- Email: [email protected]
Assessment of Growth From Foot Length in Taiwanese Neonates
Pediatr Neonatol 2009;50(6):287−290
B R IEF C O MMUNIC AT ION
Assessment of Growth From Foot Length in Taiwanese Neonates Tsyr-Yuh Ho1, Shan-Fu Ou1, Shih-Hui Huang2, Chi-Ning Lee1, Luo-Ping Ger3, Kai-Sheng Hsieh3, Shih-Ming Huang4*, Ken-Pen Weng1,2,3* 1
Department of Pediatrics, Zuoying Armed Forces General Hospital, Kaohsiung, Taiwan Department of Nursing, Fooyin University, Kaohsiung, Taiwan 3 Department of Pediatrics and Medical Education and Research, Kaohsiung Veterans General Hospital, National Yang-Ming University, Taipei, Taiwan 4 Department of Pediatrics, Kaohsiung Municipal United Hospital, Kaohsiung, Taiwan 2
Received: Nov 3, 2008 Revised: Jan 20, 2009 Accepted: Mar 12, 2009 KEY WORDS: birth body length; birth body weight; foot length
Background: Previous studies have demonstrated a positive correlation between foot length (FL) and birth body weight (BBW), birth body length (BBL), and head circumference (HC). However, there is no data on birth FL in Taiwan. The aim of this study was to evaluate FL measurement in Taiwanese neonates as a method of estimating other anthropometric indices. Methods: In this retrospective study, we enrolled 256 babies born at our hospital and Kaohsiung Veterans General Hospital from 2003−2005. Medical records were reviewed for sex, BBW, BBL, HC, gestational age, and birth FL. Ill newborns, small-for-gestational-age babies, or those with poor birth footprints were excluded. FL at birth was measured from the center of the back of the heel to the tip of the big toe. Linear regression analysis was used to investigate the relation of FL to BBW and BBL. The intraclass correlation coefficient was used to assess inter-rater reliability. Results: A total of 256 babies were reviewed. There were 136 male and 120 female neonates. The gestational age was 38.5 ± 1.3 (mean ± standard deviation) weeks, ranging from 35−42 weeks. The BBW was 3137 ± 396 g. The BBL was 51.1 ± 2.1 cm. The HC was 33.5 ± 1.7 cm. The FL was 7.4 ± 0.46 cm. The regression equation for BBW (y) on FL (x) was as follows: y = 486.2 + 360.4x (p < 0.001, r = 0.421). The regression equation for BBL (y) on FL (x) was as follows: y = 40.1 + 1.45x (p < 0.001, r = 0.305). The regression equation for HC (y) on FL (x) was as follows: y = 14.8 + 2.53x (p < 0.001, r = 0.423). FL showed excellent reliability, with an intraclass correlation coefficient of 0.965 (p < 0.001). Conclusion: Our study demonstrated a significant degree of correlation between FL and BBW, BBL and HC. However, it did not reliably estimate BBW, BBL, or HC—the three anthropometric indices were weakly correlated (r < 0.5) with FL.
*Corresponding authors. Department of Pediatrics Kaohsiung Municipal United Hospital, 976 Chunghwa 1st Road, Kaohsiung 804,Taiwan; or Department of Pediatrics, Kaohsiung Veterans General Hospital, 386 Ta-Chung 1st Road, Kaohsiung 813, Taiwan. E-mail: [email protected] or [email protected] ©2009 Taiwan Pediatric Association
288
T.Y. Ho et al
1. Introduction Accurate assessment of growth in the neonatal period is very important. Weight, height, and head circumference are the commonly used measures of growth in neonates. Weight measurements are significantly affected by changes in water, carbohydrate, fat, protein, and mineral levels.1 The accurate measurement of height in an uncooperative or critically ill neonate is difficult. Although head circumference reflects brain growth,2 the effect of head sparing during malnutrition may result in an underestimation of growth.3 The newborn foot is usually readily accessible for measurement, even in incubators. Previous studies have demonstrated close positive correlation between foot length (FL) and height.4−6 However, there is no data on birth FL in Taiwan. The aim of this study was to evaluate FL in Taiwanese neonates as a method of estimating other anthropometric indices.
