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Breastfeeding effects on newborn screening
Breastfeeding effects on newborn screening
References
To the Editor: We read with interest the article by Santoro et al1 on the amount of colostrum ingested by healthy newborns during the first 24 hours of life. Beyond their stated purpose to evaluate this variable as a predictor of successful breastfeeding, we believe their observation is also relevant to the timing of newborn screening sample collection. Early newborn discharge has led to newborn screening anticipation,2 with blood specimens collected shortly after 24 hours of life. This study showed that the amount of colostrum ingested by exclusively breastfed newborns in the prescreening interval is 15 11 g. Considering the colostrum protein composition,3 the cumulative intake by the time of blood specimen collection can be approximated to 0.2 g. This very small amount of exogenous protein is unlikely to cause an abnormal screening result in newborns affected by inborn errors of amino acid metabolism, such as phenylketonuria (PKU). Indeed, phenylalanine tolerance on PKU newborns may exceed by 20 to 40 times, from severe to benign phenotypes,4 the dietary phenylalanine intake during the first 24 hours of life. These findings validate the hypothesis that neonatal protein catabolism is the main determinant leading to abnormal screening outcomes in newborn with PKU.4 The low protein intake in the prescreening interval appears to be well below the exogenous protein tolerance (notwithstanding its wide variability) observed in urea cycle and branched chain amino acid disorders. These considerations are pertinent to many inborn errors of metabolism currently included in expanded newborn screening programs. Given the crucial role of neonatal protein catabolism in determining the outcome of newborn screening, attentive evaluation of potentially influencing factors may be relevant for the optimization of the timing of blood specimen collection, as well as for the interpretation of results.
1. Santoro W Jr., Martinez FE, Ricco RG, Jorge SM. Colostrum ingested during the first day of life by exclusively breastfed healthy newborn infants. J Pediatr 2010;56:29-32. 2. Friedman MA, Spitzer AR. Discharge criteria for the term newborn. Pediatr Clin North Am 2004;51:599-618. 3. Ra¨iha¨ NCR. Protein content of human milk, from cholostrum to mature milk. In: Ra¨iha¨ NCRR, ed. Protein Metabolism During Infancy. New York: Raven Press; 1994. p. 211-28. 4. Ponzone A, Spada M, Roasio L, Porta F, Mussa A, Ferraris S. Impact of neonatal protein metabolism and nutrition on screening for phenylketonuria. J Pediatr Gastroenterol Nutr 2008;46:561-9.
Francesco Porta, MD Alessandro Mussa, MD Biochemical Genetics Laboratory Division of Laboratory Genetics Department of Laboratory Medicine and Pathology Mayo Clinic College of Medicine Rochester, Minnesota Department of Pediatrics University of Torino
Walter Santoro, Jr, MD Francisco Eulo´gio Martinez, MD Rubens Garcia Ricco, MD Salim Moyse´s Jorge, MD University of Sa˜o Paulo Hospital Das Clı´nicas de Ribeiraˆo Preto Departamento de Pediatria Sa˜o Paulo, Brazil
Alberto Ponzone, MD Department of Pediatrics University of Torino Torino, Italy 10.1016/j.jpeds.2010.01.055
Reply To the Editor: We agree with the comments presented by Porta et al based on the results of our study. Porta et al stated that ‘‘This very small amount of exogenous protein (ingested in 24 hours) is unlikely to cause by itself an abnormal screening result in newborns affected by inborn errors of amino acid metabolism, such as phenylketonuria.’’ This consideration is particularly important when the newborn is discharged early, within 24 hours of life. Wall et al1 found that ‘‘Adequacy of newborn metabolic screening does not have to be compromised by early discharge, but care must be taken to ensure that additional specimens be obtained when appropriate according to AAP guidelines.’’2 The American Academy of Pediatrics recommends collecting a specimen for screening as close to discharge as possible, and if it is collected before 24 hours of age, that the infant be rescreened at 1 to 2 weeks of age.2 In our region in Brazil, the screening for inborn metabolic errors is obtained between 3 and 7 days of life, with most of the specimens being obtained after discharge.3 We agree that it might be possible that the small amount of ingested protein could result in false-negative screening results.
10.1016/j.jpeds.2010.02.001
References 1. Wall TC, Brumfield CG, Cliver SP, Hou J, Ashworth CS, Norris MJ. Does early discharge with nurse home visits affect adequacy of newborn metabolic screening? J Pediatr 2003;143:213-8.
