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.

Preliminary evaluation of foetal liver volume by three-dimensional ultrasound in women with gestational diabetes mellitus

The aim of the study was to assess the standard foetal biometric measurements and foetal liver volume (FLV) in pregnancies complicated by gestational diabetes mellitus (GDM) at the time of GDM screening and to compare the results with foetuses in normal pregnancies. Ninety-seven pregnant women with normal singleton uncomplicated pregnancies between 24 and 28 weeks of gestation were allocated into GDM (+) (n: 33) and GDM (-) (n: 64) groups based on their 75 g oral glucose tolerance test results. Foetal biometric measurements and FLV measurements of the groups were compared. Although there were no significant differences in the standard biometric measurements between the two groups, FLV was significantly higher in the women with GDM (p < .01). The ROC analysis implied that with a cut-off value of FLV of 32.72 cm³ for GDM prediction, the sensitivity was 78.8% and specificity was 56.3%. We suggest that FLV measurements during the second-trimester ultrasound scanning may be a tool for the prediction of GDM in the obstetric population. Impact statement What is already known on this subject? GDM is an important pregnancy disease, because of its possible foetal and maternal complications. Besides the standard biometric measurements, some other foetal body dimensions such as the anterior abdominal wall thickness, skinfold thickness, adipose tissue thickness, Wharton's jelly thickness, foetal liver length and foetal liver volume (FLV) have been evaluated as ultrasound parameters of glycaemic control. While the evaluation of foetal liver dimensions has a role in identifying foetal growth acceleration, previous studies addressed patients with insulin-dependent diabetes mellitus rather than gestational diabetes mellitus, utilised two-dimensional ultrasound and did not argue the diagnostic value of these findings. What do the results of this study add? In our study, besides the standard biometric measurements, the FLV measurements were evaluated by a three-dimensional ultrasound. Although there were no significant differences in the standard biometric measurements between the GDM (+) and GDM (-) groups, the FLV was significantly higher in women with GDM. The FLV was found to be a potential predictive factor for GDM. The ROC analysis implied that as a cut-off value of FLV of 32.72 cm³ for GDM prediction, the sensitivity was 78.8% and the specificity was 56.3%. What are the implications of these findings for clinical practise and/or further research? Screening for GDM with oral glucose tolerance test within the limited weeks of gestation may not always be feasible. On the other hand, the mid-trimester ultrasound scanning is done almost in all pregnancies. Accordingly, FLV measurement might be an alternative method for the GDM diagnosis.

Tracking of fetal growth characteristics during different trimesters and the risks of adverse birth outcomes

BACKGROUND

Fetal growth characteristics are used to identify influences of several maternal characteristics and to identify individuals at increased risk of adverse outcomes. The extent to which fetal growth characteristics track in different trimesters is not known.

METHODS

In a population-based prospective cohort study among 8636 pregnant women, we examined the extent to which fetal growth characteristics track, are influenced by maternal socio-demographic and lifestyle related determinants and are associated with birth outcomes. Fetal growth was assessed in each trimester and at birth.

RESULTS

Correlation coefficient between first-trimester crown-rump length and birthweight was r = 0.12 (P-value < 0.05). Correlation coefficients for fetal-head circumference, (femur) length and (estimated) fetal weight ranged from r = 0.16 to r = 0.30 (all P-values < 0.05) between second trimester and birth and from r = 0.36 to r = 0.58 (all P-values < 0.05) between third trimester and birth, and were highest for (estimated) fetal weight. Correlation coefficients for (estimated) fetal weight tended to be lower among overweight mothers, as compared with normal weight mothers, but were not influenced by other maternal characteristics. First, second and third-trimester fetal growth characteristics were associated with risks of preterm birth and small size for gestational age at birth,with the strongest associations present in third trimester.

CONCLUSION

Fetal growth characteristics track moderately throughout gestation, with stronger tracking coefficients present in later pregnancy. Tracking coefficients were not materially influenced by maternal socio-demographic and lifestyle characteristics. First, second and third trimester fetal growth characteristics were associated with the risk of adverse birth outcomes.