Large cross-sectional area of the umbilical cord as a predictor of fetal macrosomia

Significance of Umbilical Cord Leptin Profile during Pregnancy in Gestational Diabetes Mellitus-A Systematic Review and Meta-Analysis

BACKGROUND

The literature provides limited evidence of cord blood leptin levels in gestational diabetes mellitus (GDM), with contradictory and inconsistent results with respect to their possible implications for maternal, perinatal, and future complications.

METHODS

MEDLINE/PubMed, Embase, Scopus, and Web of Science databases were searched in order to investigate the state of evidence on the association of leptin profile in cord blood during perinatal complications in GDM. We critically assessed the risk of bias using the Newcastle-Ottawa scale. Meta-analyses were performed, and heterogeneity and publication bias were analyzed.

RESULTS

sixteen primary-level studies were included, recruiting 573 GDM and 1118 control pregnant women. Cord blood leptin levels were significantly higher in GDM participants compared to controls (standardized mean difference [SMD] = 0.59, 95% confidence intervals (CI) = 0.37 to 0.80, p < 0.001). All subgroups also maintained significant differences stratified by continents (Asia: SMD = 0.91, 95% CI = 0.45 to 1.37, p < 0.001; Europe: SMD = 0.38, 95% CI = 0.20 to 0.56, p < 0.001), analysis technique (ELISA: SMD = 0.70, 95% CI = 0.44 to 0.97, p < 0.001; RIA: SMD = 0.30, 95% CI = 0.11 to 0.49, p = 0.002), and sample source (plasma: SMD = 0.71, 95% CI = 0.33 to 1.09, p < 0.001; serum: SMD = 0.55, 95% CI = 0.34 to 0.77, p < 0.001).

CONCLUSION

Cord blood leptin levels were significantly higher in GDM compared to controls. Further research is needed to clarify its role as a predictive biomarker of subsequent metabolic diseases in mothers with GDM and offspring.

Umbilical vein blood flow: State-of-the-art

Placental blood supply to the fetus can be measured by evaluating the umbilical vein blood flow. Despite its potential application in healthcare, the umbilical vein blood flow volume is still used only in research setting. One of the reasons is a concern regarding its reproducibility, partly due to technology issues. Nowadays, technology improvements make this evaluation accurate and reproducible. The aim of this review is to refresh basic elements of the physiology of umbilical vein blood flow and its analysis. Its evaluation in normal and abnormal fetal growth is also discussed.

Umbilical Cord Biometry and Fetal Abdominal Skinfold Assessment as Potential Biomarkers for Fetal Macrosomia in a Gestational Diabetes Romanian Cohort

Backgroundand Objectives: Gestational diabetes mellitus (GDM) is a pregnancy-associated pathology commonly resulting in macrosomic fetuses, a known culprit of obstetric complications. We aimed to evaluate the potential of umbilical cord biometry and fetal abdominal skinfold assessment as screening tools for fetal macrosomia in gestational diabetes mellitus pregnant women. Materials and methods: This was a prospective case−control study conducted on pregnant patients presenting at 24−28 weeks of gestation in a tertiary-level maternity hospital in Northern Romania. Fetal biometry, fetal weight estimation, umbilical cord area and circumference, areas of the umbilical vein and arteries, Wharton jelly (WJ) area and abdominal fold thickness measurements were performed. Results: A total of 51 patients were enrolled in the study, 26 patients in the GDM group and 25 patients in the non-GDM group. There was no evidence in favor of umbilical cord area and WJ amount assessments as predictors of fetal macrosomia (p > 0.05). However, there was a statistically significant difference in the abdominal skinfold measurement during the second trimester between macrosomic and normal-weight newborns in the GDM patient group (p = 0.016). The second-trimester abdominal circumference was statistically significantly correlated with fetal macrosomia at term in the GDM patient group with a p value of 0.003, as well as when considering the global prevalence of macrosomia in the studied populations, 0.001, when considering both populations. Conclusions: The measurements of cord and WJ could not be established as predictors of fetal macrosomia in our study populations, nor differentiate between pregnancies with and without GDM. Abdominal skinfold measurement and abdominal circumference measured during the second trimester may be important markers of fetal metabolic status in pregnancies complicated by GDM.

Fetal head prior to delivery: precise measurement, using a mathematically extrapolated frontooccipital diameter

PURPOSE

To find a method that could improve the accuracy of fHC evaluation at term.

MATERIAL AND METHODS

This retrospective cohort study was based on data from the University Hospital of Zürich (USZ). Study population included singleton fetuses and newborns at term between 2015 and 2017. Fetal biometry was performed within 1 week prior to delivery. Study data consisted of two cohorts with 200 ultrasound measurements each: 200 performed by an expert, 200 by residents. fHC were compared with the newborn's head circumference (nHC). fHC was estimated using two methods: (1) fHC based on sonographically estimated frontooccipital diameter (FOD) and biparietal diameter (BPD). (2) Expected FOD was calculated as a fixed mean FOD/BPD relation, derived from biometry standards as the 50th percentile. If BPD was < 99 mm, FOD was calculated according to the formula BPD × 1.268557, If BPD was ≥ 99 mm, FOD was calculated according to the formula BPD × 1.20641443.

