Prediction of perinatal morbidity at term in small fetuses: comparison of fetal growth and Doppler ultrasound

Routine third-trimester ultrasound assessment for intrauterine growth restriction

Intrauterine growth restriction significantly impacts perinatal outcomes. Undetected IUGR escalates the risk of adverse outcomes. Serial symphysis-fundal height measurement, a recommended strategy, is insufficient in detecting abnormal fetal growth. Routine third-trimester ultrasounds significantly improve detection rates compared with this approach, but direct high-quality evidence supporting enhanced perinatal outcomes from routine scanning is lacking. In assessing fetal growth, abdominal circumference alone performs comparably to estimated fetal weight. Hadlock formulas demonstrate accurate fetal weight estimation across diverse gestational ages and settings. When choosing growth charts, prescriptive standards (encompassing healthy pregnancies) should be prioritized over descriptive ones. Customized fetal standards may enhance antenatal IUGR detection, but conclusive high-quality evidence is elusive. Emerging observational data suggest that longitudinal fetal growth assessment could predict adverse outcomes better. However, direct randomized trial evidence supporting this remains insufficient.

The magnitude rather than the rate of decline in fetal growth is a stronger risk factor for perinatal mortality in term infants

BACKGROUND

Prenatal diagnosis of an infant suspected of having fetal growth restriction is important because of its strong association with perinatal mortality and morbidity. The current Delphi consensus criteria include a decline of >50th percentiles in fetal growth when diagnosing late fetal growth restriction; however, the evidence underpinning this criterion is limited.

OBJECTIVE

This study aimed to analyze the relationships among the magnitude of decline in fetal growth and stillbirth, perinatal mortality, and adverse neonatal outcomes.

STUDY DESIGN

This cohort study of 15,861 pregnancies was conducted at the Mater Mother's Hospital in Brisbane, Australia. The decline in fetal growth was calculated as a drop in either estimated fetal weight or abdominal circumference percentiles between 2 ultrasound scans performed after 18 weeks of gestation. Relationships between declining fetal growth and the outcomes were, firstly, analyzed as a continuous variable and, if significant, further assessed with the rate of decline and different magnitudes of decline, compared to the referent category (change in growth of ±10 percentiles between scans). The 3 categories of growth decline were >10th to <25th percentiles, ≤25th to <50th percentiles, and ≥50th percentiles. Associations were analyzed by logistic regressions. The primary study outcomes were stillbirth and perinatal mortality (composite of stillbirth and neonatal death). The secondary outcomes were birth of a small-for-gestational-age infant (birthweight of <10th percentile for gestation), emergency cesarean delivery for nonreassuring fetal status, and composite severe neonatal morbidity.

RESULTS

The risks of stillbirth and perinatal mortality increased significantly by 2.6% (0.4%-4.6%) and 2.8% (1.0%-4.5%), respectively, per 1 percentile decline in fetal growth. In addition, the odds of stillbirth (adjusted odds ratio, 3.68 (1.32-10.24) and perinatal mortality (4.44) (1.82-10.84)) compared to the referent group were significantly increased only when the decline was ≥50th percentiles, regardless of birthweight. Furthermore, none of the primary outcomes were significantly associated with the rate of growth decline. The risk of a small-for-gestational-age infant increased by 2.4% (2.2%-2.7%) for every percentile decline. Conversely, reduced fetal growth was not associated with emergency cesarean delivery for nonreassuring fetal status or severe neonatal morbidity.

CONCLUSION

Our results supported the use of a ≥50th percentile decline in fetal growth as a criterion for identifying infants at risk of late fetal growth restriction. This cutoff also identified fetuses at high risk of perinatal mortality, regardless of birthweight and rate of growth decline. Our findings may guide obstetrical practice by alerting clinicians to the importance of incorporating the magnitude of fetal growth decline into antenatal counseling and decisions regarding the timing of birth.

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.

Antenatal Fetal Adrenal Measurements at 22 to 30 Weeks' Gestation, Fetal Growth Restriction, and Perinatal Morbidity

OBJECTIVE

Our objective was to test the association of fetal adrenal size with perinatal morbidity among fetuses with fetal growth restriction (FGR; estimated fetal weight [EFW] < 10th percentile).

STUDY DESIGN

This was a secondary analysis of the Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-be (nuMoM2b) adrenal study, which measured fetal adrenal gland size at 22 to 30 weeks' gestation. We analyzed the transverse adrenal area (TAA) and fetal zone area (absolute measurements and corrected for fetal size) and the ratio of the fetal zone area to the total transverse area using a composite perinatal outcome of stillbirth, neonatal intensive care unit admission, respiratory distress syndrome, necrotizing enterocolitis, retinopathy of prematurity, sepsis, mechanical ventilation, seizure, or death. Among fetuses with FGR, adrenal measurements were compared between those that did and did not experience the composite perinatal outcome.

RESULTS

There were 1,709 eligible neonates. Seven percent (n = 120) were diagnosed with FGR at the time of adrenal measurement, and 14.7% (n = 251) experienced perinatal morbidity. EFW-corrected and absolute adrenal measurements were similar among fetuses with and without FGR as well as among those who did and did not experience morbidity. The area under the curve for corrected TAA was 0.52 (95% confidence interval 0.38-0.67).

CONCLUSION

In our cohort, adrenal size was not associated with risk of morbidity among fetuses with FGR.

Reduced fetal growth velocity precedes antepartum fetal death

OBJECTIVES

To determine whether decreased fetal growth velocity precedes antepartum fetal death and to evaluate whether fetal growth velocity is a better predictor of antepartum fetal death compared to a single fetal biometric measurement at the last available ultrasound scan prior to diagnosis of demise.

METHODS

This was a retrospective, longitudinal study of 4285 singleton pregnancies in African-American women who underwent at least two fetal ultrasound examinations between 14 and 32 weeks of gestation and delivered a liveborn neonate (controls; n = 4262) or experienced antepartum fetal death (cases; n = 23). Fetal death was defined as death diagnosed at ≥ 20 weeks of gestation and confirmed by ultrasound examination. Exclusion criteria included congenital anomaly, birth at < 20 weeks of gestation, multiple gestation and intrapartum fetal death. The ultrasound examination performed at the time of fetal demise was not included in the analysis. Percentiles for estimated fetal weight (EFW) and individual biometric parameters were determined according to the Hadlock and Perinatology Research Branch/Eunice Kennedy Shriver National Institute of Child Health and Human Development (PRB/NICHD) fetal growth standards. Fetal growth velocity was defined as the slope of the regression line of the measurement percentiles as a function of gestational age based on two or more measurements in each pregnancy.

RESULTS

Cases had significantly lower growth velocities of EFW (P < 0.001) and of fetal head circumference, biparietal diameter, abdominal circumference and femur length (all P < 0.05) compared to controls, according to the PRB/NICHD and Hadlock growth standards. Fetuses with EFW growth velocity < 10^th percentile of the controls had a 9.4-fold and an 11.2-fold increased risk of antepartum death, based on the Hadlock and customized PRB/NICHD standards, respectively. At a 10% false-positive rate, the sensitivity of EFW growth velocity for predicting antepartum fetal death was 56.5%, compared to 26.1% for a single EFW percentile evaluation at the last available ultrasound examination, according to the customized PRB/NICHD standard.

CONCLUSIONS

Given that 74% of antepartum fetal death cases were not diagnosed as small-for-gestational age (EFW < 10^th percentile) at the last ultrasound examination when the fetuses were alive, alternative approaches are needed to improve detection of fetuses at risk of fetal death. Longitudinal sonographic evaluation to determine growth velocity doubles the sensitivity for prediction of antepartum fetal death compared to a single EFW measurement at the last available ultrasound examination, yet the performance is still suboptimal. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Interpretation of wave reflections in the umbilical arterial segment of the feto-placental circulation: computational modeling of the feto-placental arterial tree

Placental vascular abnormalities are associated with a host of pregnancy complications including placenta mediated fetal growth restriction (FGR). Umbilical arterial (UA) Doppler ultrasound velocity waveforms are widely used in the diagnosis of underlying placental vascular abnormalities in pregnancies with suspected FGR, which greatly help prevent stillbirth via ongoing fetal monitoring and timely delivery. However, the sensitivity of UA Doppler diagnosis diminishes late in gestation. Our goal was to present a generalized wave decomposition method to compute forward and reflected components from UA waveforms. A detailed anatomical based model was also developed to explain observed UA flow waveform and to explore how vascular properties affect the shape of flow wave components. Using pregnant mice and high frequency ultrasound microscopy, we obtained in utero Doppler and M- mode ultrasound measurements in 15 fetuses UA. Following ultrasound, the placentas were collected and perfused with contrast agent to obtain high-resolution 3D images of the feto-placental arteries. Model results indicate the significant role of terminal load impedance (capillary and/or veins) in creating positive or negative reflected waveforms. A negative reflected waveform is obtained when terminal impedance increases. This is consistent with the elongated and non-branching terminal villi that are proposed cause the highly abnormal UA waveforms found in early-onset FGR. The significance of these findings for the diagnostic utility of UA Doppler in human pregnancy is that the identification and measurement of wave reflections may aid in discriminating between healthy and abnormal placental vasculature in pregnancies with suspected late-onset FGR.

