Doppler assessment of the fetus with intrauterine growth restriction

Variation in the definition of intrauterine growth restriction in routine antenatal care: a physician survey among gynecologists in Northwest Germany

OBJECTIVE

To assess how intrauterine growth restriction (IUGR) is defined by gynecologists in routine practice.

MATERIALS AND METHODS

We surveyed primary care gynecologists in Bremen and Lower Saxony, Northwest Germany, between January and July 2014. Descriptive statistics were used to analyze the data; consensus was considered as 90% agreement among the respondents. Multiple logistic regression models were performed for the associations between respondents' background characteristics and choice of the small for gestational age (SGA) cutoff values.

RESULTS

Overall, 185 primary care gynecologists participated in the survey. Consensus was only observed in two items: (1) an accurate determination of gestational age (91%) and (2) repeated measurement of the abdominal circumference (91%). Umbilical artery Doppler (76%) and repeated ultrasonography (76%) were the most frequently used methods to confirm suspected IUGR diagnoses, but different responses prevailed. Notably, only 46% of the respondents opted for the 10th percentile of estimated fetal weight as a cutoff for SGA classification, which is the internationally recommended value.

CONCLUSIONS

The results of this survey indicate considerable practice variation regarding detection and management of IUGR pregnancies. There is a need for better agreement in terminology and definition of core aspects of IUGR in antenatal care.

Care-Related and Maternal Risk Factors Associated with the Antenatal Nondetection of Intrauterine Growth Restriction: A Case-Control Study from Bremen, Germany

Objective. To identify care-related and maternal risk factors for the antenatal nondetection of IUGR. Methods. In this hospital-based case-control study we compared antenatally undetected IUGR neonates (cases) to detected IUGR neonates (controls). Data were collected using newborn documentation sheets and standardized personal interviews with the mothers. We calculated antenatal detection rates and used uni- and multivariable logistic regression models to assess the association of antenatal nondetection of IUGR and maternal and care-related factors. Results. A total of 161 neonates from three hospitals were included in the study. Suboptimal fetal growth was identified antenatally in n = 77 pregnancies while in n = 84 it was not detected antenatally (antenatal detection rate: 47.8%). Severity of IUGR, maternal complications, and a Doppler examination during the course of pregnancy were associated with IUGR detection. We did not find statistically significant differences regarding parental socioeconomic status and maternal migration background. Conclusions. In our study, about half of all pregnancies affected by suboptimal growth remained undetected. Future in-depth studies with larger study populations should further examine factors that could increase antenatal detection rates for IUGR.

Review: Systematic review of the utility of the fetal cerebroplacental ratio measured at term for the prediction of adverse perinatal outcome

AIM

This systematic review evaluates the utility of the fetal cerebroplacental ratio (CPR) when assessed at term (from 37 + 0 weeks gestation) as a predictor of adverse obstetric and perinatal outcomes.

DATA SOURCES AND SEARCH STRATEGY

An electronic search of Pubmed and Embase using variations of 'cerebroplacental ratio' and 'cerebroumbilical ratio' was conducted by two independent reviewers. Full text studies written in English that reported on low CPR and its correlation with relevant obstetric and perinatal outcomes were included.

RESULTS

Twenty one studies satisfied inclusion with 13 prospective and eight retrospective analyses. Fetal CPR was predictive of caesarean section for intrapartum fetal compromise, small for gestational age and fetal growth restriction and neonatal intensive care unit admission. Low CPR was also significantly associated with abnormal fetal heart rate pattern, meconium stained liquor, low Apgar score, acidosis at birth and composite adverse perinatal outcome scores. The CPR when taken at term had comparable if not better predictive value than that when taken at preterm. Most studies included small for gestational age fetuses and postdate pregnancies. Subtle variation existed in the threshold for low CPR.

CONCLUSION

The CPR at term has a strong association with adverse obstetric and perinatal outcomes. This review suggests the predictive utility of CPR at term is promising however there is insufficient evidence to demonstrate its value as a stand-alone test. Inclusion of CPR as a component of clinical care may help better identify fetuses at risk of adverse outcome, and this should be tested with randomised control trials.

Placental soluble fms-like tyrosine kinase expression in small for gestational age infants and risk for adverse outcomes

INTRODUCTION

Soluble fms-like tyrosine kinase 1 (sFLT-1) is an anti-angiogenic factor implicated in the pathogenesis of preterm preeclampsia. We evaluated sFLT-1 expression and placental pathology in pregnancies complicated by small for gestational age (SGA) infants (<10th percentile), without evidence of preeclampsia.

METHODS

Clinical and histologic data were compared between groups with high or low sFLT-1 expression determined by immunohistochemistry on archived placentas.

RESULTS

Nineteen of 69 placentas showed high sFLT-1 expression. The high sFLT-1 group had higher predelivery median systolic blood pressure (BP); 140 (interquartile range (IQR) 133-152) vs. 126 (118-139) mm Hg (p = 0.003), and median diastolic BP; 87 (78-94) vs. 77.5 (71-86) mm Hg (p = 0.02). Abnormal umbilical Doppler abnormalities were more prevalent; 89.5% vs. 46% (p = 0.001). These pregnancies delivered earlier; 31.9 weeks (28.3-34.7 weeks) vs. 37.1 weeks (33.7-38.7 weeks) (p < 0.001), and infants had lower birthweight; 980 grams (520-1545 grams) vs. 2087.5 grams (1455-2340 grams) (p < 0.001). Placental-weight to fetal-weight ratios, a marker of vascular insufficiency, was increased in the high sFlt-1 group: 0.18 (0.14-0.28) vs 0.15 (0.13-0.18), p = 0.03. Placentas with high sFLT-1 showed more decidual vasculopathy; 42.1% vs. 10.0% (p = 0.005), infarction; 36.8% vs. 14.0% (p = 0.048), distal villous hypoplasia; 78.9% vs. 36.0% (p = 0.001), and fetal thrombotic vasculopathy; 47.4% vs. 16.0% (p = 0.01).

DISCUSSION

Placental sFLT-1 expression is upregulated in approximately 28% of non-preeclamptic pregnancies complicated by SGA infants. These pregnancies showed increased placental vascular pathology, more umbilical Doppler abnormalities, and earlier delivery with lower birthweight. A subgroup of non-preeclamptic fetal growth restriction with upregulated sFlt-1 expression may share a common pathogenic pathway with preterm preeclampsia. This subgroup is worthy of additional study.

