Fetal anterior abdominal wall thickness in diabetic pregnancy

Development of a semi-automated tool to measure fetal abdominal wall thickness during ultrasound at 20 weeks' gestation

OBJECTIVES

To develop a semi-automated tool for measuring fetal abdominal wall thickness (AWT). To validate the software using images captured by other centers and create a nomogram for fetal AWT between 18 and 20 weeks.

METHODS

A semiautomated tool that measured AWT was developed using images captured at the routine 20-week morphology scan. The software was developed using digital images captured routinely during scans of low-risk women. Inter- and intraobserver reliability was assessed between manual and semi-automated measures. The tool was validated using images acquired from other centers. Linear regression and quadratic polynomials were used to create a nomogram for AWT.

RESULTS

The semi-automated tool was able to measure AWT in all images. Interoperator reliability was 0.90 and 0.97 (P < 0.05) for manual and semi-automated methods, respectively. Measurement agreement varied between three operators from moderate to excellent (0.77, 0.87, 0.92), with overall agreement being good (0.85). The tool could be successfully applied to 89% of images from other centers. A nomogram was generated for AWT measurements of fetuses at 18-20 weeks in normal, low risk mothers.

CONCLUSION

Semi-automated measurement of AWT was feasible using images captured during the routine 20-week scan. This approach had lower inter- and intraobserver variability compared to manual measurement.

Fetal Growth and Adiposity of Infants Born Large for Gestational Age in Three Harmonized Randomized Trials

OBJECTIVE

 Infants born large for gestational age (LGA) are at an increased risk of short- and longer-term adverse outcomes. Understanding fetal growth and adiposity and their trajectories may help inform interventions to prevent birth of LGA infants. We aimed to compare fetal growth and adiposity measures of infants born LGA with those born not LGA, to determine whether the discrepancy at birth was primarily due to larger size throughout gestation, or instead to different trajectories of fetal growth.

STUDY DESIGN

 This was a secondary analysis of secondary outcomes of fetal growth and adiposity from three harmonized randomized trials-the LIMIT, GRoW, and Optimise randomized trials. These trials recruited women in early pregnancy, and a singleton gestation, from three major public metropolitan Adelaide maternity hospitals. Maternal body mass index (BMI) ranged from 18.5 to ≥40.0 kg/m2. Data were obtained from enrolled women who underwent research ultrasounds at 28 and 36 weeks' gestation. Outcome measures were ultrasound measures of fetal biometry and adiposity.

RESULTS

 Infants born LGA had larger fetal biometry measures, and higher growth trajectories, from 20 weeks' gestation. Fetal adiposity measures were consistently larger among infants born LGA and these differences increased over time. We did not find evidence that the differences in biometry and adiposity measurements varied according to maternal BMI.

CONCLUSION

 Infants born LGA had larger fetal biometry measures at all time points from 20 weeks' gestation, compared with infants born not LGA suggesting any interventions to prevent LGA likely need to commence earlier in pregnancy or prior to conception.

KEY POINTS

· Infants born LGA had larger fetal biometry measures from 20 weeks' gestation.. · Infants born LGA had larger fetal adiposity measures.. · Interventions to prevent LGA need to start earlier in pregnancy or prior to conception..

Diagnostic Accuracy of Fetal Anterior Abdominal Wall Thickness as an Early Sonographic Sign for Diagnosing Gestational Diabetes

Introduction  Traditionally, different fetal variable measurements are used in ultrasound to assess fetal growth. Ultrasound can detect abnormal fetal growth. Gestational diabetes mellitus (GDM) is linked to higher fetal obesity as early as 20 weeks of pregnancy. The amount of fetal adipose tissue may be measured by measuring the thickness of the anterior abdominal wall. Measuring the thickness of the fetus's anterior abdominal wall (AAWT) is a straightforward procedure that may be performed alongside standard abdominal circumference measurements. Objectives  To check the diagnostic accuracy of fetal AAWT as an early sonographic sign for diagnosing GDM, keeping oral glucose tolerance test as the gold standard. Study design  This research was conducted using a cross-sectional analysis. Study place and duration The study was conducted in the Radiology Department at Rawalpindi Medical University and Allied Hospitals from July 10, 2019 to January 9, 2020. Materials and methods  Women between the ages of 18 and 45 who had a family history of type 2 diabetes and were at risk for developing GDM were recruited. Exclusions were made for diabetic women, those carrying multiples, and those with autoimmune diseases. The AAWT measurement of the fetus, which included the skin and subcutaneous tissue, was acquired using the traditional anterior cranial view, 2-3 cm lateral to cord insertion. Pregnant patients at risk for GDM underwent screening using an oral glucose tolerance test. Those exhibiting any two abnormal values were diagnosed with GDM. Results  The overall sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of fetal AAWT as an early sonographic sign for diagnosing GDM, with the oral glucose tolerance test as the gold standard, were 93.14%, 82.65%, 84.82%, 92.05%, and 88.0%, respectively. Conclusion  The study concludes that the diagnostic accuracy of fetal AAWT as an early sonographic indicator for identifying gestational diabetes is notably high.

Mid-Trimester Fetal Anterior Abdominal Wall Subcutaneous Tissue Thickness: An Early Ultrasonographic Predictor of Gestational Diabetes Mellitus

Background This study aimed to determine whether mid-trimester fetal anterior abdominal wall subcutaneous tissue thickness (FASTT) is an early sonographic predictor of gestational diabetes mellitus (GDM), as well as to study its correlation with maternal glycemic values on GDM screening at 24-28 weeks. Methodology We conducted a prospective, case-control study. FASTT was assessed at anomaly scan in 896 uncomplicated singleton pregnancies. The 75-gram oral glucose tolerance test (OGTT) was done for all included patients at 24-28 weeks. Women diagnosed with GDM were taken as cases and appropriately matched in equal numbers as controls. Statistical analysis was done using SPSS version 20 (IBM Corp., Armonk, NY, USA). Independent-samples t-test, chi-square test, receiver operating characteristic curve, and Pearson's correlation coefficient (r) were performed wherever applicable. Results A total of 93 cases and 94 controls were included. Fetuses of women with GDM had significantly higher mean FASTT at 20 weeks (1.605 ± 0.328 mm vs. 1.222 ± 0.121 mm; p < 0.001). The FASTT cut-off obtained was 1.35 mm (sensitivity = 79.6%, specificity = 87.2%, positive predictive value = 86%, negative predictive value = 81.2%). There was a moderate positive correlation between fasting blood sugar (FBS) and two-hour OGTT values and FASTT (r = 0.332, p < 0.001 and r = 0.399, p < 0.001, respectively). FASTT >1.35 mm had an independent predictive value for GDM and was associated with a 19.608-fold increased risk of GDM. Conclusions FASTT values greater than 1.35 mm at 20 weeks are associated with a significantly increased risk of GDM. In addition, FASTT correlates with FBS and two-hour OGTT at 24-28 weeks and is a simple predictor of GDM at 18-20 weeks.

