Mothers have been urged to breastfeed for longer, with new research indicating it improves child intelligence and language.
Scientists have found that longer breastfeeding, even when it is not exclusive, leads to higher intelligence scores at age seven.
Compared with bottle-fed children, seven-year-olds breastfed for the first year of life were likely to score four points higher in a test of verbal IQ.
Verbal intelligence scores at age seven increased by 0.35 points for every extra month of breastfeeding.
A similar but less pronounced trend was seen for non-verbal IQ scores, which increased by 0.29 points per breastfeeding month
Three-year-olds also benefited, having higher scores in a picture vocabulary language acquisition test the longer they had been breastfed.
Exclusive breastfeeding - rather than any level of breastfeeding - had the greatest effect, boosting verbal IQ scores by nearly a point per month.