(CNN/WTXL) - There's a new study out suggesting more pregnant women appear to be using marijuana, sometimes to soothe anxiety and morning sickness.
The study, published Tuesday in the "Journal of the American Medical Association," observed a sample of pregnant women in California.
Pot use among the study subjects climbed from 4.2 percent to 7.1 percent from 2009 through 2016.
An expert speculates that the rise might be partially explained by the increased availability of legal marijuana in recent years.
According to the CDC, doctors caution that marijuana's effects on a fetus aren't clear, but could include low birth weight and developmental problems.
The National Institute on Drug Abuse says that some research shows that the effects of marijuana exposure could be long lasting, with marijuana-exposed children more likely to show gaps in problem-solving skills, memory, and the ability to remain focused.
However, the institute says more research must be done to determine which effects are related to marijuana exposure and which are related to environmental factors that could be associated with the mother's marijuana use, such as poverty or other drug use.
Still, the American College of Obstetricians and Gynecologists recommends that obstetrician-gynecologists counsel women against using marijuana while trying to get pregnant, during pregnancy, and while they are breastfeeding.
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