FIGO (international Federation of Gynecology and obstetrics) initiative on fetal growth: best practice advice for screening, diagnosis, and management of fetal growth restriction

Fetal growth restriction (FGR) is defined as the failure of the fetus to meet its growth potential due to a pathological factor, most commonly placental dysfunction. Worldwide, FGR is a leading cause of stillbirth, neonatal mortality, and short- and long-term morbidity. Ongoing advances in clinical care, especially in definitions, diagnosis, and management of FGR, require efforts to effectively translate these changes to the wide range of obstetric care providers. This article highlights agreements based on current research in the diagnosis and management of FGR, and the areas that need more research to provide further clarification of recommendations. The purpose of this article is to provide a comprehensive summary of available evidence along with practical recommendations concerning the care of pregnancies at risk of or complicated by FGR, with the overall goal to decrease the risk of stillbirth and neonatal mortality and morbidity associated with this condition. To achieve these goals, FIGO (the International Federation of Gynecology and Obstetrics) brought together international experts to review and summarize current knowledge of FGR. This summary is directed at multiple stakeholders, including healthcare providers, healthcare delivery organizations and providers, FIGO member societies, and professional organizations. Recognizing the variation in the resources and expertise available for the management of FGR in different countries or regions, this article attempts to take into consideration the unique aspects of antenatal care in low-resource settings (labelled “LRS” in the recommendations). This was achieved by collaboration with authors and FIGO member societies from low-resource settings such as India, Sub-Saharan Africa, the Middle East, and Latin America.

Cerebroplacental ratio as predictor of adverse perinatal outcome in the third trimester

Introduction

Fetal growth restriction is associated with adverse perinatal outcome and the clinical management of these pregnancies is a challenge. The aim of this study was to investigate the potential of cerebroplacental ratio (CPR) to predict adverse perinatal outcome in high‐risk pregnancies in the third trimester. Another aim was to study whether the CPR has better predictive value than its components, middle cerebral artery (MCA) pulsatility index (PI) and umbilical artery (UA) PI.

Material and methods

The study was a retrospective cohort study including 1573 singleton high‐risk pregnancies with Doppler examinations performed at 32⁺⁰ to 40⁺⁶ gestational weeks at Lund University Hospital and the University Hospital of Malmö between 29 December 1994 and 31 December 2017. Receiver operating characteristics (ROC) curves were used to investigate the predictive value of the gestational age‐specific z‐scores for CPR, UA PI and MCA PI, respectively, for the primary outcome “perinatal asphyxia/mortality” and the secondary outcomes “birthweight small for gestational age (SGA)” and two composite outcomes: “appropriate for gestational age/large for gestational age liveborn infants with neonatal morbidity” and “SGA liveborn infants with neonatal morbidity.”

Results

The performance in predicting perinatal asphyxia/mortality was poor for all three variables and did not differ significantly. The ROC area under curve (AUC) was 0.56, 0.55 and 0.53 for CPR, UA PI and MCA PI z‐scores, respectively. The ROC AUC for CPR z‐scores to predict SGA was 0.73, significantly higher than that for either UA PI or MCA PI (P < .001). The ability of CPR and the MCA PI to predict appropriate for gestational age/large for gestational age infant morbidity and SGA infant morbidity was similar and significantly better than UA PI (P < .001).

Conclusions

In the present study, none of the three Doppler measures proved to be useful in predicting perinatal asphyxia and mortality. CPR and MCA PI were equally good in predicting neonatal morbidity, especially in SGA pregnancies, and both were significantly better predictors than the UA PI. CPR had a high predictive value for SGA at birth, better than that of its two components, UA PI and MCA PI.

Biochemical tests of placental function versus ultrasound assessment of fetal size for stillbirth and small-for-gestational-age infants

BACKGROUND

Stillbirth affects 2.6 million pregnancies worldwide each year. Whilst the majority of cases occur in low- and middle-income countries, stillbirth remains an important clinical issue for high-income countries (HICs) - with both the UK and the USA reporting rates above the mean for HICs. In HICs, the most frequently reported association with stillbirth is placental dysfunction. Placental dysfunction may be evident clinically as fetal growth restriction (FGR) and small-for-dates infants. It can be caused by placental abruption or hypertensive disorders of pregnancy and many other disorders and factorsPlacental abnormalities are noted in 11% to 65% of stillbirths. Identification of FGA is difficult in utero. Small-for-gestational age (SGA), as assessed after birth, is the most commonly used surrogate measure for this outcome. The degree of SGA is associated with the likelihood of FGR; 30% of infants with a birthweight < 10th centile are thought to be FGR, while 70% of infants with a birthweight < 3rd centile are thought to be FGR. Critically, SGA is the most significant antenatal risk factor for a stillborn infant. Correct identification of SGA infants is associated with a reduction in the perinatal mortality rate. However, currently used tests, such as measurement of symphysis-fundal height, have a low reported sensitivity and specificity for the identification of SGA infants.

OBJECTIVES

The primary objective was to assess and compare the diagnostic accuracy of ultrasound assessment of fetal growth by estimated fetal weight (EFW) and placental biomarkers alone and in any combination used after 24 weeks of pregnancy in the identification of placental dysfunction as evidenced by either stillbirth, or birth of a SGA infant. Secondary objectives were to investigate the effect of clinical and methodological factors on test performance.

SEARCH METHODS

We developed full search strategies with no language or date restrictions. The following sources were searched: MEDLINE, MEDLINE In Process and Embase via Ovid, Cochrane (Wiley) CENTRAL, Science Citation Index (Web of Science), CINAHL (EBSCO) with search strategies adapted for each database as required; ISRCTN Registry, UK Clinical Trials Gateway, WHO International Clinical Trials Portal and ClinicalTrials.gov for ongoing studies; specialist abstract and conference proceeding resources (British Library's ZETOC and Web of Science Conference Proceedings Citation Index). Search last conducted in Ocober 2016.

SELECTION CRITERIA

We included studies of pregnant women of any age with a gestation of at least 24 weeks if relevant outcomes of pregnancy (live birth/stillbirth; SGA infant) were assessed. Studies were included irrespective of whether pregnant women were deemed to be low or high risk for complications or were of mixed populations (low and high risk). Pregnancies complicated by fetal abnormalities and multi-fetal pregnancies were excluded as they have a higher risk of stillbirth from non-placental causes. With regard to biochemical tests, we included assays performed using any technique and at any threshold used to determine test positivity.

DATA COLLECTION AND ANALYSIS

We extracted the numbers of true positive, false positive, false negative, and true negative test results from each study. We assessed risk of bias and applicability using the QUADAS-2 tool. Meta-analyses were performed using the hierarchical summary ROC model to estimate and compare test accuracy.

MAIN RESULTS

We included 91 studies that evaluated seven tests - blood tests for human placental lactogen (hPL), oestriol, placental growth factor (PlGF) and uric acid, ultrasound EFW and placental grading and urinary oestriol - in a total of 175,426 pregnant women, in which 15,471 pregnancies ended in the birth of a small baby and 740 pregnancies which ended in stillbirth. The quality of included studies was variable with most domains at low risk of bias although 59% of studies were deemed to be of unclear risk of bias for the reference standard domain. Fifty-three per cent of studies were of high concern for applicability due to inclusion of only high- or low-risk women.Using all available data for SGA (86 studies; 159,490 pregnancies involving 15,471 SGA infants), there was evidence of a difference in accuracy (P < 0.0001) between the seven tests for detecting pregnancies that are SGA at birth. Ultrasound EFW was the most accurate test for detecting SGA at birth with a diagnostic odds ratio (DOR) of 21.3 (95% CI 13.1 to 34.6); hPL was the most accurate biochemical test with a DOR of 4.78 (95% CI 3.21 to 7.13). In a hypothetical cohort of 1000 pregnant women, at the median specificity of 0.88 and median prevalence of 19%, EFW, hPL, oestriol, urinary oestriol, uric acid, PlGF and placental grading will miss 50 (95% CI 32 to 68), 116 (97 to 133), 124 (108 to 137), 127 (95 to 152), 139 (118 to 154), 144 (118 to 161), and 144 (122 to 161) SGA infants, respectively. For the detection of pregnancies ending in stillbirth (21 studies; 100,687 pregnancies involving 740 stillbirths), in an indirect comparison of the four biochemical tests, PlGF was the most accurate test with a DOR of 49.2 (95% CI 12.7 to 191). In a hypothetical cohort of 1000 pregnant women, at the median specificity of 0.78 and median prevalence of 1.7%, PlGF, hPL, urinary oestriol and uric acid will miss 2 (95% CI 0 to 4), 4 (2 to 8), 6 (6 to 7) and 8 (3 to 13) stillbirths, respectively. No studies assessed the accuracy of ultrasound EFW for detection of pregnancy ending in stillbirth.