Impact of placental insufficiency on fetal skeletal muscle growth

Intrauterine growth restriction (IUGR) caused by placental insufficiency is one of the most common and complex problems in perinatology, with no known cure. In pregnancies affected by placental insufficiency, a poorly functioning placenta restricts nutrient supply to the fetus and prevents normal fetal growth. Among other significant deficits in organ development, the IUGR fetus characteristically has less lean body and skeletal muscle mass than their appropriately-grown counterparts. Reduced skeletal muscle growth is not fully compensated after birth, as individuals who were born small for gestational age (SGA) from IUGR have persistent reductions in muscle mass and strength into adulthood. The consequences of restricted muscle growth and accelerated postnatal "catch-up" growth in the form of adiposity may contribute to the increased later life risk for visceral adiposity, peripheral insulin resistance, diabetes, and cardiovascular disease in individuals who were formerly IUGR. This review will discuss how an insufficient placenta results in impaired fetal skeletal muscle growth and how lifelong reductions in muscle mass might contribute to increased metabolic disease risk in this vulnerable population.

Small-for-gestational-age infants among uncomplicated pregnancies at term: a secondary analysis of 9 Maternal-Fetal Medicine Units Network studies

BACKGROUND

Most small (birthweight <10%) for-gestational-age cases occur at term, in uncomplicated pregnancies, and are not identified during prenatal visits as having fetal growth restriction. Hence, they do not benefit from antepartum surveillance and timed delivery. There is dismissive and disquieting opinion that small for gestational age among uncomplicated pregnancies is not associated with increased morbidities and, therefore, does not warrant improved detection. Our hypothesis was that among uncomplicated pregnancies at term, small for gestational age have significantly higher morbidity and mortality than appropriate (birthweight 10-89%) for gestational age.

OBJECTIVE

We sought to compare composite neonatal morbidity among uncomplicated term singleton pregnancies with small vs appropriate for gestational age.

STUDY DESIGN

We culled collected data from 9 completed Maternal-Fetal Medicine Units studies conducted from 1989 through 2004. All data were collected prospectively by trained staff. We excluded women who delivered <37 weeks and those with hypertension or diabetes, multiple gestation, known anomalies, and birthweight of ≥90% for gestational age. Using multivariable analysis, we compared composite neonatal morbidity, which included stillbirth and neonatal mortality between small and appropriate for gestational age. Random effect logistic regressions were used to account for study heterogeneity, with adjustment for potential confounders. We calculated adjusted odds ratios and 95% confidence intervals.

RESULTS

Of the >91,000 women enrolled in the studies, 60% (n = 50,011) met the inclusion criteria. Among the uncomplicated pregnancies, 10.8% (n = 5416) were small for gestational age. The rate of composite neonatal morbidity of 16% in small for gestational age and 10% in appropriate for gestational age persisted (adjusted odds ratio, 1.75; 95% confidence interval, 1.71-1.78). After adjustment for confounders, the following neonatal morbidities were significantly more common among term small than appropriate for gestational age: Apgar <4 at 5 minutes, respiratory distress syndrome, mechanical ventilation, necrotizing enterocolitis grade 2 or 3, and neonatal sepsis. Lastly, rate of stillbirths (3.5 vs 0.9/1000 births; adjusted odds ratio, 3.49; 95% confidence interval, 1.83-6.67) and neonatal mortality (1.1 vs 0.4/1000 births; adjusted odds ratio, 2.56; 95% confidence interval, 1.83-3.57) were significantly more common with small than appropriate for gestational age. In secondary analyses the composite neonatal morbidity among newborns at <5% and at 5-9% was significantly higher than appropriate for gestational age. Lastly, in subgroup analyses of women who delivered at 37.0-38.6 weeks or at ≥39.0 weeks, the increased rate of composite neonatal morbidity, stillbirth, and neonatal mortality among small for gestational age persisted.

CONCLUSION

Among uncomplicated pregnancies at term, small- compared to appropriate-for-gestational-age newborns have a significantly higher likelihood of composite neonatal morbidity, stillbirth, and neonatal mortality. A large multicenter trial is warranted to determine if improved detection of small for gestational age among uncomplicated pregnancies can mitigate morbidities and mortality, without disproportionate interventions and iatrogenic complications.

The use of angiogenic biomarkers in maternal blood to identify which SGA fetuses will require a preterm delivery and mothers who will develop pre-eclampsia

OBJECTIVE

To determine (1) whether maternal plasma concentrations of angiogenic and anti-angiogenic factors can predict which mothers diagnosed with "suspected small for gestational age fetuses (sSGA)" will develop pre-eclampsia (PE) or require an indicated early preterm delivery (≤ 34 weeks of gestation); and (2) whether risk assessment performance is improved using these proteins in addition to clinical factors and Doppler parameters.

METHODS

This prospective cohort study included women with singleton pregnancies diagnosed with sSGA (estimated fetal weight <10th percentile) between 24 and 34 weeks of gestation (n = 314). Plasma concentrations of soluble vascular endothelial growth factor receptor-1 (sVEGFR-1), soluble endoglin (sEng) and placental growth factor (PlGF) were determined in maternal blood obtained at the time of diagnosis. Doppler velocimetry of the umbilical (Umb) and uterine (UT) arteries was performed. The outcomes were (1) subsequent development of PE; and (2) indicated preterm delivery at ≤ 34 weeks of gestation (excluding deliveries as a result of spontaneous preterm labor, preterm pre-labor rupture of membranes or chorioamnionitis).

RESULTS

(1) The prevalence of PE and indicated preterm delivery was 9.2% (n = 29/314) and 7.3% (n = 23/314), respectively; (2) the area under the receiver operating characteristic curve (AUC) for the identification of patients who developed PE and/or required indicated preterm delivery was greater than 80% for the UT artery pulsatility index (PI) z-score and each biochemical marker (including their ratios) except sVEGFR-1 MoM; (3) using cutoffs at a false positive rate of 15%, women with abnormal plasma concentrations of angiogenic/anti-angiogenic factors were 7-13 times more likely to develop PE, and 12-22 times more likely to require preterm delivery than those with normal plasma MoM concentrations of these factors; (4) sEng, PlGF, PIGF/sEng and PIGF/sVEGFR-1 ratios MoM, each contributed significant information about the risk of PE beyond that provided by clinical factors and/or Doppler parameters: women who had low MoM values for these biomarkers were at 5-9 times greater risk of developing PE than women who had normal values, adjusting for clinical factors and Doppler parameters (adjusted odds ratio for PlGF: 9.1, PlGF/sEng: 5.6); (5) the concentrations of sVEGFR-1 and PlGF/sVEGFR-1 ratio MoM, each contributed significant information about the risk of indicated preterm delivery beyond that provided by clinical factors and/or Doppler parameters: women who had abnormal values were at 8-9 times greater risk for indicated preterm delivery, adjusting for clinical factors and Doppler parameters; and (6) for a two-stage risk assessment (Umb artery Doppler followed by Ut artery Doppler plus biochemical markers), among women who had normal Umb artery Doppler velocimetry (n = 279), 21 (7.5%) developed PE and 11 (52%) of these women were identified by an abnormal UT artery Doppler mean PI z-score (>2SD): a combination of PlGF/sEng ratio MoM concentration and abnormal UT artery Doppler velocimetry increased the sensitivity of abnormal UT artery Doppler velocimetry to 76% (16/21) at a fixed false-positive rate of 10% (p = 0.06).

