- 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: 333–337.

- 2
Hansmann M, Schumacher H, Voigt U. Mehrparametrische nicht lineare Gewichtsschätzung mittels Ultraschall unter Berücksichtigung des Gestationsalters. In Ultraschalldiagnostik, KratochwilA, ReinoldE (eds). Georg Thieme: Stuttgart, 1978; 69–71.

- 3
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 abdomen measurements. Radiology 1984; 150: 535–540.

- 4
Shepard MJ, Richards VA, Berkowitz RL, Warsof SL, Hobbins JC. An evaluation of two equations for predicting fetal weight by ultrasound. Am J Obstet Gynecol 1982; 142: 47–54.

- 5
Thurnau GR, Tamura RK, Sabbagha R, Depp OR 3rd, Dyer A, Larkin R, Lee T, Laughlin C. A simple estimated fetal weight equation based on real-time ultrasound measurements of fetuses less than thirty-four weeks' gestation. Am J Obstet Gynecol 1983; 145: 557–561.

- 6
Deter RL, Nazar R, Milner LL. Modified neonatal growth assessment score: a multivariate approach to the detection of intrauterine growth retardation in the neonate. Ultrasound Obstet Gynecol 1995; 6: 400–410.

- 7
Vintzileos AM, Campbell WA, Rodis JF, Bors-Koefoed R, Nochimson DJ. Fetal weight estimation formulas with head, abdominal, femur, and thigh circumference measurements. Am J Obstet Gynecol 1987; 157: 410–414.

- 8
McLean F, Usher R. Measurements of liveborn fetal malnutrition infants compared with similar gestation and with similar birth weight normal controls. Biol Neonate 1970; 16: 215–221.

- 9
Catalano PM, Tyzbir ED, Allen SR, McBean JH, McAuliffe TL. Evaluation of fetal growth by estimation of neonatal body composition. Obstet Gynecol 1992; 79: 46–50.

- 10
Medchill MT, Peterson CM, Kreinick C, Garbaciak J. Prediction of estimated fetal weight in extremely low birth weight neonates (500–1000 g). Obstet Gynecol 1991; 78: 286–290.

- 11
Schild RL, Fell K, Fimmers R, Gembruch U, Hansmann M. A new formula for calculating weight in the fetus of ⩽ 1600 g. Ultrasound Obstet Gynecol 2004; 24: 775–780.

- 12
Merz E, Lieser H, Schicketanz KH, Harle J. [Intrauterine fetal weight assessment using ultrasound. A comparison of several weight assessment methods and development of a new formula for the determination of fetal weight.] Ultraschall Med 1988; 9: 15–24.

- 13
Chang FM, Liang RI, Ko HC, Yao BL, Chang CH, Yu CH. Three-dimensional ultrasound-assessed fetal thigh volumetry in predicting birth weight. Obstet Gynecol 1997; 90: 331–339.

- 14
Liang RI, Chang FM, Yao BL, Chang CH, Yu CH, Ko HC. Predicting birth weight by fetal upper-arm volume with use of three-dimensional ultrasonography. Am J Obstet Gynecol 1997; 177: 632–638.

- 15
Schild RL, Fimmers R, Hansmann M. Fetal weight estimation by three-dimensional ultrasound. Ultrasound Obstet Gynecol 2000; 16: 445–452.

- 16
Hastie T, Tibshirani R. Generalized additive models for medical research. Stat Methods Med Res 1995; 4: 187–196.

- 17
Bühlmann P, Hothorn T. Boosting algorithms: regularization, prediction and model fitting. Statist Sci 2007; 22: 477–505.

- 18
Bühlmann P, Yu B. Boosting with the L2 loss: regression and classification. J Am Stat Assoc 2003; 98: 324–339.

- 19
Venables WN, Ripley BD. Modern Applied Statistics with S. Springer: New York, NY, 2002.

- 20
Sauerbrei W, Royston P. Building multivariable prognostic and diagnostic models: Transformation of the predictors by using fractional polynomials. Journal of the Royal Statistical Society Series A 1999; 162: 71–94.

- 21
Sauerbrei W, Meier-Hirmer C, Benner A, Royston P. Multivariable regression model building by using fractional polynomials: description of SAS, STATA and R programs. Computational Statistics and Data Analysis 2006; 50: 3464–3485.

- 22
Breimann L. Random forests. Machine Learning 2001; 45: 5–32.

- 23
Hothorn T, Leisch F, Zeileis A, Hornik K. The design and analysis of benchmark experiments. Computational and Graphical Statistics 2005; 14: 675–699.

- 24
Scott F, Beeby P, Abbott J, Edelman D, Boogert A. New formula for estimating fetal weight below 1000 g: comparison with existing formulas. J Ultrasound Med 1996; 15: 669–672.