AUTHORS' CONCLUSIONS

Biochemical markers of placental dysfunction used alone have insufficient accuracy to identify pregnancies ending in SGA or stillbirth. Studies combining U and placental biomarkers are needed to determine whether this approach improves diagnostic accuracy over the use of ultrasound estimation of fetal size or biochemical markers of placental dysfunction used alone. Many of the studies included in this review were carried out between 1974 and 2016. Studies of placental substances were mostly carried out before 1991 and after 2013; earlier studies may not reflect developments in test technology.

Prediction of small-for-gestational age by fetal growth rate according to gestational age

BACKGROUND

Small-for-gestational age (SGA) infants should be identified before birth because of an increased risk of adverse perinatal outcomes. The objective of this study was to assess the impact of fetal growth rate by gestational age on the prediction of SGA and to identify the optimal time to initiate intensive fetal monitoring to detect SGA in low-risk women. We also sought to determine which the ultrasonographic parameters that contribute substantially to the birthweight determination.

METHODS

This was a retrospective study of 442 healthy pregnant women with singleton pregnancies. There were 328 adequate-for-gestational age (AGA) neonates and 114 SGA infants delivered between 37+0 and 41+6 weeks of gestation. We compared the biparietal diameters (BPD), head circumferences (HC), abdominal circumferences (AC), femur lengths (FL), and estimated fetal weights (EFW) obtained on each ultrasound to determine which of these parameters was the best indicator of SGA. We created receiver operating characteristic curves, calculated the areas under the curves (AUCs), and analyzed the data using multivariable logistic regressions to assess the ultrasound screening performances and identify the best predictive factor.

RESULTS

Among the four ultrasonographic parameters, the AC measurement between 24+0~28+6 weeks achieved a sensitivity of 79.5% and a specificity of 71.7%, with an AUC of 0.806 in the prediction of SGA. AC showed consistently higher AUCs above 0.8 with 64~80% sensitivities as gestational age progressed. EFW measurements from 33+0~35+6 gestational weeks achieved a sensitivity of 60.6% and a specificity of 87.6%, with an AUC of 0.826. In a conditional growth model developed from the linear mixed regression, the value differences between AC and EFW in the SGA and AGA groups became even more pronounced after 33+0~35+6 weeks.

CONCLUSION

Healthy low-risk women with a low fetal AC after 24 weeks' gestation need to be monitored carefully for fetal growth to identify SGA infants with a risk for adverse perinatal outcomes.

Longitudinal growth assessment for prediction of adverse perinatal outcome in fetuses suspected to be small-for-gestational age

OBJECTIVE

Fetal growth restriction (FGR) is associated with an increased risk of adverse perinatal outcome. However, distinguishing this condition from small-for-gestational age (SGA) remains elusive. A set of criteria has been proposed recently for such a purpose, including the degree of smallness, Doppler parameters and growth velocity. The aim of this study was to establish whether the use of growth velocity adds value to Doppler assessment in predicting adverse perinatal outcome among SGA-suspected fetuses.

METHODS

This was a prospective cohort study of consecutive singleton pregnancies with late (diagnosis ≥ 32.0 weeks) SGA (estimated fetal weight (EFW) < 10^th centile). Longitudinal growth assessment was performed by calculation of EFW z-velocity between diagnosis and last scan before delivery. Improvement in the association with and predictive performance of EFW z-velocity for adverse perinatal outcome was compared against standard criteria of FGR evaluated before delivery (EFW < 3^rd centile, abnormal uterine Doppler or abnormal cerebroplacental ratio).

RESULT

A total of 472 patients were evaluated prospectively for suspected SGA. Of these, 231 (48.9%) qualified as late FGR. Univariate analysis showed a significant trend towards higher frequency (14.5% vs 8.2%; P = 0.041) of EFW z-velocity in the lowest decile in pregnancies with adverse perinatal outcome. Nonetheless, the addition of EFW z-velocity improved neither the association with nor the predictive performance of standard criteria of FGR for adverse perinatal outcome.

CONCLUSIONS

Longitudinal assessment of fetal growth by means of EFW z-velocity did not have any independent predictive value for adverse perinatal outcome when used in combination with Doppler in SGA-suspected fetuses. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Diagnosis and surveillance of late-onset fetal growth restriction

By consensus, late fetal growth restriction is that diagnosed >32 weeks. This condition is mildly associated with a higher risk of perinatal hypoxic events and suboptimal neurodevelopment. Histologically, it is characterized by the presence of uteroplacental vascular lesions (especially infarcts), although the incidence of such lesions is lower than in preterm fetal growth restriction. Screening procedures for fetal growth restriction need to identify small babies and then differentiate between those who are healthy and those who are pathologically small. First- or second-trimester screening strategies provide detection rates for late smallness for gestational age <50% for 10% of false positives. Compared to clinically indicated ultrasonography in the third trimester, universal screening triples the detection rate of late smallness for gestational age. As opposed to early third-trimester ultrasound, scanning late in pregnancy (around 37 weeks) increases the detection rate for birthweight <3rd centile. Contrary to early fetal growth restriction, umbilical artery Doppler velocimetry alone does not provide good differentiation between late smallness for gestational age and fetal growth restriction. A combination of biometric parameters (with severe smallness usually defined as estimated fetal weight or abdominal circumference <3rd centile) with Doppler criteria of placental insufficiency (either in the maternal [uterine Doppler] or fetal [cerebroplacental ratio] compartments) offers a classification tool that correlates with the risk for adverse perinatal outcome. There is no evidence that induction of late fetal growth restriction at term improves perinatal outcomes nor is it a cost-effective strategy, and it may increase neonatal admission when performed <38 weeks.

Second- to third-trimester longitudinal growth assessment for prediction of small-for-gestational age and late fetal growth restriction

OBJECTIVE

Detection of fetal growth restriction (FGR) remains poor and most screening strategies rely on cross-sectional evaluation of fetal size during the third trimester. A longitudinal and individualized approach has been proposed as an alternative method of evaluation. The aim of this study was to compare second- to third-trimester longitudinal growth assessment to cross-sectional evaluation in the third trimester for the prediction of small-for-gestational age (SGA) and late FGR in low-risk singleton pregnancy.

METHODS

This was a prospective cohort study of 2696 unselected consecutive low-risk singleton pregnancies scanned at 21 ± 2 and 32 ± 2 weeks. For cross-sectional growth assessment, abdominal circumference (AC) measurements were transformed to z-values according the 21st-INTERGROWTH standards. Longitudinal growth assessment was performed by calculating the AC z-velocity and the second- to third-trimester AC conditional growth centile. Longitudinal assessment was compared with cross-sectional assessment at 32 weeks. Association of cross-sectional and longitudinal evaluations with SGA and late FGR was assessed by logistic regression analysis. Predictive performance was determined by receiver-operating characteristics curve analysis.

RESULT

In total, 210 (7.8%) newborns were classified as SGA and 103 (3.8%) as late FGR. Neither longitudinal measurement improved the association with SGA or late FGR provided by cross-sectional evaluation of AC z-score at 32 weeks. Areas under the curves of AC z-velocity and conditional AC growth were significantly smaller than those of cross-sectional AC z-scores (P < 0.001), although AC z-velocity performed significantly better than did conditional AC growth (P < 0.001).