CONCLUSION

Angiogenic and anti-angiogenic factors measured in maternal blood between 24 and 34 weeks of gestation can identify the majority of mothers diagnosed with "suspected SGA" who subsequently developed PE or those who later required preterm delivery ≤ 34 weeks of gestation. Moreover, incorporation of these biochemical markers significantly improves risk assessment performance for these outcomes beyond that of clinical factors and uterine and umbilical artery Doppler velocimetry.

Maternal Calorie Restriction Causing Uteroplacental Insufficiency Differentially Affects Mammalian Placental Glucose and Leucine Transport Molecular Mechanisms

We examined the effect of mild (Mi; ∼25%) and moderate (Mo; ∼50%) maternal calorie restriction (MCR) vs ad libitum-fed controls on placental glucose and leucine transport impacting fetal growth potential. We observed in MiMCR a compensatory increase in transplacental (TP) glucose transport due to increased placental glucose transporter isoform (GLUT)-3 but no change in GLUT1 protein concentrations. This change was paralleled by increased glut3 mRNA and 5-hydroxymethylated cytosines with enhanced recruitment of histone 3 lysine demethylase to the glut3 gene locus. To assess the biologic relevance of placental GLUT1, we also examined glut1 heterozygous null vs wild-type mice and observed no difference in placental GLUT3 and TP or intraplacental glucose and leucine transport. Both MCR states led to a graded decrease in TP and intraplacental leucine transport, with a decline in placental L amino acid transporter isoform 2 (LAT2) concentrations and increased microRNA-149 (targets LAT2) and microRNA-122 (targets GLUT3) expression in MoMCR alone. These changes were accompanied by a step-wise reduction in uterine and umbilical artery Doppler blood flow with decreased fetal left ventricular ejection fraction and fractional shortening. We conclude that MiMCR transactivates placental GLUT3 toward preserving TP glucose transport in the face of reduced leucine transport. This contrasts MoMCR in which a reduction in placental GLUT3 mediated glucose transport with a reciprocal increase in miR-122 expression was encountered. A posttranscriptional reduction in LAT2-mediated leucine transport also occurred with enhanced miR-149 expression. Both MCR states, although not affecting placental GLUT1, resulted in uteroplacental insufficiency and fetal growth restriction with compromised cardiovascular health.

Diagnosis and Management of IUGR in Pregnancy Complicated by Type 1 Diabetes Mellitus

This review discusses available literature on the diagnosis and management of intrauterine growth restriction (IUGR) in women with type 1 diabetes. IUGR is diagnosed when ultrasound-estimated fetal weight is below the 10th percentile for gestational age. IUGR diagnosis implies a pathologic process behind low fetal weight. IUGR in pregnancy complicated by type 1 diabetes is usually caused by placental dysfunction related to maternal vasculopathy. Prevention of IUGR should ideally start before pregnancy. Strict glycemic control and intensive treatment of nephropathy and hypertension are essential. Low-dose aspirin initiated before 16 gestational weeks can also reduce IUGR risk in women with vasculopathy. Umbilical and uterine artery Doppler studies can guide diagnosis and surveillance of fetuses with IUGR. Decisions regarding the timing of delivery should be based on assessment of umbilical artery Doppler. The risk of prematurity and impaired fetal lung maturation should always be considered, especially in fetuses younger than 32 weeks.

Epigenetic Characterization of CDKN1C in Placenta Samples from Non-syndromic Intrauterine Growth Restriction

The cyclin-dependent kinase (CDK)-inhibitor 1C (CDKN1C) gene is expressed from the maternal allele and is located within the centromeric imprinted domain at chromosome 11p15. It is a negative regulator of proliferation, with loss-of-function mutations associated with the overgrowth disorder Beckwith–Wiedemann syndrome. Recently, gain-of-function mutations within the PCNA domain have been described in two disorders characterized by growth failure, namely IMAGe (intra-uterine growth restriction, metaphyseal dysplasia, adrenal hypoplasia congenita and genital abnormalities) syndrome and Silver–Russell syndrome (SRS). Over-expression of CDKN1C by maternally inherited microduplications also results in SRS, suggesting that in addition to activating mutations this gene may regulate growth by changes in dosage. To determine if CDKN1C is involved in non-syndromic IUGR we compared the expression and DNA methylation levels in a large cohort of placental biopsies from IUGR and uneventful pregnancies. We observe higher levels of expression of CDKN1C in IUGR placentas compared to those of controls. All placenta biopsies heterozygous for the PAPA repeat sequence in exon 2 showed appropriate monoallelic expression and no mutations in the PCNA domain were observed. The expression profile was independent of both genetic or methylation variation in the minimal CDKN1C promoter interval and of methylation of the cis-acting maternally methylated region associated with the neighboring KCNQ1OT1 non-coding RNA. Chromatin immunoprecipitation revealed binding sites for CTCF within the unmethylated CDKN1C gene body CpG island and putative enhancer regions, associated with the canonical enhancer histone signature, H3K4me1 and H3K27ac, located ∼58 and 360 kb away. Using 3C-PCR we identify constitutive higher-order chromatin loops that occur between one of these putative enhancer regions and CDKN1C in human placenta tissues, which we propose facilitates expression.

Revisiting decidual vasculopathy

INTRODUCTION

In the setting of preeclampsia (PE), decidual vasculopathy (DV) can be seen along the free membranes.

METHODS

We describe DV using stains for CD31, CD34, Cd42b, CD68, desmin, fibrin and Masson's trichrome in patients with preeclampsia and fetal growth restriction.

RESULTS

We first examined the "membrane roll" sections from the placentas of six patients with preeclampsia. Affected vessels showed endothelial proliferation with detachment. Remodeling of the media was characterized by smooth muscle loss with variable degrees of fibrin deposition. CD31 and CD34 highlighted the prominent endothelium and showed striking particulate staining throughout the media. All of these findings infer a sequence of endothelial injury, fragmentation and repair with incorporation of endothelial components into the vascular wall. We evaluated the frequency of DV by clinical presentation; in cases with PE with and without small for gestational age (SGA) (N = 15), and SGA with and without Doppler flow abnormalities (N = 15). All groups except the SGA without Doppler abnormalities showed DV. Among placentas with DV, the most severely affected group was PE with SGA; the least affected was PE without SGA.

DISCUSSION

The association with SGA suggests that the DV is a subacute process of vascular injury that accelerates in the setting of PE. The majority of DV cases were not initially recognized suggesting a role for endothelial markers for DV detection. We also propose that the rampant endothelial injury seems to be a prominent finding in the decidual vessels of subjects with PE complicated by SGA and a similar process in the systemic vasculature may be responsible for the circulating endothelial microparticles reported in such patients.

