blood flow velocities and PIV were established for the second half of pregnancy. The SVC velocities increased with advancing gestation, while the PIV remained stable from 20 weeks to term.

Can fetal heart rate variability obtained from cardiotocography provide the same diagnostic value like from electrophysiological interbeat intervals?

OBJECTIVE

Fetal heart rate variability (HRV) is widely used for monitoring fetal developmental disturbances. Only expensive fetal magnetocardiography (fMCG) allows the precise recording of the individual fetal heart beat intervals uncovering also highly frequent vagal modulation. In contrast, transabdominal fetal electrocardiography (fECG) suffers from noise overlaying the fetal cardiac signal. Cardiotocography (CTG) is the clinical method of choice, however, based on Doppler ultrasound, improper to resolve single beats concisely. The present work addresses the transferability of established electrophysiological HRV indices to CTG recordings during the fetal maturation period of 20-40 weeks of gestation (WGA).

APPROACH

We compared (a) HRV indices obtained from fMCG, CTG and fECG of short-term amplitude fluctuations (sAMPs) and long-term amplitude fluctuations (lAMPs) and complexity, and (b) their diagnostic value for identifying maturational age, fetal growth restriction (FGR) and small for gestational age (SGA). We used the functional brain age score (fABAS) and categories of long- and short-term regulation and complexity.

MAIN RESULTS

Integrating all substudies, we found: (a) indices related to long-term regulation, and with modified meaning and values of short-term regulation and sympathovagal balance (SVB) according to electrophysiological HRV standards can be obtained from CTG. (b) Models using HRV indices calculated from CTG allow the identification of maturational age and discriminate FGR from controls with almost similar precision as electrophysiological means. (c) A modified set of HRV parameters containing short- and long-term regulation and long-term/short-term ratio appeared to be most suitable to describe autonomic developmental state when CTG data is used.

SIGNIFICANCE

Whereas the predominantly vagally modulated beat-to-beat precise high frequencies of HRV are not assessable from CTG, we identified relevant related HRV indices and categories for CTG recordings with diagnostic potential. They require further evaluation and confirmation with respect to any issues of fetal developmental and perinatal problems in subsequent studies. This methodology significantly extends the measures of established CTG devices. Novelty and significance HRV indices provide predestinated diagnostic markers of autonomic control in fetuses. However, the established CTG does not provide the temporal precision of electrophysiological recordings. Beat-to-beat related, mainly vagally modulated behavior is not exactly represented in CTG. However, a set of CTG-specific HRV indices that are mainly comparable to established electrophysiological HRV parameters obtained by magnetocardiography or electrocardiography provided almost similar predictive value for fetal maturational age and were helpful in characterizing FGR. These results require validation in the monitoring of further fetal developmental disturbances. We recommend a corresponding extension of CTG methodology.

Optimizing Nutritional Strategies to Prevent Necrotizing Enterocolitis and Growth Failure after Bowel Resection

Necrotizing enterocolitis (NEC), the first cause of short bowel syndrome (SBS) in the neonate, is a serious neonatal gastrointestinal disease with an incidence of up to 11% in preterm newborns less than 1500 g of birth weight. The rate of severe NEC requiring surgery remains high, and it is estimated between 20–50%. Newborns who develop SBS need prolonged parenteral nutrition (PN), experience nutrient deficiency, failure to thrive and are at risk of neurodevelopmental impairment. Prevention of NEC is therefore mandatory to avoid SBS and its associated morbidities. In this regard, nutritional practices seem to play a key role in early life. Individualized medical and surgical therapies, as well as intestinal rehabilitation programs, are fundamental in the achievement of enteral autonomy in infants with acquired SBS. In this descriptive review, we describe the most recent evidence on nutritional practices to prevent NEC, the available tools to early detect it, the surgical management to limit bowel resection and the best nutrition to sustain growth and intestinal function.

Perinatal outcome after persistence of abnormal umbilical artery Doppler indices in the growth-restricted fetus following betamethasone administration

BACKGROUND

An optimal approach for providing sufficient antenatal surveillance for fetal growth restriction (FGR) has yet to be elucidated. Moreover, there is scant literature on the fetal response to betamethasone and its effect on fetal Dopplers.

OBJECTIVE

To compare persistence of umbilical artery Doppler abnormalities after corticosteroid administration and adverse perinatal outcome in growth restricted fetuses.

METHODS

Retrospective cohort study (2008-2018) of singleton gestations with FGR (EFW <10th percentile) and umbilical artery Doppler abnormalities (absent or reversed end diastolic velocity) between 24 and 34 weeks of gestation at two institutions. Included patients had Dopplers performed before betamethasone administration and again within 1 week. Excluded were multiple gestations, chromosomal abnormalities, fetal anomalies, or missing outcome information. Pregnancies with persistently abnormal Dopplers were compared with those in which an improvement of Dopplers was noted. The primary outcome was a composite that consisted of indicated preterm birth <32 weeks, 1 or 5 min APGAR score <7, intrauterine fetal demise, and neonatal demise. Secondary outcomes included length of NICU stay, ventilator support, gestational age at delivery, interval between steroids and delivery, and birth weight.

RESULTS

Fifty-three FGR pregnancies met inclusion criteria. Umbilical artery Dopplers improved after steroids in 32% (n = 17). No difference in the frequency of the primary outcome was observed between the persistently abnormal Doppler and improved Doppler groups (72.2% vs. 70.6%, respectively), and there was no difference in any of the secondary outcomes.

CONCLUSIONS

Perinatal outcomes in FGR pregnancies were not affected by improved versus persistently abnormal umbilical artery Dopplers after betamethasone administration.

Neurodevelopment at 2 years and umbilical artery Doppler in cases of very preterm birth after prenatal hypertensive disorder or suspected fetal growth restriction: EPIPAGE-2 prospective population-based cohort study

OBJECTIVE

To investigate the association between absent or reversed end-diastolic flow (ARED) on umbilical artery Doppler ultrasound and poor neurological outcome at 2 years of age after very preterm birth associated with suspected fetal growth restriction (FGR) or maternal hypertensive disorders.

METHODS

The study population comprised all very preterm (22-31 completed weeks) singleton pregnancies delivered because of suspected FGR and/or maternal hypertensive disorders that had umbilical artery Doppler and 2-year follow-up available included in EPIPAGE-2, a prospective, nationwide, population-based cohort of preterm births in France in 2011. Univariate and two-level multivariable logistic regression analyses were used to assess the association of ARED in the umbilical artery, as compared with normal or reduced end-diastolic flow, with severe or moderate neuromotor and/or sensory disability and with an Ages and Stages Questionnaire (ASQ) score below a threshold. This was defined as a score more than 2 SD below the mean in any of the five domains, at age 2, adjusting for gestational age at delivery. ASQ is used to identify children at risk of developmental delay requiring reinforced follow-up and further evaluation. Descriptive statistics and bivariate tests were weighted according to the duration of the inclusion periods.