Correlation of Fetal Anterior Abdominal Wall Thickness and Other Standard Biometric Ultrasound Measurements to Predict Fetal Macrosomia in Gestational Diabetes

Background

Gestational diabetes mellitus (GDM) is one of the most common medical conditions affecting pregnancy and significantly increasing the risk for maternal and perinatal complications. The aim of the present study is to study the correlation of fetal anterior abdominal wall thickness (FAAWT) and other standard fetal biometric parameters measured by ultrasound between 36 and 39 weeks of gestation with neonatal birth weight in pregnancies complicated by GDM.

Methods

Prospective cohort study in a tertiary care center including 100 singleton pregnancies with GDM were subjected to ultrasound between 36 and 39 weeks of gestation. Standard fetal biometry (Biparietal diameter, Head Circumference, Abdominal circumference [AC], and Femur Length) and estimated fetal weight were calculated. FAAWT was measured at AC section and actual neonatal birth weights were recorded after delivery. Macrosomia was defined as an absolute birth weight more than 4000 g regardless of the gestational age. Statistical analysis was done and 95% confidence level was considered significant.

Results

Among 100 neonates, 16 were macrosomic (16%) and third trimester mean FAAWT was significantly higher in macrosomic babies (6.36 ± 0.5 mm) as compared to nonmacrosomic babies (5.54 ± 0.61 mm) (P < 0.0001). FAAWT >6 mm (Receiver operating characteristic curve derived) provided a sensitivity of 87.5%, specificity of 75%, positive predictive value of 40%, and negative predictive value (NPV) of 96.9% for prediction of macrosomia. While other standard fetal biometric parameters did not correlate well with actual birth weight in macrosomic neonates, only FAAWT was found to have statistically significant correlation (correlation coefficient of 0.626, P = 0.009).

Conclusion

The FAAWT was the only sonographic parameter to have a significant correlation with neonatal birth weight in macrosomic neonates of GDM mothers. We found a high sensitivity (87.5%), specificity (75%), and NPV (96.9%) suggesting that FAAWT < 6 mm can rule out macrosomia in pregnancies with GDM.

The Significance of Exposure to Pregestational Type 2 Diabetes in Utero on Fetal Renal Size and Subcutaneous Fat Thickness

Objectives. To determine the relationship between exposure to pregestational type 2 diabetes (T2D) and renal size and subcutaneous fat thickness in fetuses during routine obstetrical ultrasound. Methods. This was a case-control study (January 1, 2019 to December 31, 2019). Routine obstetrical ultrasounds performed between 18 and 22 weeks’ gestation at a tertiary-care fetal assessment unit were reviewed. “Cases” comprised ultrasounds of fetuses exposed to pregestational T2D in utero. The control group was assembled from ultrasounds of healthy controls. Postprocessing measurements of fetal renal size and abdominal wall thickness from stored images were performed by two independent observers, and findings were compared between groups. Results. There were 54 cases and 428 ultrasounds of healthy controls. The mean maternal age of cases was 32.1 years (SD 6.2) compared to 33.2 years (SD 5.3) for healthy controls, and the majority of ultrasounds were performed in multiparous patients (83%). At the 18 to 22 week ultrasound, there was a significant reduction in renal size amongst fetuses exposed to maternal T2D in utero compared to controls; among cases, the mean renal width was 8.0 mm (95% CI 7.8–8.1) compared to 11.4 mm (95% CI 10.6–12.7) in controls ( $p<0.0001$ ); the mean renal thickness among cases was 8.1 mm (95% CI 7.9–8.2) compared to 11.5 mm (95% CI 10.7–12.9) in controls ( $p=0.001$ ). There was no obvious difference in estimated fetal weight between groups, yet fetuses exposed to maternal T2D had increased subcutaneous abdominal wall fat thickness at this early gestational age ( $p=0.008$ ). Conclusions. Fetal renal size in cases exposed to pregestational T2D is significantly smaller compared to controls, and subcutaneous abdominal wall fat is significantly thicker. Given emerging evidence about the developmental origins of disease, further study is needed to correlate the association between fetal renal size and fat distribution in the fetus and the long-term risk of chronic renal disease and diabetes in these offspring.

Maternal diabetes independent of BMI is associated with altered accretion of adipose tissue in large for gestational age fetuses

Aim

To analyse the effects of maternal diabetes mellitus (DM) and body mass Index (BMI) on central and peripheral fat accretion of large for gestational age (LGA) offspring.

Methods

This retrospective study included LGA fetuses (n = 595) with ultrasound scans at early (19.23 ± 0.68 weeks), mid (28.98 ± 1.62 weeks) and late (36.20 ± 1.59 weeks) stages of adipogenesis and measured abdominal (AFT) and mid-thigh (TFT) fat as surrogates for central and peripheral adiposity. Women were categorised according to BMI and DM status [pre-gestational (P-DM; n = 59), insulin managed (I-GDM; n = 132) and diet managed gestational diabetes (D-GDM; n = 29)]. Analysis of variance and linear regressions were applied.

Results

AFT and TFT did not differ significantly between BMI categories (normal, overweight and obese). In contrast, AFT was significantly higher in pregnancies affected by D-GDM compared to non-DM pregnancies from mid stage (0.44 mm difference, p = 0.002) and for all DM categories in late stage of adipogenesis (≥ 0.49 mm difference, p < 0.008). Late stage TFT accretion was higher than controls for P-DM and I-GDM but not for D-GDM (0.67 mm difference, p < 0.001; 0.49 mm difference, p = 0.001, 0.56 mm difference, p = 0.22 respectively). In comparison to the early non-DM group with an AFT to TFT ratio of 1.07, the I-GDM group ratio was 1.25 (p < 0.001), which normalised by 28 weeks becoming similar to control ratios.

Conclusions

DM, independent of BMI, was associated with higher abdominal and mid-thigh fat accretion in fetuses. Use of insulin improved central to peripheral fat ratios in fetuses of GDM mothers.

Antenatal prediction of fetal macrosomia in pregnancies affected by maternal pre-gestational diabetes

AIMS

Higher rates of fetal macrosomia may occur in infants of women with pre-gestational diabetes compared with non-diabetic controls. Antenatal predication of fetal macrosomia remains challenging. Ultrasound over-estimated fetal weight could result in over-classification of fetuses as macrosomic with corresponding inappropriate clinical interventions. Previously we had studied a measurement - the anterior abdominal wall measurement (AAW) - to predict fetal macrosomia in fetal estimation of weight. The purpose of the study was to study whether specific third trimester ultrasound measurements with measures of glycaemic control (HbA1c) predicted macrosomia in babies born to women with pre-gestational diabetes. In particular, a new variant of this measurement (fetal anterior abdominal wall thickness (AAW), abdominal circumference (AC) ratio: AAW:AC) was investigated.

METHODS

This was a prospective cohort study in a tertiary referral maternity hospital. Serial growth scans including measurement of AAW and AC: AAW ratio was performed at 30, 33- and 36-weeks' gestation. Birth-weight data was collected, and macrosomia was defined as >90th centile based on gestational age and gender of the baby. Serial HbA1c as measured at the first antenatal visit, 14, 20- and 36-weeks' gestation were reported for this study.

