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Key Reviewer: Barbara Cormack, Paediatric Dietitian, Auckland City Hospital

Key concepts
  • Breastfeeding is best
  • Cows' milk based formula is recommended if breastfeeding does not occur
  • Soy formula is rarely indicated and is not recommended for cows' milk allergy
  • Hydrolysed cows' milk formula can be used for infants with cows' milk allergy

While it is recognised that breastfeeding is the best option for mother and baby, some mothers cannot or choose not to breastfeed. General practitioners, practice nurses and other health professionals should have knowledge of infant formula so they can provide guidance for these mothers.

Exclusive breastfeeding for around six months is ideal, at which time complementary foods can be introduced with continued breastfeeding until the infant is aged at least one year.1 All efforts should be made to encourage breastfeeding for as long as possible.

Important considerations when infant formula is used:1

  • Encourage the maintenance of breastfeeding if possible
  • Choose an appropriate formula for the infant's age
  • Cows' milk-based formula is routinely recommended for feeding an infant who is not breastfed
  • Soy based infant formula should not be used routinely
  • At six months of age, if an infant is thriving on regular or standard infant formula and complementary foods, there is generally no advantage to changing to a follow-on formula
  • Formula should be made up as close as possible to feeding time and needs to be handled and stored carefully

How does breast milk differ from formula milk?

Breast milk is a complex nutritional food that contains antibodies, enzymes and hormones, all of which have significant health benefits. While the composition of formula milk is modelled on breast milk it cannot replicate it exactly.2

Breast is best

Breast milk is the preferred food for all infants. It is a nutritionally complete food and is all that is required for a baby's first six months of life. It has many beneficial effects for both mother and infant. See Table 1 for examples.

Table 1: Beneficial effects of breast feeding for mother and infant1, 2

Beneficial effects for infant Beneficial effects for mother
Provides optimum nutrition Encourages contraction of the uterus after birth
Reduced incidence and severity of infectious disease (e.g. gastrointestinal or respiratory infection, otitis media) May reduce the risk of ovarian and breast cancer
Associated with decreased risk of chronic disease later in life (e.g. high blood pressure, obesity, diabetes) May help the mother return to her pre-pregnancy weight
Assists with physical and emotional development May reduce risk of other conditions (e.g. type 2 diabetes, postnatal depression, osteoporosis)

There are very few reasons not to breastfeed

There are only a few situations where breastfeeding is contraindicated such as infants with galactosemia, mothers receiving chemotherapy or mothers with HIV or uncontrolled tuberculosis.

Prescribing for breastfeeding mothers2

Maternal drug therapy should rarely constitute a reason to avoid breastfeeding.

Caution should be used with the following drugs and the infant monitored:
Antiepileptics Lithium Sedatives
Antipsychotics Diuretics Codeine*

Monitor the infant for evidence of adverse effects e.g. sedation, altered bowel habit.

In New Zealand, the rates of breastfeeding do not reflect the vital role breastfeeding plays in an infant's development. Overall only 66% of infants are breastfed at six weeks and this decreases to only 25% by six months.1

Useful reference sources

Ministry of Health:

UK Drugs in Lactation Advisory Service:

Drugs and Lactation Database (LactMed):


Breastfeeding rates and use of infant formula among Māori1

In 2006*, the rate of exclusive breastfeeding for Māori infants at six weeks of age was 59% compared with 66% of infants across all ethnic groups (70% for European infants, 55% for Asian infants and 57% for Pacific infants).

Information from 2005* shows that the rates of infant formula use was highest for Māori infants across all age groups (25% at six weeks, 37% at three months and 49% at six months).

"Whanau have the biggest influence on whether a mother breastfeeds or not, and provide the best support for the breastfeeding mother. The best way to improving breastfeeding statistics is through whanau, hapu and iwi development."

- Raeleen de Joux, Māori Educator, New Zealand Breastfeeding Authority. Te Karaka 2008, Issue 39.

Infant feeding definitions

Infant formula - Formula intended as a substitute to breast milk for infants from birth to six months old.

Follow-on formula - Formula that is marketed for infants aged from six months to 12 months.

Complementary feeding - Foods fed to infants from around six months to complement breastfeeding or formula feeding.