RESULTS

The analysis included 484 children followed up at 2 years of age, for whom prenatal umbilical artery Doppler ultrasound was available. Among them, 8/484 (1.6%) had severe or moderate neuromotor and/or sensory disability, and 156/342 (45.4%) had an ASQ score below the threshold. Compared with normal or reduced end-diastolic flow in the umbilical artery (n = 305), ARED (n = 179) was associated with severe or moderate neuromotor and/or sensory disability (adjusted odds ratio (OR), 11.3; 95% CI, 1.4-93.2) but not with an ASQ score below the threshold (adjusted OR, 1.2; 95% CI, 0.8-1.9).

CONCLUSION

Among children delivered before 32 weeks of gestation due to suspected FGR and/or maternal hypertensive disorder who survived until 2 years of age, prenatal ARED in the umbilical artery was associated with a higher incidence of severe or moderate neuromotor and/or sensory disability. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

Kidney impairment in fetal growth restriction: three-dimensional evaluation of volume and vascularization

OBJECTIVES

Renal development is impaired in fetal growth restriction (FGR). Renal size can be considered a surrogate of renal function in childhood, and could be impaired in that condition. Our aim was to evaluate the ratio of total renal volume, measured by three-dimensional ultrasound, to estimated fetal weight (TRV/EFW) among fetuses with and without growth restriction. Furthermore, we correlated TRV/EFW with fetal Doppler velocimetry and renal vascularization indexes and evaluated the association of renal volume and vascular parameters with adverse neonatal events in growth-restricted fetuses.

METHODS

In a retrospective cohort, TRV and renal vascularization of growth-restricted and normal fetuses were evaluated by three-dimensional ultrasonography and VOCAL technique. Independent samples t-tests and Mann-Whitney test were used for comparisons between groups. Logistic regression model was applied to evaluate the association between renal characteristics and adverse neonatal events.

RESULTS

Seventy-one growth-restricted fetuses were compared to 194 controls. The TRV/EFW was lower in the growth-restricted group (P < .001). In our sample, this ratio did not correlate with Doppler velocimetry parameters, renal vascular indexes or any adverse neonatal events.

CONCLUSION

The TRV/EFW ratio is decreased in FGR. Further studies are needed to investigate the association of this ratio with long-term renal outcomes.

Pulsatility effects of flow on vascular tone in the fetoplacental circulation

INTRODUCTION

The regulation of vascular tone in the fetoplacental circulation is governed by endocrine and mechanical forces yielding a relaxed basal state in normal pregnancy. Flow mediated vasodilation, induced by shear stress and endothelial nitric oxide signalling, is key to driving vasorelaxation in this circulation. The pulsatile property of blood flow, as opposed to the flow rate, could provide an additional factor in this regulation, but its effects and signalling have never been explored in the fetoplacental microvasculature.

METHODS

Here, we studied the effects of non-pulsatile and pulsatile flow modalities on vascular resistance in the fetoplacental microcirculation of the human placenta using an ex vivo perfusion model; and examined a potential role for nitric oxide. We also explored whether the placental Doppler velocimetry waveform is sustained within subchorial arteries in vivo.

RESULTS

Pulsatile flow reduced basal impedance to flow during steady state perfusion compared to non-pulsatile flow, signalled through enhanced nitric oxide production. Doppler velocimetry waveforms were visible within the subchorial arteries in vivo.

CONCLUSION

This work suggests that the pulsatile property of flow through the fetoplacental circulation is sensed by the fetoplacental vasculature to mediate a signalling response and provide additional vasodilation of this microcirculation. We speculate that in pregnancy disease, altered amplitude and frequency of the subchorial pulse might impact on vascular function in a compromised high-resistance placental microcirculation.

Normative references and clinical correlates of fetal umbilical artery Doppler indices in southwestern Nigeria

OBJECTIVE

To derive normative references for umbilical artery (UA) Doppler indices, including pulsatility index (PI), resistance index (RI), and systolic/diastolic (SD) ratio, for singleton pregnancies in Ile-Ife, Nigeria, and compare them with reference values from other populations.

METHODS

A longitudinal study involving 415 women with a singleton fetus at 26-40 gestational weeks attending Obafemi Awolowo University Hospital, Ile-Ife, between July 2015 and March 2019. Fetal UA PI, RI, and SD ratio were measured every 4 weeks until delivery. Reference values from the 2.5th to the 97.5th centiles were derived from 1375 measurements. Correlations between indices and bio-demographic characteristics were assessed; regression equations were generated.

RESULTS

The RI, PI, and SD ratio decreased by 0.013, 0.027, and 0.71, respectively, for each additional week of pregnancy. There was a negative correlation between the three indices and birthweight (P<0.001), but not maternal parity, age, or fetal gender. Regression equations for RI, PI, and SD ratio were, respectively, 1.004 - 0.013x, 1.78 - 0.027x, and 4.77 - 0.71x, where x is gestational age (weeks).

CONCLUSION

The derived normative references for fetal UA Doppler indices are recommended for monitoring high-risk pregnancies in Nigeria. The indices are comparable to those derived from Norwegian, Thai, and British cohorts.

Cardiorespiratory consequences of intrauterine growth restriction: Influence of timing, severity and duration of hypoxaemia

At birth, weight of the neonate is used as a marker of the 9-month journey as a fetus. Those neonates born less than the 10th centile for their gestational age are at risk of being intrauterine growth restricted. However, this depends on their genetic potential for growth and the intrauterine environment in which they grew. Alterations in the supply of oxygen and nutrients to the fetus will decrease fetal growth, but these alterations occur due to a range of causes that are maternal, placental or fetal in nature. Consequently, IUGR neonates are a heterogeneous population. For this reason, it is likely that these neonates will respond differently to interventions compared not only to normally grown fetuses, but also to other neonates that are IUGR but have travelled a different path to get there. Thus, a range of models of IUGR should be studied to determine the effects of IUGR on the development and function of the heart and lung and subsequently the impact of interventions to improve development of these organs. Here we focus on a range of models of IUGR caused by manipulation of the maternal, placental or fetal environment on cardiorespiratory outcomes.

Circulating Delta-like homolog 1 (DLK1) at 36 weeks is correlated with birthweight and is of placental origin

INTRODUCTION

Recently, Delta-like homolog 1 (DLK1) was identified as a potential marker of small-for-gestational-age (SGA; <10th centile) fetuses; mouse studies suggest reduced levels may represent a fetal stress signal. We sought to measure DLK1 in a large independent cohort of maternal blood samples, correlate levels with measures of placental insufficiency and assess whether DLK1 might be placental derived.

METHODS

The Fetal Longitudinal Assessment of Growth (FLAG) study was a prospective blood collection from 2000 women. We assessed a case-control cohort at 28 and 36 weeks from the first 1000 FLAG women, before validating changes in the entire second 1000. A subgroup of FLAG participants underwent ultrasound examinations, and 137 neonates, body composition assessment (PEAPOD). DLK1 secretion was assessed from human placentas ex vivo.