A
B
Figure 1 Birth footprint showing the points A (tip of the big toe) and B (center of back of the heel), the distance between which was measured as foot length.
2. Patients and Methods Table 1 Demographic data of study babies*
In this retrospective study, we collected and analyzed the physical data of 256 babies at Zuoying Armed Forces General Hospital and Kaohsiung Veterans General Hospital from 2003− 2005. Medical records were reviewed for sex, birth body weight (BBW), birth body length (BBL), head circumference (HC), gestational age, and birth FL. Ill newborns, small-for-gestational-age babies, or those with poor birth FL, were excluded. The babies’ birth footprints were routinely stamped on their medical records by staff at the nurseries of these two hospitals. FL at birth was measured from the center of the back of the heel to the tip of the big toe (Figure 1). For reliable measurement of birth FL, an inter-rater reliability evaluation was completed. The FL of each baby was made by eight different nurses. A total of 20 babies were included in the interrater reliability test.
2.1. Statistical analysis The statistical software SPSS version 10 (SPSS Inc., Chicago, IL, USA) was used to analyze all data. Between-group differences were analyzed by the chi-squared test or Fisher’s exact test (for categorical measures), and by Student’s t test for continuous measures. Linear regression was used to investigate the relationship between FL and BBW/ BBL. The intraclass correlation coefficient was used to assess the inter-rater reliability. Statistical significant was defined as p < 0.05.
Number Sex (male/female) Gestational age (wk) Birth body weight (g) Birth body length (cm) FL (cm)
256 136/120 38.5 ± 1.3 3137 ± 396 51.1 ± 2.1 7.4 ± 0.46
*Data are presented as mean ± standard deviation. FL = foot length.
3. Results A total of 256 babies were reviewed. Demographic data are displayed in Table 1. There were 136 male neonates and 120 females. The gestational age was 38.5 ± 1.3 (mean ± standard deviation) weeks, ranging from 35−42 weeks. The BBW was 3137 ± 396 g; BBL was 51.1 ± 2.1 cm; HC was 33.5 ± 1.7 cm; and FL was 7.4 ± 0.46 cm. There was a significant correlation between FL and gestational age (p = 0.033, r = 0.133), BBW (p < 0.001, r = 0.421), BBL (p < 0.001, r = 0.305), and HC (p < 0.001, r = 0.423). The regression equation for BBW (y) on FL (x) was: y = 486.2 + 360.4x (Figure 2). The regression equation for BBL (y) on FL (x) was: y = 40.1 + 1.45x (Figure 3). The regression equation for HC (y) on FL (x) was: y = 14.8 + 2.53x (Figure 4). The measurement of FL showed excellent reliability, with intraclass correlation coefficient of 0.965 (p < 0.001).
Foot length in neonates
289
4500.00
40.00
y = 14.8 + 2.53x (p < 0.001, r = 0.423)
38.00
4000.00
HC (cm)
BBW (g)
36.00 3500.00
3000.00
34.00 32.00
2500.00
30.00 y = 486.2 + 360.4x (p < 0.001, r = 0.421)
2000.00 6.00
6.50
7.00
7.50 8.00 FL (cm)
8.50
9.00
Figure 2 Correlation between foot length (FL) and birth body weight (BBW).
57.50 55.00
BBL (cm)
52.50 50.00 47.50 45.00 y = 40.1 + 1.45x (p < 0.001, r = 0.305)
42.50 6.00
6.50
7.00
7.50 8.00 FL (cm)
8.50
9.00
Figure 3 Correlation between foot length (FL) and birth body length (BBL).
