Michigan study links marijuana use to lower birth weights

LANSING – A new study on pregnant women found a possible link between cannabis use and smaller newborns, but says more research is needed to see if a cause-and-effect relationship exists.

The study by researchers at Henry Ford Health’s Center for Health Policy & Health Services Research and Michigan State University found that around 15% of pregnant women surveyed in 23 clinics across the state acknowledged using cannabis during their pregnancies. 

Assessing “adverse outcomes” of cannabis on fetal growth has important potential long-term implications, including obesity and higher risk of cardiovascular diseases, the study said.

Researchers noted an earlier study showing cannabis use by pregnant women in Michigan doubled from 2007 to 2017. Medical marijuana use has been legal in Michigan since 2008, and recreational use since 2018.

The survey took place from 2017 to 2022.

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To focus on the effects of cannabis, the study excluded pregnant women who used alcohol or tobacco.

Lead author Alyssa Vanderziel, a scientist at the Henry Ford center, began work on the study while getting her Ph.D. at MSU.

“It would be incorrect to say that using cannabis during pregnancy causes smaller size. We simply detected a significant association, which is important,” Vanderziel said.

James Anthony, a coauthor from MSU’s College of Human Medicine, said cannabis research is still misunderstood due to its label as a Schedule 1 drug under federal law. 

The U.S. Drug Enforcement Administration defines Schedule 1 substances as “drugs with no currently accepted medical use and a high potential for abuse.” 

“We are left with a body of non-definitive evidence and a policy that blocks scientists in their attempts to address the uncertainties. We hope each study will be a step forward and not a step backward,” Anthony said.

Paul Armentano, the deputy director of the National Organization for the Reform of Marijuana Laws (NORML), said he wasn’t surprised by the study, which was published in the American Journal on Addictions.

“Prior studies have linked smoke inhalation, albeit tobacco smoking or cannabis smoking, with lower birth weight so this result is not particularly surprising,” Armentano said.

“That said, these results are often muddied by confounders, as women who smoke during pregnancy also often tend to receive poorer prenatal health care, are more likely to be socioeconomically underprivileged, and potentially engage in other behaviors that may also influence birth weight” Armentano said.

Vanderziel said, “We need more quality research to be able to make strong public health statements and clinical recommendations and guidelines for our clinicians to follow to be able to provide the best care.”

This story was originally published by the Capital News Service.