The growth of the fetus, which is strongly associated with the outcome of pregnancy, reflects interplay of several physiological and pathological factors. The assessment of fetal growth is based on comparison of birthweight (BW) or estimated fetal weight (EFW) to standards which define reference ranges at a spectrum of gestational ages. Most birthweight standards do not take into account effects of physiological determinants of fetal growth. Additionally, gestational age in many standards is based on the menstrual history and is often inaccurate. Fetal growth norms should be based on an early ultrasound estimate of gestational age. Customized standards, which have included only ultrasound-dated pregnancies, seem to be superior to population-based birthweight norms in predicting perinatal mortality and morbidity. Adjustment for individual variation in customized growth curves reduces false-positive diagnosis of IUGR and may lead to a very significant reduction in intervention for suspected IUGR. Customized growth potential identifies better the risk for adverse outcome than the currently used national standards, but customized charts may fail in detecting growth-restricted stillbirth. An individual’s birthweight is the sum of physiological and pathological influences operating during pregnancy. Growth potential norms are a better discriminator of aberrations of fetal growth than population, ultrasound, and customized norms. 1. Introduction The assessment of fetal growth is based on comparison of birthweight (BW) or estimated fetal weight (EFW) to standards which define reference ranges at a spectrum of gestational ages [1–3]. EFW and BW are indirect measures of the outcome of primary interest, the intrauterine fetal growth. The growth of the fetus, which is strongly associated with the outcome of pregnancy, reflects interplay of several physiological and pathological factors [4–6]. The aim of this study was to review different birthweight standards and evaluate effects of physiological determinants of fetal growth on the ability of the different standards for BW, EFW, and customized growth charts to identify adverse outcomes of pregnancy. 2. Study Design A non-systematic search in the PubMed was undertaken using terms “birthweight” combined with “gestational age,” “menstrual dating,” “ultrasound dating,” “estimated fetal weight,” “customized growth charts,” “malformation,” “stillbirth,” “family influence,” and “individualized BW ratio,” respectively. We have focused on studies that proposed fetal growth standards which took into account effects of
References
[1]
S. L. Johnsen, T. Wilsgaard, S. Rasmussen, R. Sollien, and T. Kiserud, “Longitudinal reference charts for growth of the fetal head, abdomen and femur,” European Journal of Obstetrics Gynecology and Reproductive Biology, vol. 127, no. 2, pp. 172–185, 2006.
[2]
K. Marsal, P. H. Persson, T. Larsen, H. Lilja, A. Selbing, and B. Sultan, “Intrauterine growth curves based on ultrasonically estimated foetal weights,” Acta Paediatrica, International Journal of Paediatrics, vol. 85, no. 7, pp. 843–848, 1996.
[3]
A. M. Thomson, W. Z. Billewicz, and F. E. Hytten, “The assessment of fetal growth,” The Journal of Obstetrics and Gynaecology of the British Commonwealth, vol. 75, no. 9, pp. 903–916, 1968.
[4]
F. Figueras and J. Gardosi, “Should we customize fetal growth standards?” Fetal Diagnosis and Therapy, vol. 25, no. 3, pp. 297–303, 2009.
[5]
J. Gardosi, M. Mongelli, M. Wilcox, and A. Chang, “An adjustable fetal weight standard,” Ultrasound in Obstetrics & Gynecology, vol. 6, no. 3, pp. 168–174, 1995.
[6]
K. M. Groom, K. K. Poppe, R. A. North, and L. M. E. McCowan, “Small-for-gestational-age infants classified by customized or population birthweight centiles: impact of gestational age at delivery,” American Journal of Obstetrics and Gynecology, vol. 197, no. 3, pp. 239.e1–239.e5, 2007.
[7]
T. Mul, M. Mongelli, and J. Gardosi, “A comparative analysis of second-trimester ultrasound dating formulae in pregnancies conceived with artificial reproductive techniques,” Ultrasound in Obstetrics and Gynecology, vol. 8, no. 6, pp. 397–402, 1996.
[8]
R. T. Geirsson, “Ultrasound: the rational way to determine gestational age,” Fetal and Maternal Medicine Review, vol. 9, no. 3, pp. 133–146, 1997.
