The lead researcher of a new study that has found nearly a quarter of women drink alcohol during the first three months of pregnancy says the findings prove more needs to be done.
The findings were part of the Growing Up in New Zealand study following nearly 7000 children from birth until they are aged 21.
The study found while 71 percent of women drank alcohol before becoming pregnant, 23 percent continued through the first trimester and 13 percent continued to drink further into pregnancy.
It concluded drinking was common in New Zealand women, particularly among Pākehā and Māori, and some women drank alcohol heavily during pregnancy.
Auckland University professor Chris Bullen said the findings show New Zealand's drinking culture needed to change.
"I think why we're seeing it in European and Māori women is because of the prevalent drinking culture and I think that's fundamentally where things need to change, so that alcohol isn't a norm and it certainly isn't regarded as a thing that you do if you are possibly, likely or currently planning to be pregnant."
He said children would suffer if further measures were not put in place to curb the number of women drinking during pregnancy.
"We estimate that possibly between 600 and 3000 children are born every year with foetal alcohol spectrum disorder which is this cluster of intellectual impairment, learning difficulties, behaviour problems and growth impairment."
Mr Bullen said the study's findings were disappointing because they proved efforts to provide safe environments for babies to grow in weren't working.
"Obviously the messages around not drinking if you could be pregnant or while you're pregnant are not getting through to quite a high proportion of women."
Health Minister David Clark said the research was worrying.
He said he believed women knew the risks but drank alcohol anyway.
"I'm encouraged by the work of the Health Promotion Agency, the story around if you don't know then don't drink, but clearly ongoing work is required because it's deeply concerning that some people are still choosing to drink, even when they know that they're pregnant."