Role of first-trimester umbilical vein blood flow in predicting large-for-gestational age at birth

Placental size and umbilical vein volume blood flow

INTRODUCTION

The fetus receives oxygen and nutrition from the placenta through the umbilical vein. There is a large variation in placental size and placental size relative to fetal size (placental-fetal ratio). We studied whether placental size or placental-fetal ratio is related to blood flow in the umbilical vein.

MATERIAL AND METHODS

We performed a prospective study at Akershus University Hospital in Norway and a total of 73 women were examined in gestational weeks 27 and 37. Fifty-six women were examined at both time points. B-mode ultrasound and Doppler ultrasonography were used to measure the umbilical vein volume blood flow per minute. Magnetic resonance imaging was used to measure placental and fetal volume. Pearson's and Spearman's correlation coefficients were applied for estimations of associations.

RESULTS

In gestational week 27, the umbilical vein volume blood flow was positively correlated with fetal size (Pearson's correlation coefficient r = 0.372, p = 0.003, and Spearman's correlation coefficient r = 0.384, p = 0.002), but not with placental size (Pearson's r = 0.130, p = 0.317, and Spearman's r = - 0.53, p = 0.687) or placental-fetal ratio (Pearson's r = - 0.61, p = 0.641, and Spearman's r = - 0.218, p = 0.092). In gestational week 37, we found positive correlations of the umbilical vein volume blood flow with fetal size (Pearson's r = 0.428, p = <0.001, and Spearman's r = 0.391, p <0.001), placental size (Pearson's r = 0.400, p = 0.001, and Spearman's r = 0.643, p <0.001), and with placental-fetal ratio (Pearson's r = 0.224, p = 0.066, and Spearman's r = 0.266, p = 0.028).

CONCLUSIONS

A large placenta and a high placental-fetal ratio are associated with increased umbilical vein blood flow.

Umbilical Venous Flow Volume and Fetal Combined Cardiac Output in Twin Pregnancies

This study aimed to establish normal reference ranges of combined cardiac output (CCO) and umbilical venous flow volume (UVFV) in twin fetuses at 20 to 28 weeks of gestation and to evaluate the differences between monochorionic and dichorionic twins. CCO and UVFV were prospectively measured by ultrasound at two centers. The following exclusion criteria were applied: age <18 years or >45 years, first hospital visit at >16 weeks of gestation, monochorionic monoamniotic twin pregnancy, fetal structural or chromosomal abnormality, fetal growth restriction, twin-twin transfusion syndrome, twin anemia polycythemia sequence, and severe hypertension or renal disease were excluded. The period was divided into three groups: 20-22 weeks of gestation, 23-25 weeks of gestation, and 26-28 weeks of gestation. The CCO and UVFV were measured at least once during each period. CCO and UVFV were collected from 274 and 269 fetuses and were measured 412 and 424 times, respectively. UVFV and CCO levels increased as gestation progressed. The weight-corrected UVFV (UVFV/kg) and CCO (CCO/kg) remained stable. UVFV and CCO did not differ between monochorionic and dichorionic twin fetuses. The mean ± SD of UVFV/kg and CCO/kg were determined as 127.8 ± 31.8 and 439.4 ± 80.1 mL/kg/min, respectively. The UVFV-to-CCO ratio also remained stable from 20 to 28 weeks of gestation, ranging from 27.7% to 31.8%. The values and ranges of UVFV/kg and mean CCO/kg in twins were similar to those in singletons.

Multivariable prediction models for fetal macrosomia and large for gestational age: A systematic review

BACKGROUND

The identification of large for gestational age (LGA) and macrosomic fetuses is essential for counselling and managing these pregnancies.

OBJECTIVES

To systematically review the literature for multivariable prediction models for LGA and macrosomia, assessing the performance, quality and applicability of the included model in clinical practice.

SEARCH STRATEGY

MEDLINE, EMBASE and Cochrane Library were searched until June 2022.

SELECTION CRITERIA

We included observational and experimental studies reporting the development and/or validation of any multivariable prediction model for fetal macrosomia and/or LGA. We excluded studies that used a single variable or did not evaluate model performance.