[9]
S. Rasmussen, S. Albrechtsen, L. M. Irgens et al., “Unexplained antepartum fetal death in Norway, 1985–97: diagnostic validation and some epidemiologic aspects,” Acta Obstetricia et Gynecologica Scandinavica, vol. 82, no. 2, pp. 109–115, 2003.
[10]
R. Skjaerven, H. K. Gjessing, and L. S. Bakketeig, “Birthweight by gestational age in Norway,” Acta Obstetricia et Gynecologica Scandinavica, vol. 79, no. 6, pp. 440–449, 2000.
[11]
M. J. Khoury, J. D. Erickson, J. F. Cordero, and B. J. McCarthy, “Congenital malformations and intrauterine growth retardation: a population study,” Pediatrics, vol. 82, no. 1, pp. 83–90, 1988.
[12]
R. Bukowski, G. C. S. Smith, F. D. Malone et al., “Fetal growth in early pregnancy and risk of delivering low birth weight infant: prospective cohort study,” British Medical Journal, vol. 334, no. 7598, pp. 836–838, 2007.
[13]
T. H. Beaty, R. Skjaerven, D. R. Breazeale, and K. Y. Liang, “Analyzing sibship correlations in birth weight using large sibships from Norway,” Genetic Epidemiology, vol. 14, no. 4, pp. 423–433, 1997.
[14]
M. N. Karn and L. S. Penrose, “Birth weight and gestation time in relation to maternal age, parity and infant survival,” Annals of Eugenics, vol. 16, pp. 147–164, 1952.
[15]
R. N. Pollack and M. Y. Divon, “Intrauterine growth retardation: definition, classification, and etiology,” Clinical Obstetrics and Gynecology, vol. 35, no. 1, pp. 99–107, 1992.
[16]
R. L. Goldenberg and S. P. Cliver, “Small for gestational age and intrauterine growth restriction: definitions and standards,” Clinical Obstetrics and Gynecology, vol. 40, no. 4, pp. 704–714, 1997.
[17]
P. Magnus, “Birth weight of relatives by maternal tendency to repeat small-for-gestational-age (SGA) births in successive pregnancies,” Acta Obstetricia et Gynecologica Scandinavica, Supplement, vol. 76, no. 165, pp. 35–38, 1997.
[18]
M. Mongelli and J. Gardosi, “Fetal growth,” Current Opinion in Obstetrics and Gynecology, vol. 12, no. 2, pp. 111–115, 2000.
[19]
R. Skjaerven, H. K. Gjessing, and L. S. Bakketeig, “New standards for birth weight by gestational age using family data,” American Journal of Obstetrics and Gynecology, vol. 183, no. 3, pp. 689–696, 2000.
[20]
R. Skjaerven and L. S. Bakketeig, “Classification of small-for-gestational age births: weight-by-gestation standards of second birth conditional on the size of the first,” Paediatric and Perinatal Epidemiology, vol. 3, no. 4, pp. 432–447, 1989.
[21]
L. O. Lubchenco, C. Hanseman, M. Dressler, and E. Boyde, “Intrauterine growth as estimated from liveb orn birth-weigh data at 24 to 42 weeks of gestation,” Pediatrics, vol. 32, pp. 793–800, 1963.
[22]
R. Usher and F. McLean, “Intrauterine growth of live-born Caucasian infants at sea level: standards obtained from measurements in 7 dimensions of infants born between 25 and 44 weeks,” The Journal of Pediatrics, vol. 74, no. 6, pp. 901–910, 1969.
[23]
M. R. Storms and R. S. Van Howe, “Birthweight by gestational age and sex at a rural referral center,” Journal of Perinatology, vol. 24, no. 4, pp. 236–240, 2004.
[24]
R. L. Williams, R. K. Creasy, and G. C. Cunningham, “Fetal growth and perinatal viability in California,” Obstetrics and Gynecology, vol. 59, no. 5, pp. 624–632, 1982.
[25]
M. S. Kramer, R. W. Platt, S. W. Wen et al., “A new and improved population-based Canadian reference for birth weight for gestational age,” Pediatrics, vol. 108, no. 2, p. E35, 2001.
