Meanwhile the use of marijuana among pregnant women between the ages of 18 and 24 in California jumped from 9.8 percent to 19 percent.
"The more we think about cannabis use amid pregnancy, the more we are acknowledging how destructive it can be", Bonn-Miller included.
"Marijuana is the most commonly used illicit drugs during pregnancy, and its use is increasing", the study said. According to the research published Tuesday in the Journal of the American Medical Association, "the prevalence of self-reported, past-month marijuana use among U.S. adult pregnant women increased from 2.4 percent to 3.9 percent". "University Hospital, who was not involved in either study but has interesting insight on factors at play here".
Californians voted to legalise recreational use of the drug in 2016.
Media reports noted that the time span of the study coincides with increased marijuana legalization in California, and the USA, and may be indicative of a continuing trend, as recreational legalization in California is scheduled to take effect on January 1. "With the proximity to OR and Washington, they also have experience with any use being legal".More news: Andrew McCabe Expected To Retire From FBI Early Next Year
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"Because of the possibility of concurrent use of marijuana and other substances of abuse, the evidence of its direct association with preterm labor, fetal growth restriction, preterm birth, low birthweight and stillbirth is still debatable, though these adverse effects lean more towards an increased likelihood of occurrence", Yankey continued. Overall, marijuana use during the first weeks of pregnancy increased from about 4 to 7 percent between 2009 and 2016.
But the researchers believe that urine samples are likely to provide the most accurate picture of marijuana use in pregnancy, because people tend to hesitate about admitting such behaviors. In aggregated 2002-2012 data, 14.6% of U.S. pregnant adolescents reported past-month use.
The conversation - and especially the CDC's call-out of THC as the problematic component - also raises the question as to whether CBD (a cannabis compound that doesn't have the same psychoactive effect of THC, but is used for anxiety and pain) is safe.
"Pregnant women or women contemplating pregnancy should be encouraged to discontinue use of marijuana for medicinal purposes in favor of an alternative therapy for which there are better pregnancy-specific safety data".