Introduction: Breastfeeding as a component of PKU treatment has not been well documented. Until 1980, all infants diagnosed with PKU were weaned from breastfeeding and placed on a combined diet of phenylalanine (Phe) – free formula and standard infant formula. Breast milk is lower in Phe than standard infant formula. Yet, breastfeeding alone can result in elevated Phe levels, necessitating supplementation with Phe-free formula.
Aim: To describe the incidence and duration of breastfeeding among infants with PKU who received management through the Child Development and Rehabilitation Center Metabolic Clinic, Oregon Health & Science University.
Sample: Criteria were any infant diagnosed with PKU between January 1, 1980 and December 31, 2005 and who received PKU management by one month of age.
Method: Retrospective chart review of all infants with PKU from 1980-2005. Data were collected from the clinic medical record on a variety of demographic and clinical variables.
Results: Ninety-seven infants were managed during the study period; 74 were breastfed for varying lengths of time after diagnosis. The incidence and duration of breastfeeding at time of diagnosis by decade (1980’s, 1990’s and 2000’s) for infants diagnosed with PKU was 72%, 74% and 87%, respectively.
Table 1: Incidence and Duration of Breastfeeding Infants with PKU compared with Healthy People 2000 Objectives and National US Breastfeeding Rates 1980 and 1990

Duration of Breastfeeding	HP2000 Breastfeeding Objectives	PKU Infants, OHSU 1980-1989 (n=36)	National US Breastfeeding 1980	PKU Infants, OHSU 1990-1999 (n=38)	National US Breastfeeding 1990
Initial Postpartum	64%	72%	55%	74%	52%
6 months	29%	42%	23%	21%	18%
12 months	16%	0.1%	NA	0.02%	NA

OHSU = Oregon Health & Science University
Table 2: Incidence and Duration of Breastfeeding Infants with   PKU compared with Healthy People 2010 Objectives and National US Breastfeeding Rates

Duration of Breastfeeding	HP201000 Breastfeeding Objectives	PKU Infants, OHSU 2000-2005 (n=23)	National US Breastfeeding 2005	Oregon Breastfeeding 2005
Initial Postpartum	75%	86%	73%	86%
6 months	50%	77%	39%	53%
12 months	25%	36%	20%	26%

OHSU = Oregon Health & Science University
Summarized in Tables 1 and 2, these data indicate that infants receiving metabolic management for PKU at this clinic are breastfeeding longer than normal, healthy infants not only within the state of Oregon, but the United States. The mothers are not only meeting the Healthy People 2010 objectives, but surpassing them in all three objectives. In addition, 66% of the infants (n=62) have mean Phe values within the desired treatment range (2-6mg/dl).
Conclusion: These results are remarkable considering that mothers of infants with PKU who are breastfeeding are also managing the disorder of PKU.  In addition, these results are highly encouraging since many mothers with infants with PKU at other treatment facilities still are told to wean their infants upon diagnosis.