DATA COLLECTION AND ANALYSIS

Data were extracted using the Checklist for critical appraisal and data extraction for systematic reviews of prediction modelling studies checklist. The model performance measures discrimination, calibration and validation were extracted. The quality and completion of reporting within each study was assessed by its adherence to the TRIPOD (Transparent Reporting of a multivariable prediction model for Individual Prognosis Or Diagnosis) checklist. The risk of bias and applicability were measured using PROBAST (Prediction model Risk Of Bias Assessment Tool).

MAIN RESULTS

A total of 8442 citations were identified, with 58 included in the analysis: 32/58 (55.2%) developed, 21/58 (36.2%) developed and internally validated and 2/58 (3.4%) developed and externally validated a model. Only three studies externally validated pre-existing models. Macrosomia and LGA were differentially defined by many studies. In total, 111 multivariable prediction models were developed using 112 different variables. Model discrimination was wide ranging area under the receiver operating characteristics curve (AUROC 0.56-0.96) and few studies reported calibration (11/58, 19.0%). Only 5/58 (8.6%) studies had a low risk of bias.

CONCLUSIONS

There are currently no multivariable prediction models for macrosomia/LGA that are ready for clinical implementation.

Available evidence on fetal liver changes detected by ultrasound in pregnant women with gestational diabetes mellitus: Systematic review

The aim of this systematic review was to examine the available scientific literature on ultrasound-detected fetal liver changes in pregnant women with gestational diabetes mellitus (GDM) and to explore the potential of these markers to inform clinical management and improve outcomes. A total of four articles investigating fetal liver changes in GDM pregnancies were selected. The studies varied in methodology, gestational age studied, and diagnostic criteria for GDM. Fetal liver indices, such as fetal liver length and fetal liver volume, emerged as potential markers for identifying GDM and predicting adverse outcomes. Studies suggest an association between fetal liver changes and GDM, with implications for both maternal glycemic control and fetal metabolic adaptation. Variability in study methodology highlights the need for standardized approaches to assess fetal hepatic indices and their correlation with GDM outcomes.

The role of microRNAs in pregnancies complicated by maternal diabetes

With the global prevalence of diabetes increasing, more people of reproductive age are experiencing hyperglycaemic pregnancies. Maternal Type 1 (T1DM) or Type 2 (T2DM) diabetes mellitus, and gestational diabetes mellitus (GDM) are associated with maternal cardiovascular and metabolic complications. Pregnancies complicated by maternal diabetes also increase the risk of short- and long-term health complications for the offspring, including altered fetal growth and the onset of T2DM and cardiometabolic diseases throughout life. Despite advanced methods for improving maternal glucose control, the prevalence of adverse maternal and offspring outcomes associated with maternal diabetes remains high. The placenta is a key organ at the maternal-fetal interface that regulates fetal growth and development. In pregnancies complicated by maternal diabetes, altered placental development and function has been linked to adverse outcomes in both mother and fetus. Emerging evidence suggests that microRNAs (miRNAs) are key molecules involved in mediating these changes. In this review, we describe the role of miRNAs in normal pregnancy and discuss how miRNA dysregulation in the placenta and maternal circulation is associated with suboptimal placental development and pregnancy outcomes in individuals with maternal diabetes. We also discuss evidence demonstrating that miRNA dysregulation may affect the long-term health of mothers and their offspring. As such, miRNAs are potential candidates as biomarkers and therapeutic targets in diabetic pregnancies at risk of adverse outcomes.

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.

Effect of SARS-CoV-2 infection on fetal umbilical vein flow and cardiac function: a prospective study

OBJECTIVES

To explore whether severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can affect umbilical vein blood flow (UVBF) and fetal cardiac function.

METHODS

Prospective case-control study of consecutive pregnancies complicated by SARS-CoV-2 infection during the second half of pregnancy matched with unaffected women. Measurements of UVBF normalized for fetal abdominal circumference (UVBF/AC), atrial area (AA) and ventricular sphericity indices (SI) were compared between the two study groups. Chi-square and Mann-Whitney U tests were sued to analyze the data.