CONCLUSION

Longitudinal assessment of fetal growth from the second to third trimester has a low predictive capacity for SGA and late FGR in low-risk singleton pregnancy compared with cross-sectional growth evaluation. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Long-term cardiovascular consequences of fetal growth restriction: biology, clinical implications, and opportunities for prevention of adult disease

In the modern world, cardiovascular disease is a leading cause of death for both men and women. Epidemiologic studies consistently have suggested an association between low birthweight and/or fetal growth restriction and increased rate of cardiovascular mortality in adulthood. Furthermore, experimental and clinical studies have demonstrated that sustained nutrient and oxygen restriction that are associated with fetal growth restriction activate adaptive cardiovascular changes that might explain this association. Fetal growth restriction results in metabolic programming that may increase the risk of metabolic syndrome and, consequently, of cardiovascular morbidity in the adult. In addition, fetal growth restriction is strongly associated with fetal cardiac and arterial remodeling and a subclinical state of cardiovascular dysfunction. The cardiovascular effects ocurring in fetal life, includes cardiac morphology changes, subclinical myocardial dysfunction, arterial remodeling, and impaired endothelial function, persist into childhood and adolescence. Importantly, these changes have been described in all clinical presentations of fetal growth restriction, from severe early- to milder late-onset forms. In this review we summarize the current evidence on the cardiovascular effects of fetal growth restriction, from subcellular to organ structure and function as well as from fetal to early postnatal life. Future research needs to elucidate whether and how early life cardiovascular remodeling persists into adulthood and determines the increased cardiovascular mortality rate described in epidemiologic studies.

Revealed versus concealed criteria for placental insufficiency in an unselected obstetric population in late pregnancy (RATIO37): randomised controlled trial study protocol

INTRODUCTION

Fetal growth restriction (FGR) affects 5%-10% of all pregnancies, contributing to 30%-50% of stillbirths. Unfortunately, growth restriction often is not detected antenatally. The last weeks of pregnancy are critical for preventing stillbirth among babies with FGR because there is a pronounced increase in stillbirths among growth-restricted fetuses after 37 weeks of pregnancy. Here we present a protocol (V.1, 23 May 2016) for the RATIO37 trial, which evaluates an integrated strategy for accurately selecting at-risk fetuses for delivery at term. The protocol is based on the combination of fetal biometry and cerebroplacental ratio (CPR). The primary objective is to reduce stillbirth rates. The secondary aims are to detect low birth weights and adverse perinatal outcomes.

METHODS AND ANALYSIS

The study is designed as multicentre (Spain, Chile, Mexico,Czech Republic and Israel), open-label, randomised trial with parallel groups. Singleton pregnancies will be invited to participate after routine second-trimester ultrasound scan (19+0-22+6 weeks of gestation), and participants will be randomly allocated to receive revealed or concealed CPR evaluation. Then, a routine ultrasound and Doppler scan will be performed at 36+0-37+6 weeks. Sociodemographic and clinical data will be collected at enrolment. Ultrasound and Doppler variables will be recorded at 36+0-37+6 weeks of pregnancy. Perinatal outcomes will be recorded after delivery. Univariate (with estimated effect size and its 95% CI) and multivariate (mixed-effects logistic regression) comparisons between groups will be performed.

ETHICS AND DISSEMINATION

The study will be conducted in accordance with the principles of Good Clinical Practice. This study was accepted by the Clinical Research Ethics Committee of Hospital Clinic Barcelona on 23May 2016. Subsequent approval by individual ethical committees and competent authorities was granted. The study results will be published in peer-reviewed journals and disseminated at international conferences.

TRIAL REGISTRATION NUMBER

NCT02907242; pre-results.

Single and Serial Fetal Biometry to Detect Preterm and Term Small- and Large-for-Gestational-Age Neonates: A Longitudinal Cohort Study

Objectives

To assess the value of single and serial fetal biometry for the prediction of small- (SGA) and large-for-gestational-age (LGA) neonates delivered preterm or at term.

Methods

A cohort study of 3,971 women with singleton pregnancies was conducted from the first trimester until delivery with 3,440 pregnancies (17,334 scans) meeting the following inclusion criteria: 1) delivery of a live neonate after 33 gestational weeks and 2) two or more ultrasound examinations with fetal biometry parameters obtained at ≤36 weeks. Primary outcomes were SGA (<5^th centile) and LGA (>95^th centile) at birth based on INTERGROWTH-21^st gender-specific standards. Fetus-specific estimated fetal weight (EFW) trajectories were calculated by linear mixed-effects models using data up to a fixed gestational age (GA) cutoff (28, 32, or 36 weeks) for fetuses having two or more measurements before the GA cutoff and not already delivered. A screen test positive for single biometry was based on Z-scores of EFW at the last scan before each GA cut-off so that the false positive rate (FPR) was 10%. Similarly, a screen test positive for the longitudinal analysis was based on the projected (extrapolated) EFW at 40 weeks from all available measurements before each cutoff for each fetus.

Results

Fetal abdominal and head circumference measurements, as well as birth weights in the Detroit population, matched well to the INTERGROWTH-21^st standards, yet this was not the case for biparietal diameter (BPD) and femur length (FL) (up to 9% and 10% discrepancy for mean and confidence intervals, respectively), mainly due to differences in the measurement technique. Single biometry based on EFW at the last scan at ≤32 weeks (GA IQR: 27.4–30.9 weeks) had a sensitivity of 50% and 53% (FPR = 10%) to detect preterm and term SGA and LGA neonates, respectively (AUC of 82% both). For the detection of LGA using data up to 32- and 36-week cutoffs, single biometry analysis had higher sensitivity than longitudinal analysis (52% vs 46% and 62% vs 52%, respectively; both p<0.05). Restricting the analysis to subjects with the last observation taken within two weeks from the cutoff, the sensitivity for detection of LGA, but not SGA, increased to 65% and 72% for single biometry at the 32- and 36-week cutoffs, respectively. SGA screening performance was higher for preterm (<37 weeks) than for term cases (73% vs 46% sensitivity; p<0.05) for single biometry at ≤32 weeks.

Conclusions

When growth abnormalities are defined based on birth weight, growth velocity (captured in the longitudinal analysis) does not provide additional information when compared to the last measurement for predicting SGA and LGA neonates, with both approaches detecting one-half of the neonates (FPR = 10%) from data collected at ≤32 weeks. Unlike for SGA, LGA detection can be improved if ultrasound scans are scheduled as close as possible to the gestational-age cutoff when a decision regarding the clinical management of the patient needs to be made. Screening performance for SGA is higher for neonates that will be delivered preterm.

An integrated approach to fetal growth restriction

Fetal growth restriction (FGR) is among the most common complications of pregnancy. FGR is associated with placental insufficiency and poor perinatal outcomes. Clinical management is challenging because of variability in clinical presentation. Fetal smallness (estimated fetal weight <10th centile for gestational age) remains the best clinical surrogate for FGR. However, it is commonly accepted that not all forms of fetal smallness represent true FGR. In a significant subset of small fetuses, there is no evidence of placental involvement, perinatal outcomes are nearly normal, and they are clinically referred to as "only" small for gestational age (SGA). Doppler may improve the clinical management of FGR; however, the need to use several parameters sometimes results in a number of combinations that may render interpretation challenging when translating into clinical decisions. We propose that the management of FGR can be simplified using a sequential approach based on three steps: (1) identification of the "small fetus," (2) differentiation between FGR and SGA, and (3) timing of delivery according to a protocol based on stages of fetal deterioration.

Ultrasound screening for fetal growth restriction at 36 vs 32 weeks' gestation: a randomized trial (ROUTE)

OBJECTIVE

To compare the utility of routine third-trimester ultrasound examination at 36 weeks' gestation with that at 32 weeks in detecting fetal growth restriction (FGR).

METHODS

This was an open-label parallel randomized trial (ROUTE study) conducted at a single general hospital serving a geographically well-defined catchment area in Barcelona, Spain, between May 2011 and April 2014. Women with no adverse medical or obstetric history and a singleton pregnancy without fetal abnormalities at routine second-trimester scan were assigned randomly to undergo a scan at 32 weeks' gestation (n = 1272) or at 36 weeks' gestation (n = 1314). Primary outcome measures were detection rates of FGR (customized birth weight < 10(th) centile) and severe FGR (customized birth weight < 3(rd) centile).

RESULTS

There were no significant differences in perinatal outcome between those who underwent a scan at 32 weeks' gestation and those who underwent a scan at 36 weeks' gestation. Severe FGR at birth was associated significantly with emergency Cesarean delivery for fetal distress (odds ratio (OR), 3.4 (95% CI, 1.8-6.7)), neonatal admission (OR, 2.23 (95% CI, 1.23-4.05)), hypoglycemia (OR, 9.5 (95% CI, 1.8-49.8)) and hyperbilirubinemia (OR, 9.0 (95% CI, 4.6-17.6)). Despite similar false-positive rates (FPRs) (6.4% vs 8.2%), FGR detection rates were superior at 36 vs 32 weeks' gestation (sensitivity, 38.8% vs 22.5%; P = 0.006), with positive and negative likelihood ratios of 6.1 vs 2.7 and 0.65 vs 0.84, respectively. In cases of severe FGR, FPRs for both scans were also similar (8.5% vs 8.7%), but detection rates were superior at 36 vs 32 weeks' gestation (61.4% vs 32.5%; P = 0.008). Positive and negative likelihood ratios were 7.2 vs 3.7 and 0.4 vs 0.74, respectively.