RESULTS

Circulating DLK1 was significantly reduced at 28 and 36 weeks' gestation in women destined to deliver a SGA fetus and associated with birthweight centile (n = 999, p < 0.0001), and placental weight (n = 96, p = 0.0064). Ex vivo, DLK1 was abundantly released from human placenta and significantly reduced under hypoxia (n = 7, p < 0.05). We found no relationship between circulating DLK1 and estimated fetal weight, cerebroplacental ratio, uterine artery or umbilical artery pulsatility index. Nor was there a relationship between DLK1 and neonatal fat or lean mass (n = 137).

CONCLUSION

We confirmed circulating DLK1 is reduced at both 28 and 36 weeks' gestation preceding delivery of a SGA infant, shown that it is not significantly associated with clinical measures of placental insufficiency, and provide new data demonstrating it may be placenta-derived in humans.

Perinatal outcomes after intrauterine growth restriction and intermittently elevated umbilical artery Doppler

BACKGROUND

Intermittently elevated umbilical artery pulsatility index has been identified among pregnancies with intrauterine growth restriction but has unclear clinical significance.

OBJECTIVE

The purpose of this study was to analyze perinatal morbidity and stillbirth after intrauterine growth restriction with an intermittently elevated umbilical artery pulsatility index.

STUDY DESIGN

This retrospective cohort study included nonanomalous singleton, intrauterine growth-restricted pregnancies that received umbilical artery pulsatility index testing at a tertiary-care prenatal diagnostic center from 2010-2016. Women with persistently elevated umbilical artery pulsatility index, absent or reversed end-diastolic blood flow on umbilical artery pulsatility index, or only 1 umbilical artery pulsatility index result were excluded. Intermittently elevated umbilical artery pulsatility index was defined as ≥1 elevated umbilical artery pulsatility index (>95%) and ≥1 normal umbilical artery pulsatility index (≤95%). Women with an intermittently elevated umbilical artery pulsatility index were matched 1:3 by gestational age at intrauterine growth restriction diagnosis to those with a normal umbilical artery pulsatility index. The primary outcome was composite neonatal morbidity and deaths (stillbirth, mechanical ventilation, sepsis, intraventricular hemorrhage, and necrotizing enterocolitis). Secondary outcomes included 5-minute Apgar score, umbilical artery pH, delivery type, and interval from intrauterine growth restriction diagnosis to delivery. We compared outcomes after intermittently elevated umbilical artery pulsatility index with those after normal umbilical artery pulsatility index with multivariable logistic regression, adjusting for gestational age at delivery, betamethasone use, and maternal factors.

RESULTS

Of 1893 women, 143 (7.6%) had an intermittently elevated umbilical artery pulsatility index and were matched to 429 control subjects. Among the 143 women with an intermittently elevated umbilical artery pulsatility index, 78 (54.5%), 52 (36.4%), and 13 (0.9%) women had elevated umbilical artery pulsatility index for 1-24%, 25-49%, and 50-74% of recorded Doppler measurements, respectively. None of the women had an elevated umbilical artery pulsatility index for 75-99% of recorded umbilical artery pulsatility index measurements. The last recorded umbilical artery pulsatility index was elevated for 37 women with an intermittently elevated umbilical artery pulsatility index (25.9%). Overall, the odds of composite neonatal morbidity was similar among intrauterine growth-restricted pregnancies with an intermittently elevated vs a normal umbilical artery pulsatility index (adjusted odds ratio, 1.05; 95% confidence interval, 0.59-1.87); there were no stillbirths. There was no difference in 5-minute Apgar scores, umbilical artery pH, rate of cesarean delivery for fetal distress, or interval from intrauterine growth restriction diagnosis to delivery between the 2 groups. Similarly, sensitivity analyses that stratified the population of intermittently elevated umbilical artery pulsatility index by the proportion of elevated umbilical artery pulsatility index to overall umbilical artery pulsatility index measurements and by whether the last umbilical artery pulsatility index recorded was normal or elevated showed no difference in neonatal morbidity or obstetric outcomes between the comparator groups.

CONCLUSION

Among intrauterine growth-restricted pregnancies, an intermittently elevated umbilical artery pulsatility index is neither uncommon nor associated with an increased risk of neonatal morbidity, stillbirth, or cesarean delivery. These findings suggest intrauterine growth-restricted pregnancies with intermittently elevated umbilical artery pulsatility index could be managed clinically as are those with normal umbilical artery pulsatility index.

Quantitative Flow Imaging in Human Umbilical Vessels In Utero Using Nongated 2D Phase Contrast MRI

BACKGROUND

Volumetric assessment of afferent blood flow rate provides a measure of global organ perfusion. Phase-contrast magnetic resonance imaging (PCMRI) is a reliable tool for volumetric flow quantification, but given the challenges with motion and lack of physiologic gating signal, such studies, in vivo on the human placenta, are scant.

PURPOSE

To evaluate and apply a nongated (ng) PCMRI technique for quantifying blood flow rates in utero in umbilical vessels.

STUDY TYPE

Prospective study design.

STUDY POPULATION

Twenty-four pregnant women with median gestational age (GA) 30 4/7 weeks and interquartile range (IQR) 8 1/7 weeks.

FIELD STRENGTH/SEQUENCE

All scans were performed on a 3.0T Siemens Verio system using the ng-PCMRI technique.

ASSESSMENT

The GA-dependent increase in umbilical vein (UV) and arterial (UA) flow was compared to previously published values. Systematic error to be expected from ng-PCMRI, in the context of pulsatile UA flow and partial voluming, was studied through Monte-Carlo simulations, as a function of resolution and number of averages.

STATISTICAL TESTS

Correlation between the UA and UV was evaluated using a generalized linear model.

RESULTS

Simulations showed that ng-PCMRI measurement variance reduced by increasing the number of averages. For vessels on the order of 2 voxels in radius, partial voluming led to 10% underestimation in the flow. In fetuses, the average flow rates in UAs and UV were measured to be 203 ± 80 ml/min and 232 ± 92 ml/min and the normalized average flow rates were 140 ± 59 ml/min/kg and 155 ± 57 ml/min/kg, respectively. Excellent correlation was found between the total arterial flow vs. corresponding venous flow, with a slope of 1.08 (P = 0.036).

DATA CONCLUSION

Ng-PCMRI can provide accurate volumetric flow measurements in utero in the human umbilical vessels. Care needs to be taken to ensure sufficiently high-resolution data are acquired to minimize partial voluming-related errors.