RESULTS

Of the 416 pregnancies analyzed, mean maternal age was 33.3 years. One in five women were primigravida's. The mean birthweight was 3548 g (+/- 581 g), of which 142 (34%) babies were classified as macrosomic. The median gestational age at delivery was 38³ weeks (31⁴ - 40² weeks). There were 37 (9%) babies born preterm at <37 weeks' gestation. Mean AC measurements in fetuses that would be born with macrosomia compared with those with a non-macrosomic birth weight were 282 mm vs. 266 mm at 30 weeks, 318.3 mm vs. 297 mm at 33 weeks and 350 mm vs. 325 mm at 36 weeks' gestation (all p < .001). Mean AAW measurements in macrosomic fetuses compared with normal size fetuses were 3.7 mm vs. 3.3 mm at 30 weeks, 4.9 mm vs 4.3 mm at 33 weeks and 5.9 mm vs. 5.3 mm at 36 weeks' gestation (all p < .001). The mean AC: AAW was 0.01 for both normal and macrosomic fetuses at 30 weeks. There was no clinical or statistical difference in AC:AAW ratios between non-macrosomic and macrosomic infants. Binary logistic regression showed that AC at 36 weeks was most predictive of macrosomia (76.5%), followed by AAW at 30 weeks (68.5%). Using a combination of HbA1c booking, 14, 20, 36 weeks and AAW 30, 33, 36 weeks and AC 30, 33, 36 weeks predicted macrosomia in 80.9%. The ratio of AC: AAW did not act as a useful antenatal clinical predictor of macrosomia at birth.

CONCLUSIONS

Abdominal circumference at 36 weeks was the single best predictor of fetal macrosomia. A combined model of HbA1c, AC and AAW was the best antenatal predictor of macrosomia, with intriguing clinical possibilities in the possible prevention of maternal and fetal complications of macrosomia.

Fetal anterior abdominal wall thickness between gestational diabetes and normal pregnant women

OBJECTIVES

To compare fetal anterior abdominal wall thickness (AAWT) between women with and without GDM during third trimester and to determine accuracy of AAWT to predict large for gestational age (LGA) infants.

MATERIALS AND METHODS

A total of 250 pregnant women, including 125 women with GDM and 125 women without GDM, were enrolled. Tansabdominal ultrasonographic examinations were performed at 28-30, 32-34 and 36-38 weeks. In addition to standard fetal biometries, AAWT was measured. Patient characteristics and ultrasonographic measurements were compared between groups. Sensitivity and specificity of AAWT for identifying LGA were evaluated.

RESULTS

While standard fetal biometries were comparable, mean fetal AAWT in GDM women were significantly higher than those without GDM at 28-30 weeks (2.8 ± 0.8 vs. 2.6 ± 0.6, p = 0.006) and 32-34 weeks (4.0 ± 0.9 vs. 3.5 ± 0.8, p = 0.042). LGA infants had significantly higher fetal AAWT at each time point only in GDM women. Using cut off values of AAWT of ≥2.0, 3.0, and 4.0 mm at 28-30, 32-34, and 36-38 weeks, sensitivity for LGA diagnosis in GDM women were 94.4%, 93.9%, and 89.3%, respectively. The use of abdominal circumference (AC) at >90th percentile showed lower sensitivity but higher specificity, regardless of GDM status. Combination of both measurements increased sensitivity to approximately 90% or higher in every time point, especially among GDM women.

CONCLUSION

Significant increase in fetal AAWT was observed in GDM women at 28-30 and 32-34 weeks. Fetal AAWT significantly increased among LGA infants and had higher sensitivity than AC in identifying LGA during third trimester. In GDM women at 28-30 weeks, AAWT ≥2.0 mm and AC >90th percentile had 97.2% sensitivity for LGA diagnosis.

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.

The Relationship between Fetal Abdominal Wall Thickness and Intrapartum Complications amongst Mothers with Pregestational Type 2 Diabetes

OBJECTIVES

To evaluate the utility of fetal abdominal wall thickness (AWT) for predicting intrapartum complications amongst mothers with pregestational type 2 diabetes.

METHODS

This was a historical cohort study of pregnant mothers with pregestational type 2 diabetes delivering at a Canadian tertiary-care center between January 1, 2014, and December 31, 2018. Delivery records were reviewed to collect information about demographics and peripartum complications. Stored fetal ultrasound images from 36 weeks' gestation were reviewed to collect fetal biometry and postprocessing measurement of AWT performed in a standardized fashion by 2 blinded and independent observers. The relationship between fetal AWT was then correlated with risk of intrapartum complications including emergency Caesarean section (CS) and shoulder dystocia.

RESULTS

216 pregnant women with type 2 diabetes had planned vaginal deliveries and were eligible for inclusion. Mean maternal age was 31.3 years, and almost all were overweight or obese at the time of delivery (96.8%). Overall, the incidence of shoulder dystocia and emergency intrapartum CS was 7.4% and 17.6%, respectively. There was no difference in mean fetal AWT between those having a spontaneous vaginal delivery (8.2 mm (95% CI 7.9-8.5)) and those needing emergency intrapartum CS (8.1 mm (95% CI 7.4-8.8); p = 0.71) or shoulder dystocia (8.7 mm (95% CI 7.9-9.5); p = 0.23). There was strong interobserver correlation of AWT measurements (r = 0.838; p < 0.00001). The strongest association with intrapartum complications was birthweight (p = 0.003): with birthweight > 4000 grams, the relative risk of shoulder dystocia or CS is 2.75 (95% CI 1.74-4.36; p < 0.001).

CONCLUSIONS

There was no obvious benefit of AWT measurement at 36 weeks for predicting shoulder dystocia or intrapartum CS amongst women with type 2 diabetes in our population. The strongest predictor of intrapartum complications remained birthweight, and so studies for improving estimation of fetal weight and evaluating the role of intrapartum ultrasound for predicting risk of delivery complications are still needed.

The Relevance of Fetal Abdominal Subcutaneous Tissue Recording in Predicting Perinatal Outcome of GDM Pregnancies: A Retrospective Study

Guidelines on the management of gestational diabetes (GDM) instruct physicians to involve ultrasound-based monitoring of fetal growth in addition to blood glucose. So far, glucose control besides clinical parameters like maternal body mass index (BMI) and gestational weight gain have been shown to predict neonatal outcome. We aimed to evaluate the discriminative ability of fetal abdominal subcutaneous tissue (FAST) in addition to standard ultrasound parameters like abdominal circumference (AC) and estimated fetal weight (EFW) for perinatal complications like large for gestational age (LGA), hypoglycemia, hyperbilirubinemia, mode of delivery and admission to neonatal intensive care unit (NICU). Ultrasound data and neonatal outcome was collected of 805 GDM cases from 2012 to 2016: 3205 FAST, 3195 AC-measurements and 3190 EFW calculations were included. AC, EFW and FAST increased linear with gestational age. Combining ultrasound and clinical parameters improved predictive power for LGA. In the subgroup where fetuses grow with an AC > 75th additional adding of FAST to standard ultrasound parameters increased predictive power for hypoglycemia. Our results confirm inclusion of ultrasound parameters to be beneficial in monitoring GDM pregnancies. Additional FAST determination revealed to be of potential clinical relevance in the subgroup AC > 75th percentile.

