Women who use marijuana before pregnancy more than double their risk of giving birth to a premature baby, says a study conducted by researchers at the University of Adelaide and published in the journal PLoS ONE.
According to previous research conducted by researchers at Tufts University, mothers who used marijuana as teenagers put their children at an increased risk for future drug use and abuse. As Research Assistant Professor John J. Byrnes, the lead author of the Tufts study, commented:
“[T]he results suggest that maternal drug use, even prior to pregnancy, can impact future offspring.”
The present study on maternal marijuana use from the University of Adelaide brings more bad news to women who used marijuana prior to conceiving.
According to the study, which looked at 3,234 healthy pregnant women without any previous children, factors such as a family history of low birth weight, diabetes before and during pregnancy, and hypertension all increase the risk for premature birth.
More surprisingly, however, is that regular marijuana use up to the time of conception is associated with a more than doubled increase risk of giving birth to a premature baby. As the researchers conclude:
“We have shown that marijuana is a strong environmental risk factor…in this population. We are unable to determine whether this association is due to a toxic effect of marijuana or is a marker of a suite of lifestyle factors that contribute to the risk. Pre-pregnancy marijuana use may be a more reliable marker since one can anticipate that women would be more likely to disclose it than persistent marijuana use during pregnancy.”
However, as the researchers point out, the reason for the increased risk of premature birth linked to marijuana use has yet to be determined. The marijuana may be directly to blame, or additional lifestyle factors associated with marijuana use may be the cause.
The results of this study are in contrast with a previous study that did not find a link between maternal marijuana use and premature birth.