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References
To the Editor: We read with interest the article by Santoro et al1 on the amount of colostrum ingested by healthy newborns during the first 24 hours of life. Beyond their stated purpose to evaluate this variable as a predictor of successful breastfeeding, we believe their observation is also relevant to the timing of newborn screening sample collection. Early newborn discharge has led to newborn screening anticipation,2 with blood specimens collected shortly after 24 hours of life. This study showed that the amount of colostrum ingested by exclusively breastfed newborns in the prescreening interval is 15 11 g. Considering the colostrum protein composition,3 the cumulative intake by the time of blood specimen collection can be approximated to 0.2 g. This very small amount of exogenous protein is unlikely to cause an abnormal screening result in newborns affected by inborn errors of amino acid metabolism, such as phenylketonuria (PKU). Indeed, phenylalanine tolerance on PKU newborns may exceed by 20 to 40 times, from severe to benign phenotypes,4 the dietary phenylalanine intake during the first 24 hours of life. These findings validate the hypothesis that neonatal protein catabolism is the main determinant leading to abnormal screening outcomes in newborn with PKU.4 The low protein intake in the prescreening interval appears to be well below the exogenous protein tolerance (notwithstanding its wide variability) observed in urea cycle and branched chain amino acid disorders. These considerations are pertinent to many inborn errors of metabolism currently included in expanded newborn screening programs. Given the crucial role of neonatal protein catabolism in determining the outcome of newborn screening, attentive evaluation of potentially influencing factors may be relevant for the optimization of the timing of blood specimen collection, as well as for the interpretation of results.
1. Santoro W Jr., Martinez FE, Ricco RG, Jorge SM. Colostrum ingested during the first day of life by exclusively breastfed healthy newborn infants. J Pediatr 2010;56:29-32. 2. Friedman MA, Spitzer AR. Discharge criteria for the term newborn. Pediatr Clin North Am 2004;51:599-618. 3. Ra¨iha¨ NCR. Protein content of human milk, from cholostrum to mature milk. In: Ra¨iha¨ NCRR, ed. Protein Metabolism During Infancy. New York: Raven Press; 1994. p. 211-28. 4. Ponzone A, Spada M, Roasio L, Porta F, Mussa A, Ferraris S. Impact of neonatal protein metabolism and nutrition on screening for phenylketonuria. J Pediatr Gastroenterol Nutr 2008;46:561-9.
Francesco Porta, MD Alessandro Mussa, MD Biochemical Genetics Laboratory Division of Laboratory Genetics Department of Laboratory Medicine and Pathology Mayo Clinic College of Medicine Rochester, Minnesota Department of Pediatrics University of Torino
Walter Santoro, Jr, MD Francisco Eulo´gio Martinez, MD Rubens Garcia Ricco, MD Salim Moyse´s Jorge, MD University of Sa˜o Paulo Hospital Das Clı´nicas de Ribeiraˆo Preto Departamento de Pediatria Sa˜o Paulo, Brazil
Alberto Ponzone, MD Department of Pediatrics University of Torino Torino, Italy 10.1016/j.jpeds.2010.01.055
Reply To the Editor: We agree with the comments presented by Porta et al based on the results of our study. Porta et al stated that ‘‘This very small amount of exogenous protein (ingested in 24 hours) is unlikely to cause by itself an abnormal screening result in newborns affected by inborn errors of amino acid metabolism, such as phenylketonuria.’’ This consideration is particularly important when the newborn is discharged early, within 24 hours of life. Wall et al1 found that ‘‘Adequacy of newborn metabolic screening does not have to be compromised by early discharge, but care must be taken to ensure that additional specimens be obtained when appropriate according to AAP guidelines.’’2 The American Academy of Pediatrics recommends collecting a specimen for screening as close to discharge as possible, and if it is collected before 24 hours of age, that the infant be rescreened at 1 to 2 weeks of age.2 In our region in Brazil, the screening for inborn metabolic errors is obtained between 3 and 7 days of life, with most of the specimens being obtained after discharge.3 We agree that it might be possible that the small amount of ingested protein could result in false-negative screening results.
10.1016/j.jpeds.2010.02.001
References 1. Wall TC, Brumfield CG, Cliver SP, Hou J, Ashworth CS, Norris MJ. Does early discharge with nurse home visits affect adequacy of newborn metabolic screening? J Pediatr 2003;143:213-8.
1033