Over 50 percent of women do not know that drinking alcohol when pregnant could harm their unborn child, politicians were told today.
Speaking to Parliament's health select committee, Law Commission president Sir Geoffrey Palmer said 55 percent of women thought it was okay to drink during pregnancy.
"That figure is concerning."
[commentcaption=Do you think it's okay to drink when pregnant?]The drinking rate among women of child-bearing age was increasing and a major barrier was that education campaigns would not work, Sir Geoffrey said.
Policy analyst Susan Joy said for many young women the damage was done before they knew they were pregnant.
One solution was to change the binge drinking culture among young women, she said.
Alcohol was often a factor in unwanted pregnancies, abortion rates and sexually transmitted diseases with schools reporting an increase in services associated with these issues on Mondays - following a weekend of partying.
Once a woman knew she was pregnant advice could be given through primary health carers, Sir Geoffrey said.
Fetal Alcohol Spectrum Disorder (FASD) is the name given to a range of birth defects resulting from prenatal alcohol exposure
The disorders were all caused by mothers drinking during pregnancy and were not genetic, inherited or curable, the Alcohol Liquor Advisory Council's (Alac's) website says.
Birth defects could include growth retardation, central nervous system dysfunction, characteristic facial malformations, heart and kidney defects, hearing and sight impairments, limited joint movement, hernias, cleft lip or palate and brain damage.
Alac early intervention manager Sue Paton said Sir Geoffrey was quoting figures that came out of a report they commissioned in 2007.
The research found only 40 percent believed women should abstain altogether from drinking during pregnancy. Half of the women surveyed said one drink or less was safe to be consumed on a typical drinking occasion in pregnancy.
"It really is a concern because there is no known safe limit and some children have been damaged with relatively small amounts of alcohol.
"There has been inconsistent medical advice around it."
The Ministry of Health and Alac both advise "not to play Russian roulette" and for expectant mothers to avoid alcohol altogether.
In Canada 2/3 babies per 1000 births have severe FASD defects and 4/5 have lesser effects.
The lesser effects of FASD could still be "quite devastating", Ms Paton said.
New Zealand figures were hard to get and diagnosis was not always made correctly.