Inaccurate markings on low-cost feeding bottles for babies being sold in New Zealand could mean some babies are getting formula that is too concentrated.
Some bottles over-estimate the fluid volume by up to 40% and Consumer Affairs says this could cause vomiting, diarrhoea and constipation in babies.
The Ministry surveyed volume indicator markings on 35 bottles and found 15, mostly purchased from discount shops, had markings that were inaccurate by more than 5%.
Formula that is too concentrated can cause health problems that if untreated can cause serious dehydration. And the Ministry says this formula will provide excess energy calories and other nutrients which could lead to overweight or obese babies and toddlers.
It could also harm organs such as the kidneys, when they are still immature.
Most feeding bottles are imported and some meet a European regulatory standard (the EN14350 standard) which ensures the bottles are accurate. However, these bottles can be more expensive than bottles sold at discount shops.
The survey findings have prompted the Ministry of Health, in conjunction with Consumer Affairs (Ministry of Business, Innovation and Employment), the Pharmacy Guild and Plunket to develop guidance for caregivers.
The accuracy of feeding bottles can be checked at a pharmacy which has accurate measuring equipment. If necessary, the correct measures of volume can then be marked on their bottles.