RESULTS

fHC was underestimated compared with nHC in the expert group: percentage error (PE =  - 3.68%, SD = 2.79), as well as in the group of residents (PE =  - 3.78%, SD = 3.20) using method 1. fHC measurement was significantly more accurate using method 2. In the expert group PE =  - 1.17%, SD = 3.08, in the group of residents PE =  - 0.95%, SD = 3.33. Bland-Altman analysis showed limits of agreement (LOA) between - 2.41338 and 0.5537828 cm for fHC.

CONCLUSIONS

Accuracy of fHC estimation could be improved by extrapolation of FOD when real-time FOD cannot be measured.

Current Perspectives of Prenatal Sonography of Umbilical Cord Morphology

The umbilical cord constitutes a continuation of the fetal cardiovascular system anatomically bridging between the placenta and the fetus. This structure, critical in human development, enables mobility of the developing fetus within the gestational sac in contrast to the placenta, which is anchored to the uterine wall. The umbilical cord is protected by unique, robust anatomical features, which include: length of the umbilical cord, Wharton’s jelly, two umbilical arteries, coiling, and suspension in amniotic fluid. These features all contribute to protect and buffer this essential structure from potential detrimental twisting, shearing, torsion, and compression forces throughout gestation, and specifically during labor and delivery. The arterial components of the umbilical cord are further protected by the presence of Hyrtl’s anastomosis between the two respective umbilical arteries. Abnormalities of the umbilical cord are uncommon yet include excessively long or short cords, hyper or hypocoiling, cysts, single umbilical artery, supernumerary vessels, rarely an absent umbilical cord, stricture, furcate and velamentous insertions (including vasa previa), umbilical vein and arterial thrombosis, umbilical artery aneurysm, hematomas, and tumors (including hemangioma angiomyxoma and teratoma). This commentary will address current perspectives of prenatal sonography of the umbilical cord, including structural anomalies and the potential impact of future imaging technologies.

Third Trimester Umbilical Artery Doppler in Low-Risk Pregnancies and its Correlation to Estimated Fetal Weight and Birthweight

PURPOSE

 This study investigated the correlation between the umbilical artery (UA) pulsatility index (PI) and the estimated fetal weight percentile and birthweight (BW) percentile, respectively.

MATERIALS AND METHODS

 We included low-risk pregnancies, in which UA Doppler investigations after 28 weeks were performed. Cases were allocated according to BW percentiles: small for gestational age (SGA) with BW < 10^th percentile; appropriate for gestational age (AGA) and large for gestational age (LGA) with BW > 90^th percentile. We analyzed differences in the mean UA-PI and UA-PI z-score for gestational age according to the three groups. Linear regression was performed to evaluate any relationship between Doppler indices and BW percentiles. Multiple logistic regression analysis was performed to determine the independent association of UA-PI with LGA babies. In a second step, we considered data on estimated fetal weight (EFW) percentiles and performed the same analysis.

RESULTS

 We analyzed 14 554 pregnancies from 2004 to 2015. The mean UA-PI and mean UA-PI z-scores in the LGA group were lower than in the AGA and SGA groups (p < 0.001). UA-PI and UA-PI z-scores were linearly related to birthweight percentiles (p < 0.001) and to EFW percentiles (p < 0.001). Logistic regression analysis showed that low UA-PI was independently associated with neonatal LGA (p < 0.001).

CONCLUSION

 The higher the EFW and BW percentiles, the lower the UA-PI. However, reference ranges for UA Doppler are only based on gestation weeks. Further studies are needed to clarify whether customized reference ranges based on EFW percentiles are more appropriate for the evaluation of fetal wellbeing in the third trimester.

Ultrasound evaluation of the fetal fat tissue, heart, liver and umbilical cord measurements in pregnancies complicated by gestational and type 1 diabetes mellitus: potential application in the fetal birth-weight estimation and prediction of the fetal macrosomia

BACKGROUND

The aim of the study was to evaluate the ultrasound-derived measurements of the fetal soft-tissue, heart, liver and umbilical cord in pregnancies complicated by gestational (GDM) and type 1 diabetes mellitus (T1DM), and further to assess their applicability in the estimation of the fetal birth-weight and prediction of fetal macrosomia.

