According to a new study pregnant teenagers don't get the no smoking message and almost half of all Australian teenage prospective mothers continue to smoke during pregnancy.
The research by scientists from the University of NSW's School of Women's and Children's Health has revealed that only 1 in 15 teenage smokers quits after they get pregnant.
This is despite scientific evidence that smoking beyond the 20th week of gestation leads to a sicklier baby with a significantly lower birth weight and a greater propensity for chronic diseases later in life.
Author, associate professor Elizabeth Sullivan, says the research shows that women should be encouraged to give up smoking throughout their pregnancy, because there are positive benefits from doing so.
Dr. Sullivan's research used data from the National Perinatal Data Collection on births in five Australian states, including Victoria, from 2001 to 2004.
The research found that 43.2% of teenage mothers smoked during pregnancy, compared with 17.9% of all mothers and only 6.7% of teenage mothers who were smokers quit before the second half of their pregnancy.
Scientific research has linked smoking during pregnancy with low birthweight, slower development and a predisposition to chronic disease in later life; it has also been linked to sudden infant death syndrome, childhood obesity and diabetes.
Dr. Sullivan's study found on average that babies born to teenage smokers were 180 grams lighter than babies born to teenage non-smokers but there was no noticeable difference in birth weight if the mothers quit smoking the before 20 weeks' gestation.
The study also found that reducing the quantity of cigarettes smoked during pregnancy also reduced the risk of low birthweight.
The researchers say health professionals need to target smoking cessation at all contacts with pregnant women who continue to smoke.
The research is published in The Medical Journal of Australia.