CONCLUSION

In low-risk pregnancies, routine ultrasound examination at 36 weeks' gestation was more effective than that at 32 weeks' gestation in detecting FGR and related adverse perinatal and neonatal outcomes.

The association between fetal Doppler and admission to neonatal unit at term

OBJECTIVE

Fetal cerebroplacental ratio is emerging as a better proxy than birthweight for placental insufficiency and as a marker of fetal compromise at term. The extent to which these fetal Doppler changes are related to neonatal outcomes has not been systematically assessed. The main aim of this study was to evaluate the association between estimated fetal weight percentile, cerebroplacental ratio recorded at 34(+0)-35(+6) weeks' gestation, and neonatal unit admission at term.

STUDY DESIGN

This was a retrospective cohort study in a tertiary referral center over an 11 year period from 2002 to 2012. The umbilical artery pulsatility index (PI), middle cerebral artery PI, and cerebroplacental ratio were recorded at 34(+0)-35(+6) weeks. Weight values were converted into percentiles and Doppler parameters into multiples of the median (MoM), adjusting for gestational age. Logistic regression analysis was performed to identify, and adjust for, potential confounders.

RESULTS

We identified 2518 pregnancies in which a scan was performed at 34(+0)-35(+6) weeks and delivery occurred at or beyond 37 weeks. In the 2485 pregnancies included in the analysis, the umbilical artery PI MoM was significantly higher, and the middle cerebral artery PI and cerebroplacental ratio MoM significantly lower in the babies requiring neonatal unit admission (P < .05). However, the estimated fetal weight percentile was not significantly different between those who required neonatal unit admission and those who did not (P = .087). According to multivariate logistic regression, cerebroplacental ratio MoM (odds ratio, 0.39; 95% confidence interval, 0.19-0.79; P = .008) and gestational age at delivery (odds ratio, 0.70; 95% confidence interval, 0.61-0.80; P < .001) were significantly associated with the risk of neonatal unit admission, whereas maternal age and birthweight percentile were not (P = .183 and P = .460, respectively). Irrespective of birthweight or estimated fetal weight percentile, the fetal cerebroplacental ratio appears to be a better predictor of the need for neonatal unit admission (P < .001).

CONCLUSION

Lower cerebroplacental ratio and gestational age at delivery, but not fetal size, were independently associated with the need for admission to the neonatal unit at term in a high-risk patient group. The extent to which fetal hemodynamic assessment could be used to predict perinatal morbidity and optimize the timing of delivery merits further investigation.

Is fetal cerebroplacental ratio an independent predictor of intrapartum fetal compromise and neonatal unit admission?

OBJECTIVE

We sought to evaluate the association between fetal cerebroplacental ratio (CPR) and intrapartum fetal compromise and admission to the neonatal unit (NNU) in term pregnancies.

STUDY DESIGN

This was a retrospective cohort study in a single tertiary referral center over a 14-year period from 2000 through 2013. The umbilical artery pulsatility index, middle cerebral artery pulsatility index, and CPR were recorded within 2 weeks of delivery. The birthweight (BW) values were converted into centiles and Doppler parameters converted into multiples of median (MoM), adjusting for gestational age using reference ranges. Logistic regression analysis was performed to identify, and adjust for, potential confounders.

RESULTS

The study cohort included 9772 singleton pregnancies. The rates of operative delivery for presumed fetal compromise and neonatal admission were 17.2% and 3.9%, respectively. Doppler CPR MoM was significantly lower in pregnancies requiring operative delivery or admission to NNU for presumed fetal compromise (P < .01). On multivariate logistic regression, both CPR MoM and BW centile were independently associated with the risk of operative delivery for presumed fetal compromise (adjusted odds ratio [OR], 0.67; 95% confidence interval [CI], 0.52-0.87; P = .003 and adjusted OR, 0.994; 95% CI, 0.992-0.997; P < .001, respectively). The latter associations persisted even after exclusion of small-for-gestational-age cases from the cohort. Multivariate logistic regression also demonstrated that CPR MoM was an independent predictor for NNU admission at term (adjusted OR, 0.55; 95% CI, 0.33-0.92; P = .021), while BW centile was not (adjusted OR, 1.00; 95% CI, 0.99-1.00; P = .794). The rates of operative delivery for presumed fetal compromise were significantly higher for appropriate-for-gestational-age fetuses with low CPR MoM (22.3%) compared to small-for-gestational-age fetuses with normal CPR MoM (17.3%).

CONCLUSION

Lower fetal CPR, regardless of the fetal size, was independently associated with the need for operative delivery for presumed fetal compromise and with NNU admission at term. The extent to which fetal hemodynamic status could be used to predict perinatal morbidity and optimize the mode of delivery merits further investigation.

An integrated model with classification criteria to predict small-for-gestational-age fetuses at risk of adverse perinatal outcome

OBJECTIVE

To develop an integrated model with the best performing criteria for predicting adverse outcome in small-for-gestational-age (SGA) pregnancies.

METHODS

A cohort of 509 pregnancies with a suspected SGA fetus, eligible for trial of labor, was recruited prospectively and data on perinatal outcome were recorded. A predictive model for emergency Cesarean delivery because of non-reassuring fetal status or neonatal acidosis was constructed using a decision tree analysis algorithm, with predictors: maternal age, body mass index, smoking, nulliparity, gestational age at delivery, onset of labor (induced vs spontaneous), estimated fetal weight (EFW), umbilical artery pulsatility index (PI), mean uterine artery (UtA) PI, fetal middle cerebral artery PI and cerebroplacental ratio (CPR).

RESULTS

An adverse outcome occurred in 134 (26.3%) cases. The best performing predictors for defining a high risk for adverse outcome in SGA fetuses was the presence of a CPR < 10th centile, a mean UtA-PI > 95th centile or an EFW < 3rd centile. The algorithm showed a sensitivity, specificity and positive and negative predictive values for adverse outcome of 82.8% (95% CI, 75.1-88.6%), 47.7% (95% CI, 42.6-52.9%), 36.2% (95% CI, 30.8-41.8%) and 88.6% (95% CI, 83.2-92.5%), respectively. Positive and negative likelihood ratios were 1.58 and 0.36.

CONCLUSIONS

Our model could be used as a diagnostic tool for discriminating SGA pregnancies at risk of adverse perinatal outcome.

MANAGEMENT OF REDUCED FETAL MOVEMENTS

Reduced fetal movement (RFM) is commonly defined as any reduction in maternal perception of fetal activity. Perceived fetal activity may be movement of limbs, trunk or head movement, but excludes fetal hiccoughs (as this is involuntary movement). The perception of fetal movement by an expectant mother is the first, and ongoing, non-sonographic indicator of fetal viability. The “normal” pattern of fetal movements varies from pregnancy to pregnancy, and often does not become established until 28 weeks’ gestation. Many babies have particularly active periods of the day, usually corresponding to periods of maternal rest and inactivity (which may in itself reflect increased maternal awareness of fetal movement). A variable percentage of sonographically observed fetal movements are perceived by prospective mothers (commonly 30–40%, although some studies report rates as high as 80%).

Sildenafil citrate increases fetal weight in a mouse model of fetal growth restriction with a normal vascular phenotype

Fetal growth restriction (FGR) is defined as the inability of a fetus to achieve its genetic growth potential and is associated with a significantly increased risk of morbidity and mortality. Clinically, FGR is diagnosed as a fetus falling below the 5(th) centile of customised growth charts. Sildenafil citrate (SC, Viagra™), a potent and selective phosphodiesterase-5 inhibitor, corrects ex vivo placental vascular dysfunction in FGR, demonstrating potential as a therapy for this condition. However, many FGR cases present without an abnormal vascular phenotype, as assessed by Doppler measures of uterine/umbilical artery blood flow velocity. Thus, we hypothesized that SC would not increase fetal growth in a mouse model of FGR, the placental-specific Igf2 knockout mouse, which has altered placental exchange capacity but normal placental blood flow. Fetal weights were increased (by 8%) in P0 mice following maternal SC treatment (0.4 mg/ml) via drinking water. There was also a trend towards increased placental weight in treated P0 mice (P = 0.056). Additionally, 75% of the P0 fetal weights were below the 5(th) centile, the criterion used to define human FGR, of the non-treated WT fetal weights; this was reduced to 51% when dams were treated with SC. Umbilical artery and vein blood flow velocity measures confirmed the lack of an abnormal vascular phenotype in the P0 mouse; and were unaffected by SC treatment. (14)C-methylaminoisobutyric acid transfer (measured to assess effects on placental nutrient transporter activity) per g placenta was unaffected by SC, versus untreated, though total transfer was increased, commensurate with the trend towards larger placentas in this group. These data suggest that SC may improve fetal growth even in the absence of an abnormal placental blood flow, potentially affording use in multiple sub-populations of individuals presenting with FGR.