METHODS

Measurements were obtained from diet-controlled GDM (GDMG1) (n = 40), insulin-controlled GDM (GDMG2) (n = 40), T1DM (n = 24) and healthy control (n = 40) patients. The following parameters were selected for analysis: fetal sub-scapular fat mass (SSFM), abdominal fat mass (AFM), mid-thigh fat/lean mass (MTFM/MTLM) and inter-ventricular septum (IVS) thicknesses, heart and thorax circumference and area (HeC/HeA; ThC/ThA), liver length (LL), umbilical cord/vein/arteries circumference and area (UmC/UmA; UvC/UvA; UaC/UaA) together with total umbilical vessels (UveA) and Wharton's jelly area (WjA). Regression models were created in order to assess the contribution of selected parameters to fetal birth-weight (FBW) and risk of fetal macrosomia.

RESULTS

Measurements of the fetal SSFM, AFM, MTFM, MTFM/MTLM ratio, HeC, HeA, IVS, LL, UmC, UmA, UaC, UaA, UveA and WjA were significantly increased among patients with GDMG2/T1DM as compared to GDMG1 and/or control groups (p < .05). The regression analysis revealed that maternal height as well as fetal biparietal diameter, abdominal circumference (AC), AFM and LL measurements were independent predictors of the FBW (p < .05). In addition, increase in the fetal AFM, AC and femur length (FL) was associated with a significant risk of fetal macrosomia occurrence (p < .05). The equation developed for the FBW estimation [FBW(g) = - 2254,942 + 17,204 * FL (mm) + 105,531 * AC (cm) + 131,347 * AFM (mm)] provided significantly lower mean absolute percent error than standard formula in the sub-group of women with T1DM (5.7% vs 9.4%, p < .05). Moreover, new equation including AC, FL and AFM parameters yielded sensitivity of 93.8%, specificity 77.7%, positive predictive value 54.5% and negative predictive value of 97.8% in the prediction of fetal macrosomia.

CONCLUSIONS

Ultrasound measurements of the fetal soft tissue, heart, liver and umbilical cord are significantly increased among women with GDM treated with insulin and T1DM. In addition to standard biometric measurements, parameters, such as AFM, may find application in the management of diabetes-complicated pregnancies.

Universal late pregnancy ultrasound screening to predict adverse outcomes in nulliparous women: a systematic review and cost-effectiveness analysis

BACKGROUND

Currently, pregnant women are screened using ultrasound to perform gestational aging, typically at around 12 weeks' gestation, and around the middle of pregnancy. Ultrasound scans thereafter are performed for clinical indications only.

OBJECTIVES

We sought to assess the case for offering universal late pregnancy ultrasound to all nulliparous women in the UK. The main questions addressed were the diagnostic effectiveness of universal late pregnancy ultrasound to predict adverse outcomes and the cost-effectiveness of either implementing universal ultrasound or conducting further research in this area.

DESIGN

We performed diagnostic test accuracy reviews of five ultrasonic measurements in late pregnancy. We conducted cost-effectiveness and value-of-information analyses of screening for fetal presentation, screening for small for gestational age fetuses and screening for large for gestational age fetuses. Finally, we conducted a survey and a focus group to determine the willingness of women to participate in a future randomised controlled trial.

DATA SOURCES

We searched MEDLINE, EMBASE and the Cochrane Library from inception to June 2019.

REVIEW METHODS

The protocol for the review was designed a priori and registered. Eligible studies were identified using keywords, with no restrictions for language or location. The risk of bias in studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) tool. Health economic modelling employed a decision tree analysed via Monte Carlo simulation. Health outcomes were from the fetal perspective and presented as quality-adjusted life-years. Costs were from the perspective of the public sector, defined as NHS England, and the costs of special educational needs. All costs and quality-adjusted life-years were discounted by 3.5% per annum and the reference case time horizon was 20 years.

RESULTS

Umbilical artery Doppler flow velocimetry, cerebroplacental ratio, severe oligohydramnios and borderline oligohydramnios were all either non-predictive or weakly predictive of the risk of neonatal morbidity (summary positive likelihood ratios between 1 and 2) and were all weakly predictive of the risk of delivering a small for gestational age infant (summary positive likelihood ratios between 2 and 4). Suspicion of fetal macrosomia is strongly predictive of the risk of delivering a large infant, but it is only weakly, albeit statistically significantly, predictive of the risk of shoulder dystocia. Very few studies blinded the result of the ultrasound scan and most studies were rated as being at a high risk of bias as a result of treatment paradox, ascertainment bias or iatrogenic harm. Health economic analysis indicated that universal ultrasound for fetal presentation only may be both clinically and economically justified on the basis of existing evidence. Universal ultrasound including fetal biometry was of borderline cost-effectiveness and was sensitive to assumptions. Value-of-information analysis indicated that the parameter that had the largest impact on decision uncertainty was the net difference in cost between an induced delivery and expectant management.

LIMITATIONS

The primary literature on the diagnostic effectiveness of ultrasound in late pregnancy is weak. Value-of-information analysis may have underestimated the uncertainty in the literature as it was focused on the internal validity of parameters, which is quantified, whereas the greatest uncertainty may be in the external validity to the research question, which is unquantified.

