Researcher Dr Sherly Parackal says the only way to reduce the risk of fetal alcohol spectrum disorder is for all sexually active women of child bearing age to reduce their alcohol consumption.

Up to one in two pregnant women may be exposing their unborn child to fetal alcohol spectrum disorder (FASD), a University of Otago researcher says.

Dr Sherly Parackal shared some of the findings of her study about alcohol exposure during pre-conception and early pregnancy at the Public Health Association conference in Christchurch on Tuesday.

She said the issue was a serious and underestimated public health problem in New Zealand as there were up to 3000 babies born each year with undiagnosed FASD.

123RF A study has found high levels of pre and early pregnancy drinking among Kiwi women.

Binge drinking during the peri-conception period – one month before conception and two months afterwards – put a fetus at risk as the first eight weeks was when organs including the brain and heart were developing.

READ MORE:

* Teenage murderer denied sentence appeal

​* Calls for disability screening for kids at age 5

* Raising a FASD child is a 'life sentence'

In the yet to be published study by Parackal and her husband Dr Mathew Parackal, 1075 women aged 18 to 35 were asked about their drinking habits and understanding of the effects of alcohol on fetal development.

They found 55 to 61 per cent of the survey participants drank more than five standard drinks on a "usual drinking day" and were classified as "risky" or "binge" drinkers.

Of the pregnant women in the survey, 50 per cent stopped drinking when they learned they were pregnant, while 10 per cent carried on drinking throughout.

Pre-pregnancy drinking habits meant 60 per cent of pregnancies were exposed to alcohol, Parackal said.

Even women who were not planning a pregnancy were putting a potential fetus at risk by continuing with risky drinking, as 40 per cent were using "ineffective" contraception, the study found.

The effects of alcohol were moderated according to a range of factors including the amount drunk, how much food was consumed, the genetic make-up of the woman and her nutritional status, Parackal said.

"We can't say what the safe level of consumption is because most of the studies are done on animals as it is not ethical to do this on humans."

Observational studies on the drinking patterns of pregnant women and the effects on their babies were less accurate because they relied on subjective recall.

Parackal said alcohol was an established teratogen – a substance that caused birth defects – which meant periconception consumption would increase the risk of an abnormality, Parackal said.

FASD included a range of behavioural and mental health conditions that could become apparent well after a baby was born and even in to adulthood.

"There are women who have had a binge during that period and had a baby that was perfectly normal at birth, but we don't know because the child might be perfectly normal to look at and then later on when they go to school they might have learning issues or other defects."

​Ministry of Health guidelines recommend pregnant women stop drinking for the duration of their pregnancy as there is no known safe level of alcohol consumption.

Last year, the Government launched a FASD action plan, which encouraged whānau to support pregnant women to stop drinking during pregnancy.

But Parackal said it did not address women who were risky drinkers and did not know they were pregnant.

The only way to reduce the risk of FASD was for all sexually active women of child bearing age to reduce their alcohol consumption.

"It's not just FASD, alcohol is also a carcinogen it can increase the risk of breast cancer, it affects the metabolism of certain nutrients . . . so her health is at risk and then if she goes on to get pregnant she is risking the health of the baby."

Parackal hopes the study will lead to a public health campaign encouraging a reduction in alcohol consumption among young women.