Uncomplicated Pregnancies and Ultrasounds for Fetal Growth Restriction: A Pilot Randomized Clinical Trial

Objective The purpose of this multicenter pilot study was to determine the feasibility of randomizing uncomplicated pregnancies (UPs) to have third trimester ultrasonographic exams (USE) versus routine prenatal care (RPNC) to improve the detection of small for gestational age (SGA; birth weight < 10% for GA). Material and Methods At three referral centers, 50 UPs were randomized after gestational diabetes was ruled out. Women needed to screen, consenting, and loss to follow-up was ascertained, as was the detection rate of SGA in the two groups. Results During the study period at the three centers, there were 7,680 births, of which 64% were uncomplicated. Of the 234 women approached for randomization, 36% declined. We recruited 149 women and had follow-up delivery data on 97%. The antenatal detection rate of SGA in the intervention group was 67% (95% confidence intervals 31-91%) and 9% (0.5-43%) in control. Conclusion The pilot study provides feasibility data for a multicenter randomized clinical trial to determine if third trimester USE, compared with RPNC, improves the detection of SGA and composite neonatal morbidity.

Acute feTal behavioral Response to prenatal Yoga: a single, blinded, randomized controlled trial (TRY yoga)

BACKGROUND

In 2012, yoga was practiced by 20 million Americans, of whom 82% were women. A recent literature review on prenatal yoga noted a reduction in some pregnancy complications (ie, preterm birth, lumbar pain, and growth restriction) in those who practiced yoga; to date, there is no evidence on fetal response after yoga.

OBJECTIVES

We aimed to characterize the acute changes in maternal and fetal response to prenatal yoga exercises using common standardized tests to assess the well-being of the maternal-fetal unit.

STUDY DESIGN

We conducted a single, blinded, randomized controlled trial. Uncomplicated pregnancies between 28 0/7 and 36 6/7 weeks with a nonanomalous singleton fetus of women who did not smoke, use narcotics, or have prior experience with yoga were included. A computer-generated simple randomization sequence with a 1:1 allocation ratio was used to randomize participants into the yoga or control group. Women in the yoga group participated in a 1-time, 1 hour yoga class with a certified instructor who taught a predetermined yoga sequence. In the control group, each participant attended a 1-time, 1 hour PowerPoint presentation by an obstetrician on American Congress of Obstetricians and Gynecologists recommendations for exercise, nutrition, and obesity in pregnancy. All participants underwent pre- and postintervention testing, which consisted of umbilical and uterine artery Doppler ultrasound, nonstress testing, a biophysical profile, maternal blood pressure, and maternal heart rate. A board-certified maternal-fetal medicine specialist, at a different tertiary center, interpreted all nonstress tests and biophysical profile data and was blinded to group assignment and pre- or postintervention testing. The primary outcome was a change in umbilical artery Doppler systolic to diastolic ratio. Sample size calculations indicated 19 women per group would be sufficient to detect this difference in Doppler indices (alpha, 0.05; power, 80%). Data were analyzed using a repeated-measures analysis of variance, a χ(2), and a Fisher exact test. A value of P < .05 was considered significant.

RESULTS

Of the 52 women randomized, 46 (88%) completed the study. There was no clinically significant change in umbilical artery systolic to diastolic ratio (P = .34), pulsatility index (P = .53), or resistance index (P = .66) between the 2 groups before and after the intervention. Fetal and maternal heart rate, maternal blood pressure, and uterine artery Dopplers remained unchanged over time. When umbilical artery indices were individually compared with gestational age references, there was no difference between those who improved or worsened between the groups.

CONCLUSION

There was no significant change in fetal blood flow acutely after performing yoga for the first time in pregnancy. Yoga can be recommended for low-risk women to begin during pregnancy.

Umbilical Artery Half-Peak Systolic Velocity Deceleration Time in Fetal Growth Restriction

Objective: To study the umbilical artery (UA) half-peak systolic velocity deceleration time (hPSV-DT) in pregnancies complicated by fetal growth restriction (FGR). Methods: The study included 266 singleton, high-risk pregnancies with an estimated fetal weight <10th percentile, which were examined between 24 and 40 weeks' gestation and delivered within a week from the last ultrasound evaluation. UA hPSV-DT was measured with Doppler ultrasound in the same wave used to measure the pulsatility index. UA hPSV-DT values were correlated with perinatal outcome. Results: UA hPSV-DT <5th percentile was found in 87 and 98% of fetuses with moderate and severe FGR, respectively. 94% of fetuses with a UA hPSV-DT <90 ms had poor perinatal outcome including perinatal death or prolonged admission to the neonatal intensive care unit. None of the fetuses had a UA hPSV-DT <70 ms. Perinatal death occurred in 39 fetuses; UA hPSV-DT was abnormal in all of them, with 95% of these fetuses having values of ≤120 ms. In the group of fetuses with absent/reverse end-diastolic velocity in the UA, the perinatal mortality rate was 51% for those with a UA hPSV-DT ≤90 ms and only 23% for those having a UA hPSV-DT >90 ms (p < 0.01). Conclusions: UA hPSV-DT seems to be a useful technique in the evaluation of pregnancies at risk for FGR and perinatal death. Additionally, hPSV-DT was shown to be a good predictor of perinatal death, with values of <90 ms corresponding to imminent risk of intrauterine demise and values of <70 ms being likely to be incompatible with intrauterine life.

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.

Genomic imprinting in the human placenta

With the launch of the National Institute of Child Health and Human Development/National Institutes of Health Human Placenta Project, the anticipation is that this often-overlooked organ will be the subject of much intense research. Compared with somatic tissues, the cells of the placenta have a unique epigenetic profile that dictates its transcription patterns, which when disturbed may be associated with adverse pregnancy outcomes. One major class of genes that is dependent on strict epigenetic regulation in the placenta is subject to genomic imprinting, the parent-of-origin-dependent monoallelic gene expression. This review discusses the differences in allelic expression and epigenetic profiles of imprinted genes that are identified between different species, which reflect the continuous evolutionary adaption of this form of epigenetic regulation. These observations divulge that placenta-specific imprinted gene that is reliant on repressive histone signatures in mice are unlikely to be imprinted in humans, whereas intense methylation profiling in humans has uncovered numerous maternally methylated regions that are restricted to the placenta that are not conserved in mice. Imprinting has been proposed to be a mechanism that regulates parental resource allocation and ultimately can influence fetal growth, with the placenta being the key in this process. Furthermore, I discuss the developmental dynamics of both classic and transient placenta-specific imprinting and examine the evidence for an involvement of these genes in intrauterine growth restriction and placenta-associated complications. Finally, I focus on examples of genes that are regulated aberrantly in complicated pregnancies, emphasizing their application as pregnancy-related disease biomarkers to aid the diagnosis of at-risk pregnancies early in gestation.

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.