LEVEL OF EVIDENCE

2 Technical Efficacy Stage 1 J. Magn. Reson. Imaging 2017.

Near to One's Heart: The Intimate Relationship Between the Placenta and Fetal Heart

The development of the fetal heart is exquisitely controlled by a multitude of factors, ranging from humoral to mechanical forces. The gatekeeper regulating many of these factors is the placenta, an external fetal organ. As such, resistance within the placental vascular bed has a direct influence on the fetal circulation and therefore, the developing heart. In addition, the placenta serves as the interface between the mother and fetus, controlling substrate exchange and release of hormones into both circulations. The intricate relationship between the placenta and fetal heart is appreciated in instances of clinical placental pathology. Abnormal umbilical cord insertion is associated with congenital heart defects. Likewise, twin-to-twin transfusion syndrome, where monochorionic twins have unequal sharing of their placenta due to inter-twin vascular anastomoses, can result in cardiac remodeling and dysfunction in both fetuses. Moreover, epidemiological studies have suggested a link between placental phenotypic traits and increased risk of cardiovascular disease in adult life. To date, the mechanistic basis of the relationships between the placenta, fetal heart development and later risk of cardiac dysfunction have not been fully elucidated. However, studies using environmental exposures and gene manipulations in experimental animals are providing insights into the pathways involved. Likewise, surgical instrumentation of the maternal and fetal circulations in large animal species has enabled the manipulation of specific humoral and mechanical factors to investigate their roles in fetal cardiac development. This review will focus on such studies and what is known to date about the link between the placenta and heart development.

Restricted physical activity in pregnancy reduces maternal vascular resistance and improves fetal growth

OBJECTIVES

To test the efficacy of maternal activity restriction for reducing peripheral vascular resistance in normotensive pregnant women with raised total vascular resistance (TVR) and to evaluate its effect on fetal growth.

METHODS

This was a prospective case-control study of 30 women enrolled between 27 and 29 weeks' gestation. All patients met the following criteria: normal blood pressure before and during pregnancy, TVR between 1300 and 1400 dynes × s/cm⁵ at enrolment, normal fetal Doppler parameters at enrolment and abdominal circumference between the 10^th and 25^th centiles. Patients were assigned to activity restriction (activity-restriction group; n = 15) or no treatment (control group; n = 15) and were assessed after 4 weeks for TVR and fetal growth.

RESULTS

TVR at enrolment and estimated fetal weight centile were similar in the activity-restriction group vs controls (1358 ± 26 vs 1353 ± 30 dynes × s/cm⁵ ; 18^th  ± 4 vs 19^th  ± 4 centile; P = NS). After 4 weeks, the activity-restriction group compared with controls showed significantly lower TVR (1165 ± 159 vs 1314 ± 190 dynes × s/cm⁵ ; P < 0.05), which was associated with higher estimated fetal weight centile (25^th  ± 5 vs 20^th  ± 5 centile; P < 0.05). TVR was lower and estimated fetal weight centile higher for the activity-restriction group after 4 weeks compared with at enrolment.

CONCLUSIONS

In normotensive pregnant women with raised TVR, maternal activity restriction appears to be effective in reducing TVR and therefore enhancing fetal growth. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Planning management and delivery of the growth-restricted fetus

A uniform approach to management of fetal growth restriction (FGR) improves outcome, prevents stillbirth, and allows appropriately timed delivery. An estimated fetal weight below the tenth percentile with coexisting abnormal umbilical artery (UA), middle cerebral artery (MCA), or cerebroplacental ratio Doppler index best identifies the small fetus requiring surveillance. Placental perfusion defects are more common earlier in gestation; accordingly, early-onset (≤32 weeks of gestation) and late-onset (>32 weeks) FGR differ in clinical phenotype. In early-onset FGR, progression of UA Doppler abnormality determines clinical acceleration, while abnormal ductus venosus (DV) Doppler precedes deterioration of biophysical variables and stillbirth. Accordingly, late DV Doppler changes, abnormal biophysical variables, or an abnormal cCTG require delivery. In late-onset FGR, MCA Doppler abnormalities precede deterioration and stillbirth. However, from 34 to 38 weeks, randomized evidence on optimal delivery timing is lacking. From 38 weeks onward, the balance of neonatal versus fetal risks favors delivery.

Early versus Late Enteral Feeding in Preterm Intrauterine Growth Restricted Neonates with Antenatal Doppler Abnormalities: An Open-Label Randomized Trial

BACKGROUND OF THE STUDY

Enteral feeding in preterm neonates with intrauterine growth restriction (IUGR) and absent or reversed end diastolic flow (AREDF) on umbilical artery (UA) Doppler is delayed owing to an increased risk of necrotizing enterocolitis (NEC). Delaying enteral feeding with longer duration of parenteral nutrition (PN) carries an increased risk of sepsis.

OBJECTIVES

To study early versus late feeding in preterm IUGR neonates for time required to attain sufficient feed volume to discontinue PN and increased risk of NEC or feed intolerance (FI).

DESIGN

Open-label randomized controlled trial.

SETTING

Tertiary care neonatal unit and fetal-maternal medicine unit in India.

PARTICIPANTS

Preterm intrauterine growth restricted neonates' ≤32 weeks with AREDF on UA Doppler enrolled from 1 January 2014 to 31 July 2015.

INTERVENTION

Randomized to receive early or late feeding using mothers own or donor breast milk as per a feed initiation and advancement protocol.

PRIMARY OUTCOME

Time in days required to attain sufficient feed volume allowing discontinuation of PN and incidence of NEC in neonates fed early versus late.

RESULTS

There were 77 eligible neonates. Sixty-two neonates were included and stratified as extreme preterm (27-29 weeks) (n = 20) and very preterm (30-32 weeks) (n = 42). Ten extreme preterm and 21 very preterm neonates were randomized to each early feeding and late feeding arm. There was a significantly faster attainment of sufficient feeds in the early feeding arm of both the stratified groups [extreme preterm: median 14 days (Interquartile range IQR: 12-15) compared with 18 days (IQR: 18-20), hazard ratio (HR): 1.59, 95% CI: 0.626-4.078; very preterm: 12 days (IQR: 10-14) as compared with 16 days (IQR 15-17), HR: 1.89, 95% CI: 1.011-3.555]. There was no difference in the incidence of NEC, FI and combined outcome of NEC and FI.

CONCLUSION

Early feeding in preterm IUGR neonates with AREDF on antenatal UA Doppler allowed earlier discontinuation of PN, allowing birth weight to be regained earlier and did not increase the incidence of NEC and FI.

