Preterm human milk : Human breast milk is considered the reference 'Gold standard' for comparison with other milks. The various nutritional advantages (more cystine & taurine, better fat absorption; greater bioavailability of trace elements like Iron) as well as non nutritional advantages of human milk (immunological & antimicrobial protection, hormones & growth factors, emotional etc) are well established. These are of special importance to LBW babies with immature gut & susceptibility to infections.

It is amazing that the composition of preterm mother's milk is suited to increased requirement of certain nutrients of the preterm baby.

Thus, milk of mother delivering prematurely has higher content of proteins, sodium, fatty acids, energy, Ca+, Mg+, Zn, Cu, Fe, IgA & other host defence factors. These difference are more marked between 28 - 32 weeks of gestation.

Gastric emptying is faster with human milk than formula milk.

Many studies comparing long term neurodevelopment outcome have shown higher scores on babies fed human milk.

Thus, preterm milk if fed at higher volumes of 180-200 ml/kg/day may provide adequate calories & proteins in most LBW babies (especially in babies weighing 1.5 - 2.5 kg) & is the ideal feed.

However, there are practical problems:

• The mother may not be available in the NICU.
• The rates of secondary lactation failure are high in these mothers who are emotionally stressed & worried due to multiple factors like separation of babies who are kept in NICU, sick babies etc.

Thus, one has to consider other alternatives. Also in VLBW babies, human milk may not meet the increase nutritional demands.

Bank - human milk : There are various disadvantages of using milk from breast milk banks. Heat treatment (which is essential to prevent spread of infection) & storage destroys the important anti-infective factors (IgA, IgG, lactoferrin etc). Also, since most of the banked milk is derived from full term donor mother's drip milk (drip milk has very low calories & protein content), it is likely to be inadequate for the LBW baby's need.

Animal (cow's) milk : Fresh dairy milk is an easily available & affordable breast milk substitute, which is traditionally used in our country. It can be humanized by diluting it & adding sugar. Thus, it could match the protein & energy content of breast milk quantitatively but there are definite qualitative differences in the various components, which are not suited for optional growth of LBW baby. The disadvantages are:

• High solute load due to excess sodium & proteins, which the immature kidneys cannot handle.
• Different whey : Casein ratio (80:20)
• Allergenic properties (more important in Family history of atopy)
• Poor in essential fatty acids, iron & minerals.

AAP has recommended against use of dairy milk in 1st 6 months of life. This is obviously impractical in our country where cow's milk forms a cheaper alternative to breast milk. The other advantage is that no preparation (as opposed to formula milk) is required thereby reducing chances of infection.

Formula milk : These are artificially prepared to match the breast milk composition of various nutrients & are considered next best alternative to breast milk. They are based on various recommendations given by committees on nutrition of LBW.

Regarding use of formula milk, it is extremely important to have correct handling of these formulae as unhygienic preparation & wrong dilution can prove extremely hazardous to the baby.

Therefore, formula should be used only if one is convinced that the mother can afford it & can used it hygienically & in correct dilution.