The use of marijuana while pregnant can have negative effects on the baby including premature birth, lower weight at birth and early infant death, according to a new analysis released by the journal Addiction.
The journal analyzed the medical records of nearly 5 million women in California who gave birth between 2001 and 2012, the National Institutes of Health said in a press release for the study.
The data included more than 20,000 women whose delivery records noted that they were cannabis dependent or used cannabis more recreationally during pregnancy.
The study found that women who frequently used marijuana during their pregnancy had babies that were 6 percent more likely to be born prematurely.
The study also found frequent marijuana use led to a baby being 13 percent more likely to be born underweight and 35 percent more likely to die in their first year of life.
The study was limited since the researchers do not know exactly how much or what form of marijuana a person consumed. However, researchers noted that the study’s large sample size and information on heavy cannabis exposure during pregnancy was an advantage.
The news comes as an increasing number of states have recently focused their legislative attention on legalizing recreational marijuana.
At the end of March, New York Gov. Andrew Cuomo (D) signed into law legislation that would legalize recreational marijuana use in the state.
Other states such as Florida and North Carolina have brought the issue to their legislatures.
“Because many states in the U.S. now have approved medical and/or recreational cannabis, we recommend regulatory approaches targeting pregnant women, such as developing guidelines for physicians to appropriately recommend medical cannabis and communicating potential risks of prenatal cannabis use,” Yuyan Shi, the study’s lead author, said.