Adverse Placental Perfusion and Pregnancy Outcomes in a New Nonhuman Primate Model of Gestational Protein Restriction

Maternal malnutrition during pregnancy impacts fetal growth, with developmental consequences that extend to later life outcomes. In underdeveloped countries, this malnutrition typically takes the form of poor dietary protein content and quality, even if adequate calories are consumed. Here, we report the establishment of a nonhuman primate model of gestational protein restriction (PR) in order to understand how placental function and pregnancy outcomes are affected by protein deficiency. Rhesus macaques were assigned to either a control diet containing 26% protein or switched to a 13% PR diet prior to conception and maintained on this PR diet throughout pregnancy. Standard fetal biometry, Doppler ultrasound of uteroplacental blood flow, ultrasound-guided amniocentesis, and contrast-enhanced ultrasound (CE-US) to assess placental perfusion were performed mid-gestation (gestational day 85 [G85] where term is G168) and in the early third trimester (G135). Our data demonstrate that a 50% reduction in dietary protein throughout gestation results in reduced placental perfusion, fetal growth restriction, and a 50% rate of pregnancy loss. In addition, we demonstrate reduced total protein content and evidence of fetal hypoxia in the amniotic fluid. This report highlights the use of CE-US for in vivo assessment of placental vascular function. The ability to detect placental dysfunction, and thus a compromised pregnancy, early in gestation, may facilitate the development of interventional strategies to optimize clinical care and improve long-term offspring outcomes, which are future areas of study in this new model.

Use of Doppler velocimetry in diagnosis and prognosis of intrauterine growth restriction (IUGR): A Review

Intrauterine growth restriction (IUGR) is a condition which has been difficult to assess at an early stage, resulting in the delivery of children who have poor genetic growth potential. Currently, IUGR classification is based upon the system of ultrasound biometry. Doppler velocimetry allows the measurement of hemodynamic flow of major fetal vessels, comparing the flow indices and patterns of normal and IUGR cases. In this review, the effectiveness of Doppler velocimetry in assessing blood flow in major vessels including the umbilical artery, ductus venosus, and middle cerebral artery was studied for both diagnostic and prognostic screening of IUGR. The umbilical artery is the most frequently studied vessel in Doppler velocimetry due to its accessibility and the strength of its associations with fetal outcomes. Abnormalities in the ductus venosus waveform can be indicative of increased resistance in the right atrium due to placental abnormalities. The middle cerebral artery is the most studied fetal cerebral artery and can detect cerebral blood flow and direction, which is why these three vessels were selected to be examined in this context. A potential mathematical model could be developed to incorporate these Doppler measurements which are indicative of IUGR, in order to reduce perinatal mortality. The purpose of the proposed algorithm is to integrate Doppler velocimetry with biophysical profiling in order to determine the optimal timing of delivery, thus reducing the risks of adverse perinatal outcomes.

Prospective association of fetal liver blood flow at 30 weeks gestation with newborn adiposity

BACKGROUND

The production of variation in adipose tissue accretion represents a key fetal adaptation to energy substrate availability during gestation. Because umbilical venous blood transports nutrient substrate from the maternal to the fetal compartment and because the fetal liver is the primary organ in which nutrient interconversion occurs, it has been proposed that variations in the relative distribution of umbilical venous blood flow shunting either through ductus venosus or perfusing the fetal liver represents a mechanism underlying this adaptation.

OBJECTIVE

The objective of the present study was to determine whether fetal liver blood flow assessed before the period of maximal fetal fat deposition (ie, the third trimester of gestation) is prospectively associated with newborn adiposity.

STUDY DESIGN

A prospective study was conducted in a cohort of 62 uncomplicated singleton pregnancies. Fetal ultrasonography was performed at 30 weeks gestation for conventional fetal biometry and characterization of fetal liver blood flow (quantified by subtracting ductus venosus flow from umbilical vein flow). Newborn body fat percentage was quantified by dual energy X-ray absorptiometry imaging at 25.8 ± 3.3 (mean ± standard error of the mean) postnatal days. Multiple regression analysis was used to determine the proportion of variation in newborn body fat percentage explained by fetal liver blood flow. Potential confounding factors included maternal age, parity, prepregnancy body mass index, gestational weight gain, gestational age at birth, infant sex, postnatal age at dual energy X-ray absorptiometry scan, and mode of infant feeding.

RESULTS

Newborn body fat percentage was 13.5% ± 2.4% (mean ± standard error of the mean). Fetal liver blood flow at 30 weeks gestation was significantly and positively associated with newborn total fat mass (r=0.397; P<.001) and body fat percentage (r=0.369; P=.004), but not with lean mass (r=0.100; P=.441). After accounting for the effects of covariates, fetal liver blood flow explained 13.5% of the variance in newborn fat mass. The magnitude of this association was pronounced particularly in nonoverweight/nonobese mothers (prepregnancy body mass index, <25 kg/m²; n=36) in whom fetal liver blood flow explained 24.4% of the variation in newborn body fat percentage.

CONCLUSION

Fetal liver blood flow at the beginning of the third trimester of gestation is associated positively with newborn adiposity, particularly among nonoverweight/nonobese mothers. This finding supports the role of fetal liver blood flow as a putative fetal adaptation underlying variation in adipose tissue accretion.

Is middle cerebral artery Doppler related to neonatal and 2-year infant outcome in early fetal growth restriction?

BACKGROUND

Reduced fetal middle cerebral artery Doppler impedance is associated with hypoxemia in fetal growth restriction. It remains unclear as to whether this finding could be useful in timing delivery, especially in the third trimester. In this regard there is a paucity of evidence from prospective studies.

OBJECTIVES

The aim of this study was to determine whether there is an association between middle cerebral artery Doppler impedance and its ratio with the umbilical artery in relation to neonatal and 2 year infant outcome in early fetal growth restriction (26⁺⁰-31⁺⁶ weeks of gestation). Additionally we sought to explore which ratio is more informative for clinical use.

STUDY DESIGN

This is a secondary analysis from the Trial of Randomized Umbilical and Fetal Flow in Europe, a prospective, multicenter, randomized management study on different antenatal monitoring strategies (ductus venosus Doppler changes and computerized cardiotocography short-term variation) in fetal growth restriction diagnosed between 26⁺⁰ and 31⁺⁶ weeks. We analyzed women with middle cerebral artery Doppler measurement at study entry and within 1 week before delivery and with complete postnatal follow-up (374 of 503). The primary outcome was survival without neurodevelopmental impairment at 2 years corrected for prematurity. Neonatal outcome was defined as survival until first discharge home without severe neonatal morbidity. Z-scores were calculated for middle cerebral artery pulsatility index and both umbilicocerebral and cerebroplacental ratios. Odds ratios of Doppler parameter Z-scores for neonatal and 2 year infant outcome were calculated by multivariable logistic regression analysis adjusted for gestational age and birthweight p50 ratio.

RESULTS

Higher middle cerebral artery pulsatility index at inclusion but not within 1 week before delivery was associated with neonatal survival without severe morbidity (odds ratio, 1.24; 95% confidence interval, 1.02-1.52). Middle cerebral artery pulsatility index Z-score and umbilicocerebral ratio Z-score at inclusion were associated with 2 year survival with normal neurodevelopmental outcome (odds ratio, 1.33; 95% confidence interval, 1.03-1.72, and odds ratio, 0.88; 95% confidence interval, 0.78-0.99, respectively) as were gestation at delivery and birthweight p50 ratio (odds ratio, 1.41; 95% confidence interval, 1.20-1.66, and odds ratio, 1.86; 95% confidence interval, 1.33-2.60, respectively). When comparing cerebroplacental ratio against umbilicocerebral ratio, the incremental range of the cerebroplacental ratio tended toward zero, whereas the umbilicocerebral ratio tended toward infinity as the values became more abnormal.