CONCLUSIONS

Universal screening for presentation at term may be justified on the basis of current knowledge. The current literature does not support universal ultrasonic screening for fetal growth disorders.

FUTURE WORK

We describe proof-of-principle randomised controlled trials that could better inform the case for screening using ultrasound in late pregnancy.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42017064093.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 15. See the NIHR Journals Library website for further project information.

Universal third-trimester ultrasonic screening using fetal macrosomia in the prediction of adverse perinatal outcome: A systematic review and meta-analysis of diagnostic test accuracy

BACKGROUND

The effectiveness of screening for macrosomia is not well established. One of the critical elements of an effective screening program is the diagnostic accuracy of a test at predicting the condition. The objective of this study is to investigate the diagnostic effectiveness of universal ultrasonic fetal biometry in predicting the delivery of a macrosomic infant, shoulder dystocia, and associated neonatal morbidity in low- and mixed-risk populations.

METHODS AND FINDINGS

We conducted a predefined literature search in Medline, Excerpta Medica database (EMBASE), the Cochrane library and ClinicalTrials.gov from inception to May 2020. No language restrictions were applied. We included studies where the ultrasound was performed as part of universal screening and those that included low- and mixed-risk pregnancies and excluded studies confined to high risk pregnancies. We used the estimated fetal weight (EFW) (multiple formulas and thresholds) and the abdominal circumference (AC) to define suspected large for gestational age (LGA). Adverse perinatal outcomes included macrosomia (multiple thresholds), shoulder dystocia, and other markers of neonatal morbidity. The risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. Meta-analysis was carried out using the hierarchical summary receiver operating characteristic (ROC) and the bivariate logit-normal (Reitsma) models. We identified 41 studies that met our inclusion criteria involving 112,034 patients in total. These included 11 prospective cohort studies (N = 9986), one randomized controlled trial (RCT) (N = 367), and 29 retrospective cohort studies (N = 101,681). The quality of the studies was variable, and only three studies blinded the ultrasound findings to the clinicians. Both EFW >4,000 g (or 90th centile for the gestational age) and AC >36 cm (or 90th centile) had >50% sensitivity for predicting macrosomia (birthweight above 4,000 g or 90th centile) at birth with positive likelihood ratios (LRs) of 8.74 (95% confidence interval [CI] 6.84-11.17) and 7.56 (95% CI 5.85-9.77), respectively. There was significant heterogeneity at predicting macrosomia, which could reflect the different study designs, the characteristics of the included populations, and differences in the formulas used. An EFW >4,000 g (or 90th centile) had 22% sensitivity at predicting shoulder dystocia with a positive likelihood ratio of 2.12 (95% CI 1.34-3.35). There was insufficient data to analyze other markers of neonatal morbidity.

CONCLUSIONS

In this study, we found that suspected LGA is strongly predictive of the risk of delivering a large infant in low- and mixed-risk populations. However, it is only weakly (albeit statistically significantly) predictive of the risk of shoulder dystocia. There was insufficient data to analyze other markers of neonatal morbidity.

Correlations between the Status of the Umbilical Cord and Neonatal Health Status

Purpose: This study aimed to identify correlations between the status of the umbilical cord and neonatal health status.Methods: In total, 172 newborns were enrolled who were admitted to the newborn nursery with a gestational age of 35 weeks or older and a body weight of 2 kg or above. Data were collected on the basic personal information of the newborns, the diameter and soft tissue status of the umbilical cord, and neonatal health status after birth. Analyses were performed using t-test, analysis of variance, <i>x</i>² test, and Fisher exact test.Results: Umbilical cord diameter exhibited a statistically significant difference by sex (t=2.71, <i>p</i>=.007). A thin umbilical cord diameter was associated with a 1-minute Apgar score less than 8 points (t=2.47, <i>p</i>=.015) and with being transferred to the intensive care unit (t=2.45, p=.015). Poor soft tissue status of the umbilical cord was associated with a 1-minute Apgar score of less than 8 points (<i>x</i>²=16.68, <i>p</i><.001) and with oxygen being supplied (<i>x</i>²=4.81, <i>p</i>=.028).Conclusion: Assessing the umbilical cord diameter and status in newborns is an important tool for evaluating neonatal health status after birth, and this point also underscores the importance of professionals' careful observations in the newborn nursery.

Pregestational diabetes in pregnancy: Complications, management, surveillance, and mechanisms of disease-A review

Diabetes is an increasingly common diagnosis among pregnant women. Pregestational diabetes is associated with an increase in many adverse pregnancy outcomes, which impact both on the woman and her fetus. The models of pregnancy care for women with diabetes are based largely on observational data or consensus opinion. Strategies for aneuploidy screening and monitoring for fetal well-being should be modified in women with diabetes. There is an increasing understanding of the mechanisms by which congenital anomalies and disorders of fetal growth occur, involving epigenetic modifications, changes in gene expression in critical developmental pathways, and oxidative stress. This knowledge may lead to pathways for improved care for these high-risk pregnancies.

