Pregnant women who drink and take ecstasy are exposing their unborn babies to a dangerous drug duo more damaging than swallowing each substance alone, a study shows.
Tests on rats by University of Canterbury researchers has revealed the two drugs taken in tandem can cause severe brain abnormalities.
The study is the first direct evidence that the drug cocktail poses particular risk above the well-documented dangers posed by alcohol and ecstasy independently.
Babies born to women who take drugs while pregnant are more likely to be born prematurely, exhibit birth defects and develop behavioural and learning disabilities, psychology researcher Dr Juan Canales said.
As ecstasy users tend to also binge drink, the research team studied the combined effect of the drugs on the brains of female rats exposed to both ecstasy and alcohol in the womb.
The rodents had impaired memory function, produced fewer learning and memory-related neurons, and had fewer exploratory skills, Dr Canales said.
"These effects were minimal in subjects exposed to only one of the drugs, suggesting that the mixing of drugs can have very negative consequences," he said.
One in four women drink during pregnancy.
Eight per cent of New Zealanders aged 15 to 45 have used ecstasy at some time, with many younger adults taking the stimulant alongside cannabis, cigarettes and alcohol.
Dr Canales said the use of ecstasy has been reported among a small sub-group of pregnant women who are also highly likely to binge drink.