CONCLUSION

In a monitoring protocol based on ductus venosus and cardiotocography in early fetal growth restriction (26⁺⁰-31⁺⁶ weeks of gestation), the impact of middle cerebral artery Doppler and its ratios on outcome is modest and less marked than birthweight and delivery gestation. It is unlikely that middle cerebral artery Doppler and its ratios are informative in optimizing the timing of delivery in fetal growth restriction before 32 weeks of gestation. The umbilicocerebral ratio allows for a better differentiation in the abnormal range than the cerebroplacental ratio.

Longitudinal analysis of head and somatic growth in fetuses with congenital heart defects

PURPOSE

Fetal head and somatic growth dynamics differs in fetuses with congenital heart defects (CHD). We longitudinally characterized fetal head and somatic growth in relation to the type of CHD.

METHODS

Four hundred eleven exams from isolated CHD were compared with 1,219 controls. Head and somatic growth was assessed using head circumference (HC), brain volume (BrV = 1/6 × π × (HC/π)3)/2), fetal cephalization index (FCI = BrV/[estimated fetal weight]), and growth percentile. Umbilical and middle cerebral artery Doppler indices were obtained. CHD were grouped as: (1) d-transposition of great arteries (n = 11); (2) left ventricular outflow tract obstruction with retrograde isthmic flow (n = 18); (3) left ventricular outflow tract obstruction with antegrade isthmic flow (n = 16); (4) pulmonary outflow tract obstructions (n = 22).

RESULTS

The smallest head size was seen in group 1. Growth asymmetry was diagnosed in group 2. Brain sparing was seen in groups 2 and 4 (p < 0.0001). HC and BrV percentiles decreased with advancing gestational age (p < 0.001) in group 2, and a significant drop was observed around 28 weeks.

CONCLUSIONS

d-Transposition of great arteries and left-sided CHD leading to isthmic blood flow reversal are associated with delayed head growth. Prenatal evaluation of central hemodynamics in CHD may be contributive for predicting neurodevelopmental risks in CHD and help directing prenatal interventions. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 45:96-104, 2017.

Ductus venosus Doppler in the assessment of fetal cardiovascular health: an updated practical approach

The ductus venosus has a central role in the distribution of highly oxygenated umbilical venous blood to the heart. Its waveform is related to the pressure-volume changes in the cardiac atria and it is therefore important in the monitoring of any fetal condition that may affect forward cardiac function. The cardiovascular parameters that can influence forward cardiac function include afterload, myocardial performance and preload. Decreased forward flow during atrial systole (a-wave) is the most sensitive and ubiquitous finding when any of these parameters is affected. In contrast, decreased forward velocities during end-systolic relaxation (v-wave) are more specifically related to myocardial performance. The ductus venosus pulsatility index alone does not accurately reflect cardiac function, and in cases of suspected fetal cardiac dysfunction, echocardiography is required to identify the underlying mechanism. The role of ductus venosus Doppler in the assessment of fetal growth restriction, supraventricular tachycardia, fetal hydrops, complicated monochorionic twins and congenital heart disease is discussed with these considerations in mind.

Transabdominal Insonation of Fetal Basilar Artery: A Feasibility Study

BACKGROUND

Fetal anterior, middle, and posterior cerebral arteries have been studied using transabdominal Doppler ultrasound. We performed a feasibility study to determine whether basilar artery can be identified and blood flow velocities measured using transabdominal fetal Doppler ultrasound.

METHODS

The basilar artery was identified in sagittal plane behind the clivus bone using directional color Doppler with 6-2 and 7-4 MHz curved array probes. The clivus was identified by hyperechoic linear signal anterior to junction of vertebral processes and occipital bone and superior to first vertebral body. The flow direction was away from the probe in the basilar artery consistent with caudo cephalic orientation. The Doppler ultrasound probe was placed at insonation angles of less than 30° at the visualized segment of the basilar artery. Peak systolic and end diastolic velocities were measured.

RESULTS

We attempted insonation of the basilar artery in 20 fetuses. The basilar artery was adequately insonated in 18 fetuses with a mean gestational age of 27 weeks (range 19 to 38 weeks). The mean value (±SD) of peak systolic velocity of the basilar artery was 22.1 ± 8.5 cm/second (range 10.4-36.7 cm/second). The mean value (±SD) of end diastolic velocity was 6.8 ± 2.8 cm/second (range 3.5-13.5 cm/second). There was an increase in peak systolic velocity values according to gestational age of fetus.

CONCLUSIONS

We demonstrate the feasibility of fetal basilar artery insonation using directional color Doppler ultrasound via transabdominal approach.

Assessment of nitrite oxide and maternal-fetal Doppler parameters during pregnancy

OBJECTIVE

The objective was to evaluate and compare the whole blood nitrite concentration in the three trimesters of pregnancy. Additionally, we investigate whether there is any relation between nitrite concentrations and Doppler ultrasound analysis of some maternal and fetal vessels.

METHODS

Thirty-three healthy pregnant women were examined at the first (11-14 weeks), second (20-24 weeks) and third trimester (34-36 weeks) of pregnancy. In the three exams, we determined the maternal whole blood nitrite concentration and uterine arteries Doppler analysis to determine pulsatility index (PI), and resistance index (RI). In the second and third trimester we also performed fetal umbilical and middle cerebral arteries PI and RI. We compared the concentrations of nitrite in three trimesters and correlated with Doppler parameters.

RESULTS

No difference was observed in the whole blood nitrite concentrations across trimesters: 151.70 ± 77.90 nmol/ml, 142.10 ± 73.50 nmol/ml and 147.10 ± 87.30 nmol/ml; first, second and third trimesters, respectively. We found no difference in correlation between whole blood nitrite concentration and Doppler parameters from the evaluated vessels.

CONCLUSIONS

In healthy pregnant women, the nitrite concentrations did not change across gestational trimesters and there was also no strong correlation with Doppler impedance indices from maternal uterine arteries and fetal umbilical and middle cerebral arteries.

Doppler flowmetry of the superior mesenteric artery and portal vein: impact for the early prediction of necrotizing enterocolitis in neonates

PURPOSE

Necrotizing enterocolitis (NEC) is a serious gastrointestinal disorder in newborns. Early diagnosis and rapid treatment is essential for seeking good outcome for neonates. The aim of our study was to evaluate intestinal blood flow in superior mesenteric artery (SMA) and portal vein (PV) in neonates with suspected or confirmed NEC and investigate the prognostic cut-off values to develop NEC.