RESULTS

Fifty-four consecutive pregnancies complicated and 108 not complicated by SARS-CoV-2 infection were included. The median gestational age at infection was 30.2 (interquartile range [IQR] 26.2 34.1). General baseline and pregnancy characteristics were similar between pregnant women with compared to those without SARS-CoV-2 infection. There was no difference in UVBF/AC (study groups z value -0.11 vs. 0.14 control p 0.751) values between pregnancies complicated compared to those not complicated by SARS-CoV-2 infection. Likewise, there was no difference in the left and right AA (left 1.30 vs. 1.28 p=0.221 and right 1.33 vs. 1.31 p=0.324) and SI (left 1.75 vs. 1.77 p=0.208 and right 1.51 vs. 1.54 p=0.121) between the two groups.

CONCLUSIONS

SARS-CoV-2 infection does not affect UVBF and fetal cardiac function in uncomplicated pregnancies.

Prediction of Fetal Growth Restriction for Fetal Umbilical Arterial/Venous Blood Flow Index Evaluated by Ultrasonic Doppler under Intelligent Algorithm

The empirical wavelet transform (EWT) algorithm was applied in ultrasound to explore the predictive value for fetal growth restriction (FGR) in fetal arteriovenous indexes. 142 pregnant women who received prenatal ultrasonic examination and delivered were selected. They were classified into control group and FGR group. There were 102 patients with normal pregnancy in the control group, and 40 patients with delayed fetal growth in the FGR group. The extended triple collocation (ETC) algorithm was employed to divide the Fourier spectrum of signals adaptively, and the constructed small filter banks were classified into corresponding intervals. The instantaneous frequency was analyzed, and the arterial blood flow indexes of the two groups were compared. The results showed that the time-frequency analysis method under EWT had lower normalization error and higher accuracy. The inner diameter and cross-sectional area of FGR were remarkably smaller than those of the control group, and the differences were statistically significant (P < 0.05). There were no significant differences in mean blood flow and mean blood velocity between the control group and FGR group (P > 0.05). The arterial blood flow parameters of the systolic flow velocity (VS) and the diastolic flow velocity (VD) in the FGR group were notably lower than those in the control group, and the differences were significant (P < 0.05). In conclusion, the frequency principal component extracted by EWT algorithm was less disturbed by noise, which could accurately and effectively evaluate fetal arteriovenous blood flow indexes and predict FGR.

Macrosomia and fetal growth restriction: evidence for similar extrauterine metabolic risks but with differences in pathophysiology

PURPOSE

To investigate and compare the causes of macrosomia and FGR fetuses, their ultrasound characteristics and the importance of their similar metabolic profile in intrauterine and extrauterine life.

MATERIALS AND METHODS

We searched Pubmed/Google Scholar database up until 15 December 2020 using keywords. Out of the 70 matching results we selected 50 most representative and matching papers.

RESULTS

We found similar causes and metabolic profiles and in both conditions offspring are at increased risk of developing metabolic and cardiovascular diseases in the extrauterine life.

CONCLUSION

Despite similarities of the maternal factors and fetal metabolic profile it is still unknown which of them has worse metabolic status during intrauterine and extrauterine life.

The added value of umbilical vein flow in predicting fetal macrosomia at 36 weeks of gestation: A prospective cohort study

INTRODUCTION

Current models based on fetal biometry and maternal characteristics have a poor performance in predicting macrosomia. The primary aim of this study was to elucidate the diagnostic performance of fetal venous and arterial Dopplers in predicting macrosomia in the third trimester of pregnancy; the secondary aim was to build a multiparametric prediction model including pregnancy, ultrasound and Doppler characteristics able to predict macrosomia accurately.

MATERIAL AND METHODS

Prospective cohort study including 2156 singleton pregnancies scheduled for routine ultrasound assessment at 36 weeks of gestation. Fetal biometry, estimated fetal weight (EFW), pulsatility index of the uterine, umbilical, and middle cerebral arteries, cerebroplacental ratio and umbilical vein blood flow (UVBF) normalized for fetal abdominal circumference (UVBF/AC) were recorded. Primary outcome was the prediction of fetal macrosomia, defined as a birthweight >90th percentile; secondary outcome was the prediction of newborns >4000 g. Logistic regression and area under the curve (AUC) analyses were used to analyze the data.