Fetal front-abdominal wall thickness in the second trimester as a predictor of abnormal fetal growth

Objectives: Worldwide, approximately 9% of infants have a birth weight ≥4000 g, who are defined as fetal macrosomia, with wide variations between countries. Another form of abnormal fetal growth is fetal growth restriction. Infants with low birth weight (LBW) for their gestational age are primarily categorized as either small for gestational age (SGA) or fetal (intrauterine) growth restriction (FGR). All forms of abnormal fetal growth have high morbidity rates of neonatal. Therefore, diagnosis of abnormal fetal growth as early as possible is crucial for optimal clinical care. The measurement of fetal front-abdominal wall thickness (FAWT) is an easy examination. We conducted this study, wondering whether FAWT can predict birth weight or can determine LGA/macrosomia and/or LBW infants in advance.Methods: This longitudinal cohort study was done in a tertiary center between September 2016 and September 2019. In total, 768 pregnant women with who attended our clinic for oral glucose tolerance test (OGTT) screening between the 26th and 28th weeks of gestation were included in this study. A total of 768 patients were evaluated in the present study. However, 186 of them were excluded in the follow-up of the study because they met the exclusion criteria or they gave birth in another hospital. Eventually, 582 pregnant women were included, with 57 in the LBW group, 461 in the AGA group, and 64 in the LGA group. In addition, 55 fetuses in the LGA group were determined to be macrosomic (birth weight > 4000 g). The FAWT and classic fetal biometric measurements, such as BPD, AC, FL, and EFW, were compared between the AGA group and the macrosomic infants. Statistical analysis was performed to compare the AGA group and the macrosomic infants group. There were no macrosomic infants in the AGA group, so this was used as the control group.Results: There were no significant differences between the groups for maternal age, gravidity, parity, gestational age on the day of the examination, and gestational age at birth. The mean FAWT was significantly thinner in the SGA group than in the appropriate for gestational age (AGA) group (3.4 versus 3.9 mm, respectively, p < .001), while it was significantly thicker in the LGA group than in the AGA group (4.1 versus 3.9 mm, respectively, p < .001).Conclusion: FAWT measurement can provide more information and may be more sensitive toward fetal nutrition and growth than the AC value during the second trimester. Some benefits can be gained through the measurement of FAWT at the end of the second trimester. FAWT measurements can be used in obstetrical practice with a similar performance in predicting the LGA and macrosomic infant like AC and EFW.

The Accuracy of 22 Fetal Weight Estimation Formulas in Diabetic Pregnancies

PURPOSE

The objective of this study was to estimate the accuracy of 22 fetal weight estimation formulas in diabetic pregnancies uncomplicated and complicated by fetal macrosomia.

METHODS

Retrospectively collected data of 317 pregnancies complicated by gestational diabetes mellitus and 78 cases of fetal macrosomia were used in this study. Study inclusion criteria were women diagnosed with gestational diabetes mellitus, full-term singleton pregnancy, and an interval from the ultrasound to delivery of ≤7 days. The estimated fetal weight was calculated using 22 formulas. The mean absolute percentage error (MAPE) and two-way random interclass correlation coefficient were chosen for statistical analysis.

RESULTS

In the group of gestational diabetes, MAPE ranged from 8.43 ± 10.17 to 54.01 ± 9.50%. Most of the formulas showed a tendency to estimate a lower fetal weight in comparison to the actual birth weight. In the group of fetal macrosomia, the correlations were poor. Only three formulas reached the threshold of MAPE <10%.

CONCLUSIONS

The formula by Hsieh might be considered the best for fetal weight estimation in diabetic pregnancies. The combination of the best formulas might improve the accuracy of estimation. None of the formulas were accurate enough to predict fetal macrosomia.

Can fetal abdominal visceral adipose tissue and subcutaneous fat thickness be used for correct estimation of fetal weight? A preliminary study

The aim of this study was to assess the accuracy of a new formula for the calculation of an estimated fetal weight (EFW) and to evaluate value of fetal visceral adipose tissue (VAT) and abdominal subcutaneous fat (SF) thickness on the prediction of birth weight. In this prospective study, fetal biometry, EFW, fetal VAT and SF thickness were measured in low-risk 37-41 gestational weeks pregnant women by ultrasonography. The linear regression analysis was performed to investigate the relationship between birth weight and obstetric measurements. It was found that the most important factors in the prediction of a birth weight were the abdominal circumference (AC), SF and VAT. The new formula for EFW was EFW=-2748.622+13.811*AC+56.795*SF+17.913*VAT According to the Hadlock 3 and the new formula, 92% and 95% of all fetal weight estimations were within 10% of actual birth weight, respectively. Measurement of VAT and SF thickness in prediction of fetal weight could reduce a weight estimation error. Impact statement What is already known on this subject? An accurate prediction of fetal weight during gestation provides useful information for assessing the fetal and newborn health status. As the detection of growth abnormalities is vital, there is a need for a reliable method of assessing birth weight during labour. Unfortunately, although different methods are available, a simple, quick and reliable method of assessing birth weight is still in debate. Fetal visceral adipose (VAT) tissue measurement is a new method which could be used for the correct estimation of fetal weight. Like adults, the VAT and subcutaneous fat tissue (SF) thickness could be correlated with the weight and body-mass index. What do the results of this study add? It was found that SF and VAT are important factors in the prediction of birth weight, like the abdominal circumference (AC). What are the implications of these findings for clinical practice and/or further research? The measurement of VAT and SF thickness in prediction of fetal weight could reduce a weight estimation error.

Fetal growth trajectories and their association with maternal and child characteristics

Background: The growth of the fetus is a complex process, influenced by genetic and environmental factors. Longitudinal patterns of fetal growth are required to fully understand this process, however to date, a paucity of data exists in this area.Objective: To identify fetal growth trajectories in-utero and to assess their association with maternal and child characteristics up to 5 years postnatal.Methods: Data from 781 mother-child pairs from the ROLO longitudinal birth cohort study were analyzed. The ROLO study was a randomized control trial of a low glycemic index diet in pregnancy to prevent recurrence of macrosomia. Fetal ultrasound measurements were recorded at 20 and 34 weeks gestation, and birth weight was recorded. Abdominal circumference (AC), weight (fetal weight, or birth weight), a standardized proxy for length (femur length or birth length, individually standardized), and AC:length ratio were examined for trajectory classes using latent class trajectory mixture models. Two-, three-, four-, and five-class models were evaluated for fit, using a linear (first order) trajectory over three time-points. ANOVA and chi-square tests were applied to test associations between trajectory membership and maternal and child characteristics up to age 5.Results: For AC, two fetal growth trajectories were identified, with 29% of participants on a "slow" trajectory and 71% on a "fast" trajectory. Those on a fast trajectory had higher rates of maternal impaired glucose tolerance (28.7 versus 16.5%, p<.001) and higher rates of mean child 5-year body mass index (BMI) centiles (64th versus 58th centile, p<.05) compared to those on the slow trajectory. For estimated fetal weight, four trajectories were identified, with 4% on a "very-slow" trajectory, 63% in a "moderate-slow" trajectory, 30% in a "moderate-fast" trajectory and 3% on a "very-fast" trajectory. Mothers with a fetus on the fastest trajectory had higher antenatal serum glucose levels (p<.05), and were more likely to deliver by cesarean section (59.1 versus 20%, p<.001). At 5 years of age, children on the fastest growth trajectory had the highest mean BMI centile (86th versus 60th centile, p<.05).Conclusions: This study shows that specific fetal growth trajectories may be associated with maternal serum glucose concentrations during pregnancy, mode of delivery and child BMI at 5 years of age. Diet and lifestyle measures that target maternal glucose levels during pregnancy may have lifelong benefits for children's BMI. Identifying those on an accelerated growth trajectory during fetal life provides a unique opportunity for antenatal and infant interventions that may have long-lasting health benefits.

