Marijuana—recreational and medicinal alike–has been on a tear over the past several years. States are legalizing it (in some form or another) left and right; legal cannabis sales are projected to reach an astounding $10 billion in 2017. But the weed boom’s long-term effect on public health is still murky—and a new study suggests that a larger share of younger, pregnant women are using marijuana, raising questions about how its use may affect the fetuses of expectant mothers.
Columbia University researchers found that 3.9% of pregnant women (and 7.6% of non-pregnant women of reproductive age) reported using marijuana in the previous month between 2007 and 2012. “Among pregnant women, the prevalence of past-month marijuana use increased 62% from 2002 through 2014. Prevalence was highest among women aged 18 to 25 years, indicating that young women are at greater risk for prenatal marijuana use,” wrote the study authors.
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The numbers aren’t a cause for alarm in and of themselves. As the authors note, marijuana health effect research is relatively new. But there are some studies which suggest there may be a relationship between marijuana use during pregnancy and lower birth weight or brain development in offspring.
It’s also unclear that the increased marijuana use by pregnant women represents drug abuse; for instance, nausea and anxiety (both common among pregnancy) are among the most common symptoms of medical marijuana users, which may in part explain the increase in usage. But, as the Columbia researchers note, as cannabis use balloons across society, it’s important to keep tabs on who’s using it—and on potential health effects we don’t currently know about.