4. Discussion Our study demonstrated a significant degree of correlation between FL and BBW, BBL, and HC. However, FL is not a reliable estimator of BBW, BBL, or HC; the three anthropometric indices were weakly correlated (r < 0.5) with FL. To the authors’ knowledge, this is the first study exploring the relationship between neonate FL and other anthropometric indices in Taiwan. The relationship between FL and other anthropometric measurements have been reported in previous studies.4−6 Rutishauser reported a highly significant degree of association between height and FL in young children.4 The measurement of
28.00 6.00
6.50
7.00 7.50 FL (cm)
8.00
8.50
Figure 4 Correlation between foot length (FL) and head circumference (HC).
height from FL in the children is of value both in field surveys and in case of deformity. James et al demonstrated a positive linear correlation between FL and other indices of babies of gestational age 26−42 weeks.5 They concluded that birthweight and crown-heel length can be estimated from a measurement of FL that is performed simply and rapidly. Gohil et al carried out a similar study with a larger sample.6 They found FL correlated well with birth weight, crown heel length, and head circumference. They suggested when it is difficult to weigh or measure the body length accurately, FL can serve as a useful measurement to assess a baby quickly. Our result was not compatible with previous findings.5,6 The inconsistent results between previous studies and ours may be caused by different methods of FL measurement. In previous studies,5,6 FL had been suggested to be useful in ill neonates nursed in incubators and receiving intensive care. Such babies usually require a variety of interventions, including intravenous fluids, antibiotics, and inotropic agents. The dosage of these are calculated according to body weight. In neonates who are inaccessible for measurements of body weight and length, the measurement of FL might provide an alternative method of calculating fluid requirements and drug dosages. This makes the measurement of FL in ill babies an important issue. However, the relationship between FL and weight in ill neonates has not been investigated (in previous studies or this study), so no conclusion can be reliably drawn. FL has been proved to be useful in other clinical conditions.7−11 Anderson et al reported that the relationship between FL and stature showed little change with increasing age from 1−18 years.7 The
290 foot was found to grow in synchrony with the body as a whole rather than with the lower extremity. The length from heel to toe maintained the same relationship with the length from heel to head at all ages (during which the foot was increasing in size). Mercer et al showed that ultrasonographic measurement of fetal FL was useful in the assessment of gestational age.8 They concluded that fetal FL is a reliable parameter for use in the assessment of gestational age and is particularly useful when other parameters do not accurately predict gestational age—for example, hydrocephalus, anencephaly, and short-limb dysplasia. Markowski and Lawler also showed that FL was positively related to gestational age.9 Pospisilova-Zuzakora reported that fetal FL was related positively to fetal body length.10 A study by Embleton et al showed that FL was the best predictor of naris-midtracheal length.11 They concluded that FL is a reliable and reproducible predictor of nasotracheal tube length and is at least as accurate as the conventional weightbased estimation. This method may be particularly valuable in ill and unstable infants. The mechanisms which explain the role of FL in various clinical conditions has yet to be elucidated. As FL is a linear body measurement from the fetal period to adolescence, it may correlate closely with gestational age, body weight, body length, head circumference, or tracheal length. Several limitations in this study need to be specified. This study was a retrospective investigation with only a small number of patients; this may introduce bias into our results. The variable degree of measurement clarity may affect the measurement of FL. Although inter-rater reliability was high in this study, different staff members at the nurseries may have measured footprints in different ways, causing bias in measurement of FL. We did not use a specially designed foot gauge as used by James et al.5 We also did not include a smallfor-gestational-age group. FL was not measured serially from the fetal stage. A prospective cohort study with a large sample size is required to confirm the accuracy of the relationship between FL and other anthropometric indices in Taiwan.
T.Y. Ho et al In conclusion, our study demonstrated a significant correlation between FL and BBW, BBL, and HC. However, it FL is not a reliable estimator of BBW, BBL, or HC.
Acknowledgments This study was supported by a grant from the Zuoying Armed Forces General Hospital (9602) and Veterans General Hospital-Kaohsiung, Taiwan (VGHKS 97-092).
References 1.