Placental findings in late-onset SGA births without Doppler signs of placental insufficiency

OBJECTIVES

To describe placental pathological findings in late-onset small-for-gestational age (SGA) births for which Doppler signs of placental insufficiency are lacking.

METHODS

A series of placentas were evaluated from singleton pregnancies of SGA births (birth weight below the 10th percentile) delivered after 34 weeks with normal umbilical artery Doppler (pulsatility index below the 95th percentile), that were matched by gestational age with adequate-for-gestational age (AGA) controls. Using a hierarchical and standardized system, placental lesions were classified histologically as consequence of maternal underperfusion, fetal underperfusion or inflammation.

RESULTS

A total of 284 placentas were evaluated (142 SGA and 142 AGA). In the SGA group, 54.2% (77/142) of the placentas had weights below the 3rd percentile for GA while it was a 9.9% (14/142) in the AGA group (p < 0.001). Only 21.8% (31/142) of SGA placentas were free of histological abnormalities, while it was 74.6% (106/142) in the AGA group (p < 0.001). In the abnormal SGA placentas (111/142) there were a total of 161 lesions, attributable to MUP in 64% (103/161), FUP in 15.5% (25/161), and inflammation in 20.5% (33/161).

DISCUSSION

In most placentas of term SGA neonates with normal UA Doppler histological abnormalities secondary to maternal underperfusion prevail, reflecting latent insufficiency in uteroplacental blood supply. This is consistent with the higher risk of adverse perinatal outcome reported in this population and underscores a need for new markers of placental disease.

CONCLUSIONS

A significant proportion of late-onset SGA births with normal umbilical artery Doppler may still be explained by placental insufficiency.

Added value of umbilical vein flow as a predictor of perinatal outcome in term small-for-gestational-age fetuses

OBJECTIVE

To compare umbilical vein (UV) flow with standard Doppler parameters in prediction of adverse perinatal outcome in late-onset small-for-gestational age (SGA) fetuses.

METHODS

Umbilical, uterine and middle cerebral arteries, and UV blood flow were evaluated by Doppler before delivery in a cohort of 193 term SGA fetuses. The value of the Doppler parameters to predict risk of emergency delivery for non-reassuring fetal status and neonatal metabolic acidosis was analyzed.

RESULTS

Fifty-three (27%) fetuses had non-reassuring fetal status requiring emergency delivery, whereas 21 (11%) newborns developed neonatal metabolic acidosis. Multivariable analysis showed that significant contributions to prediction of emergency delivery for non-reassuring fetal status and neonatal metabolic acidosis were provided by middle cerebral artery (MCA) pulsatility index (PI) and UV blood flow normalized by fetal weight. Decision tree analysis defined three groups with increasing risk of need for emergency delivery for non-reassuring fetal status: MCA-PI > 1.46 (risk 15.6%); MCA-PI ≤ 1.46 and UV blood flow > 68 mL/min/kg (risk 25%); and MCA-PI ≤ 1.46 and UV flow ≤ 68 mL/min/kg (risk 53.1%); and two groups with different risks of neonatal metabolic acidosis: UV flow > 68 mL/min/kg or UV flow ≤ 68 mL/min/kg and MCA-PI > 1.23 (risk ≤ 10%); and UV flow ≤ 68 mL/min/kg and MCA-PI ≤ 1.23 (risk 39.1%).

CONCLUSION

The evaluation of UV blood flow with spectral brain Doppler allows better identification of SGA fetuses with late-onset intrauterine growth restriction at risk of adverse perinatal outcome.

Fetal growth: a review of terms, concepts and issues relevant to obstetrics

The perinatal literature includes several potentially confusing and controversial terms and concepts related to fetal size and growth. This article discusses fetal growth from an obstetric perspective and addresses various issues including the physiologic mechanisms that determine fetal growth trajectories, known risk factors for abnormal fetal growth, diagnostic and prognostic issues related to restricted and excessive growth and temporal trends in fetal growth. Also addressed are distinctions between fetal growth 'standards' and fetal growth 'references', and between fetal growth charts based on estimated fetal weight vs those based on birth weight. Other concepts discussed include the incidence of fetal growth restriction in pregnancy (does the frequency of fetal growth restriction increase or decrease with increasing gestation?), the obstetric implications of studies showing associations between fetal growth and adult chronic illnesses (such as coronary heart disease) and the need for customizing fetal growth standards.

Umbilical venous blood flow and its measurement in the human fetus

In this review, we evaluate the published methodologies to describe a noninvasive technique for the quantitative assessment of umbilical venous blood flow in the human fetus. We identify a number of variations in the reported methodologies and address some of the common errors associated with Doppler assessment of umbilical venous flow volume. The potential role of umbilical venous flow volumetry in the management of intrauterine growth restriction is briefly evaluated including its utility and reliability in everyday clinical practice.

Doppler in obstetrics: beyond the umbilical artery

Doppler analysis of the umbilical and uterine arteries has long been performed in perinatal medicine to assess fetal health and maternal risk for preeclampsia. Several other vessels can be interrogated to obtain additional, vital information. Velocimetry in the fetal middle cerebral artery can yield evidence of the presence or absence of anemia and, in cases of delayed growth, of the risk of hypoxic damage. Ductus venosus waveforms are a very good indicator of impeding fetal jeopardy and should be used when umbilical artery waveforms become abnormal. Early pregnancy uterine artery Doppler reflects the status of the placental vasculature and, as such, is an excellent tool for predicting the risk of preeclampsia or intrauterine growth restriction.

Maternal health-related quality of life after induction of labor or expectant monitoring in pregnancy complicated by intrauterine growth retardation beyond 36 weeks

OBJECTIVE

Pregnancies complicated by intrauterine growth retardation (IUGR) beyond 36 weeks of gestation are at increased risk of neonatal morbidity and mortality. Optimal treatment in IUGR at term is highly debated. Results from the multicenter DIGITAT (Disproportionate Intrauterine Growth Intervention Trial At Term) trial show that induction of labor and expectant monitoring result in equal neonatal and maternal outcomes for comparable cesarean section rates. We report the maternal health-related quality of life (HR-QoL) that was measured alongside the trial at several points in time.

METHODS

Both randomized and non-randomized women were asked to participate in the HR-QoL study. Women were asked to fill out written validated questionnaires, covering background characteristics, condition-specific issues and the Short Form (SF-36), European Quality of Life (EuroQoL 6D3L), Hospital Anxiety and Depression scale (HADS), and Symptom Check List (SCL-90) at baseline, 6 weeks postpartum and 6 months postpartum. We compared the difference scores of all summary measures between the two management strategies by ANOVA. A repeated measures multivariate mixed model was defined to assess the effect of the management strategies on the physical (PCS) and mental (MCS) components of the SF-36. Analysis was by intention to treat.

RESULTS

We analyzed data of 361 randomized and 198 non-randomized patients. There were no clinically relevant differences between the treatments at 6 weeks or 6 months postpartum on any summary measures; e.g., on the SF-36 (PCS: P = .09; MCS: P = .48). The PCS and the MCS were below norm values at inclusion. The PCS improved over time but stayed below norm values at 6 months, while the MCS did not improve.

CONCLUSION

In pregnancies complicated by IUGR beyond 36 weeks, induction of labor does not affect the long-term maternal quality of life.

The impact of umbilical and uterine artery Doppler indices on antenatal course, labor and delivery in a low-risk primigravid population

AIMS

To evaluate the impact of umbilical and uterine artery Doppler in the second and third trimester on antenatal course, labor and delivery in a low-risk primigravid population.

METHODS

Prospective recruitment of 1011 low-risk primigravidas with uterine and umbilical artery Doppler assessment at 22-24 weeks and 36 weeks. All mothers and infants were reviewed postnatally with a retrospective analysis of ultrasound and clinical outcome data.

RESULTS

Elevated uterine artery indices were associated with increased rates of threatened miscarriage, higher rates of pre-eclampsia (PET) and a higher incidence of fetal birth weight <2nd and 9th centile for gestation. Uterine artery pulsatility index (PI) >95th centile for gestation was associated with statistically higher rates of small-for-gestational age (SGA) infants. Elevated umbilical artery indices were associated with higher rates of induction of labor and a higher incidence of fetal birth weight infants <2nd and 9th centile for gestation. Umbilical artery PI >95th centile for gestation was associated with statistically higher rates of SGA infants.