Intermediate Diastolic Velocity as a Parameter of Cardiac Dysfunction in Growth-Restricted Fetuses

OBJECTIVE

To evaluate the intermediate intracardiac diastolic velocities in fetuses with growth restriction.

METHODS

Doppler waveforms of the two atrioventricular valves were obtained. Peak velocities of the E (early) and A (atrial) components, and the lowest intermediate velocity (IDV) between them, were measured in 400 normally grown and in 100 growth-restricted fetuses. The prevalence of abnormal IDV, E/IDV, and A/IDV ratios in fetuses presenting with perinatal death or acidemia at birth (pH ≤7.1) was estimated.

RESULTS

IDV was significantly lower and E/IDV ratios significantly higher in the two ventricles of growth-restricted fetuses with reduced diastolic velocities in the umbilical artery (p < 0.05). In 13 fetuses presenting with perinatal death or acidemia at birth, 11 (85%) had either an E/IDV or A/IDV ratio >95th percentile, whereas 5 (38%) showed absent or reversed atrial velocities in the ductus venosus (DV-ARAV; p < 0.04). Fetuses without DV-ARAV but with elevated E/IDV ratios in either ventricle were nearly 7-fold more likely to have perinatal demise or acidemia at birth (OR 6.9, 95% CI 1.4-34) than those with E/IDV ratios <95th percentile.

CONCLUSION

The E/IDV and A/IDV ratios in the two cardiac ventricles might provide information about the risk of perinatal demise or acidemia in growth-restricted fetuses.

Discordance in fetal biometry and Doppler are independent predictors of the risk of perinatal loss in twin pregnancies

OBJECTIVE

Impaired fetal growth might be better evaluated in twin pregnancies by assessing the intertwin discordance rather than the individual fetal size. The aim of this study was to investigate the prediction of perinatal loss in twin pregnancy using discordance in fetal biometry and Doppler.

STUDY DESIGN

This was a retrospective cohort study in a tertiary referral center. The estimated fetal weight (EFW), umbilical artery (UA) pulsatility index (PI), middle cerebral artery (MCA) PI, cerebroplacental ratio (CPR), and their discordance recorded at the last ultrasound assessment before delivery or demise of one or both fetuses were converted into centiles or multiples of the median (MoM). The discordance was calculated as the larger value-smaller value/larger value. A logistic regression analysis was performed to identify, and adjust for, potential confounders. The predictive accuracy was assessed using receiver-operating characteristic curve analysis.

RESULTS

The analysis included 620 (464 dichorionic diamniotic and 156 monochorionic diamniotic) twin pregnancies (1240 fetuses). Perinatal loss of one or both fetuses complicated 16 pregnancies (2.6%). The combination of EFW discordance and CPR discordance had the best predictive performance (area under the curve, 0.96; 95% confidence interval, 0.92-1.00) for perinatal mortality. The detection rate, false-positive rate, positive likelihood ratio, and negative likelihood ratio were 87.5%, 6.7%, 13.08, and 0.13, respectively. The EFW centile, EFW below the 10th centile (small for gestational age), UA PI discordance, MCA PI discordance, and MCA PI MoM were significantly associated with the risk of perinatal loss on univariate analysis, but these associations became nonsignificant after adjusting for other confounders (P = .097, P = .090, P = .687, P = .360, and P = .074, respectively). The UA PI MoM, CPR MoM, EFW discordance, and CPR discordance were all independent predictors of the risk of perinatal loss, even after adjusting for potential confounders (P = .022, P = .002, P < .001, and P = .010, respectively).

CONCLUSION

EFW discordance and CPR discordance are independent predictors of the risk of perinatal loss in twin pregnancies. Their combination could identify the majority of twin pregnancies at risk of perinatal loss. These findings highlight the importance of discordance in Doppler indices of fetal hypoxia, as well as fetal size, in assessing the risk of perinatal mortality.

Effect of prenatal betamethasone on fetal, uteroplacental, and maternal blood flow velocity in pregnancies complicated by fetal growth restriction

OBJECTIVE

To assess Doppler flow velocity in fetal, uteroplacental, and maternal arteries before and after betamethasone therapy among singleton pregnancies complicated by fetal growth restriction (FGR).

METHODS

A prospective, longitudinal, multicenter study was conducted at three university-affiliated hospitals in Tehran, Iran, between January 1 and November 30, 2013. The inclusion criteria were FGR, a gestational age of 24-34 weeks, no fetal anomalies, and no previous betamethasone therapy. Doppler blood flow was measured in uterine, umbilical, and middle cerebral arteries before treatment, and 24 hours and 5 days after completion of betamethasone therapy (two 12-mg doses at a 24-hour interval).

RESULTS

Overall, 40 women were enrolled. Doppler blood flow through the uterine and umbilical arteries showed significant but transient changes across the three timepoints (P<0.001), whereas the middle cerebral artery showed no changes.

CONCLUSION

Prenatal betamethasone led to transient improvements in blood flow in the uterine and umbilical arteries among pregnancies affected by FGR.

Predictive accuracy of the first trimester Doppler scan: a meta-study

AIM

To determine sensitivity and cut-off indices of the uterine artery Doppler (UAD) in prediction of preeclampsia and fetal growth restriction (FGR).

METHODS

Seventy-six studies published in 1995-2014, present 298,329 prenatal Doppler screenings performed in nullipara in the first and early second trimesters of singleton pregnancies. The sample is stratified into four groups based on the Doppler sensitivity and specificity indices pertaining to the major clinical endpoints of the cohort.

RESULTS

The FGR diagnostic specificity (r = 0.728) and bilateral notching index (r = 0.803) correlations indicate that the UAD accuracy depends on the placental bed and the screening mode.

CONCLUSIONS

Predictive sensitivity of the UAD increases after 16 weeks + 3 days (115 days) of gestation. The best predictive parameter of preeclampsia and FGR is the placental side uterine artery resistance index which confers to the highest means when the placenta is on the midline (OR 0.9).

Antenatal tests of fetal wellbeing

In current obstetric practice, there is frequently a need to assess fetal wellbeing. This is particularly so in those fetuses at risk, including the small-for-gestational-age fetus or the fetus of a mother who presents with reduced fetal movements or who has an obstetric complication such as pre-eclampsia. It is important that the clinician is able to assess fetal wellbeing in such cases, especially in preterm gestations, when inappropriate delivery could have serious adverse consequences. In this paper, we review the current evidence for the use and the limitations of widely used methods of antenatal monitoring including the use of cardiotocography, biophysical profile, and ultrasound-derived parameters including umbilical artery, middle cerebral artery, and ductus venosus Doppler flow.

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.

