Evaluation of the Fetal Thigh Cross-Section to Predict Fetal Birth Weight in Normal-Term Pregnant Women

Background: Fetal weight is an important factor in assessing fetus growth, and arranging for delivery. Different parameters and different models were used to estimate fetal weight, and the 3-dimensional ultrasound plays a crucial role in many aspects, including assessing the fetus's weight. Aim of the study: To precisely assess third-trimester ultrasound using fetal limb cross-section area by 3D ultrasound to predict birth weight of the fetus versus sonographic parameters for predicted fetal weight by two-dimensional ultrasound. Materials and methods: This Prospective-cohort study recruited one hundred pregnant women with a normal pregnancy in their late third trimester. They were taken from the antenatal clinic and had their fetal weights estimated by two-dimensional ultrasound by Modified Hadlock (MH) and three-dimensional ultrasound by measuring the thickness of the soft tissue of thigh, assessment of fetal weight, and follow up to delivery to measure the actual birth weight of the infant and comparing the results. A study was done in the department of Obstetrics and Gynecology at Al-Yarmouk Teaching Hospital. The Ethical Committee code was obtained after getting the scientific approval. Results: One hundred pregnant women were enrolled in this study, their mean age of the women was ‎‎32.6 years old, their mean BMI was 25.6 kg/m2, and most of them had a cephalic ‎presentation (92%); in the current study, Modified Hadlock overestimate fetal weight 159.9 g, while midthigh soft tissue thickness (MTSTT) underestimates the fetal weight - 67.3 gm. Modified Hadlock was non significantly different from zero. In terms of systemic errors, there was a non-significant difference between MH from zero, whereas MTSTT significantly differs from MH., and in terms of absolute error, the 3D model was significantly different from MH. Conclusion: ‎This study found that compared with using the traditional Hadlock's formula, the fetal thigh soft tissue thickness measured by the novel method of three-dimensional ultrasonography is more precisely and specifically related to the antenatal anticipated birth weight.