Umbilical Cord Diameter at Early Second Trimester: Relation to Trisomy 21

Background:

To compare the umbilical cord diameter (UCD) at early second trimester (at 17–19 weeks of gestation) in trisomy 21 and normal fetuses and determined value of measuring UCD in screening trisomy 21.

Methods:

This was a case–control study. The UCD was measured in 39 fetuses with trisomy 21 (documented by chorionic villus sampling or amniocentesis) and 39 fetuses in control group at 17–19 weeks of gestation. The control groups were low-risk fetuses for aneuploidy in routine screening and were shown not to have aneuploidy after birth.

Results:

Mean of UCD in fetuses with trisomy 21 was lower than normal fetuses, but there were no significant differences between them (7.48 ± 0.99 mm vs. 7.66 ± 0.91 mm; P = 0.41). Mean of UCD had no significant difference between other maternal variable, for example, body mass index and obstetric history. Mean of UCD among mothers who had previous cesarean section was significantly lower than without it (7.21 ± 0.97 vs. 7.71 ± 0.97; P = 0.03).

Conclusions:

At 17–19 weeks of gestation, the UCD of fetuses with trisomy 21 is thinner than normal, but the importance of this difference is too small for using this measurement in screening.

Sonographic Estimation of Umbilical Cord Cross-section Area and its Reference Value in Normal Pregnancy

INTRODUCTION

The routine antenatal sonographic investigations of the umbilical cord are limited for assessment of number of umbilical vessels and doppler evaluation of umbilical blood flow. With the advancements of the sonographic techniques it is now possible to have more detailed evaluation of umbilical cord. There exist only few literatures on assessment of umbilical cord cross-sectional area during pregnancy to provide a baseline reference value.

AIM

To establish the reference intervals of cross-sectional area of the umbilical cord during gestation and to find the correlation of umbilical cord cross-sectional area with the foetal anthropometric measurements.

MATERIALS AND METHODS

This study was conducted among 214 normal pregnant women who underwent a routine antenatal sonogram during gestational age ranging from 24-39 weeks in the Department of Radiodiagnosis. The umbilical cord cross-sectional area was calculated at a plane immediately close to the umbilical cord insertion to the foetal abdomen. The following foetal parameters were studied: Biparietal Diameters (BPD), Head Circumference (HC), Abdominal Circumference (AC), Femur Length (FL), and Estimated Foetal weight (EFW). The relationship between foetal anthropometric measurements and umbilical cord cross sectional area was assessed using spearman rank correlation. The 5^th, 10^th, 50^th, 90^th and 95^th percentiles of umbilical cord cross-sectional area were calculated for each gestational groups using polynomial regression analysis.

RESULTS

A statistically significant correlation was observed between cross-sectional area of umbilical cord with both gestational age and foetal anthropometric parameters. The mean age of study population was 25.08±3.5 years and the mean gestational age was 34.42±2.5 weeks. We observed a strong correlation between head circumference and umbilical cord cross-sectional area.

CONCLUSION

The mean umbilical cord cross-section area increases steadily with gestational age for up to 34 weeks and then it declines. Umbilical cord cross-sectional area can be easily measured and hence it can be included in routine antenatal sonographic evaluations to predict the perinatal outcome. Careful monitoring of the pregnancy is needed in case of abnormal cross-sectional area measurements.

Does fetal macrosomia affect umbilical artery Doppler velocity waveforms in pregnancies complicated by gestational diabetes?

OBJECTIVES

We aimed to establish whether macrosomic fetuses in pregnancies complicated by gestational diabetes (GDM) show different Pulsatility Index (PI) values in umbilical artery (UA) than in non-macrosomic fetuses.

METHODS

We considered 106 pregnant women with GDM. Doppler recordings of UA-PI were performed at 34-41 weeks and related to neonatal birthweight. Pregnancies were divided in two groups according to birthweight, macrosomic group (>4000 g) and controls (<4000 g), and according to birthweight centile, >90th centile and <90th centile. Differences in UA-PI and maternal and fetal characteristics between groups were tested.

RESULTS

Mean UA-PI was significantly lower in newborns with birthweight >4000 g than in controls (PI = 0.69; 95% CI 0.64-0.74 versus PI = 0.87; 95% CI 0.84-0.90, p < 000.1). Mean UA-PI was significantly lower in newborns with birthweight centile >90th centile than in controls (PI = 0.79; 95% CI 0.74-0.84 versus PI = 0.87; 95% CI 0.83-0.90; t = 2.653; p = 0.01). Linear regression analysis revealed a significant correlation between UA-PI and neonatal birthweight and between UA-PI and neonatal birthweight centile.

CONCLUSIONS

Macrosomic fetuses of pregnancies complicated by GDM show lower values of UA-PI compared with controls. Despite UA-PI results, a variable related to macrosomia its role in the management of these pregnancies remains to be established.

