Breastfeeding indicators among a nationally representative multi-ethnic sample of New Zealand children.

Aims: To describe breastfeeding initiation and duration, and demographic associations with breastfeeding duration within a representative sample of New Zealand infants.

Methods: In 6,685 singletons enrolled in the Growing Up in New Zealand cohort we described breastfeeding initiation (96%), any (94%) and exclusive (93%) breastfeeding (EBF) duration. We used adjusted relative risk (RR) and 95% confidence intervals (CI) to describe associations with breastfeeding duration.

Results: Breastfeeding initiation occurred for 97%. Sixteen percent were EBF to age six months and 13% were breastfed to age 24 months. Exclusive breastfeeding for ≥4 months was less likely for children of mothers of Māori (RR=0.80, 95% CI 0.73-0.87), Pacific (0.90, 95% CI 0.83-0.98) or Asian (0.80, 95% CI 0.74-0.86) ethnicity. Children of mothers aged 20-29 years (1.24, 95% CI 1.04-1.49); ≥30 years (1.36, 95% CI 1.14-1); with a tertiary education (1.14, 95% CI 1.08-1.21); or planned pregnancy (1.14, 95% CI 1.08-1.21); and children with older siblings (RR=1.31, 95% CI 1.17-1.47) were more likely to be exclusively breastfed for ≥4 months. Children were more likely to be breastfed ≥6 months if their mother was aged 20-29 (1.26, 95% CI 1.10-1.45) or ≥30 years (1.40, 95% CI 1.22-1.61), had a tertiary education (1.11, 95% CI 1.06-1.59) or planned pregnancy (1.11, 95% CI 1.06-1.15), or if they had older siblings (1.04, 95% CI 1.00-1.08).

Conclusion: In New Zealand, most children are initially breastfed, however a large proportion did not receive the recommended duration of any or exclusive breastfeeding. Maternal age, education, parity and pregnancy planning identify children at risk of shorter duration of breastfeeding and EBF, and maternal ethnicity identifies children at risk of shorter EBF duration.