CONCLUSION

Elevated uterine and umbilical artery indices are associated with higher rates of maternal and fetal disease.

Longitudinal changes in uterine, umbilical and fetal cerebral Doppler indices in late-onset small-for-gestational age fetuses

OBJECTIVES

To determine the longitudinal trends and rates of conversion of normal to abnormal uterine (UtA), umbilical (UA) and middle cerebral artery (MCA) Doppler velocimetry throughout the third trimester in late-onset small-for-gestational-age (SGA) fetuses.

METHODS

UtA, UA and MCA Doppler velocimetry was serially performed in a cohort of singleton consecutive late-onset SGA fetuses with normal Doppler values at diagnosis. The rate of conversion of normal to abnormal Doppler values was evaluated by survival analysis. Longitudinal trends were modeled by means of multilevel analysis.

RESULTS

A total of 616 scans were performed on 171 SGA fetuses. Mean gestational age at inclusion and at delivery was 34.1 (SD 1.6) and 38.7 (SD 1.7) weeks, respectively. The proportions of abnormal UtA (2.3 vs. 4.1%) and UA (2.3 vs. 2.9%) pulsatility index (PI) were not significantly different between 37 weeks and before delivery. On the other hand, the proportions of abnormal MCA-PI (4.1 vs. 13.5%) and cerebroplacental ratio (CPR) (7 vs. 22.8%) were significantly different between these two examinations. The remaining proportion of cases with normal UtA-, UA- and MCA-PIs and CPR at 40 weeks were 98.6, 94.5, 85 and 49.6%, respectively. Whereas a slight increasing trend was observed for the UtA-PI (β = 0.002) and UA-PI (β = 0.01), MCA-PI (β = 0.044) and CPR (β = 0.124) showed a progressive decrease until delivery.

CONCLUSIONS

Late-onset SGA fetuses with normal Doppler velocimetry upon diagnosis show progression from 37 weeks' gestation with worsening CPR followed by a decrease in MCA-PI.

Labour and neonatal outcome in small for gestational age babies delivered beyond 36+0 weeks: a retrospective cohort study

OBJECTIVE

Small for gestational age (SGA) is associated with increased neonatal morbidity and mortality. At present, evidence on whether these pregnancies should be managed expectantly or by induction is lacking. To get insight in current policy we analysed data of the National Dutch Perinatal Registry (PRN).

METHODS

We used data of all nulliparae between 2000 and 2005 with a singleton in cephalic presentation beyond 36+0 weeks, with a birth weight below the 10th percentile. We analysed two groups of pregnancies: (I) with isolated SGA and (II) with both SGA and hypertensive disorders. Onset of labour was related to route of delivery and neonatal outcome.

RESULTS

Induction was associated with a higher risk of emergency caesarean section (CS), without improvement in neonatal outcome. For women with isolated SGA the relative risk of emergency CS after induction was 2.3 (95% Confidence Interval [CI] 2.1 to 2.5) and for women with both SGA and hypertensive disorders the relative risk was 2.7 (95% CI 2.3 to 3.1).

CONCLUSION

Induction in pregnancies complicated by SGA at term is associated with a higher risk of instrumental deliveries without improvement of neonatal outcome. Prospective studies are needed to determine the best strategy in suspected IUGR at term.

A comparison of stillborn birth weights and postmortem weights

Birth weights obtained by the nurses in the labor and delivery room were compared with the postmortem weights examination prospectively in 212 stillborns. The effects of gestational age, degree of maceration, birth weight, gender, and time elapsed from delivery to postmortem examinations were also examined. There were 96 female and 116 male stillborns in the study. The gestational ages ranged from 14 to 42 weeks. The degree of maceration ranged from 0 to 5, 0 being no maceration and 5 representing the most extreme condition, which was mummification. There was an average of a 50 g decrease in the weights of all stillborns when their birth weights and postmortem weights were compared. This was equal to an average relative weight loss of 7.1%. When all the variables were examined, only the degree of maceration and gestational age were identified to play significant roles in weight loss (P < 0.0001 for both). A higher degree of maceration meant more weight loss, whereas older gestational age led to less weight loss. There is significant discrepancy between the birth and postmortem examination weights of stillborns. Although gender, birth weight, and time elapsed from delivery to postmortem examination did not have any significant effects, the degree of maceration and gestational age affected the observed weight loss. In stillborns, birth weights are more accurate than weights obtained at postmortem examination.

Can adverse neonatal outcome be predicted in late preterm or term fetal growth restriction?

OBJECTIVE

To identify independent predictors of adverse neonatal outcome in cases of fetal growth restriction (FGR) at > or = 34 weeks.

METHODS

From a cohort of 481 FGR cases delivered at > or = 34 weeks, demographic and obstetric variables, fetal biometry and Doppler indices of the uterine, umbilical and fetal middle cerebral arteries available within 2 weeks of delivery, were related to adverse neonatal outcome, defined as admission to the neonatal intensive care unit for indications other than low birth weight alone.

RESULTS

Logistic regression analysis showed that gestational age (GA) at delivery (odds ratio (OR) = 0.59; 95% CI, 0.50-0.70), abdominal circumference (AC) centile (OR = 0.69; 95% CI, 0.59-0.81) and umbilical artery (UA) pulsatility index (PI) centile (OR = 1.02; 95% CI, 1.01-1.04) significantly correlated with adverse neonatal outcome. From this model we calculated a score of adverse neonatal outcome expressed by the formula: (UA-PI centile/3) - (10 x AC centile) + (10 x (40 - GA at delivery in weeks)). Receiver-operating characteristics curve analysis demonstrated that a score of > or = 25 optimally predicted adverse neonatal outcome (sensitivity of 75%, false-positive rate of 18%). Beyond 37.5 weeks, gestational age no longer had an independent impact on outcome.

CONCLUSIONS

In late preterm or term FGR, GA at delivery is the most important predictor of adverse neonatal outcome. At > 37.5 weeks, delivery may be the best option to minimize adverse outcome in all FGR cases. At 34-37 weeks, a score based on GA at delivery, UA-PI centile and AC centile optimally predicts adverse neonatal outcome.

The predictive ability of conditional fetal growth percentiles

Conditional fetal growth percentiles are percentiles that are calculated taking into account (conditional on) an infant's weight earlier in pregnancy. Although they have been proposed in the statistical literature as a more methodologically appropriate method of measuring fetal growth, their ability to predict adverse perinatal outcomes due to fetal growth restriction is unknown. Using a large, unselected clinical ultrasound database at the Royal Victoria Hospital in Montreal, Canada, we calculated conditional growth percentiles for infants' weight at birth, given their weight at the time of a routine 32- or 33-week ultrasound. The risk of adverse perinatal outcome (perinatal mortality, low Apgar, acidaemia, or seizures/organ failure due to asphyxia) among small-for-gestational-age infants (SGA) as established by conditional growth percentiles was calculated as well as the risk among infants classified as SGA by conventional weight-for-gestational-age percentiles. Regardless of the threshold used to define SGA (fifth, 10th, 15th, 20th), conditional percentiles did not appear to improve the identification of adverse perinatal outcomes compared with conventional weight-for-gestational-age charts. Further work is needed to confirm our results as well as to explore potential reasons for the lack of benefits from using a measure of growth instead of size to identify fetal growth restriction.

Obstetric management of intrauterine growth restriction

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

The role of Doppler and placental screening

Placental-associated diseases account for most cases of adverse perinatal outcome in developing countries. Uterine Doppler evaluation predicts most instances of early-onset preeclampsia and intrauterine growth restriction, but there is no evidence in favour of any prophylactic strategy in cases of an abnormal screening result. Umbilical artery Doppler investigation allows identifying those small-for-gestational-age foetuses at higher risk, and its use in these pregnancies improves a number of perinatal outcomes. Middle cerebral artery Doppler investigation reflects brain redistribution, and its use in combination with the umbilical artery in a cerebroplacental ratio seems to improve prediction of adverse outcome, mainly in near-term pregnancies, where most instances of adverse outcome occur in foetuses with normal umbilical artery. Ductus venosus Doppler waveform is a surrogate parameter of the foetal acid-base status. However, the benefits of its use in the management of early-onset growth restriction needs further evidence.

Prediction of adverse perinatal outcome at term in small-for-gestational age fetuses: comparison of growth velocity vs. customized assessment

OBJECTIVE

To explore the ability of growth velocity and customized standards of fetal weight to predict adverse outcomes in small fetuses delivered at term.