The potential perinatal origin of placentation disorders in the young primigravida

The fetus is exposed to high plasma concentrations of unbound estrogens and progesterone throughout pregnancy. However, secretory or decidual changes in the fetal uterus occur relatively infrequently before birth, suggesting a variable endometrial progesterone response at the time of birth. Arguably, partial progesterone resistance that persists into adolescent years may compromise the physiological transformation of the spiral arteries and predispose for defective placentation in the case of pregnancy. Decidualization of the endometrial stromal compartment and junctional zone myometrium precedes trophoblast invasion. It represents the first step in the process of spiral artery remodeling needed to establish effective uteroplacental blood flow by midpregnancy. The major obstetric syndromes caused by impaired placental bed spiral artery remodeling are prevalent in teenage pregnancies, including preeclampsia, fetal growth restriction, and spontaneous preterm labor. Preconditioning of the uterus in response to cyclic menstruation during adolescence may be critical to achieve full uterine responsiveness to hormonal cues. Understanding the mechanisms of functional maturation of the uterus during the early reproductive years may yield novel insights into the major obstetric syndromes.

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.

Association between an abnormal cerebroplacental ratio and the development of severe pre-eclampsia

OBJECTIVE

To study the association between the cerebroplacental ratio (CPR) and the development of pre-eclampsia.

STUDY DESIGN

Three study groups were determined: Group 1-normal umbilical artery (UA; referent), Group 2-abnormal UA and normal CPR and Group 3-abnormal UA and an abnormal CPR. The primary outcome was the development of severe pre-eclampsia.

RESULTS

We included 270 women. Women in Group 3 had significantly elevated rates of severe pre-eclampsia versus those in Group 1 and Group 2, 52.5% versus 5.1% and 15.4%, respectively, (P<0.01), adjusted odds ratio 4.14 (95% confidence interval, 2.59 to 6.61). Kaplan-Meier analysis revealed earlier delivery in women with pre-eclampsia in Group 3 versus Group 1, Cox-Mantel hazard ratio 2.39 (1.17 to 4.88), log rank P=0.01.

CONCLUSION

An abnormal CPR is associated with a higher rate severe pre-eclampsia with delivery at earlier gestational ages than with a normal UA or an abnormal UA, but normal CPR.

A practical approach to fetal growth restriction

Fetal growth restriction is one of the most complex problems encountered by obstetricians. Ultrasound-estimated fetal weight less than the 10th percentile for the gestational age is the most widely accepted diagnostic criterion. Management protocols vary from institution to institution. Doppler velocimetry provides valuable information about fetal status. We offer a practical approach to management and timing of delivery based on available data in the literature.

Do Doppler studies enhance surveillance of uncomplicated monochorionic diamniotic twins?

OBJECTIVES

To determine whether isolated abnormal Doppler indices before 28 weeks predict adverse pregnancy outcomes in uncomplicated monochorionic diamniotic (MCDA) twins.

METHODS

A retrospective cohort study of MCDA twin pregnancies receiving antenatal testing at a single center between 2007 and 2013 was conducted. Sonographic surveillance, including Doppler velocimetric studies of the umbilical artery, ductus venosus, and middle cerebral artery of each twin, was initiated by 28 weeks and repeated at least every 2 weeks. All pregnancies were deemed "uncomplicated" at initial sonography, without evidence of polyhydramnios, oligohydramnios, intrauterine growth restriction, twin growth discordance of at least 20%, structural or chromosomal anomalies, or unclear chorionicity. Pregnancies were divided into 2 groups: those with isolated Doppler abnormalities before 28 weeks and those with normal Doppler indices. The primary outcome was a composite including twin-twin transfusion syndrome, intrauterine growth restriction of more than 1 twin, growth discordance of at least 20%, preterm delivery before 34 weeks for fetal indications, or demise of more than 1 fetus.

RESULTS

Ninety-six patients were included, with 22 (22.9%) having isolated Doppler abnormalities before 28 weeks. The incidence of the primary outcome did not differ between groups (36.4% versus 28.4%; P = .47). The abnormal Doppler group underwent a greater number of sonographic examinations (15 versus 10; P= .001) and more antenatal admissions for fetal concerns (50.0% versus 12.2%; P < .001).

CONCLUSIONS

Isolated Doppler abnormalities are commonly encountered in uncomplicated MCDA pregnancies before 28 weeks yet are not clearly predictive of twin-specific complications. Doppler abnormalities were associated with increased sonographic surveillance and antenatal hospitalizations, suggesting an influence on physician practice patterns. Data may not support Doppler studies before 28 weeks for routine MCDA twin monitoring.

Uterine artery blood flow, fetal hypoxia and fetal growth

Evolutionary trade-offs required for bipedalism and brain expansion influence the pregnancy rise in uterine artery (UtA) blood flow and, in turn, reproductive success. We consider the importance of UtA blood flow by reviewing its determinants and presenting data from 191 normotensive (normal, n = 125) or hypertensive (preeclampsia (PE) or gestational hypertension (GH), n = 29) Andean residents of very high (4100-4300 m) or low altitude (400 m, n = 37). Prior studies show that UtA blood flow is reduced in pregnancies with intrauterine growth restriction (IUGR) but whether the IUGR is due to resultant fetal hypoxia is unclear. We found higher UtA blood flow and Doppler indices of fetal hypoxia in normotensive women at high versus low altitude but similar fetal growth. UtA blood flow was markedly lower in early-onset PE versus normal high-altitude women, and their fetuses more hypoxic as indicated by lower fetal heart rate, Doppler indices and greater IUGR. We concluded that, despite greater fetal hypoxia, fetal growth was well defended by higher UtA blood flows in normal Andeans at high altitude but when compounded by lower UtA blood flow in early-onset PE, exaggerated fetal hypoxia caused the fetus to respond by decreasing cardiac output and redistributing blood flow to help maintain brain development at the expense of growth elsewhere. We speculate that UtA blood flow is not only an important supply line but also a trigger for stimulating the metabolic and other processes regulating feto-placental metabolism and growth. Studies using the natural laboratory of high altitude are valuable for identifying the physiological and genetic mechanisms involved in human reproductive success.

The clinical and diagnostic utility of S100B in preterm newborns

Preterm birth is still the most important cause of perinatal mortality and morbidity. Follow-up studies showed that the majority of neurological abnormalities during childhood are already present in the first week after birth. In this light, the knowledge of the timing of the insult and/or of the contributing factors is of utmost relevance in order to avoid adverse neurological outcome. Notwithstanding, the considerable advances in perinatal clinical care and monitoring, the early detection of cases at risk for brain damage is still a challenge because, when radiological pictures are still negative, brain damage may be already at a subclinical stage, with symptoms hidden by therapeutic strategies. Thus, it could be very relevant to measure quantitative parameters, such as neuroproteins, able to detect subclinical lesions at a stage when routine brain monitoring procedures are still silent. In the last decade, the assay of the brain-specific protein S100B in different biological fluids proved useful information on brain function and damage in the perinatal period. Therefore, the present study provides an overview of the most recent findings on S100B role as a reliable marker of brain development/damage in preterm high risk fetuses and newborns.