Sampling and Definitions of Placental Lesions: Amsterdam Placental Workshop Group Consensus Statement

CONTEXT

-The value of placental examination in investigations of adverse pregnancy outcomes may be compromised by sampling and definition differences between laboratories.

OBJECTIVE

-To establish an agreed-upon protocol for sampling the placenta, and for diagnostic criteria for placental lesions. Recommendations would cover reporting placentas in tertiary centers as well as in community hospitals and district general hospitals, and are also relevant to the scientific research community.

DATA SOURCES

-Areas of controversy or uncertainty were explored prior to a 1-day meeting where placental and perinatal pathologists, and maternal-fetal medicine specialists discussed available evidence and subsequently reached consensus where possible.

CONCLUSIONS

-The group agreed on sets of uniform sampling criteria, placental gross descriptors, pathologic terminologies, and diagnostic criteria. The terminology and microscopic descriptions for maternal vascular malperfusion, fetal vascular malperfusion, delayed villous maturation, patterns of ascending intrauterine infection, and villitis of unknown etiology were agreed upon. Topics requiring further discussion were highlighted. Ongoing developments in our understanding of the pathology of the placenta, scientific bases of the maternofetoplacental triad, and evolution of the clinical significance of defined lesions may necessitate further refinements of these consensus guidelines. The proposed structure will assist in international comparability of clinicopathologic and scientific studies and assist in refining the significance of lesions associated with adverse pregnancy and later health outcomes.

Large-for-Gestational-Age Ultrasound Diagnosis and Risk for Cesarean Delivery in Women With Gestational Diabetes Mellitus

OBJECTIVE

To assess the accuracy of a large-for-gestational-age (LGA) ultrasound diagnosis and the subsequent risk for cesarean delivery associated with ultrasound diagnosis of LGA among women with gestational diabetes mellitus.

METHODS

This was a retrospective cohort study of 903 women with GDM who delivered after 36 weeks of gestation with an ultrasound-estimated fetal weight within 31 days of delivery. Delivery outcomes were compared between women with an ultrasound diagnosis of LGA and a non-LGA ultrasound diagnosis.

RESULTS

Based on ultrasound assessments, we identified 248 women with an LGA fetus and 655 women with a non-LGA fetus. Among women with an LGA ultrasound diagnosis, 56 of 248 (22.6%) delivered an LGA neonate, whereas, of women with a non-LGA ultrasound diagnosis, 18 of 655 (2.8%) delivered an LGA neonate. Ultrasound diagnosis of LGA was associated with increased risk for cesarean delivery (adjusted odds ratio [OR] 3.13, 95% confidence interval [CI] 2.10-4.67, P<.001) after adjusting for relevant covariates. Stratified analyses demonstrated that ultrasound diagnosis of LGA was associated with an increased risk for cesarean delivery whether the birth weight was between 2,500 and 3,499 g (OR 2.82, 95% CI 1.62-4.84, P<.001) or between 3,500 and 4,500 g (OR 3.47, 95% CI 2.06-5.88, P<.001).

CONCLUSION

Ultrasonography significantly overestimates the prevalence of LGA in women with gestational diabetes mellitus, and an ultrasound diagnosis of LGA is associated with an increased risk for cesarean delivery independent of birth weight.

LEVEL OF EVIDENCE

II.

How does tobacco smoke influence the morphometry of the fetus and the umbilical cord?-Research on pregnant women with intrauterine growth restriction exposed to tobacco smoke

Proper structure of the umbilical cord is important for the fetal development. We evaluated effects of toxic factors from tobacco smoke on fetal and umbilical cord morphometry. 109 women in weeks 29-40 of pregnancy (31 smokers with intrauterine growth restriction (IUGR); 28 non-smoking women with IUGR; 50 healthy pregnancies) were included. In smokers with IUGR, cotinine, cadmium and lead concentrations were significantly higher than in controls (mean 55.23ng/l; 1.52ng/ml; 14.85ng/ml vs 1.07; 0.34; 9.42) and inverse correlation between lead concentration and uncoiled umbilical cord was significant (r=-0.80). In smokers with IUGR, area of Wharton's jelly was increased compared to nonsmokers and controls. Inverse correlations occurred between cotinine and cadmium concentration and fetal percentile in smokers (r=-0.87; r=-0.87) and non-smokers (r=-0.47; r=-0.78) with IUGR. Exposure to tobacco smoke measured by cotinine, cadmium and lead concentration has an impact on fetal growth and umbilical cord morphometry and correlates with intensity of IUGR.

Maternal diabetes induces changes in the umbilical cord gene expression

INTRODUCTION

Since maternal diabetes may affect fetal development and the umbilical cord provides an extension of the fetal vasculature, we decided to investigate cords' biological responses to maternal diabetic milieu.