- 25
Weiner CP, Sabbagha RE, Vaisrub N, Socol ML. Ultrasonic fetal weight prediction: role of head circumference and femur length. Obstet Gynecol 1985; 65: 812–817.

- 26
Mielke G, Pietsch-Breitfeld B, Salinas R, Risse T, Marzusch K. A new formula for prenatal ultrasonographic weight estimation in extremely preterm fetuses. Gynecol Obstet Invest 1995; 40: 84–88.

- 27
Mielke G, Pietsch-Breitfeld B, Regele B, Gonser M, Marzusch K. An accurate method for sonographic estimation of the weight of very preterm fetuses. Gynecol Obstet Invest 1997; 43: 98–103.

- 28
Team RDC. R: A Language and Environment for Statistical Computing. R Foundation for Statistical Computing: Vienna, 2007.

- 29
Hothorn T, Bühlmann P, Kneib T, Schmid M. mboost: Model-based Boosting; R-package version 0.6–2. http://r-forge.r-project.org [Accessed 15 November 2007]. - 30
Hollander M, Wolfe DA. Nonparametric Statistical Methods (2^{nd} edn). John Wiley & Sons: New York, NY, 1999.

- 31
Balouet P, Hamel P, Domessent D, Allouche C, Speckel D, Barjot P, Herlicoviez M. [The estimation of fetal weight by measurement of the adipose tissue of the extremities. Use in the diagnosis of hypotrophy.] J Gynecol Obstet Biol Reprod (Paris) 1994; 23: 64–68.

- 32
Balouet P, Speckel D, Herlicoviez M. [Ultrasonic estimation of fetal weight. Value of measuring limb fat.] J Gynecol Obstet Biol Reprod (Paris) 1992; 21: 795–802.

- 33
Brinkley JF, McCallum WD, Muramatsu SK, Liu DY. Fetal weight estimation from ultrasonic three-dimensional head and trunk reconstructions: evaluation *in vitro*. Am J Obstet Gynecol 1982; 144: 715–721.

- 34
Combs CA, Jaekle RK, Rosenn B, Pope M, Miodovnik M, Siddiqi TA. Sonographic estimation of fetal weight based on a model of fetal volume. Obstet Gynecol 1993; 82: 365–370.

- 35
Deter RL, Warda A, Rossavik IK, Duncan G, Hadlock FP. Fetal thigh circumference: a critical evaluation of its relationship to menstrual age. J Clin Ultrasound 1986; 14: 105–110.

- 36
Favre R, Bader AM, Nisand G. Prospective study on fetal weight estimation using limb circumferences obtained by three-dimensional ultrasound. Ultrasound Obstet Gynecol 1995; 6: 140–144.

- 37
Favre R, Nisand G, Bettahar K, Grange G, Nisand I. Measurement of limb circumferences with three-dimensional ultrasound for fetal weight estimation. Ultrasound Obstet Gynecol 1993; 3: 176–179.

- 38
Jeanty P, Romero R, Hobbins JC. Fetal limb volume: a new parameter to assess fetal growth and nutrition. J Ultrasound Med 1985; 4: 273–282.

- 39
Landon MB, Sonek J, Foy P, Hamilton L, Gabbe SG. Sonographic measurement of fetal humeral soft tissue thickness in pregnancy complicated by GDM. Diabetes 1991; 40(Suppl 2): 66–70.

- 40
Lee W, Comstock CH, Kirk JS, Smith RS, Monck JW, Deenadayalu R, Bendick PJ. Birthweight prediction by three-dimensional ultrasonographic volumes of the fetal thigh and abdomen. J Ultrasound Med 1997; 16: 799–805.

- 41
Schild RL, Fimmers R, Hansmann M. [Can 3D volumetric analysis of the fetal upper arm and thigh improve conventional 2D weight estimates?]. Ultraschall Med 1999; 20: 31–37.

- 42
Shinozuka N, Okai T, Kohzuma S, Mukubo M, Shih CT, Maeda T, Kuwabara Y, Mizuno M. Formulas for fetal weight estimation by ultrasound measurements based on neonatal specific gravities and volumes. Am J Obstet Gynecol 1987; 157: 1140–1145.

- 43
Sood AK, Yancey M, Richards D. Prediction of fetal macrosomia using humeral soft tissue thickness. Obstet Gynecol 1995; 85: 937–940.

- 44
Warda A, Deter RL, Duncan G, Hadlock FP. Evaluation of fetal thigh circumference measurements: a comparative ultrasound and anatomical study. J Clin Ultrasound 1986; 14: 99–103.

- 45
Voigt M, Schneider KT, Jahrig K. [Analysis of a 1992 birth sample in Germany. 1: New percentile values of the body weight of newborn infants.] Geburtshilfe Frauenheilkd 1996; 56: 550–558.

- 46
Snedecor GW, Cochran WG. Statistical Methods. Iowa State University Press: Ames, IA, 1989; 192.