Prevalence and significance of persistently positive antiphospholipid antibodies in women with preeclampsia

OBJECTIVE

To determine the prevalence of antiphospholipid antibodies (aPL) and their association with obstetric outcomes in women with preeclampsia.

METHODS

The study included 150 patients. Clinical variables, risk factors, and severity criteria for preeclampsia and aPL were analyzed.

RESULTS

We found aPL in 4% of patients without risk factors for preeclampsia and in no women with risk factors (p = 0.03). Fifty percent of aPL-positive patients had a fetus with intrauterine growth restriction versus 13.9% (p = 0.04). No relation between aPL and severe preeclampsia was found.

CONCLUSION

The prevalence of aPL among women with preeclampsia is low. aPL can predispose women without risk factors to preeclampsia.

Defining the residual risk of adverse perinatal outcome in growth-restricted fetuses with normal umbilical artery blood flow

OBJECTIVE

We sought to determine the cause of adverse perinatal outcome in fetal growth restriction (FGR) where umbilical artery (UA) Doppler was normal, as identified from the Prospective Observational Trial to Optimize Pediatric Health (PORTO). We compared cases of adverse outcome where UA Doppler was normal and abnormal.

STUDY DESIGN

The PORTO study was a national multicenter study of >1100 ultrasound-dated singleton pregnancies with an estimated fetal weight <10th centile. Each pregnancy underwent intensive ultrasound, including multivessel Doppler. UA Doppler was considered abnormal when the pulsatility index was >95th centile or end-diastolic flow was absent/reversed. Adverse perinatal outcome was defined as a composite of intraventricular hemorrhage, periventricular leukomalacia, hypoxic ischemic encephalopathy, necrotizing enterocolitis, bronchopulmonary dysplasia, sepsis, or death.

RESULTS

In all, 57 (5.0%) of the 1116 fetuses had an adverse perinatal outcome. Nine (1.3%) of 698 fetuses with normal UA Doppler had an adverse outcome, compared with 48 (11.5%) of 418 with abnormal UA Doppler (P < .0001). There were 2 perinatal deaths in the normal group and 6 in the abnormal group (P = .01). The perinatal deaths in the normal group were 1 case of pulmonary hypoplasia after prolonged preterm rupture of the membranes from 12 weeks' gestation and a case of placental abruption. Gestation at delivery was 33 ± 3 vs 31 ± 4 weeks (P = .05) and mean birthweight was 1830 ± 737 vs 1146 ± 508 g (P = .001) in the respective groups. Neonatal sepsis was the commonest adverse outcome in both groups: 0.1% and 0.4%, respectively (P = .01).

CONCLUSION

Adverse perinatal outcome is uncommon in FGR with normal UA Doppler. The cases we identified were associated with heterogenous pathologies. FGR with normal UA blood flow is a largely benign condition.

Early origins of adult disease: low birth weight and vascular remodeling

Cardiovascular diseases (CVD) and diabetes still represent the main cause of mortality and morbidity in the industrialized world. Low birth weight (LBW), caused by intrauterine growth restriction (IUGR), was recently known to be associated with increased rates of CVD and non-insulin dependent diabetes in adult life (Barker's hypothesis). Well-established animal models have shown that environmentally induced IUGR (diet, diabetes, hormone exposure, hypoxia) increases the risk of a variety of diseases later in life with similar phenotypic outcomes in target organs. This suggests that a range of disruptions in fetal and postnatal growth may act through common pathways to regulate the developmental programming and produce a similar adult phenotype. The identification of all involved signaling cascades, underlying the physiopathology of these damages in IUGR fetuses, with their influence on adult health, is still far from satisfactory. The endothelium may be important for long-term remodeling and in the control of elastic properties of the arterial wall. Several clinical and experimental studies showed that IUGR fetuses, neonates, children and adolescents present signs of endothelial dysfunction, valuated by aorta intima media thickness, carotid intima media thickness and stiffness, central pulse wave velocity, brachial artery flow-mediated dilation, laser Doppler skin perfusion and by the measure of arterial blood pressure. In utero identification of high risk fetuses and long-term follow-up are necessary to assess the effects of interventions aimed at preventing pregnancy-induced hypertension, reducing maternal obesity, encouraging a healthy life style and preventing childhood obesity on adult blood pressure and cardiovascular disease in later life.

[Fetus, small for gestational age]

A small for gestational age foetus is defined by the foetal weight below the 10th centile for the corresponding gestational age. However, the vast majority of these cases has no apparent underlying abnormality, while in other cases a serious causative pathological condition can be identified. The detection, follow-up and treatment of an intrauterine growth retarded, compromised foetus has great obstetric and neonatologic relevance. In this review, the causes, clinical aspects and screening methods of intrauterine growth retardation are summarized based on the most recent international guidelines. Furthermore, recommendations regarding the monitoring and the optimal timing of the labour induction of pregnancies complicated with intrauterine growth retardation are discussed.

Irisin in idiopathic foetal growth restriction

PURPOSE

The aim of the present study was to compare maternal serum and cord blood irisin levels in females whose pregnancies were or were not complicated by idiopathic foetal growth restriction.

METHODS

A total of 30 subjects participated. The study group consisted of 15 female patients who were referred to our perinatology clinic for delivery because of foetal growth restriction developing in the third trimester. Fifteen females with uncomplicated singleton pregnancies constituted the control group. Irisin levels were assessed in maternal serum, as well as in serum from the umbilical vein and artery.

RESULTS

The demographic features of the two groups were similar (p > 0.05). Gestational age at delivery and birth weight were higher in females with uncomplicated pregnancies (p = 0.001). Umbilical artery irisin levels were significantly lower in pregnancies complicated by foetal growth restriction compared to controls (p = 0.003). Umbilical artery irisin levels were positively correlated with foetal weight (p = 0.01) and foetal abdominal circumference (measured by ultrasonography) (p = 0.01). Maternal and umbilical vein irisin levels did not differ between the two groups (p > 0.05).

CONCLUSIONS

The data suggest that umbilical artery irisin levels were lower in pregnancies complicated by foetal growth restriction. Such lower irisin levels may contribute to the pathogenesis of this common condition, and metabolic syndrome may be a long-term consequence of idiopathic FGR.

Prognostic value of obstetric Doppler ultrasound in fetuses with fetal growth restriction: an observational study in a tertiary care hospital

OBJECTIVE

To determine the prognostic value of umbilical artery Doppler (UAD) with fetal growth restriction (FGR) and their perinatal outcomes.

METHODS

This was a retrospective cohort study of fetuses with growth≤5th centile from 2001 to 2012. Pregnancy outcomes were compared according to UAD findings for 253 cases. Doppler findings were categorized as; Normal End Diastolic Flow (NEDF), Reduced End Diastolic Flow (REDF) and Absent/Reverse End Diastolic Flow (AREDF). Mean and proportion were calculated and odds of perinatal complications were compared by using logistic regression for REDF and AREDF with NEDF at 5% level of significance.

