Estimation of Fetal Weight by Clinical Methods and Ultrasonography and Comparing With Actual Birth Weight

Introduction: Assessment of fetal weight is a vital factor in antenatal care, not only in the management of labor and delivery but also in identifying fetal weight disorders. Objective: This study compares the accuracy of clinical methods and ultrasonography in Estimating Fetal Weight (EFW) with Actual Birth Weight (ABW) in term pregnant women. Materials and Methods: This diagnostic test evaluation study was performed on 247 single-term pregnant women admitted to an educational, therapeutic hospital in Rasht City, Iran. In this study, abdominal palpation, Johnson’s formula, Insler’s formula, and ultrasonography were used to estimate fetal weight. One-sample t-test, the Chi-square, and the Bland-Altman plot were used to compare the diagnostic value of fetal weight estimation methods. The accuracy of tests was estimated based on sensitivity and specificity in fetal weight groups (below 2500 g, 2500- 4000 g, and above 4000 g) by the Bland-Altman plot. Results: The participating pregnant women had a Mean±SD age of 28.86±4.24 years, body mass index of 32.98±6.0 kg/m2, and gestational age of 39±1.04 wk. Their Mean±SD actual birth weight was 3343.352±432.799 gr, Also, the Mean±SD birth weight found by abdominal palpation was 3371.053±345.561 gr, Mean±SD birth weight by Johnson’s formula 3041.206 ±411 gr, by Insler’s formula 3556.316±531.567 gr, and by ultrasonography 3294.28±380.09 gr, Based on the one-sample t-test, the abdominal palpation had the lowest (P=0.261), and the Insler’s formula (P=0.001) had the highest difference with the actual birth weight. Regarding the fetal weight groups, Insler’s formula (96.33%) was highly accurate in Low Birth Weight (LBW), but abdominal palpation (91.09%) was more accurate in normal weight and macrosomia (94.72%) groups. There was a significant difference between clinical methods with ABW (P=0.026). Conclusion: Clinical methods are accessible, affordable, and available and can estimate fetal weight in developing countries, especially in our country.

Higher Concordance in Clinical Assessment versus Ultrasound to Estimate Fetal Weight when it compares with Birth Weight in Full-Term Newborns

Introduction: the aim of this trial was to estimate fetal weight by clinical and ultrasound methods and to compare with the weight at birth in full-term newborns. Methods: This is an epidemiological, observational, cross-sectional study of a cohort of healthy full-term newborns. The sample size was 102 neonates born at the Pablo Arturo Suarez Hospital, in Quito, Ecuador, from November 2019 to January 2020. Results: In full-term neonates, the estimate on ultrasound was 80.00%, while in the clinical assessment was 72.29%. The profile of newborn analyzed is man, mestizo, Ecuadorian, born in the highlands region, with a mean gestational age of 38.67 weeks and a mean birth weight of 3,023 grams, in whom it estimated the fetal weight through ultrasound and clinical assessment. The estimation of the absolute error in both methods analyzed was 2.43% to ultrasound and -4.65% to clinical assessment, and both showed moderate concordance, 78.2% to ultrasound, and 85.6% to clinical assessment. Multivariate analysis showed the neonates with modified weight by ultrasound are 13.44 times more likely to show altered weight at birth, while neonates with modified weight by the clinical assessment are 11.95 times more likely to show altered weight at birth. Conclusions: Accuracy in the clinical assessment was always higher than in the ultrasound method, especially in low weight newborns.

Swedish intrauterine growth reference ranges for estimated fetal weight

Fetal growth restriction is a strong risk factor for perinatal morbidity and mortality. Reliable standards are indispensable, both to assess fetal growth and to evaluate birthweight and early postnatal growth in infants born preterm. The aim of this study was to create updated Swedish reference ranges for estimated fetal weight (EFW) from gestational week 12–42. This prospective longitudinal multicentre study included 583 women without known conditions causing aberrant fetal growth. Each woman was assigned a randomly selected protocol of five ultrasound scans from gestational week 12 + 3 to 41 + 6. Hadlock’s 3rd formula was used to estimate fetal weight. A two-level hierarchical regression model was employed to calculate the expected median and variance, expressed in standard deviations and percentiles, for EFW. EFW was higher for males than females. The reference ranges were compared with the presently used Swedish, and international reference ranges. Our reference ranges had higher EFW than the presently used Swedish reference ranges from gestational week 33, and higher median, 2.5th and 97.5th percentiles from gestational week 24 compared with INTERGROWTH-21st. The new reference ranges can be used both for assessment of intrauterine fetal weight and growth, and early postnatal growth in children born preterm.

The Accuracy of Risanto's Formula and Ultrasound Measurement in Estimating Fetal Weight

Background: Accurate estimated fetal weight (EFW) is crucial in determining delivery management. Several methods to estimate fetal weight were used such as abdominal palpation, measurement of symphisis fundal height (SFH), and ultrasound examination. Risanto’s formula based on Indonesian population had been already proven to be more accurate than Johnson’s formula. The formula was as follows: Y = 125 X - 880 where Y was EFW in grams, X was SFH in cm, and 125 was the constanta.Objective: To compare the accuracy of Risanto’s formula and ultrasound examination in estimating fetal weight.Method: A cross sectional study was carried out in Sardjito hospital, Faculty of Medicine Universitas Gadjah Mada, from March 2013 to March 2014. A total of 400 pregnant women meeting the inclusion criteria at 37 – 42 weeks of gestation were recruited. The estimated fetal weight using Risanto’s formula (R_EFW) was compared to the estimated fetal weight using ultrasound measurement (U_EFW). The U_EFW was done by obstetricians on duty or senior residents using Hadlock’s formula. Actual birth weight (ABW) was measured using the same calibrated baby scale. Accuracy was determined by comparing the mean difference between the R_EFW minus ABW (ΔR_EFW) and the U_EFW minus ABW (ΔU_EFW). Paired t-test was used for statistical analysis.Result and Discussion: The mean ABW was 3025.3 ± 414.6 gram and the mean R_EFW was 2972.7 ± 365.4 grams, while the mean U_EFW was 3058.7 ± 423.2 grams. The mean ΔR_EFW was lower than the mean ΔU_EFW (178.2 ± 147.6 grams vs 197.5 ± 155.4 grams; 95% CI 1.24 – 36.68; p = 0.04).Conclusion: Risanto’s formula was more accurate than ultrasound measurement in estimating fetal weight.Keywords: Estimated fetal weight, Risanto’s formula, Ultrasonography, Fundal height

Estimation of mouse fetal weight by ultrasonography: application from clinic to laboratory

Ultrasonographic assessment of fetal growth to estimate fetal weight has been widely used in clinical obstetrics but not in laboratory mice. Even though it is important to assess fetal growth abnormalities for gene-targeting studies using mice, there have been no reports of accurately estimated fetal weight using fetal biometric parameters in mice. The aim of this study was to establish an accurate mouse formula using fetal biometric parameters under ultrasound imaging. Using a high-frequency ultrasound system with a 40 MHz transducer, we measured 293 fetuses of biparietal diameter and mean abdominal diameter from day 12.5 postcoitus (p.c.) until day 18.5 p.c every day. Thirteen algorithms for humans based on head and/or abdominal measurements were assessed. We established an accurate formula based on measurement of the abdomen in Jcl:ICR mice to investigate gestational complications, such as intrauterine growth restriction.