METHODS

Using microarray analysis, we determined the gene expression profiles in the umbilical cords of six neonates born to type 1 diabetic mothers and in six control cords. Umbilical cord tissue was collected immediately after elective cesarean section. Expression data were confirmed by real-time polymerase chain reaction (11 genes). Additionally, the same umbilical cords were analyzed histologically.

RESULTS

Two hundred eighty six genes were differentially expressed in the umbilical cords from diabetic pregnancies compared to the controls (fold change ±1.5 and P < 0.01). Maternal diabetes had a major effect on the expression of genes involved in vascular development (Bone morphogenetic protein 4, Delta-like 1, and Notch homolog 4), vessel wall integrity (Collagen type VIII alpha 1, Myocyte enhancer factor 2C, and Matrix metalloproteinase 2), and vascular function (Natriuretic peptide precursor B, Endothelin 1, Endothelin receptor B, Cyclooxygenase 1, and Phosphodiesterase 5A). Maternal diabetes was associated with thicker umbilical vein intima-media layers and larger umbilical vein and artery intima-media areas compared to the controls.

DISCUSSION

Maternal diabetic environment seems to alter umbilical cord expression of genes involved in the regulation of vascular development and function with simultaneous umbilical vessel muscle layer thickening. These alterations suggest vascular phenotypic modifications, which in turn may lead to long-term vascular consequences in various tissues in infants of diabetic mothers.

Relationship between sonographic umbilical cord size and gestational age among pregnant women in Enugu, Nigeria

BACKGROUND

Common fetal parameters for gestational age (GA) estimation have pitfalls especially in advanced pregnancy and pregnancy complicated by fetal structural anomaly.

OBJECTIVE

To assess the relationship between umbilical cord size and gestational age of the fetus.

SUBJECTS AND METHODS

A sonographic cross sectional study involving 300 pregnant women with GA between 14 weeks to 40 weeks was done in Enugu, Nigeria. Gestational ages were first estimated by use of Naegele's formula for GA estimation based on the date of onset of each subject's last menstrual period. Fetal parameters such as biparietal diameter, femur length, head circumference and abdominal circumference were measured and also used to estimate GA. Umbilical cord diameters were measured and used to compute the umbilical cord cross-sectional area.

RESULTS

The mean umbilical cord diameter and cross-sectional area were 14.5mm ± 7.2mm and 201.6mm ± 139.5mm(2) respectively. Umbilical cord growth rate of 1.0mm/week was noted between the 14(th) and 35(th) week of pregnancy. There were significant correlations (p < 0.001) between umbilical cord size and other fetal parameters for GA estimation.

CONCLUSION

Umbilical cord size had strong linear relationship with common fetal GA estimation parameters and could be used to compliment these parameters for GA estimation.

Sonographic measurement of the umbilical cord area and the diameters of its vessels during pregnancy

The objective was to determine the cross-sectional area of the umbilical cord, its diameter and the diameter of its vessels to establish a reference curve for these parameters during pregnancy, through a prospective cross-sectional study, including 2,310 low-risk pregnancies between 12 and 40 weeks' gestation. Means and standard deviations (SDs), plus the 10th, 50th and 90th percentiles for each measurement were calculated using polynomial regression analysis. Mann-Whitney, Kruskal-Wallis and Wilcoxon tests were used for statistical analysis. These parameters increased significantly with gestational age. The area of the cord also varied significantly with parity. Their new reference curves for low risk pregnancies were calculated using polynomial regression, and an almost linear increase in values was found up to 32 weeks of pregnancy, tending to stabilise from then onwards. The regression equation of the umbilical cord area according to gestational age (GA) was: -1.417 + 0.3026*GA-0.008*GA(2) + 0.000007*GA(3) and the degree of adjustment (R(2)) was 0.89.

Sonographic Assessment of the Umbilical Cord

The umbilical cord is not an inert structure, suspended between the fetus and placenta, but it plays an active role and it is involved in several processes afflicting the feto-placental unit.

Its study has to be regarding not only its morphology and morphometry, and the impendance of blood flow by Doppler waveform analysis, but it includes also an analysis of the coiling type and the amount of the Wharton Jelly. The umbilical cord has been considered like an important and huge source of informations, useful to assess the well-being of the fetus and the outcome of pregnancy.

The standardization of ultrasound techniques is the first step to speak the same language and make the study of this structure a fundamental part of well-being fetus assessment.

This article is carefully focused on morphologic, morphometric and functional ultrasound examination of umbilical cord and suggests that any anomaly detected should provide an indication for an intense fetal follow-up, useful for early helpful therapy, preventing serious complication for the pregnancy.

How to cite this article

Di Naro E, Raio L, Cromi A Giocolano A. Sonographic Assessment of the Umbilical Cord. Donald School J Ultrasound Obstet Gynecol 2012;6(1):66-75.

The role of umbilical cord thickness and HbA1c levels for the prediction of fetal macrosomia in patients with gestational diabetes mellitus

OBJECTIVE

The aim of this study was to investigate the effects of HbA1c levels and umbilical cord thickness upon birth weight, particularly in pregestational and gestational diabetic patients.