The mediating effects of gestational diabetes on fetal growth and adiposity in women who are overweight and obese: secondary analysis of the LIMIT randomised trial

OBJECTIVE

To describe the mediating effect of maternal gestational diabetes on fetal biometry and adiposity measures among overweight or obese pregnant women.

DESIGN

Secondary analysis of the LIMIT randomised trial.

SETTING

Public hospitals, metropolitan Adelaide, South Australia.

POPULATION

Pregnant women with body mass index (BMI) ≥25 kg/m² and singleton gestation.

METHODS

Fetal ultrasound measures at 36 weeks of gestation and baseline BMI from women randomised to the LIMIT trial Standard Care group (n = 912 women) were used to conduct causal mediation analyses using regression-based methods.

MAIN OUTCOMES MEASURES

Ultrasound measures of fetal biometry and adiposity at 36 weeks of gestation.

RESULTS

Increased maternal BMI was associated with increased measures of fetal head circumference [direct (unmediated) effect 0.18 (95% CI: 0.05-0.31), P = 0.005; total effect 0.17 (95% CI: 0.02-0.31), P = 0.018], abdominal circumference [direct effect 0.26 (95% CI: 0.11-0.41), P = 0.001; total effect 0.26 (95% CI: 0.11-0.42), P = 0.001] and estimated fetal weight [direct effect 0.22 (95% CI: 0.08-0.35), P = 0.002; total effect 0.22 (95% CI: 0.08-0.35), P = 0.002], with no evidence of mediation by treated gestational diabetes. There was no apparent association between maternal BMI and fetal adiposity measures, or mediation by treated gestational diabetes.

CONCLUSIONS

We show an important association between increased maternal BMI and fetal growth, not mediated by treated gestational diabetes. There was no association between increased maternal BMI and fetal adiposity measures, or mediation by treated gestational diabetes. Whether these findings represent 'saturation' in the effect of maternal BMI on fetal growth or the effect of treatment of GDM is unclear.

FUNDING

This project was funded by a 4-year project grant from the National Health and Medical Research Council (NHMRC), Australia (ID 519240); The Channel 7 Children's Research Foundation, South Australia; and the US National Institutes of Health (R01 HL094235-01).

TWEETABLE ABSTRACT

Increased fetal growth associated with maternal obesity is not mediated by gestational diabetes.

Antenatal dietary and lifestyle advice for women who are overweight or obese and the effect on fetal growth and adiposity: the LIMIT randomised trial

OBJECTIVE

To report the influence of maternal overweight and obesity on fetal growth and adiposity and effects of an antenatal dietary and lifestyle intervention among these women on measures of fetal growth and adiposity as secondary outcomes of the LIMIT Trial.

DESIGN

Randomised controlled trial.

SETTING

Public maternity hospitals in metropolitan Adelaide, South Australia.

POPULATION

Pregnant women with a body mass index ≥ 25 kg/m(2), and singleton gestation between 10(+0) and 20(+0) weeks.

METHODS

Women were randomised to Lifestyle Advice or continued Standard Care and offered two research ultrasound scans at 28 and 36 weeks of gestation.

MAIN OUTCOME MEASURES

Ultrasound measures of fetal growth and adiposity.

RESULTS

For each fetal body composition parameter, mean Z-scores were substantially higher when compared with population standards. Fetuses of women receiving Lifestyle Advice demonstrated significantly greater mean mid-thigh fat mass, when compared with fetuses of women receiving Standard Care (adjusted difference in means 0.17; 95% CI 0.02-0.32; P = 0.0245). While subscapular fat mass increased between 28 and 36 weeks of gestation in fetuses in both treatment groups, the rate of adipose tissue deposition slowed among fetuses of women receiving Lifestyle Advice, when compared with fetuses of women receiving Standard Care (P = 0.0160). No other significant differences were observed.

CONCLUSIONS

These findings provide the first evidence of changes to fetal growth following an antenatal dietary and lifestyle intervention among women who are overweight or obese.

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.

The Effects of Fetal Gender on Maternal and Fetal Insulin Resistance

OBJECTIVE

Gender plays a role in the development of a number of cardiovascular and metabolic diseases and it has been suggested that females may be more insulin resistant in utero. We sought to assess the relationship between infant gender and insulin resistance in a large pregnancy cohort.

STUDY DESIGN

This is a secondary analysis of a cohort from the ROLO randomized control trial of low GI diet in pregnancy. Serum insulin, glucose and leptin were measured in early pregnancy and at 28 weeks. At delivery cord blood C-peptide and leptin were measured. A comparison of maternal factors, fetal biometry, insulin resistance and leptin was made between male and female offspring. A multivariate regression model was built to account for the possible effects of maternal BMI, birthweight and original study group assignment on findings.

RESULTS

A total of 582 women were included in this secondary analysis, of whom 304 (52.2%) gave birth to male and 278 (47.8%) gave birth to female infants. Compared to male infants at birth, female infants were significantly lighter, (3945 ± 436 vs. 4081± 549g, p<0.001), shorter in length (52.36 ± 2.3 vs. 53.05 ± 2.4cm, p<0.001) and with smaller head circumferences (35.36 ± 1.5 vs. 36.10 ± 1.1cm, p<0.001) than males. On multiple regression analysis, women pregnant with female fetuses were less insulin resistant in early pregnancy, i.e. had lower HOMA indices (B = -0.19, p = 0.01). Additionally female fetuses had higher concentrations of both cord blood leptin and C-peptide at birth when compared to male offspring (B = 0.38, p<0.001 and B = 0.31, p = 0.03 respectively).

CONCLUSION

These findings suggest gender is a risk factor for insulin resistance in-utero. Additionally, carrying a female fetus decreases the risk of insulin resistance in the mother, from as early as the first trimester.

The effect of impaired 50-gram oral glucose challenge test on fetal abdominal wall thickness

BACKGROUND

Patients with impaired 50-g oral glucose challenge test (OGCT) have not been investigated for fetal anterior abdominal wall thickness until now. We aimed to investigate patients with impaired 50-g OGCT, but not gestational diabetes and match them with healthy uneventful pregnant participants for anterior abdominal wall thickness, estimated fetal weight, fetal gender, biparietal diameter, femur length and abdominal circumference.

METHODS

A total of 99 pregnant women between 26 and 28 weeks of gestation were enrolled in the study. These patients were divided into two groups according to their 50-g OGCT results. Fifty-one pregnant women with uncomplicated healthy singleton pregnancies constituted our control group, and 48 singleton pregnant women with impaired 50-g OGCT but normal 100-g oral glucose tolerance test constituted our study group.