Lucas A. Enteral nutrition. In: Tsang R, Lucas A, Uaay R, et al, eds. Nutritional Needs of the Preterm Infant: Scientific Basis and Practical Guidelines. Baltimore: Williams and Wilkins, 1993:209−24. 2. Cooke RW, Lucas A, Yudkin PL, et al. Head circumference as an index of brain weight in the fetus and newborn. Early Hum Dev 1977;1:145−9. 3. Sparks JW, Ross JC, Cetin I. Intrauterine growth and nutrition. In: Polin RA, Fox WW, eds. Fetal and Neonatal Physiology. Philadelphia: WB Saunders, 1992:267−90. 4. Rutishauser IH. Prediction of height from foot length: Use of measurement in field surveys. Arch Dis Child 1968;43:310−2. 5. James DK, Dryburgh EH, Chiswick ML. Foot length: a new and potentially useful measurement in the neonate. Arch Dis Child 1979;54:226−30. 6. Gohil JR, Sosi M, Vani SN, Desai AB. Foot length measurement in the neonate. Indian J Pediatr 1991;58:675−7. 7. Anderson M, Blais M, Green WT. Growth of the normal foot during childhood and adolescence: length of the foot and interrelations of foot, stature, and lower extremity as seen in serial records of children between 1−18 years of age. Am J Phys Anthropol 1956;14:287−308. 8. Mercer BM, Sklar S, Shariatmadar A, Gillieson MS, D’Alton ME. Fetal foot length as a predictor of gestational age. Am J Obstet Gynecol 1987;156:350−5. 9. Markowski B, Lawler SD. Use of early fetal tissues obtained from suction termination of pregnancy. Lancet 1977;1: 186−8. 10. Pospisilova-Zuzakora V. Determination of the body length of the fetus with the aid of the length of the sole of the foot. Biologia 1962;17:49−52. 11. Embleton ND, Deshpande SA, Scott D, Wright C, Milligan DW. Foot length, an accurate predictor of nasotracheal tube length in neonates. Arch Dis Child Fetal Neonatal Ed 2001;85:60−4.
B R IEF C O MMUNIC AT ION
Assessment of Growth From Foot Length in Taiwanese Neonates Tsyr-Yuh Ho1, Shan-Fu Ou1, Shih-Hui Huang2, Chi-Ning Lee1, Luo-Ping Ger3, Kai-Sheng Hsieh3, Shih-Ming Huang4*, Ken-Pen Weng1,2,3* 1
Department of Pediatrics, Zuoying Armed Forces General Hospital, Kaohsiung, Taiwan Department of Nursing, Fooyin University, Kaohsiung, Taiwan 3 Department of Pediatrics and Medical Education and Research, Kaohsiung Veterans General Hospital, National Yang-Ming University, Taipei, Taiwan 4 Department of Pediatrics, Kaohsiung Municipal United Hospital, Kaohsiung, Taiwan 2
Received: Nov 3, 2008 Revised: Jan 20, 2009 Accepted: Mar 12, 2009 KEY WORDS: birth body length; birth body weight; foot length
Background: Previous studies have demonstrated a positive correlation between foot length (FL) and birth body weight (BBW), birth body length (BBL), and head circumference (HC). However, there is no data on birth FL in Taiwan. The aim of this study was to evaluate FL measurement in Taiwanese neonates as a method of estimating other anthropometric indices. Methods: In this retrospective study, we enrolled 256 babies born at our hospital and Kaohsiung Veterans General Hospital from 2003−2005. Medical records were reviewed for sex, BBW, BBL, HC, gestational age, and birth FL. Ill newborns, small-for-gestational-age babies, or those with poor birth footprints were excluded. FL at birth was measured from the center of the back of the heel to the tip of the big toe. Linear regression analysis was used to investigate the relation of FL to BBW and BBL. The intraclass correlation coefficient was used to assess inter-rater reliability. Results: A total of 256 babies were reviewed. There were 136 male and 120 female neonates. The gestational age was 38.5 ± 1.3 (mean ± standard deviation) weeks, ranging from 35−42 weeks. The BBW was 3137 ± 396 g. The BBL was 51.1 ± 2.1 cm. The HC was 33.5 ± 1.7 cm. The FL was 7.4 ± 0.46 cm. The regression equation for BBW (y) on FL (x) was as follows: y = 486.2 + 360.4x (p < 0.001, r = 0.421). The regression equation for BBL (y) on FL (x) was as follows: y = 40.1 + 1.45x (p < 0.001, r = 0.305). The regression equation for HC (y) on FL (x) was as follows: y = 14.8 + 2.53x (p < 0.001, r = 0.423). FL showed excellent reliability, with an intraclass correlation coefficient of 0.965 (p < 0.001). Conclusion: Our study demonstrated a significant degree of correlation between FL and BBW, BBL and HC. However, it did not reliably estimate BBW, BBL, or HC—the three anthropometric indices were weakly correlated (r < 0.5) with FL.
