A new study shows more women are using marijuana before and during their pregnancy.
Researchers at Kaiser Permanente analyzed data from more than 277,000 pregnant women who reported their marijuana use. The women lived in California before recreational marijuana was legalized in that state.
In the year before pregnancy, marijuana use by the women increased from nearly seven percent in 2009 to over 12 percent in 2017. When it comes to use during pregnancy, rates increased from close to two percent to over three percent.
Previous studies have shown that marijuana use during pregnancy has been linked to low birth weight in the baby.
"No amount of cannabis use has been shown to be safe during pregnancy," Kelly Young-Wolff, lead author of the new report and a research scientist with Kaiser Permanente Northern California told NBC News. "We do know that cannabis crosses the placenta and reaches the fetus."
The study did not address reasons why the women used cannabis during their pregnancy, but anectodal evidence shows some women may use it to ease the stress and nausea related to morning sickness, NBC News reported.