RESULTS

We detected statistically significant high body mass index in impaired 50-g glucose test group. Biparietal diameter, femur length, abdominal circumference and estimated fetal weight values were not significantly different between groups; however, anterior abdominal wall thickness value was significantly width in impaired 50-g glucose test group. Moreover, there were no statistically significant differences between two groups for gender of fetuses.

CONCLUSION

Impaired 50-g glucose test in pregnancy is related not only to increased maternal body mass index but also to fetal fat distribution. Although fetal abdominal circumference measurement and estimated fetal weight were not different between study and control group, increased anterior abdominal wall thickness can be detected in impaired 50-g OGCT group.

Impact of maternal nutrition on pregnancy outcome--does it matter what pregnant women eat?

Pregnancy presents a unique époque in life with considerable potential to influence not only maternal health but also the health of the next generation. Nutritional interventions in pregnancy can influence maternal, foetal and infant health. This chapter describes the findings of a large randomised controlled trial on the impact of a low glycaemic index diet on maternal and foetal health and discusses areas of future research in this important area.

Obstetric and metabolic implications of excessive gestational weight gain in pregnancy

OBJECTIVE

To compare maternal characteristics, obstetric outcomes and insulin resistance in a cohort of women subdivided into those who did and those who did not exceed the Institute of Medicine (IOM) gestational weight gain guidelines.

METHODS

This is a prospective study of 621 women without diabetes. Concentrations of glucose, insulin and leptin were measured in early pregnancy and at 28 weeks. Ultrasound at 34 weeks assessed fetal anthropometry including abdominal wall width (AAW). At delivery birthweight was recorded and fetal glucose, C-peptide and leptin measured in cord blood. Insulin resistance was calculated using the HOMA equation. Outcomes in those who did and did not exceed IOM guidelines were compared.

RESULTS

Overall, 267 women (43%) exceeded IOM guidelines and 354 (57%) did not. On 34-week ultrasound women with excessive weight gain had higher fetal weights (2681 ± 356 g vs. 2574 ± 331, P = 0.001) and fetal adiposity (AAW) (5.29 ± 1.3 vs. 4.8 ± 1.2, P = 0.001). Infant birthweight and birthweight centiles were also higher in those who exceeded the guidelines. There was no difference between the two groups in maternal insulin resistance in early pregnancy, but by 28 weeks those with excessive weight gain had higher maternal HOMA indices and higher maternal leptin concentrations.

CONCLUSION

Excessive maternal gestational weight gain has significant implications for infant growth and adiposity, with potential implications for later adult health.

Leptin, fetal growth and insulin resistance in non-diabetic pregnancies

BACKGROUND

Interrogation of the association between leptin, insulin resistance and fetal growth may provide a biological link for the fetal programming of later metabolic health.

AIMS

Our aim was to clarify the relationship between maternal and fetal leptin, insulin resistance and fetal growth.

STUDY DESIGN

Maternal leptin, glucose and insulin were measured in early pregnancy and at 28weeks and the HOMA index calculated. At 34weeks, ultrasound scan assessed fetal weight and adiposity (abdominal wall width). At delivery birthweight was recorded and cord blood analyzed for fetal c-peptide and leptin. Analysis was performed using a multivariate linear regression model.

SUBJECTS

574 non-diabetic pregnant women.

OUTCOME MEASURES

Fetal growth and maternal and fetal insulin resistance.

RESULTS

On multivariate analysis a relationship was identified between maternal and fetal leptin concentrations at each time point and maternal body mass index. Maternal leptin was related to insulin resistance in early pregnancy (β=0.15, p=0.02) and at 28week gestation (β=0.27, p<0.001). Fetal insulin resistance correlated with maternal leptin in early pregnancy (β=0.17, p=0.004); at 28weeks (β=0.12, p=0.05), and with leptin in cord blood (r=0.28, p<0.001). Fetal weight at 34weeks was related to maternal leptin in early pregnancy (β=0.16, p=0.02). Both maternal and fetal leptin correlated with infant size at birth (β=0.12, p=0.07 in early pregnancy, β=0.21, p=0.004 in cord blood), independent of all other outcome measures.

CONCLUSION

Our findings have confirmed that in a non-diabetic cohort there is a link between maternal and fetal leptin and insulin resistance. We also established a link between maternal leptin in early pregnancy and both fetal and neonatal size. These results add to the growing body of evidence suggesting a role for leptin in the fetal programming of childhood obesity and metabolic dysfunction.

Probiotics in obese pregnancy do not reduce maternal fasting glucose: a double-blind, placebo-controlled, randomized trial (Probiotics in Pregnancy Study)

BACKGROUND

Recent studies have reported beneficial effects of probiotics on maternal glycemia in healthy pregnant women. Obesity significantly increases risk of impaired glucose tolerance in pregnancy, but glycemic effects of probiotics in this specific obstetric group require additional investigation.

OBJECTIVE

The aim of the Probiotics in Pregnancy Study was to investigate the effect of a probiotic capsule on maternal fasting glucose in obese pregnant women.

DESIGN

In this placebo-controlled, double-blind, randomized trial, 175 pregnant women with an early pregnancy body mass index (BMI; in kg/m²) from 30.0 to 39.9 were recruited from antenatal clinics at the National Maternity Hospital, Dublin, Ireland. Exclusion criteria were BMI <30.0 or >39.9, prepregnancy or gestational diabetes, age <18 y, multiple pregnancy, and fetal anomaly. Women were randomly assigned to receive either a daily probiotic or a placebo capsule from 24 to 28 wk of gestation in addition to routine antenatal care. The primary outcome was the change in fasting glucose between groups from preintervention to postintervention. Secondary outcomes were the incidence of gestational diabetes and neonatal anthropometric measures.

RESULTS

In 138 women who completed the study (63 women in the probiotic group; 75 women in the placebo group), mean (±SD) early pregnancy BMI was 33.6 ± 2.6, which differed significantly between probiotic (32.9 ± 2.4) and placebo (34.1 ± 2.7) groups. With adjustment for BMI, the change in maternal fasting glucose did not differ significantly between treated and control groups [-0.09 ± 0.27 compared with -0.07 ± 0.39 mmol/L; P = 0.391; B = -0.05 (95% CI: -0.17, 0.07)]. There were also no differences in the incidence of impaired glycemia (16% in the probiotic group compared with 15% in the placebo group; P = 0.561), birth weight (3.70 kg in the probiotic group compared with 3.68 kg in the placebo group; P = 0.723), or other metabolic variables or pregnancy outcomes. A secondary analysis of 110 women, excluding antibiotic users and poor compliers, also revealed no differences in maternal glucose or other outcomes between groups.

CONCLUSION

Probiotic treatment of 4 wk during pregnancy did not influence maternal fasting glucose, the metabolic profile, or pregnancy outcomes in obese women.

Correlation of fetal abdominal subcutaneous tissue thickness by ultrasound to predict birth weight

INTRODUCTION

Fetal growth abnormality is associated with changes in the soft tissue mass, which is decreased in growth restricted fetuses and increased in macrosomia.

OBJECTIVE

To correlate fetal abdominal subcutaneous tissue thickness (FASTT) measured by ultrasound at term and birth weight and to obtain a cut-off value of FASTT to predict large and small for gestational age babies in our population.