RESULTS

Fetal macrosomia complicated 9.8% of pregnancies, and 7.7% of newborns had a birthweight >4000 g. At multivariate logistic regression analysis, maternal body mass index (adjusted odds ratio [aOR] 1.23), pregestational diabetes (aOR 1.83), a prior newborn with a birthweight >95th centile (aOR 1.49), EFW (aOR 2.23) and UVBF (aOR1.84) were independently associated with macrosomia, whereas gestational diabetes mellitus (P = .07) or any of the other Doppler parameters were not. EFW had an AUC of 0.750 and of 0.801 alone and in association with maternal characteristics for the prediction of macrosomia, respectively. The addition of UVBF to this model significantly improved the prediction of fetal macrosomia provided by maternal and ultrasound parameters with an AUC of 0.892 (De Long P = .044 and P = .0078, respectively). The predictive performance for birthweight >4000 g was similar and significantly improved when UVBF was included in the diagnostic algorithm.

CONCLUSIONS

Umbilical vein blood flow evaluation in the third trimester improves the diagnosis of fetal macrosomia. The optimal diagnostic performance for macrosomia is achieved by a multiparametric model including umbilical vein flow, maternal characteristics and EFW.

Fetal Growth Acceleration-Current Approach to the Big Baby Issue

Background and Objectives: Fetal overgrowth is related to many perinatal complications, including stillbirth, cesarean section, maternal and neonatal injuries, and shoulder dystocia. It is related to maternal diabetes, obesity, and gestational weight gain but also happens in low-risk pregnancies. There is ongoing discussion regarding definitions, methods of detection, and classification. The method used for detection is crucial as it draws a line between those at risk and low-risk popula-tions. Materials and Methods: For this narrative review, relevant evidence was identified through PubMed search with one of the general terms (macrosomia, large-for-gestational-age) combined with the outcome of interest. Results: This review summarizes evidence on the relation of fetal overgrowth with stillbirth, cesarean sections, shoulder dystocia, anal sphincter injury, and hem-orrhage. Customized growth charts help to detect mothers and fetuses at risk of those complica-tions. Relations between fetal overgrowth and diabetes, maternal weight, and gestational weight gain were investigated. Conclusions: a substantial proportion of complications are an effect of the fetus growing above its potential and should be recognized as a new dangerous condition of Fetal Growth Acceleration.

The Role of Maternal Weight in the Hierarchy of Macrosomia Predictors; Overall Effect of Analysis of Three Prediction Indicators

So far it has not been established which maternal features play the most important role in newborn macrosomia. The aim of this study is to provide assessment of a hierarchy of twenty six (26) maternal characteristics in macrosomia prediction. A Polish prospective cohort of women with singleton pregnancy (N = 912) which was recruited in the years 2015–2016 has been studied. Two analyses were performed: for probability of macrosomia > 4000 g (n = 97) (vs. 755 newborns 2500–4000 g); and for birthweight > 90th percentile (n = 99) (vs. 741 newborns 10–90th percentile). A multiple logistic regression was used (with 95% confidence intervals (CI)). A hierarchy of significance of potential predictors was established after summing up of three prediction indicators (NRI, IDI and AUC) calculated for the basic prediction model (maternal age + parity) extended with one (test) predictor. ‘Net reclassification improvement’ (NRI) focuses on the reclassification table describing the number of women in whom an upward or downward shift in the disease probability value occurred after a new factor had been added, including the results for healthy and ill women. ‘Integrated discrimination improvement’ (IDI) shows the difference between the value of mean change in predicted probability between the group of ill and healthy women when a new factor is added to the model. The area under curve (AUC) is a commonly used indicator. Results. The macrosomia risk was the highest for prior macrosomia (AOR = 7.53, 95%CI: 3.15–18.00, p < 0.001). A few maternal characteristics were associated with more than three times higher macrosomia odds ratios, e.g., maternal obesity and gestational age ≥ 38 weeks. A different hierarchy was shown by the prediction study. Compared to the basic prediction model (AUC = 0.564 (0.501–0.627), p = 0.04), AUC increased most when pre-pregnancy weight (kg) was added to the base model (AUC = 0.706 (0.649–0.764), p < 0.001). The values of IDI and NRI were also the highest for the model with maternal weight (IDI = 0.061 (0.039–0.083), p < 0.001), and (NRI = 0.538 (0.33–0.746), p < 0.001). Adding another factor to the base model was connected with significantly weaker prediction, e.g., for gestational age ≥ 38 weeks (AUC = 0.602 (0.543–0.662), p = 0.001), (IDI = 0.009 (0.004; 0.013), p < 0.001), and (NRI = 0.155 (0.073; 0.237), p < 0.001). After summing up the effects of NRI, IDI and AUC, the probability of macrosomia was most strongly improved (in order) by: pre-pregnancy weight, body mass index (BMI), excessive gestational weight gain (GWG) and BMI ≥ 25 kg/m². Maternal height, prior macrosomia, fetal sex-son, and gestational diabetes mellitus (GDM) occupied an intermediate place in the hierarchy. The main conclusions: newer prediction indicators showed that (among 26 features) excessive pre-pregnancy weight/BMI and excessive GWG played a much more important role in macrosomia prediction than other maternal characteristics. These indicators more strongly highlighted the differences between predictors than the results of commonly used odds ratios.