METHODS

Doppler flowmetry of SMA and PV was performed for 62 newborns. Resistive (RI) and pulsatility (PI) indexes were measured in SMA as well as Volumetric blood flow (Vflow) in PV. ROC curves were applied to estimate sensitivity and specificity and to identify cut-off values.

RESULTS

There were 93.5% preterm neonates. 29 patients (46.8%) were diagnosed with NEC and 33 (53.2%) formed a control group. 96.3% NEC patients had RI >0.75 with sensitivity of 96.3% and specificity of 90.9% (OR 260). 88.9% NEC patients had PI >1.85 with sensitivity of 88.9% and specificity of 78.8% (OR 29). Portal Vflow lower than 37 ml/min was present in 89.7% patients with NEC (OR 11.7).

CONCLUSION

Intestinal blood flow Dopplerography can be a useful tool for diagnosing and predicting NEC.

Placental vascularization alterations in hypertensive disorders complicating pregnancy (HDCP) and small for gestational age with HDCP using three-dimensional power doppler in a prospective case control study

Background

Hypertensive disorders complicating pregnancy (HDCP) continues to be a leading cause of maternal and neonatal mortality and morbidity. The clinical value of placental three-dimensional power Doppler (3DPD) in assessing HDCP requires further confirmation. The research was developed to assess changes of placental vascularity in HDCP using 3DPD and to investigate the placental vascularity in small for gestational age (SGA) compared with not-SGA in patients with HDCP.

Methods

There were 126 normotensive and 128 hypertensive pregnant women included in this prospective case–control study from March 2011 to March 2013. Pregnant women underwent 3DPD. Vascularization index (VI), flow index (FI) and vascularization flow index (VFI) were obtained. The placental 3DPD indices, umbilical artery systolic and diastolic ratio (S/D) and pregnancy outcomes were compared between the groups.

Results

The placental VI and VFI were significantly lower in hypertensive women compared with normotensive women (P < 0.001 and P = 0.014, respectively), and these parameters were significantly reduced in severe preeclampsia (P < 0.001 and P = 0.003, respectively). A weak correlation was found between VI and umbilical artery S/D in HDCP group (r = -0.277, P = 0.001). In HDCP population, neonates who were postnatally diagnosed with SGA had lower VI (P = 0.041) and higher S/D (P < 0.001).

Discussion

The placental vascularity indices decreased in hypertensive women and the reduction inplacental perfusion was consistent with the severity of the hypertensive disorder. The associations betweenplacental vascularization and umbilical artery impedance may be valuable for further researches and arerequired confirmation. The significant differences in the 3DPD placental vascularization between SGA andnot-SGA in hypertensive pregnancy population may show some clinical importance that we could use tobetter assess or predict the progression and adverse outcomes in the future. Although 3DPD quantificationhas been widely used in multiple publications, we have to acknowledge its limitations.

Conclusions

The intraplacental vascularization was poor in HDCP, and especially in severe preeclampsia. Neonates with SGA had poor placental vascularization and higher umbilical artery S/D. Further studies should focus on the clinical assessment of placental 3DPD as well as a combination of placental 3DPD and other fetal Doppler indices to better predict the development and outcomes of preeclampsia.

Role of the fetoplacental endothelium in fetal growth restriction with abnormal umbilical artery Doppler velocimetry

Growth-restricted fetuses with absent or reversed end-diastolic velocities in the umbilical artery are at substantially increased risk for adverse perinatal and long-term outcome, even in comparison to growth-restricted fetuses with preserved end-diastolic velocities. Translational studies show that this Doppler velocimetry correlates with fetoplacental blood flow, with absent or reversed end-diastolic velocities signifying abnormally elevated resistance within the placental vasculature. The fetoplacental vasculature is unique in that it is not subject to autonomic regulation, unlike other vascular beds. Instead, humoral mediators, many of which are synthesized by local endothelial cells, regulate placental vascular resistance. Existing data demonstrate that in growth-restricted pregnancies complicated by absent or reversed umbilical artery end-diastolic velocities, an imbalance in production of these vasoactive substances occurs, favoring vasoconstriction. Morphologically, placentas from these pregnancies also demonstrate impaired angiogenesis, whereby vessels within the terminal villi are sparsely branched, abnormally thin, and elongated. This structural deviation from normal placental angiogenesis restricts blood flow and further contributes to elevated fetoplacental vascular resistance. Although considerable work has been done in the field of fetoplacental vascular development and function, much remains unknown about the mechanisms underlying impaired development and function of the human fetoplacental vasculature, especially in the context of severe fetal growth restriction with absent or reversed umbilical artery end-diastolic velocities. Fetoplacental endothelial cells are key regulators of angiogenesis and vasomotor tone. A thorough understanding of their role in placental vascular biology carries the significant potential of discovering clinically relevant and innovative approaches to prevention and treatment of fetal growth restriction with compromised umbilical artery end-diastolic velocities.

Clinical relevance of fetal hemodynamic monitoring: Perinatal implications

Comprehensive assessment of fetal wellbeing involves monitoring of fetal growth, placental function, central venous pressure, and cardiac function. Ultrasound evaluation of the fetus using 2D, color Doppler, and pulse-wave Doppler techniques form the foundation of antenatal diagnosis of structural anomalies, rhythm abnormalities and altered fetal circulation. Accurate and timely prenatal identification of the fetus at risk is critical for appropriate parental counseling, antenatal diagnostic testing, consideration for fetal intervention, perinatal planning, and coordination of postnatal care delivery. Fetal hemodynamic monitoring and serial assessment are vital to ensuring fetal wellbeing, particularly in the setting of complex congenital anomalies. A complete hemodynamic evaluation of the fetus gives important information on the likelihood of a smooth postnatal transition and contributes to ensuring the best possible outcome for the neonate.

Doppler for growth restriction: the association between the cerebroplacental ratio and a reduced interval to delivery

OBJECTIVE

Evaluation of the cerebroplacental ratio (CPR) as an adjunct to umbilical artery Doppler (UA) to assess risk of delivery before 32 weeks and/or delivery within 2 weeks from diagnosis of fetal growth restriction (FGR).

STUDY DESIGN

In a cohort of fetuses with suspected FGR, UA Doppler was performed, and when abnormal the CPR was calculated (middle cerebral pulsatility index/umbilical artery pulsatility index). Doppler characteristics were used to determine three study groups: (1) normal UA, (2) abnormal UA with normal CPR and (3) abnormal UA with abnormal CPR. The primary outcomes were delivery before 32 weeks and delivery within 2 weeks. Adjusted odds ratio (aOR) with 95% confidence intervals (CIs) were calculated controlling for maternal age, chronic hypertension and tobacco use. We performed a linear regression analysis comparing the value of the CPR with the gestational age at delivery. Kaplan-Meier survival curve analysis with log-rank tests for probability was performed.

