NEARLY half of Australia's teenage mothers smoke during pregnancy, a study has found. And only one in 15 teenage smokers quits after they get pregnant, despite proof that smoking past the 20th week of gestation leads to a sicklier baby that weighs significantly less and is prone to chronic diseases later in life.
But the researchers say they are taking some positives out of the research, published in The Medical Journal of Australia.
"It shows that women should be encouraged to give up smoking throughout their pregnancy, because there are positive benefits (from doing so) the whole way through, especially before halfway," said associate professor Elizabeth Sullivan from the University of NSW's School of Women's and Children's Health.
The research was taken from data on births in five Australian states from 2001 to 2004.
It found that 43.2% of teenage mothers smoked during pregnancy, compared with 17.9% of all mothers. Only 6.7% of teenage mothers who were smokers quit before the second half of their pregnancy.
Previous studies have linked smoking during pregnancy with low birthweight, slower development and a predisposition to chronic disease in later life in the child. It has also been linked to sudden infant death syndrome, childhood obesity and diabetes.
This study found that, on average, babies born to teenage smokers were 180 grams lighter than babies born to teenage non-smokers. However, there was no noticeable difference in birth weight if the teenage smoking mothers quit the habit before 20 weeks' gestation.
Reducing the quantity of cigarettes smoked during pregnancy also reduced the risk of low birthweight.