[26]
G. R. Alexander, J. H. Himes, R. B. Kaufman, J. Mor, and M. Kogan, “A United States National reference for fetal growth,” Obstetrics and Gynecology, vol. 87, no. 2, pp. 163–168, 1996.
[27]
W. C. Graafmans, J. H. Richardus, G. J. J. M. Borsboom et al., “Birth weight and perinatal mortality: a comparison of “optimal” birth weight in seven western European countries,” Epidemiology, vol. 13, no. 5, pp. 569–574, 2002.
[28]
T. E. Arbuckle, R. Wilkins, and G. J. Sherman, “Birth weight percentiles by gestational age in Canada,” Obstetrics and Gynecology, vol. 81, no. 1, pp. 39–48, 1993.
[29]
U. Chike-Obi, R. J. David, R. Coutinho, and S. Y. Wu, “Birth weight has increased over a generation,” American Journal of Epidemiology, vol. 144, no. 6, pp. 563–569, 1996.
[30]
S. L. Johnsen, S. Rasmussen, T. Wilsgaard, R. Sollien, and T. Kiserud, “Longitudinal reference ranges for estimated fetal weight,” Acta Obstetricia et Gynecologica Scandinavica, vol. 85, no. 3, pp. 286–297, 2006.
[31]
R. Bukowski, D. Gahn, J. Denning, and G. Saade, “Impairment of growth in fetuses destined to deliver preterm,” American Journal of Obstetrics and Gynecology, vol. 185, no. 2, pp. 463–467, 2001.
[32]
R. Bukowski, “Fetal growth potential and pregnancy outcome,” Seminars in Perinatology, vol. 28, no. 1, pp. 51–58, 2004.
[33]
P. Royston and E. M. Wright, “How to construct “normal ranges” for fetal variables,” Ultrasound in Obstetrics and Gynecology, vol. 11, no. 1, pp. 30–38, 1998.
[34]
M. Wilcox, J. Gardosi, M. Mongelli, C. Ray, and I. Johnson, “Birth weight from pregnancies dated by ultrasonography in a multicultural British population,” British Medical Journal, vol. 307, no. 6904, pp. 588–591, 1993.
[35]
I. E. Olsen, S. A. Groveman, M. L. Lawson, R. H. Clark, and B. S. Zemel, “New intrauterine growth curves based on United States data,” Pediatrics, vol. 125, no. 2, pp. e214–e224, 2010.
[36]
M. S. Kramer, “Determinants of low birth weight: methodological assessment and meta-analysis,” Bulletin of the World Health Organization, vol. 65, no. 5, pp. 663–737, 1987.
[37]
J. Gardosi, A. Chang, B. Kalyan, D. Sahota, and E. M. Symonds, “Customised antenatal growth charts,” The Lancet, vol. 339, no. 8788, pp. 283–287, 1992.
[38]
J. Gardosi, F. Figueras, B. Clausson, and A. Francis, “The customised growth potential: an international research tool to study the epidemiology of fetal growth,” Paediatric and Perinatal Epidemiology, vol. 25, no. 1, pp. 2–10, 2011.
[39]
B. Clausson, J. Gardosi, A. Francis, and S. Cnattingius, “Perinatal outcome in SGA births defined by customised versus population-based birthweight standards,” British Journal of Obstetrics and Gynaecology, vol. 108, no. 8, pp. 830–834, 2001.
[40]
J. Gardosi and A. Francis, “Adverse pregnancy outcome and association with small for gestational age birthweight by customized and population-based percentiles,” American Journal of Obstetrics and Gynecology, vol. 201, no. 1, pp. 28.e1–28.e8, 2009.
[41]
A. C. Sciscione, R. Gorman, and N. A. Callan, “Adjustment of birth weight standards for maternal and infant characteristics improves the prediction of outcome in the small-for-gestational-age infant,” American Journal of Obstetrics and Gynecology, vol. 175, no. 3, part 1, pp. 544–547, 1996.
[42]
C. L. D. de Jong, J. Gardosi, G. A. Dekker, G. J. Colenbrander, and H. P. Van Geijn, “Application of a customised birthweight standard in the assessment of perinatal outcome in a high risk population,” British Journal of Obstetrics and Gynaecology, vol. 105, no. 5, pp. 531–535, 1998.
