Maternal milk is the major source of nutrients and growthpromoting substances in the first weeks of life for the majority of neonates. Epidermal growth factor (EGF) and transforming growth factor-␣ (TGF-␣) are trophic peptides present in human milk with significant healing effects on injured gastrointestinal mucosa. Decreasing gestational age of neonates is associated with higher risk of developing gastrointestinal disorders, and human milk provides better protection against these diseases compared with formula. The aim of this study was to evaluate the concentrations of EGF and TGF-␣ in human milk collected from mothers with infants born: extremely preterm, preterm, and full term. Milk samples were collected at the end of first, second, and fourth week postpartum from each mother of infants born in one of the three gestational age groups: extremely preterm (23-27 wk, n ϭ 16), preterm (32-36 wk, n ϭ 16), and full term (38 -42 wk, n ϭ 15). Milk concentrations of EGF and TGF-␣ were quantified with a homologous RIA in the milk aqueous fraction. Concentrations of EGF in human milk from the extremely preterm group (23-27 wk) were significantly higher compared with values from the preterm and full-term groups throughout the first month of lactation. A similar pattern was observed with human milk TGF-␣; however, milk TGF-␣ levels were lower than EGF.In conclusion, we have found higher concentrations of EGF and TGF-␣ in human milk of mothers with extremely preterm babies. These data may indicate the potential importance of milk-borne EGF and TGF-␣ for the development of extremely premature infants. (Pediatr Res 54: 15-19, 2003) Abbreviations EGF, epidermal growth factor EGF-R, epidermal growth factor receptor EPT, extremely preterm FT, full term PT, preterm NEC, necrotizing enterocolitis TGF-␣, transforming growth factor-␣ Human milk is a unique and well-balanced source of nutrition for the newborn. Milk contains not only major nutrients (proteins, carbohydrates, and lipids) but also a variety of components such as minerals, vitamins, enzymes, hormones, growth factors, and immunoglobulins important for growth and healthy development during the neonatal period (1-3). As advances in neonatal care have significantly increased, the survival of extremely prematurely born neonates have increased (4). Yet these infants have the highest incidence of morbid events, such as NEC (5). Questions have arisen about the most suitable and relevant nutritional support for these immature infants (6, 7).Within the last three decades, a large number of biologically active peptides have been identified in human milk (8 -10), and the list is continuously growing (11-13). Among these, EGF is one of the major peptide growth factors present both in colostrum and human milk (14 -17). Human milk EGF levels are highest in the first days after parturition and then gradually decrease during the first 2 wk of lactation (17). Another structural homolog of EGF, TGF-␣ is also present in human colostrum and milk (15, 18), but at much lower concentrations ...