[Breast feeding: health benefits for child and mother].

Breast milk contains hormones, growth factors, cytokines, cells, etc., and offers many advantages over cow's milk or soy protein infant formulae. The composition of breast milk is influenced by gestational and postnatal age. Prevalence of breastfeeding in France is one of the lowest in Europe: in 2003, only 58% of infants were breastfed when leaving the maternity ward, for a median duration of 10 weeks. Breastfeeding allows normal growth until at least 6 months of age, and can be prolonged until the age of 2 years or more, provided that complementary feeding is started after 6 months. Breastfeeding is associated with slightly enhanced performance on tests of cognitive development. Exclusive breastfeeding for at least 3 months is associated with a lower incidence and severity of diarrhoea, otitis media and respiratory infection. Exclusive breastfeeding for at least 6 months is associated with a lower incidence of allergic disease in at-risk infants (infants with at least one first-degree relative presenting with allergy). Breastfeeding is also associated with a lower incidence of obesity during childhood and adolescence, as well as with a lower incidence of hypertension and hypercholesterolemia in adulthood. Maternal infection with hepatitis B and C virus is not a contraindication to breastfeeding, as opposed to HIV infection and galactosemia. A supplementation with vitamin D and K is necessary in the breastfed infant. Very few medications contraindicate breastfeeding. Premature babies can be breastfed and/or receive mother's milk and/or bank milk, provided they receive energy, protein and mineral supplements. Return to prepregnancy weight is earlier in breastfeeding mothers. Breastfeeding is also associated with a decreased risk of breast and ovarian cancer in the premenopausal period, and of hip fractures and osteoporosis in the postmenopausal period.