Many new mothers will become pregnant again, and given that a new paper argues for continue anti-smoking campaigns after children are born to reduce the risk of future preterm births.

The longitudinal analysis of surveys results examined the records and histories across 23 years, of 63,540 Australian women with more than one child, who smoked during their first pregnancy.

Lead researcher, Professor Gavin Pereira from Curtin's School of Population Health said more than one third of women who smoked during pregnancy were able to stop smoking for their next pregnancy. "While the benefit of quitting in reducing the harm to unborn babies is well established, less well understood was the prevalence of maintaining the quit message at the next pregnancy and the associated risk of pre-term birth. This is what our research was looking to address."

Smoking during pregnancy is unequivocally bad. Unlike a small amount of alcohol, ceasing smoking isn't American Puritanism the rest of the world refuses to accept, it is well-established. The Australian Institute of Health and Welfare, for example, claims that 75% of smokers continue to smoke after 20 weeks, after finding out that they are pregnant. The second trimester is vital to an unborn babies' growth and formation - organs continue to develop, and the liver, pancreas and kidneys all start to function. Babies also begin to hear sounds, such as the mother's heartbeat.

The authors contend the results show the need for continuing anti-smoking campaigns for those who chose to smoke during their first pregnancies, Professor Pereira has urged those considering having a family, those already pregnant, or who have recently given birth to not smoke at all.

"Among mothers who smoked in their first pregnancy, the risk of having a preterm birth at their second pregnancy was 26% lower than those who continued to smoke. Despite smoking during a first pregnancy, woman can turn this around for their next pregnancy to reduce complications to their unborn. Quitting is achievable and is always the safest option."