A new study says pregnant women are using marijuana to deal with morning sickness. Researchers in California found that more pregnant women in general are turning to the drug. Those who experience nausea and vomiting during their first trimester, though, are four times more likely to use it. The American College of Obstetricians and Gynecologists urges women to refrain from marijuana while pregnant, trying to get pregnant, or breastfeeding. The drug can cause attention deficit and behavioral problems in babies, and can also make them more likely to use it as teenagers.