Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2025 Jun;17(Suppl 2):S1855-S1857.
doi: 10.4103/jpbs.jpbs_574_25. Epub 2025 Jun 18.

Comparison of Various Formulas (Hadlock's I and II, Merz, Shepard, Campbell, Wilkin's) to Calculate Birth Weight by Antenatal Ultrasound

R Mahesh Anirudh  1 , T Shriram  2 , C S Prabhu  3 , P Ramya  4
Affiliations

Comparison of Various Formulas (Hadlock's I and II, Merz, Shepard, Campbell, Wilkin's) to Calculate Birth Weight by Antenatal Ultrasound

R Mahesh Anirudh et al. J Pharm Bioallied Sci. 2025 Jun.

Abstract

Background: Accurate fetal weight estimation is crucial in obstetric care, aiding in the management of intrauterine growth restriction, macrosomia, and perinatal decision-making.

Aim: To compare the accuracy of different sonographic formulas for estimating fetal birth weight and determine the most reliable formula.

Materials and methods: A prospective comparative study was conducted in the Department of Radiology at Aarupadai Veedu Medical College and Hospital, Puducherry. A total of 110 pregnant women with gestational ages above 37 weeks were enrolled. Ultrasound examinations were performed using the Mindray DC 80 scanner. Estimated fetal weights using Hadlock's I and II, Merz, Shepard, Campbell, and Wilkin's formulas were compared with actual birth weights. Statistical analysis included paired t-tests, ANOVA, and post hoc Tukey's test, with significance set at P < 0.05.

Results: Hadlock I and III demonstrated the highest accuracy, particularly in the 2.6-3.0 kg range. Merz and Wilkin's formulas overestimated higher birth weights, while the Shepard formula consistently underestimated fetal weight.

Conclusion: Hadlock I and III are the most reliable formulas for fetal weight estimation. Selection of an appropriate formula is essential for clinical accuracy.

Keywords: Birth weight prediction; Campbell formula; Hadlock’s formula; Merz formula; Shepard formula; Wilkin’s formula; fetal weight estimation; ultrasound.

PubMed Disclaimer

Conflict of interest statement

There are no conflicts of interest.

References

    1. Ju H, Chadha Y, Donovan T, O’Rourke P. Fetal macrosomia and pregnancy outcomes. Aust N Z J Obstet Gynaecol. 2009;49:504–9. - PubMed
    1. Ugwu EO, Udealor PC, Dim CC, Obi SN, Ozumba BC, Okeke DO, et al. Accuracy of clinical and ultrasound estimation of fetal weight in predicting actual birth weight in Enugu, Southeastern Nigeria. Niger J Clin Pract. 2014;17:270–5. - PubMed
    1. Frick AP, Syngelaki A, Zheng M, Poon LC, Nicolaides KH. Prediction of large-for-gestational-age neonates: screening by maternal factors and biomarkers in the three trimesters of pregnancy. Ultrasound Obstet Gynecol. 2016;47:332–9. - PubMed
    1. Hadlock FP, Harrist RB, Sharman RS, Deter RL, Park SK. Estimation of fetal weight with the use of head, body, and femur measurements-a prospective study. Am J Obstet Gynecol. 1985;151:333–7. - PubMed
    1. Campbell S, Wilkin D. Ultrasonic measurement of fetal abdomen circumference in the estimation of fetal weight. Br J Obstet Gynaecol. 1975;82:689–97. - PubMed

LinkOut - more resources