Answer to Q21.
Use of infant formula in addition to breastfeeding is usually strongly discouraged since it is likely to reduce the output of mother's milk, and could result in unintended early ending of breastfeeding. This is because the rate of production of breastmilk is determined by the amount which the baby consumes.
However there can be circumstances where breastmilk production is simply insufficient to provide for baby's needs, and consequently baby can remain hungry after feeding. In such cases it may be helpful to add some feed in the form of a proprietary infant formula. This should only be done after discussion with your health care professional, and when it has been clearly established that the mother is probably not going to be able to breastfeed fully. The likely consequences for later breastfeeding must be fully explained and an informed decision made.
If the reduction in supply of mother's milk is likely to be only temporary, a plan must be made to replace the formula again progressively with mother's milk until the supply is re-established.
Such partial replacement of breast milk must only be with infant formula: cow's milk (diluted or not) or other fluids are completely unsuitable and could be dangerous. The formula must be made according to instructions and no other food added to the bottle.