*Corresponding authors. Department of Pediatrics Kaohsiung Municipal United Hospital, 976 Chunghwa 1st Road, Kaohsiung 804,Taiwan; or Department of Pediatrics, Kaohsiung Veterans General Hospital, 386 Ta-Chung 1st Road, Kaohsiung 813, Taiwan. E-mail: [email protected] or [email protected] ©2009 Taiwan Pediatric Association
288
T.Y. Ho et al
1. Introduction Accurate assessment of growth in the neonatal period is very important. Weight, height, and head circumference are the commonly used measures of growth in neonates. Weight measurements are significantly affected by changes in water, carbohydrate, fat, protein, and mineral levels.1 The accurate measurement of height in an uncooperative or critically ill neonate is difficult. Although head circumference reflects brain growth,2 the effect of head sparing during malnutrition may result in an underestimation of growth.3 The newborn foot is usually readily accessible for measurement, even in incubators. Previous studies have demonstrated close positive correlation between foot length (FL) and height.4−6 However, there is no data on birth FL in Taiwan. The aim of this study was to evaluate FL in Taiwanese neonates as a method of estimating other anthropometric indices.
A
B
Figure 1 Birth footprint showing the points A (tip of the big toe) and B (center of back of the heel), the distance between which was measured as foot length.
2. Patients and Methods Table 1 Demographic data of study babies*
In this retrospective study, we collected and analyzed the physical data of 256 babies at Zuoying Armed Forces General Hospital and Kaohsiung Veterans General Hospital from 2003− 2005. Medical records were reviewed for sex, birth body weight (BBW), birth body length (BBL), head circumference (HC), gestational age, and birth FL. Ill newborns, small-for-gestational-age babies, or those with poor birth FL, were excluded. The babies’ birth footprints were routinely stamped on their medical records by staff at the nurseries of these two hospitals. FL at birth was measured from the center of the back of the heel to the tip of the big toe (Figure 1). For reliable measurement of birth FL, an inter-rater reliability evaluation was completed. The FL of each baby was made by eight different nurses. A total of 20 babies were included in the interrater reliability test.
2.1. Statistical analysis The statistical software SPSS version 10 (SPSS Inc., Chicago, IL, USA) was used to analyze all data. Between-group differences were analyzed by the chi-squared test or Fisher’s exact test (for categorical measures), and by Student’s t test for continuous measures. Linear regression was used to investigate the relationship between FL and BBW/ BBL. The intraclass correlation coefficient was used to assess the inter-rater reliability. Statistical significant was defined as p < 0.05.
Number Sex (male/female) Gestational age (wk) Birth body weight (g) Birth body length (cm) FL (cm)
256 136/120 38.5 ± 1.3 3137 ± 396 51.1 ± 2.1 7.4 ± 0.46
*Data are presented as mean ± standard deviation. FL = foot length.
