Comparison of various method of fetal birth weight estimation in term pregnancy

Darshit G. Prajapati, Riddhi M. Patel


Introduction: Knowledge of fetal weight in utero is vital for the obstetrician in deciding whether or not to deliver the fetus as well as in fixing the mode of delivery. Both low birth weight and excessive fetal weight at delivery are associated with increased risk of newborn complications during labor and the puerperium. Various clinical formulae like Johnson's formula & Dare's formula and USG are in use for fetal weight estimation.

Objectives: The aim of this study was to assess the fetal weight in term pregnancies by various methods- Dare’s formula, Johnson's formula and Hadlock's formula using ultrasound, and to compare the methods after knowing the actual weight of the baby after birth.

Methods: It is a prospective observational study of 227 women at term pregnancy at GMERS medical college & Hospital, sola , Ahmedabad from April 2014 to April 2016. The formulas used in this study are: Johnson's formula, Dare’s formula and Hadlock-4 formula using ultrasound.

Result: Results vary in terms of accuracy with various methods employed for estimating the fetal weight. This study showed that Hadlock-4 was the best indicator among all other methods assessed followed by Dare’s formula.

Conclusion: Whenever the Facility is available, Ultrasound is the best method for birth weight assessment. Dare’s formula is an inexpensive method for screening for fetal growth restriction. It continues to be used in many countries on large scale because of its low cost, ease of use, and need for little training as the setup for ultrasonographic evaluation is not readily available in rural setups.


Dare’s formula, Fetal birth weight, Hadlock-4 formula, Johnson’s formula

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Baum JD, Gussman D, Wirth III JC. Clinical and patient estimation of fetal weight vs. ultrasound estimation. Obstet Gynecologic Survey. 2002;57(9):558-9.

Chauhan SP, Hendrix NW, Magann EF, Morrison JC, Kenney SP, Devoe LD. Limitations of clinical and sonographic estimates of birth weight: experience with 1,034 parturients. Obstet Gynecol. 1998;91:72-7.

Kurmanavicius J, Burkhardt T, Wisser J, Huch R. Ultrasonographic fetal weight estimation: accuracy of formulas and accuracy of examiners by birth weight from 500 to 5000 g. J Perinat Med. 2004;32:155-61.

Ben‐Haroush A, Yogev Y, Bar J, Mashiach R, Kaplan B, Hod M et al. Accuracy of sonographically estimated fetal weight in 840 women with different pregnancy complications prior to induction of labor. Ultrasound Obstet Gynecol. 2004 Feb 1;23(2):172-6.

McIntire DD, Bloom SL, Casey BM, Leveno KJ. Birth weight in relation to morbidity and mortality among newborn infants. New Engl J Med. 1999;340(16):1234-8.

Jolly MC, Sebire NJ, Harris JP, Regan L, Robinson S. Risk factors for macrosomia and its clinical consequences: a study of 350, 311 pregnancies. Eur J Obstet Gynecol Reprod Biol. 2003;111(1):9-14.

Campbell S, Thomas A. Ultrasound measurement of the fetal head to abdominal circumference ratio in the assessment of fetal growth retardation. Br J Obstet Gynecol. 1977;84:165-74.

Campbell S, Wilkin D. Ultrasonic measurement of the fetal abdominal circumference in estimation of fetal weight. Br J Obstet Gynecol. 1975;82:689-97.

Hadlock FP, Harrist RB, Carpenter RJ, Deter RL, Park SK. Sonographic Estimation of Fetal weight. The value of femur length in addition to head and abdominal measurements. Radiology. 1984;150:535-40.

Nzeh DA, Rimmer S, Moore WMO, Hunt L. Prediction of Birth weight by fetal ultrasound biometry. Br J Radiol. 1992;66:987-9.

Njoku C, Emechebe C, Odusolu P, Abeshi S, Chukwu C, Ekabua J. Determination of accuracy of fetal weight using ultrasound and clinical fetal weight estimations in Calabar South, South Nigeria. Int Scholarly Res Notices. 2014;2014.

Raghuvanshi T, Pawar M, Patil A. Comparative study of fetal weight estimation by various methods among term pregnancies at rural tertiary care centre, Maharashtra. J Evol Med Dental Sci. 2014 Sep;3(41):10291-6.

Amritha BA, Patric PJ, Ashwin SP. Comparative study of various methods of fetal weight estimation at term pregnancy. J Obstet Gynecol Ind. 2004;54(4):336-9.

Sowjanya R, Lavanya S. Comparative study of clinical assessment of fetal weight estimation using johnson’s formula and ultrasonographic assessment using Hadlock’s Formula at or near term. IOSR-JDMS. 2015;14(4):20-3.