METHODS

We evaluated a cohort of 86 consecutive singletons suspected to be small for gestational age during the third trimester (estimated fetal weight <10(th) centile), who had normal umbilical artery Doppler and ultimately delivered at term. Conditional growth velocity and customized fetal growth were compared for the prediction of adverse outcome.

RESULTS

Overall, customized growth assessment showed better sensitivity than growth velocity assessment (57.1% vs. 42.9% for a 10(th) centile cut-off) for the prediction of adverse outcome, but with comparable specificity. The odds of having an adverse outcome for women with a positive test compared with women with a negative test were 1.54 and 3.22 for the 10(th) centile growth velocity and customized definitions, respectively. The area under the curve for the prediction of adverse outcome was larger for customized than for growth velocity standards (0.65 vs. 0.59), albeit without statistical significance.

CONCLUSIONS

Our study suggests that customized growth assessment may have better accuracy in predicting adverse perinatal outcome than growth velocity in small fetuses with normal umbilical Doppler delivered at term.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Disproportionate Intrauterine Growth Intervention Trial At Term: DIGITAT

Background

Around 80% of intrauterine growth restricted (IUGR) infants are born at term. They have an increase in perinatal mortality and morbidity including behavioral problems, minor developmental delay and spastic cerebral palsy. Management is controversial, in particular the decision whether to induce labour or await spontaneous delivery with strict fetal and maternal surveillance. We propose a randomised trial to compare effectiveness, costs and maternal quality of life for induction of labour versus expectant management in women with a suspected IUGR fetus at term.

Methods/design

The proposed trial is a multi-centre randomised study in pregnant women who are suspected on clinical grounds of having an IUGR child at a gestational age between 36+0 and 41+0 weeks. After informed consent women will be randomly allocated to either induction of labour or expectant management with maternal and fetal monitoring. Randomisation will be web-based. The primary outcome measure will be a composite neonatal morbidity and mortality. Secondary outcomes will be severe maternal morbidity, maternal quality of life and costs. Moreover, we aim to assess neurodevelopmental and neurobehavioral outcome at two years as assessed by a postal enquiry (Child Behavioral Check List-CBCL and Ages and Stages Questionnaire-ASQ). Analysis will be by intention to treat. Quality of life analysis and a preference study will also be performed in the same study population. Health technology assessment with an economic analysis is part of this so called Digitat trial (Disproportionate Intrauterine Growth Intervention Trial At Term). The study aims to include 325 patients per arm.

Discussion

This trial will provide evidence for which strategy is superior in terms of neonatal and maternal morbidity and mortality, costs and maternal quality of life aspects. This will be the first randomised trial for IUGR at term.

Trial registration

Dutch Trial Register and ISRCTN-Register: ISRCTN10363217.

High maternal and fetal plasma urocortin levels in pregnancies complicated by hypertension

OBJECTIVE

We evaluated maternal and fetal plasma levels and placental mRNA expression of urocortin, a placental vasoactive neuropeptide, in singleton pregnancies (n = 70) complicated by hypertensive disorders classified as gestational hypertension (n = 36), pre-eclampsia (n = 19), and pre-eclampsia complicated by intrauterine growth restriction (PE/IUGR, n = 15), and in 70 healthy normotensive singleton pregnancies.

METHODS

Plasma levels were assayed by radioimmunoassay, fetal biometry by ultrasound scans, utero-placental and fetal perfusion by Doppler velocimetry, and placental urocortin mRNA expression by quantitative real time reverse transcriptase-polymerase chain reaction. The main outcome measures were the correlation of urocortin concentrations with patterns of the utero-placental and fetal circulation, and the early prediction of a poor neonatal outcome such as the occurrence of perinatal death and intraventricular hemorrhage.

RESULTS

Maternal and fetal urocortin levels were significantly (both P < 0.001) higher in gestational hypertension, pre-eclampsia and PE/IUGR women than in controls, and correlated with Doppler velocimetry patterns. Fetal concentrations were significantly (P < 0.0001) higher than and significantly (P < 0.0001) correlated to maternal levels. Placental mRNA expression did not change. Ten out of 140 newborns had a poor neonatal outcome, with an overall prevalence of 7.14% (pretest probability). Using the receiver operator characteristics curve analysis cut-off values, the probability of a poor neonatal outcome was 66.7% when urocortin was used, and was 0% if levels were unaltered.

CONCLUSIONS

Maternal and fetal urocortin levels are increased in hypertensive disorders of pregnancy. Since urocortin has vasoactive properties, the evidence of increased urocortin levels in hypertensive disorders may represent an adaptive fetal response.

Use of umbilical-cerebral Doppler ratios in predicting fetal growth restriction in near-term fetuses

OBJECTIVE

To compare the sensitivity and specificity of different umbilical-cerebral ratios in the prediction and detection of fetal growth restriction in near-term fetuses when the umbilical arterial waveform is within normal.

METHODS

A prospective cross-sectional observational study was carried out recruiting consecutive singleton pregnancies with clinically suspected fetal growth restriction after 34 weeks gestation. The umbilical-cerebral ratios were then calculated from the S/D, RI and PI values and correlated with immediate perinatal outcome.

RESULTS

A total of 187 patients were recruited. Twelve cases had abnormal UA Doppler flow velocity waveform studies. Of the 175 with normal UA Doppler findings, 92 (53.1%) were confirmed to have fetal growth restriction (FGR) with birth weights below the tenth centile for gestation. The detection rate of FGR by ultrasound biometry was 96.7%. The mean umbilical artery S/D, RI and PI values were higher in the fetal growth restriction group, while the middle cerebral artery values were lower as compared to fetuses with no growth restriction. A small but significant difference was seen in the umbilical-cerebral ratios of the different indices between the two groups. Receiver operator characteristic curves showed that there was little difference between the performances of the S/D, RI or PI ratios and all had limited power in predicting fetal growth restriction.

CONCLUSION

In the presence of normal umbilical artery Doppler waveforms, umbilical-cerebral ratios have limited power to predict fetal growth restriction.

Prognostic Value of Umbilical Artery Doppler Studies in Unselected Preterm Deliveries

OBJECTIVE

To evaluate the prognostic value of umbilical artery Doppler studies in premature deliveries.

METHODS

In this cohort study of 582 singleton pregnancies delivered between 24 and 35 weeks of gestation, we evaluated the ratio of peak-systolic to end-diastolic (S/D) blood flow velocities in the umbilical artery of all the patients. The correlations among the results of the Doppler studies, short-term neonatal complications, and the infants' neurodevelopmental outcome at 2 years were studied by univariable and multivariable methods.

RESULTS

The prevalences of either neonatal death or cerebral palsy among the 266 (45.7%) growth restricted fetuses were 3.4% (3/88) in pregnancies with a S/D ratio below the 95th percentile, 4.9% (5/103) in pregnancies with a S/D at or above the 95th percentile, and 17.3% (13/75) in those with absent or reversed end-diastolic blood flow in the umbilical artery (P for trend = .001). The corresponding figures in the 316 pregnancies with adequate fetal growth were 6.4% (15/234) and 4.3% (3/69) among pregnancies with a S/D ratio below and at or above 95th percentile, respectively, whereas no cases of either neonatal death or cerebral palsy were recorded in the 13 pregnancies with adequate fetal growth and absent or reversed end-diastolic blood flow velocity (P for trend = .28; chi(2) for heterogeneity of linear trends compared with growth-restricted infants = 7.02, P = .008). In logistic regression, in pregnancies complicated by fetal growth restriction, absent or reversed end-diastolic blood flow in the umbilical artery was still associated with an increased risk of either neonatal death or cerebral palsy even after adjustment for gestational age and proportion of expected birth weight, (odds ratio 3.2, 95% confidence interval 1.18-8.66, P = .02).

CONCLUSION

Absent or reversed end-diastolic flow in the umbilical artery is an independent predictor of either neonatal death or cerebral palsy in preterm growth-restricted fetuses. In the absence of fetal growth restriction, umbilical artery Doppler study was associated with none of the infant outcome parameters studied.

Assessing fetal health

Fetal surveillance significantly reduces the incidence of fetal loss, perinatal morbidity and maternal distress. Obstetricians traditionally classify pregnancies as 'low' or 'high risk' and apply various methods of fetal surveillance in the latter group. However, the majority of stillbirths now occur in 'low-risk' women. This seemingly anomalous observation emphasises the need to develop more effective ways of identifying 'at-risk' fetuses in 'low-risk' women. This chapter describes and critically evaluates eleven currently available tools for fetal surveillance. It also reviews the criteria for ascribing risk status in pregnancy and suggests a pragmatic approach to health assessment in normally formed fetuses for each group. It does not address fetal surveillance during labour and delivery.