smoking marijuana before conception increases premature labor

http://www.abc.net.au/news/2012-07-18/study-finds-pregnancy-and-marijuana-a-dangerous-mix/4137666

Researchers have released the results of a study into risk factors that affect a woman's likelihood of going into early labour - including smoking marijuana before conception.

It is widely known that smoking cannabis during pregnancy increases the risk of giving birth before 37 weeks, but Professor Claire Roberts from Adelaide University's Robinson Institute says this study is the first to recognise that smoking the drug before conception also has an effect.

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"We also asked them about things that they were doing during pregnancy, but it turned out that using marijuana prior to pregnancy had a more significant effect than even smoking it during pregnancy," she said.

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More than 3,000 women from Adelaide and Auckland took part in the study which considered a range of things including the woman's health and weight, living arrangements and medical history.

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