3. Results A total of 256 babies were reviewed. Demographic data are displayed in Table 1. There were 136 male neonates and 120 females. The gestational age was 38.5 ± 1.3 (mean ± standard deviation) weeks, ranging from 35−42 weeks. The BBW was 3137 ± 396 g; BBL was 51.1 ± 2.1 cm; HC was 33.5 ± 1.7 cm; and FL was 7.4 ± 0.46 cm. There was a significant correlation between FL and gestational age (p = 0.033, r = 0.133), BBW (p < 0.001, r = 0.421), BBL (p < 0.001, r = 0.305), and HC (p < 0.001, r = 0.423). The regression equation for BBW (y) on FL (x) was: y = 486.2 + 360.4x (Figure 2). The regression equation for BBL (y) on FL (x) was: y = 40.1 + 1.45x (Figure 3). The regression equation for HC (y) on FL (x) was: y = 14.8 + 2.53x (Figure 4). The measurement of FL showed excellent reliability, with intraclass correlation coefficient of 0.965 (p < 0.001).
Foot length in neonates
289
4500.00
40.00
y = 14.8 + 2.53x (p < 0.001, r = 0.423)
38.00
4000.00
HC (cm)
BBW (g)
36.00 3500.00
3000.00
34.00 32.00
2500.00
30.00 y = 486.2 + 360.4x (p < 0.001, r = 0.421)
2000.00 6.00
6.50
7.00
7.50 8.00 FL (cm)
8.50
9.00
Figure 2 Correlation between foot length (FL) and birth body weight (BBW).
57.50 55.00
BBL (cm)
52.50 50.00 47.50 45.00 y = 40.1 + 1.45x (p < 0.001, r = 0.305)
42.50 6.00
6.50
7.00
7.50 8.00 FL (cm)
8.50
9.00
Figure 3 Correlation between foot length (FL) and birth body length (BBL).
4. Discussion Our study demonstrated a significant degree of correlation between FL and BBW, BBL, and HC. However, FL is not a reliable estimator of BBW, BBL, or HC; the three anthropometric indices were weakly correlated (r < 0.5) with FL. To the authors’ knowledge, this is the first study exploring the relationship between neonate FL and other anthropometric indices in Taiwan. The relationship between FL and other anthropometric measurements have been reported in previous studies.4−6 Rutishauser reported a highly significant degree of association between height and FL in young children.4 The measurement of
28.00 6.00
6.50
7.00 7.50 FL (cm)
8.00
8.50
Figure 4 Correlation between foot length (FL) and head circumference (HC).
height from FL in the children is of value both in field surveys and in case of deformity. James et al demonstrated a positive linear correlation between FL and other indices of babies of gestational age 26−42 weeks.5 They concluded that birthweight and crown-heel length can be estimated from a measurement of FL that is performed simply and rapidly. Gohil et al carried out a similar study with a larger sample.6 They found FL correlated well with birth weight, crown heel length, and head circumference. They suggested when it is difficult to weigh or measure the body length accurately, FL can serve as a useful measurement to assess a baby quickly. Our result was not compatible with previous findings.5,6 The inconsistent results between previous studies and ours may be caused by different methods of FL measurement. In previous studies,5,6 FL had been suggested to be useful in ill neonates nursed in incubators and receiving intensive care. Such babies usually require a variety of interventions, including intravenous fluids, antibiotics, and inotropic agents. The dosage of these are calculated according to body weight. In neonates who are inaccessible for measurements of body weight and length, the measurement of FL might provide an alternative method of calculating fluid requirements and drug dosages. This makes the measurement of FL in ill babies an important issue. However, the relationship between FL and weight in ill neonates has not been investigated (in previous studies or this study), so no conclusion can be reliably drawn. FL has been proved to be useful in other clinical conditions.7−11 Anderson et al reported that the relationship between FL and stature showed little change with increasing age from 1−18 years.7 The