METHODS

FASTT was measured at the anterior 1/3(rd) of abdominal circumference by ultrasound after 36 weeks and weight of the baby measured after birth.

RESULTS

There was positive correlation between FASTT and birth weight. FASTT of 6.25 mm was sensitive to predict large for gestational age (LGA) babies and had a high negative predictive value; FASTT measurement for prediction of small babies with birth weight < 2500 g was not sensitive.

CONCLUSION

FASTT can be used as an additional indicator to predict large for gestational age babies along with other known birth weight indicators.

Measurement of fetal fat in utero in normal and diabetic pregnancies using magnetic resonance imaging

OBJECTIVES

To assess the reliability of magnetic resonance imaging (MRI) to measure fetal fat volume in utero, and to study fetal growth in women with and without diabetes in view of the increased prevalence of macrosomia in the former.

METHODS

We studied 26 pregnant women, 14 with pre-gestational diabetes and 12 non-diabetic controls. Fetal assessment took place at 24 weeks' gestation and again at 34 weeks by standard ultrasound biometry followed by MRI at 1.5 T. Fetal fat volume was determined from T1-weighted water-suppressed images using a semi-automated approach based on pixel intensity and taking into account partial volume effects. Fetal volume was also determined from the MRI images. Fetal weight was calculated using published fat and lean tissue densities.

RESULTS

There was little fetal fat at 24 weeks' gestation, but at 34 weeks the fetal fat content was considerably higher in the women with diabetes, with a mean fat content of 1090 ± 417 cm(3) compared with 541 ± 348 cm(3) in the controls (P = 0.006). Measurements of fetal fat volume showed low intra- and interobserver variability at 34 weeks, with intraclass correlation coefficients consistently above 0.99. Birth-weight centile correlated with fetal fat volume (R(2)  = 0.496, P < 0.001), percentage of fetal fat (R(2)  = 0.362, P = 0.008) and calculated fetal weight (R(2)  = 0.492, P < 0.001) at 34 weeks.

CONCLUSIONS

MRI appears to be a promising tool for the determination of fetal fat, body composition and weight in utero during the third trimester of pregnancy.

Longitudinal measurement of fetal thigh soft tissue parameters and its role in the prediction of birth weight

OBJECTIVE

The aim of this study was to profile longitudinal changes in thigh muscle and fat with gestation and to determine whether thigh measurements can improve the prediction of birth weight (BW).

METHODS

A prospective longitudinal study of subcutaneous soft tissue measurements was conducted in 328 singleton fetuses at 28 and 37 weeks gestation. Estimated fetal weight (EFW) was calculated using abdominal circumference, femur length, biparietal diameter, and head circumference.

RESULTS

The fetal abdominal subcutaneous tissue (FAST) and thigh muscle and fat show an increase with gestation. At 28 weeks gestation, the abdominal circumference, thigh fat, FAST, and EFW percentile were found to be significant predictors of BW. A combination of EFW percentile and thigh fat were found to be the optimal multivariate model at 28 weeks for predicting BW. At 37 weeks, BW prediction using EFW percentile, FAST, and thigh fat was the most accurate. The results revealed acceptable reproducibility for fetal thigh muscle and fat.

CONCLUSION

This study provides reference ranges for thigh fat and muscle at 28 and 37 weeks gestation. The inclusion of fetal thigh fat in the algorithm improves the predictive power for birth weight. This information is important to explore the role of fetal thigh in the detection of aberrant growth.

The molecular mechanisms of offspring effects from obese pregnancy

The incidence of obesity, increased weight gain and the popularity of high-fat / high-sugar diets are seriously impacting upon the global population. Billions of individuals are affected, and although diet and lifestyle are of paramount importance to the development of adult obesity, compelling evidence is emerging which suggests that maternal obesity and related disorders may be passed on to the next generation by non-genetic means. The processes acting within the uteri of obese mothers may permanently predispose offspring to a diverse plethora of diseases ranging from obesity and diabetes to psychiatric disorders. This review aims to summarise some of the molecular mechanisms and active processes currently known about maternal obesity and its effect on foetal and neonatal physiology and metabolism. Complex and multifactorial networks of molecules are intertwined and culminate in a pathologically synergistic manner to cause disruption and disorganisation of foetal physiology. This altered phenotype may potentiate the cycle of intergenerational transmission of obesity and related disorders.

The relationship between maternal and fetal vitamin D, insulin resistance, and fetal growth

Evidence for a role of vitamin D in maintaining normal glucose homeostasis is inconclusive. We sought to clarify the relationship between maternal and fetal insulin resistance and vitamin D status. This is a prospective cohort study of 60 caucasian pregnant women. Concentrations of 25-hydroxyvitamin D (25-OHD), glucose, insulin, and leptin were measured in early pregnancy and at 28 weeks. Ultrasound at 34 weeks assessed fetal anthropometry including abdominal wall width, a marker of fetal adiposity. At delivery birth weight was recorded and fetal 25-OHD, glucose, C-peptide, and leptin measured in cord blood. Insulin resistance was calculated using the Homeostasis Model Assessment (HOMA) equation. We found that those with lower 25-OHD in early pregnancy had higher HOMA indices at 28 weeks, (r = -.32, P = .02). No significant relationship existed between maternal or fetal leptin and 25-OHD, or between maternal or fetal 25-OHD and fetal anthropometry or birth weight. The incidence of vitamin D deficiency was high at each time point (15%-45%). These findings lend support to routine antenatal supplementation with vitamin D in at risk populations.

Maternal and fetal cocaine- and amphetamine-regulated transcript in diabetic and non-diabetic pregnancy

Cocaine- and amphetamine-regulated transcript (CART) is a leptin-regulated anorectic neuropeptide. Increased levels of leptin in cord blood of diabetic mothers have previously been described. The aim of this study was to quantify maternal and fetal serum CART levels in type 1 diabetes mellitus (T1DM, n = 10) and non-diabetic pregnancy (n = 10). Matched maternal serum samples (n = 20) were obtained at 36-weeks gestation and cord samples from the umbilical vein at delivery (n = 20), CART was quantified using a competitive enzyme immunoassay. Statistical analysis was performed using Spearmans correlation and t test. There was no difference in maternal CART levels at 36-weeks gestation between T1DM (mean = 331.13 pg/ml, Standard Error of the Mean (SEM) = 114.54) and non-diabetic pregnancy (mean = 195.01 pg/ml SEM = 29.37) (p = 0.106). Fetal CART levels in the umbilical vein were similar in T1DM (mean = 199.27 pg/ml, SEM = 39.81) and non-diabetic pregnancy (mean = 149.76 pg/ml, SEM = 26.08) (p = 0.143). Maternal serum CART levels measured at 36-weeks gestation correlated with maternal BMI at booking (Spearmans ρ = 0.332) (p = 0.001) irrespective of diabetes. Serum CART can be detected in both diabetic and non-diabetic human pregnancy and may play an important role in body mass regulation in pregnancy.

Low glycaemic index diet in pregnancy to prevent macrosomia (ROLO study): randomised control trial

OBJECTIVE

To determine if a low glycaemic index diet in pregnancy could reduce the incidence of macrosomia in an at risk group.