[43]
P. Owen, T. Farrell, J. C. R. Hardwick, and K. S. Khan, “Relationship between customised birthweight centiles and neonatal anthropometric features of growth restriction,” An International Journal of Obstetrics and Gynaecology, vol. 109, no. 6, pp. 658–662, 2002.
[44]
A. Dua and C. Schram, “An investigation into the applicability of customised charts for the assessment of fetal growth in antenatal population at Blackburn, Lancashire, UK,” Journal of Obstetrics and Gynaecology, vol. 26, no. 5, pp. 411–413, 2006.
[45]
J. F. Fr？en, J. O. Gardosi, A. Thurmann, A. Francis, and B. Stray-Pedersen, “Restricted fetal growth in sudden intrauterine unexplained death,” Acta Obstetricia et Gynecologica Scandinavica, vol. 83, no. 9, pp. 801–807, 2004.
[46]
V. Lyon, A. Howatson, K. S. Khan, and P. Owen, “Unadjusted and customised weight centiles in the identification of growth restriction among stillborn infants,” An International Journal of Obstetrics and Gynaecology, vol. 111, no. 12, pp. 1460–1463, 2004.
[47]
A. O. Odibo, A. Francis, A. G. Cahill, G. A. MacOnes, J. P. Crane, and J. Gardosi, “Association between pregnancy complications and small-for-gestational-age birth weight defined by customized fetal growth standard versus a population-based standard,” Journal of Maternal-Fetal and Neonatal Medicine, vol. 24, no. 3, pp. 411–417, 2011.
[48]
A. O. Odibo, A. G. Cahill, L. Odibo, K. Roehl, and G. A. Macones, “Prediction of intrauterine fetal death in small-forgestational-age fetuses: impact of including ultrasound biometry in customized models,” Ultrasound in Obstetrics & Gynecology, vol. 39, no. 3, pp. 288–292, 2012.
[49]
R. Resnik, “To customise or not to customise: that is the question,” Paediatric and Perinatal Epidemiology, vol. 25, no. 1, pp. 17–19, 2011.
[50]
J. A. Hutcheon, X. Zhang, R. W. Platt, S. Cnattingius, and M. S. Kramer, “The case against customised birthweight standards,” Paediatric and Perinatal Epidemiology, vol. 25, no. 1, pp. 11–16, 2011.
[51]
X. Zhang, R. W. Platt, S. Cnattingius, K. S. Joseph, and M. S. Kramer, “The use of customised versus population-based birthweight standards in predicting perinatal mortality,” An International Journal of Obstetrics and Gynaecology, vol. 114, no. 4, pp. 474–477, 2007.
[52]
J. A. Hutcheon, X. Zhang, and R. W. Platt, “The benefits of customizing for maternal factors or the benefits of using an intrauterine standard at preterm ages?” American Journal of Obstetrics and Gynecology, vol. 199, no. 1, pp. e18–e19, 2008.
[53]
P. Owen, J. Ogah, L. M. Bachmann, and K. S. Khan, “Prediction of intrauterine growth restriction with customised estimated fetal weight centiles,” An International Journal of Obstetrics and Gynaecology, vol. 110, no. 4, pp. 411–415, 2003.
[54]
D. A. Sanderson, M. A. Wilcox, and I. R. Johnson, “The individualised birthweight ratio: a new method of identifying intrauterine growth retardation,” British Journal of Obstetrics and Gynaecology, vol. 101, no. 4, pp. 310–314, 1994.
[55]
R. L. Deter, I. K. Rossavik, and R. J. Carpenter, “Development of individual growth standards for estimated fetal weight: II. Weight prediction during the third trimester and at birth,” Journal of Clinical Ultrasound, vol. 17, no. 2, pp. 83–88, 1989.
[56]
R. Bukowski, T. Uchida, G. C. S. Smith et al., “Individualized norms of optimal fetal growth: fetal growth potential,” Obstetrics and Gynecology, vol. 111, no. 5, pp. 1065–1076, 2008.
[57]
M. Mongelli and J. Gardosi, “Reduction of false-positive diagnosis of fetal growth restriction by application of customized fetal growth standards,” Obstetrics and Gynecology, vol. 88, no. 5, pp. 844–848, 1996.