RESULTS

We included 154 patients: 91, 31 and 32 in Group 1, 2 and 3, respectively. Subjects in Group 3 had higher rates of the two primary outcomes: there was a fivefold increased risk (aOR=5.2 (95% CI=2.85-9.48)) for delivery before 32 weeks and over a fourfold increased risk for delivery within 2 weeks (aOR=4.76 (95% CI=2.32-9.76)) compared with those with a normal CPR (Group 1). In contrast, subjects in Group 2 (abnormal UA Doppler but normal CPR) had a similar rate of delivery before 32 weeks (aOR=1.16 (95% CI=0.55-2.48)) and within 2 weeks (aOR=1.07 (95% CI=0.43-2.69)). The median gestational age at delivery was 36, 36 and 29 weeks in Groups 1, 2 and 3, respectively (P<0.001). Linear regression analysis revealed a strong correlation between the value of the CPR and gestational age at delivery: R(2)=0.56, correlation coefficient=0.75. Kaplan-Meier analysis revealed a significantly decreased latency to delivery in Group 3, as opposed to Groups 1 and 2 (Cox-Mantel hazard ratio (HR) of Group 2 versus Group 1 HR=1.20 (95% CI=0.78-1.83) and Group 3 versus Group 1 HR=5.00 (95% CI=2.4-10.21)).

CONCLUSION

The CPR differentiates those fetuses with suspected growth restriction most at risk for delivery before 32 weeks and delivery within 2 weeks from those likely to have a more prolonged latency until delivery is required. In patients with suspected FGR and an abnormal UA, the CPR can be used to guide management decisions, such as maternal hospitalization and/or transport, aggressive fetal monitoring and antenatal corticosteroid administration.

Estimation of the growth rate in fetuses with an abnormal cerebroplacental ratio compared to those with suspected growth restriction without evidence of centralization of blood flow

OBJECTIVES

To evaluate the growth rate in fetuses with suspected growth restriction according to their Doppler characteristics.

METHODS

A retrospective cohort of fetuses with suspected growth restriction was identified. We reviewed umbilical artery and middle cerebral Doppler pulsatility indices and calculated the cerebroplacental ratio. Three study groups were determined: (1) normal umbilical artery Doppler findings; (2) abnormal umbilical artery findings with a normal cerebroplacental ratio; and (3) abnormal umbilical artery findings with an abnormal cerebroplacental ratio. The primary outcome was the growth rate as estimated by fetal biometry from serial sonographic evaluations. Analysis of the mean growth rate in each study group was performed by analysis of variance. In addition, linear regression analysis comparing the cerebroplacental ratio to the growth rate was performed.

RESULTS

Fetal growth restriction was suspected in 416 patients; 176 patients were included in this analysis: 113, 38, and 25 in groups 1, 2, and 3 respectively. The estimated mean (SD) growth rate in group 3 was significantly lower than in groups 1 and 2: 8.3 (4.4) versus 19.6 (6.0) and 18.6 (7.7) g/d, respectively (P < .001). Linear regression analysis revealed a strong correlation between the growth rate and cerebroplacental ratio (r = 0.76; R(2) = 0.58) as well as the birth weight and cerebroplacental ratio (r = 0.78; R(2) = 0.61).

CONCLUSIONS

In fetuses with suspected growth restriction and abnormal umbilical artery Doppler findings, an abnormal cerebroplacental ratio is strongly associated with reduced fetal growth. In contrast, if the cerebroplacental ratio is normal, even in the setting of abnormal umbilical artery Doppler findings, fetuses grow similarly to those with normal umbilical artery findings.

Vitamin C supplementation ameliorates the adverse effects of nicotine on placental hemodynamics and histology in nonhuman primates

OBJECTIVE

We previously demonstrated that prenatal nicotine exposure decreases neonatal pulmonary function in nonhuman primates, and maternal vitamin C supplementation attenuates these deleterious effects. However, the effect of nicotine on placental perfusion and development is not fully understood. This study utilizes noninvasive imaging techniques and histological analysis in a nonhuman primate model to test the hypothesis that prenatal nicotine exposure adversely effects placental hemodynamics and development but is ameliorated by vitamin C.

STUDY DESIGN

Time-mated macaques (n = 27) were divided into 4 treatment groups: control (n = 5), nicotine only (n = 4), vitamin C only (n = 9), and nicotine plus vitamin C (n = 9). Nicotine animals received 2 mg/kg per day of nicotine bitartrate (approximately 0.7 mg/kg per day free nicotine levels in pregnant human smokers) from days 26 to 160 (term, 168 days). Vitamin C groups received ascorbic acid at 50, 100, or 250 mg/kg per day with or without nicotine. All underwent placental dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) at 135-140 days and Doppler ultrasound at 155 days to measure uterine artery and umbilical vein velocimetry and diameter to calculate uterine artery volume blood flow and placental volume blood flow. Animals were delivered by cesarean delivery at 160 days. A novel DCE-MRI protocol was utilized to calculate placental perfusion from maternal spiral arteries. Placental tissue was processed for histopathology.

RESULTS

Placental volume blood flow was significantly reduced in nicotine-only animals compared with controls and nicotine plus vitamin C groups (P = .03). Maternal placental blood flow was not different between experimental groups by DCE-MRI, ranging from 0.75 to 1.94 mL/mL per minute (P = .93). Placental histology showed increased numbers of villous cytotrophoblast cell islands (P < .05) and increased syncytiotrophoblast sprouting (P < .001) in nicotine-only animals, which was mitigated by vitamin C.

CONCLUSION

Prenatal nicotine exposure significantly decreased fetal blood supply via reduced placental volume blood flow, which corresponded with placental histological findings previously associated with cigarette smoking. Vitamin C supplementation mitigated the harmful effects of prenatal nicotine exposure on placental hemodynamics and development, suggesting that its use may limit some of the adverse effects associated with smoking during pregnancy.

IUGR management: new perspectives

AIM OF THE STUDY

Analyzing velocimetric (umbilical artery, UA; ductus venosus, DV; middle cerebral artery, MCA) and computerized cardiotocographic (cCTG) (fetal heart rate, FHR; short term variability, STV; approximate entropy, ApEn) parameters in intrauterine growth restriction, IUGR, in order to detect early signs of fetal compromise. POPULATION STUDY: 375 pregnant women assisted from the 28th week of amenorrhea to delivery and monitored through cCTG and Doppler ultrasound investigation. The patients were divided into three groups according to the age of gestation at the time of delivery, before the 34th week, from 34th to 37th week, and after the 37th week. Data were analyzed in relation to the days before delivery and according to the physiology or pathology of velocimetry. Statistical analysis was performed through the t-test, chi-square test, and Pearson correlation test (P < 0.05). Our results evidenced an earlier alteration of UA, DV, and MCA. The analysis between cCTG and velocimetric parameters (the last distinguished into physiological and pathological values) suggests a possible relation between cCTG alterations and Doppler ones. The present study emphasizes the need for an antenatal testing in IUGR fetuses using multiple surveillance modalities to enhance prediction of neonatal outcome.