Fetal Cardiac Remodeling Is Affected by the Type of Embryo Transfer in Pregnancies Conceived by in vitro Fertilization: A Prospective Cohort Study

OBJECTIVE

Pregnancies conceived via intracytoplasmic sperm injection (ICSI) are associated with a higher risk of fetal cardiac remodeling. The aim of this study was to evaluate whether the type of embryo transfer may affect the magnitude of fetal cardiac remodeling in pregnancies conceived via ICSI.

METHODS

Prospective cross-sectional study including 212 pregnancies conceived by ICSI (111 with frozen and 101 with fresh embryos) and 120 spontaneously conceived gestations. All women underwent ultrasound biometric evaluation, Doppler, and echocardiographic assessment, including evaluation of left and right atrial areas and sphericity index (SI), at 20-24 weeks of gestation. The χ2 and Kruskal-Wallis H tests were used to analyze the data.

RESULTS

There was no difference in maternal characteristics, gestational age at ultrasound, Doppler, and fetal weight among the study groups. In pregnancies conceived by ICSI, left and right atrial areas were higher (p < 0.0001) and SI was lower (p < 0.0001) compared to spontaneously conceived pregnancies. Left (p = 0.004) and right (p = 0.023) atrial areas and left (p = 0.036) and right (p = 0.002) SIs were more affected in ICSI pregnancies conceived by fresh embryos.

CONCLUSION

The risk of fetal cardiac remodeling is higher in pregnancies conceived by ICSI and independent from fetal size and Doppler. The magnitude of these changes is affected by the type of ICSI technique and is higher in pregnancies conceived by fresh embryos.

Serum Microelements in Early Pregnancy and their Risk of Large-for-Gestational Age Birth Weight

Excessive birth weight has serious perinatal consequences, and it “programs” long-term health. Mother’s nutritional status can be an important element in fetal “programming”; microelements such as selenium (Se), zinc (Zn), copper (Cu), and iron (Fe) are involved in many metabolic processes. However, there are no studies assessing the relationship of the microelements in the peri-conceptual period with the risk of excessive birth weight. We performed a nested case control study of serum microelements’ levels in the 10–14th week of pregnancy and assessed the risk of large-for-gestational age (LGA) newborns using the data from a prospective cohort of pregnant women recruited in 2015–2016 in Poznań, Poland. Mothers delivering LGA newborns (n = 66) were examined with matched mothers delivering appropriate-for-gestational age (AGA) newborns (n = 264). Microelements’ levels were quantified using mass spectrometry. The odds ratios of LGA (and 95% confidence intervals) were calculated by multivariate logistic regression. In the whole group, women with the lowest quartile of Se had a 3 times higher LGA risk compared with women in the highest Se quartile (AOR = 3.00; p = 0.013). Importantly, the result was sustained in the subgroup of women with the normal pre-pregnancy BMI (AOR = 4.79; p = 0.033) and in women with a male fetus (AOR = 6.28; p = 0.004), but it was not sustained in women with a female fetus. There were no statistical associations between Zn, Cu, and Fe levels and LGA. Our study provides some preliminary evidence for the relationships between lower serum Se levels in early pregnancy and a higher risk of large-for-gestational age birth weight. Appropriate Se intake in the periconceptual period may be important for optimal fetal growth.