METHOD

Pregnant women were included in the study and were divided into two groups. The first group consisted of patients who were diagnosed with pregestational or gestational diabetes mellitus. The control group consisted of pregnant women who were not diagnosed with pregestational or gestational diabetes mellitus. Ultrasound examination was performed twice. Examinations were performed at 27-28 weeks and 36-37 weeks of gestation, respectively. During ultrasound examinations, fetal anthropometric parameters, biparietal diameter, abdominal circumference, femur length and estimated fetal weight (which was calculated automatically according to Hadlock's formula) were measured. Additionally, the sonographic cross-sectional areas of the umbilical cord, the umbilical arteries and the umbilical vein were measured in a free loop of the umbilical cord, using the software of the ultrasound machine. The cross-sectional area of Wharton's jelly was computed by subtracting the cross-sectional area of the vessels from that of the umbilical cord. HbA1c levels were measured for diabetic patients.

RESULTS

At 27-28 gestational weeks, umbilical cord area and Wharton's jelly values were found to be statistically different in macrosomic fetuses compared with non-macrosomic fetuses for both groups (for cord area, P = 0.012; for Wharton's jelly, P = 0.001). Additionally, umbilical cord diameter vein and artery values were not statistically different between the two groups when macrosomic fetuses were compared with non-macrosomic fetuses. At 36-37 gestational weeks, when the relationship between umbilical cord components and birth weight was examined, there was a statistically significant difference when comparing macrosomic fetuses with non-macrosomic fetuses. There was a statistically significant correlation between umbilical cord area, umbilical cord diameter and fetal weight estimation at 36-37 gestational weeks. HbA1c values and fetal macrosomia did not show a statistically significant relationship (P = 0.701).

CONCLUSION

A significant relationship between umbilical cord components and birth weight was not specific for the diabetic group. There was a significant relationship between birth weight and umbilical cord components for the control group as well. If the estimated fetal weight is combined with umbilical cord components, macrosomic fetuses can be predicted with more accuracy.

Sonographic evaluation and the pregnancy complicated by diabetes

Sonography is a fundamental tool in the management of pregnancies affected by maternal diabetes. Purposeful use of ultrasound in each trimester provides an invaluable amount of information about the developing fetus including gestational age and growth patterns, anatomical structure and function, assessment of fetal well-being, and prediction of adverse outcome. There are great ongoing research efforts in this field of prenatal diagnosis and management, yet even more are needed.

Use of ultrasound in the labor and delivery

Ultrasound machines are nowadays part of the armamentarium of all modern Labor and Delivery Suites. Due to their portability, these machines are ideal for use in emergencies which can occur at any of the labor and delivery rooms. Many of the emergencies in Labor and Delivery can be life threatening; thus, maternal and fetal safety requires efficient and timely ultrasound evaluation. The purpose of this article is to provide guidelines for quick and efficient use of ultrasound based on both the authors' experience and the published literature.

Sonographic prediction of macrosomia cannot be improved by combination with pregnancy-specific characteristics

OBJECTIVE

To evaluate the predictive value of a combination of sonographic, clinical and demographic data for detecting fetal macrosomia compared to ultrasound fetal weight estimation alone.

METHODS

Retrospective cohort data were obtained from 1062 pregnancies in an unselected population. Estimated fetal sonographic weight was obtained within the last week prior to delivery. Two different combination models-published by Mazouni et al. and Nahum and Stanislaw-were employed to predict the presence of macrosomia at birth in these infants. Receiver-operating characteristics (ROC) curves were generated to compare the prediction of macrosomia when using different observation methods and sensitivity, specificity, positive predictive value, negative predictive value (NPV) and accuracy were calculated.

RESULTS

Macrosomia (birth weight >or= 4000 g) was present in 135/1062 (12.7%) newborns. ROC curve analysis revealed the prediction of macrosomia using ultrasound alone to be significantly superior to the combined method of Mazouni et al. (area under the curve (AUC) 0.922, 95% CI 0.902-0.943 vs. 0.747, 95% CI 0.700-0.794, respectively; P < 0.0005), whereas the performance of the Nahum and Stanislaw equation was similar but not superior to ultrasound alone (AUC 0.895, 95% CI 0.839-0.950 vs. 0.912, 95% CI 0.867-0.958, respectively; P > 0.05). The accuracy of macrosomia prediction was similar for ultrasound alone and the Nahum and Stanislaw equation (approximately 90%), whereas the nomogram of Mazouni et al. reached only 51.7% accuracy (using a probability cut-off level of 50%). The NPV was found to be over 90% for all methods.

CONCLUSIONS

Combination of sonographic estimates with clinical and demographic variables does not improve the prediction of macrosomia at delivery in comparison with a routine ultrasound scan within a week before delivery, at least in unselected populations.