Breast-feeding by a mother with cystic fibrosis.

A 20-year-old white women with cystic fibrosis who breast-fed her normal infant is described. Extensive breast milk analysis revealed normal sodium and chloride concentrations but elevated total protein and low total fat content; IgG and IgM levels were low to absent. The infant tolerated breast-feeding well, with normal growth and without infections, but the nutritional status of the mother appeared to be adversely affected. This case illustrates that breast-feeding by a mother with cystic fibrosis appears to be feasible but is fraught with difficulties.