290 foot was found to grow in synchrony with the body as a whole rather than with the lower extremity. The length from heel to toe maintained the same relationship with the length from heel to head at all ages (during which the foot was increasing in size). Mercer et al showed that ultrasonographic measurement of fetal FL was useful in the assessment of gestational age.8 They concluded that fetal FL is a reliable parameter for use in the assessment of gestational age and is particularly useful when other parameters do not accurately predict gestational age—for example, hydrocephalus, anencephaly, and short-limb dysplasia. Markowski and Lawler also showed that FL was positively related to gestational age.9 Pospisilova-Zuzakora reported that fetal FL was related positively to fetal body length.10 A study by Embleton et al showed that FL was the best predictor of naris-midtracheal length.11 They concluded that FL is a reliable and reproducible predictor of nasotracheal tube length and is at least as accurate as the conventional weightbased estimation. This method may be particularly valuable in ill and unstable infants. The mechanisms which explain the role of FL in various clinical conditions has yet to be elucidated. As FL is a linear body measurement from the fetal period to adolescence, it may correlate closely with gestational age, body weight, body length, head circumference, or tracheal length. Several limitations in this study need to be specified. This study was a retrospective investigation with only a small number of patients; this may introduce bias into our results. The variable degree of measurement clarity may affect the measurement of FL. Although inter-rater reliability was high in this study, different staff members at the nurseries may have measured footprints in different ways, causing bias in measurement of FL. We did not use a specially designed foot gauge as used by James et al.5 We also did not include a smallfor-gestational-age group. FL was not measured serially from the fetal stage. A prospective cohort study with a large sample size is required to confirm the accuracy of the relationship between FL and other anthropometric indices in Taiwan.
T.Y. Ho et al In conclusion, our study demonstrated a significant correlation between FL and BBW, BBL, and HC. However, it FL is not a reliable estimator of BBW, BBL, or HC.
Acknowledgments This study was supported by a grant from the Zuoying Armed Forces General Hospital (9602) and Veterans General Hospital-Kaohsiung, Taiwan (VGHKS 97-092).
References 1.
Lucas A. Enteral nutrition. In: Tsang R, Lucas A, Uaay R, et al, eds. Nutritional Needs of the Preterm Infant: Scientific Basis and Practical Guidelines. Baltimore: Williams and Wilkins, 1993:209−24. 2. Cooke RW, Lucas A, Yudkin PL, et al. Head circumference as an index of brain weight in the fetus and newborn. Early Hum Dev 1977;1:145−9. 3. Sparks JW, Ross JC, Cetin I. Intrauterine growth and nutrition. In: Polin RA, Fox WW, eds. Fetal and Neonatal Physiology. Philadelphia: WB Saunders, 1992:267−90. 4. Rutishauser IH. Prediction of height from foot length: Use of measurement in field surveys. Arch Dis Child 1968;43:310−2. 5. James DK, Dryburgh EH, Chiswick ML. Foot length: a new and potentially useful measurement in the neonate. Arch Dis Child 1979;54:226−30. 6. Gohil JR, Sosi M, Vani SN, Desai AB. Foot length measurement in the neonate. Indian J Pediatr 1991;58:675−7. 7. Anderson M, Blais M, Green WT. Growth of the normal foot during childhood and adolescence: length of the foot and interrelations of foot, stature, and lower extremity as seen in serial records of children between 1−18 years of age. Am J Phys Anthropol 1956;14:287−308. 8. Mercer BM, Sklar S, Shariatmadar A, Gillieson MS, D’Alton ME. Fetal foot length as a predictor of gestational age. Am J Obstet Gynecol 1987;156:350−5. 9. Markowski B, Lawler SD. Use of early fetal tissues obtained from suction termination of pregnancy. Lancet 1977;1: 186−8. 10. Pospisilova-Zuzakora V. Determination of the body length of the fetus with the aid of the length of the sole of the foot. Biologia 1962;17:49−52. 11. Embleton ND, Deshpande SA, Scott D, Wright C, Milligan DW. Foot length, an accurate predictor of nasotracheal tube length in neonates. Arch Dis Child Fetal Neonatal Ed 2001;85:60−4.