RESULTS

The perinatal morality rate was 3.2%. Neonates with abnormal Doppler were at increased risk of cesarean delivery, low birth weights and low Apgar scores. Among the perinatal morbidity, neonatal intensive care unit (NICU) admission was 4.2 and 15.3 times in neonates with REDF and AREDF and similarly the perinatal mortality of AREDF was 12.5 times higher as compared to NEDF. Other morbidities were also much higher in abnormal Doppler groups.

CONCLUSION

There is a prognostic value of UAD in predicting the outcomes for FGR fetuses and therefore recommend its use in the conservative management of such pregnancies to reduce perinatal mortality and morbidity.

Second- and third-trimester biochemical and ultrasound markers predictive of ischemic placental disease

Ischemic placental disease is a recently coined term that describes the vascular insufficiency now believed to be an important etiologic factor in preeclampsia, intrauterine fetal growth restriction, and placental abruption. Given the increased risk for poor maternal and fetal outcomes, early prediction and prevention of this disorder is of significant clinical interest for many. In this article, we review the second- and third-trimester serum and ultrasound markers predictive of ischemic placental disease. Limited first-trimester data is also presented. While current studies report a statistical association between marker levels and various adverse perinatal outcomes, the observed diagnostic accuracy is below the threshold required for clinical utility. An exception to this generalization is uterine artery Doppler for the prediction of early-onset preeclampsia. Metabolomics is a relatively new analytic platform that holds promise as a first-trimester marker for the prediction of both early- and late-onset preeclampsia.

Reference values for fetal aortic isthmus blood flow parameters at 24 to 38 weeks' gestation

OBJECTIVE

The goal of this study is to establish population-specific nomograms of fetal aortic isthmus (AoI) Doppler indices in the period of 24-38 weeks' gestation.

METHODS

This was a cross-sectional study of 240 Asian singleton pregnant women at 24-38 completed weeks' gestation. Fetal AoI blood flow was evaluated by Doppler study with automatic calculation of pulsatility index, resistance index, peak systolic velocity, end-diastolic velocity, and time-averaged maximum velocity. The relationship of these indices and gestational age was estimated by using regression analysis, and the best predictive models were determined to define mean, 5th, and 95th centile of each gestational age. The reproducibility was expressed by intraclass correlation coefficients and limits of agreement.

RESULTS

The mean maternal age was 28 ± 5.7 years. A total of 97% of all attempts to obtain AoI Doppler waveforms were successful with high interobserver and intraobserver reproducibility. Pulsatility index and peak systolic velocity significantly correlated with gestational age (P = 0.03 and 0.001, respectively), whereas no significant change of resistance index, end-diastolic velocity, and time-averaged maximum velocity with advancing gestation was observed.

CONCLUSION

This study offers normative values of fetal AoI Doppler indices, which may be useful in the difficult task of fetal surveillance in growth-restricted fetuses among our population.

Definition and management of fetal growth restriction: a survey of contemporary attitudes

OBJECTIVE

To evaluate opinions among Irish obstetricians and obstetric trainees regarding the optimal definition, assessment and management of pregnancies affected by intrauterine growth restriction (IUGR).

STUDY DESIGN

An anonymous, structured, web-based survey that comprised 14 questions was sent to 200 obstetricians and obstetric trainees in Ireland.

RESULTS

Of the 113 participants (57% response rate), the majority (50%) were consultants, with over 10 years' clinical experience (46%), who worked in large maternity units (58%) with neonatal units providing care for preterm IUGR fetuses (94%). Eighty-three clinicians (74%) agreed that an estimated fetal weight (EFW) below the 10th centile constitutes small-for-gestational age (SGA). The majority (n=93; 82%) would deliver the SGA fetus between 37(+0) and 39(+6) weeks gestation. In total, the survey yielded 30 different IUGR definitions; the top three definitions were (i) an EFW below the 5th centile (n=18; 16%), (ii) an EFW below the 10th centile with oligohydramnios and abnormal umbilical artery (UA) Doppler (n=16; 14%), and (iii) an EFW below the 10th centile (n=12; 11%). In the evaluation of the preterm IUGR fetus with abnormal UA Doppler, the assessment of amniotic fluid volume, middle cerebral artery, ductus venosus, cardiotocograph (CTG) and biophysical profiling was performed in 74%, 60%, 60%, 54% and 52% respectively. The majority of clinicians applied three or more assessment modalities and 60% referred to a maternal-fetal medicine (MFM) subspecialist. Interestingly, even among MFM subspecialists there was no common consistent management approach. Most doctors (81%) would deliver the IUGR fetus for CTG abnormalities but MFM subspecialists more commonly deliver on the basis of absent end-diastolic flow in the UA alone (37% vs. 10%; p=0.006). Two-thirds of doctors (n=74) would implement customised growth charts if they became available for their population and over 80% thought that a national guideline on IUGR would be beneficial.

CONCLUSION

The results of this survey confirm the inconsistencies surrounding the clinical management of IUGR pregnancies and highlight the need for standardisation of terminology and antenatal surveillance, implementation of fetal weight customisation and national guidance for Ireland.

Predictable progressive Doppler deterioration in IUGR: does it really exist?

OBJECTIVE

An objective of the Prospective Observational Trial to Optimize Pediatric Health in IUGR (PORTO) study was to evaluate multivessel Doppler changes in a large cohort of intrauterine growth restriction (IUGR) fetuses to establish whether a predictable progressive sequence of Doppler deterioration exists and to correlate these Doppler findings with respective perinatal outcomes.

STUDY DESIGN

More than 1100 unselected consecutive ultrasound-dated singleton pregnancies with estimated fetal weight (EFW) less than the 10th centile were recruited between January 2010 and June 2012. Eligible pregnancies were assessed by serial Doppler interrogation of umbilical (UA) and middle cerebral (MCA) arteries, ductus venosus (DV), aortic isthmus, and myocardial performance index (MPI). Intervals between Doppler changes and patterns of deterioration were recorded and correlated with respective perinatal outcomes.

RESULTS

Our study of 1116 nonanomalous fetuses comprised 7769 individual Doppler data points. Five hundred eleven patients (46%) had an abnormal UA, 300 (27%) had an abnormal MCA, and 129 (11%) had an abnormal DV Doppler. The classic pattern from abnormal UA to MCA to DV existed but no more frequently than any of the other potential pattern. Doppler interrogation of the UA and MCA remains the most useful and practical tool in identifying fetuses at risk of adverse perinatal outcome, capturing 88% of all adverse outcomes.

CONCLUSION

In contrast to previous reports, we have demonstrated multiple potential patterns of Doppler deterioration in this large prospective cohort of IUGR pregnancies, which calls into question the usefulness of multivessel Doppler assessment to inform frequency of surveillance and timing of delivery of IUGR fetuses. These data will be critically important for planning any future intervention trials.