DESIGN

Randomised controlled trial.

SETTING

Maternity hospital in Dublin, Ireland.

PARTICIPANTS

800 women without diabetes, all in their second pregnancy between January 2007 to January 2011, having previously delivered an infant weighing greater than 4 kg.

INTERVENTION

Women were randomised to receive no dietary intervention or start on a low glycaemic index diet from early pregnancy.

MAIN OUTCOMES

The primary outcome measure was difference in birth weight. The secondary outcome measure was difference in gestational weight gain.

RESULTS

No significant difference was seen between the two groups in absolute birth weight, birthweight centile, or ponderal index. Significantly less gestational weight gain occurred in women in the intervention arm (12.2 v 13.7 kg; mean difference -1.3, 95% confidence interval -2.4 to -0.2; P=0.01). The rate of glucose intolerance was also lower in the intervention arm: 21% (67/320) compared with 28% (100/352) of controls had a fasting glucose of 5.1 mmol/L or greater or a 1 hour glucose challenge test result of greater than 7.8 mmol/L (P=0.02).

CONCLUSION

A low glycaemic index diet in pregnancy did not reduce the incidence of large for gestational age infants in a group at risk of fetal macrosomia. It did, however, have a significant positive effect on gestational weight gain and maternal glucose intolerance.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN54392969.

Prediction and prevention of the macrosomic fetus

Fetal macrosomia is associated with significant maternal and neonatal morbidity. In the long term, infants who are large for gestational age are more likely than other infants to be obese in childhood, adolescence and early adulthood, and are inherently at higher risk of cardiovascular and metabolic complications in adulthood. With over one billion adults in the world now overweight and more than 600 million clinically obese, preventing the vicious cycle effect of fetal macrosomia and childhood obesity is an increasingly pertinent issue. Fetal growth is determined by a complex interplay of various genetic and environmental influences. Consequently the prediction of pregnancies at risk of pathological overgrowth is difficult. Many risk factors for fetal macrosomia, such as maternal obesity and advanced maternal age, are also conversely associated with intrauterine growth restriction. Sonographic detection of fetal macrosomia is notoriously fraught with difficulties, with dozens of formulas for estimated fetal weight proposed but few with sufficient sensitivity to alter clinical practice. This calls into question policies of elective delivery based on projected estimated fetal weight cut-offs alone. More recently the identification of markers of fetal adiposity and maternal serum biomarkers are being investigated to improve the antenatal detection of the large for gestational age fetus. Prevention of fetal macrosomia is entirely dependent upon correct identification of those at risk. Maternal weight, gestational weight gain and glycaemic control are the risk factors for fetal macrosomia that are most amenable to intervention, and have potential maternal health benefits beyond pregnancy and childbirth. The ideal method of optimising maternal weight and glucose homeostasis is yet to be elucidated, though a number of promising advances are recently being reported. In this review we outline the contemporary evidence for the prediction and prevention of fetal macrosomia, which is indeed a contemporary dilemma.

Maternal and fetal placental growth hormone and IGF axis in type 1 diabetic pregnancy

AIM

Placental growth hormone (PGH) is a major growth hormone in pregnancy and acts with Insulin Like Growth Factor I (IGF-I) and Insulin Like Growth Hormone Binding Protein 3 (IGFBP3). The aim of this study was to investigate PGH, IGF-I and IGFBP3 in non-diabetic (ND) compared to Type 1 Diabetic (T1DM) pregnancies.

METHODS

This is a prospective study. Maternal samples were obtained from 25 ND and 25 T1DM mothers at 36 weeks gestation. Cord blood was obtained after delivery. PGH, IGF-I and IGFBP3 were measured using ELISA.

RESULTS

There was no difference in delivery type, gender of infants or birth weight between groups. In T1DM, maternal PGH significantly correlated with ultrasound estimated fetal weight (r = 0.4, p = 0.02), birth weight (r = 0.51, p<0.05) and birth weight centile (r = 0.41, p = 0.03) PGH did not correlate with HbA1c. Maternal IGF-I was lower in T1DM (p = 0.03). Maternal and fetal serum IGFBP3 was higher in T1DM. Maternal third trimester T1DM serum had a significant band at 16 kD on western blot, which was not present in ND.

CONCLUSION

Maternal T1DM PGH correlated with both antenatal fetal weight and birth weight, suggesting a significant role for PGH in growth in diabetic pregnancy. IGFBP3 is significantly increased in maternal and fetal serum in T1DM pregnancies compared to ND controls, which was explained by increased proteolysis in maternal but not fetal serum. These results suggest that the normal PGH-IGF-I-IGFBP3 axis in pregnancy is abnormal in T1DM pregnancies, which are at higher risk of macrosomia.

Clinical associations with a placental diagnosis of delayed villous maturation: a retrospective study

Delayed villous maturation (DVM) is a spectrum of placental disease characterized by decreased tertiary villus formation, reduced vasculosyncytial membrane formation, and, in its more severe forms, increased large bullous villi. In some series it has been associated with an increased risk of stillbirth in the late third trimester, but overall there are few data on its significance. The aim of this study was to assess perinatal factors associated with, and the clinical significance of, the finding of DVM on placental histology. This was a retrospective study investigating all pregnancies with DVM diagnosed on placental histology in a tertiary level unit between December 2001 and August 2006. Over a 6-year period, 2915 placentas were triaged for histopathological assessment, representing 6.1% of all 48 054 deliveries in this time period. One hundred ninety (6.3%) of these selected cases showed DVM. Fifteen placentas from infants with less than 34 completed weeks of gestation were excluded, leaving 175 for further analysis. When compared with controls matched for gestation and delivering within the same time period (n  =  175), DVM was significantly associated with pregestational diabetes (8% vs 2.8%, P < .05; relative risk 2.8 [95% confidence interval 1.03-7.6]), gestational diabetes (8.6% vs 3.4%, P < 0.05; relative risk 2.5 [95% confidence interval 0.99-6.3]), and prenatal or intrapartum intrauterine death (8.6% vs 0%, P < 0.05). Delayed villous maturation is associated with both gestational and pregestational diabetes mellitus and with perinatal death.

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.

Are there sex differences in Fetal Abdominal Subcutaneous Tissue (FAST) measurements?

OBJECTIVE

To determine if Fetal Abdominal Subcutaneous Tissue (FAST) measurements using antenatal ultrasound differ between male and female fetuses.

STUDY DESIGN

Women who had an ultrasound examination for fetal growth between 20 and 40 weeks gestation were studied. Women with diabetes mellitus were excluded. The fetal anterior abdominal subcutaneous tissue was measured on the anterior abdominal wall in millimetres anterior to the margins of the ribs, using magnification at the level of the abdominal circumference. The fetal sex was recorded after delivery.

RESULTS

A total of 557 fetuses were measured, 290 male and 267 female. The FAST measurements increased with gestational age. The FAST increased at the same rate for both male and female fetuses and at any given week there was no sex difference.

CONCLUSIONS

The increased fat composition in females reported after birth was not found in abdominal wall subcutaneous fat measurements using ultrasound during pregnancy. Antenatal centile charts for FAST do not need to be based on sex.