MONDAY, Aug. 20, 2018 (HealthDay News) -- A substantial number of pregnant women may be turning to marijuana to ease morning sickness, a new study suggests.
The study of more than 220,000 pregnant women found that more than 5 percent had recently used marijuana. And it was more common among women who'd been suffering from morning sickness.
Of those with milder symptoms, just over 8 percent screened positive for marijuana. That rate topped 11 percent among women with severe morning sickness, according to the findings.
But the study does not prove that morning sickness drove women to smoke pot, said lead researcher Kelly Young-Wolff.
But it does suggest some women are using the drug to self-medicate, said Young-Wolff, a research scientist at Kaiser Permanente Northern California, in Oakland.
"These findings are concerning," she said. "It's really important that we connect women with medically approved treatments for nausea and vomiting during pregnancy."
Between 50 and 80 percent of pregnant women suffer some degree of nausea and vomiting, usually in the first trimester, according to the American College of Obstetricians and Gynecologists (ACOG). While it's commonly called "morning sickness," the symptoms can arise any time, and for women with severe cases, they may last for several hours each day, ACOG says.
Marijuana can ease nausea, but pregnant women are advised to avoid the drug. Some studies have linked prenatal marijuana use to heightened risks of stillbirth, preterm delivery and having an underweight baby.
Yet research suggests marijuana use is rising among pregnant women, Young-Wolff said, and it's important to understand why.
So, her team studied records from 220,510 women in the Kaiser health system who underwent drug screening in their first trimester. Overall, 5.3 percent had used marijuana.
The likelihood was greater among women with morning sickness than those without: It was more than doubled among women with mild symptoms, and nearly four times higher among those with severe symptoms.
The study leaves questions open, according to Young-Wolff. It's not clear how many women were truly self-treating with marijuana. And the researchers don't know how many women might have used the drug only before learning they were pregnant.
Plus, the study was limited to women in northern California -- so it's not clear whether the findings would be similar elsewhere, Young-Wolff said.
But Dr. Anthony Scialli, an obstetrician/gynecologist in Washington, D.C., was not surprised by the findings.
"I see this all the time," he said. According to Scialli, women who use pot for morning sickness often were using the drug before they became pregnant.
"They also believe that it's safe to use during pregnancy," he noted.
Scialli is a member of the Organization of Teratology Information Specialists. The group runs the MotherToBaby service, which provides research-based information on the effects of medications and other exposures during pregnancy.
Studies into the effects of marijuana use during pregnancy have been mixed. But, Scialli said, "I think the research is pretty clear there are effects on brain function."
It appears those effects are "subtle," he noted, and show up as difficulties with planning, for example.
Young-Wolff said the bottom line is straightforward: "We don't want pregnant women using marijuana for nausea and vomiting. Talk to your provider about medically approved options."
ACOG recommends women try diet and lifestyle changes -- like eating bland foods, getting plenty of fluids and eating frequent small meals. If medication is needed, the group advises a combination of vitamin B6 and doxylamine, an antihistamine.
They are available together as a prescription drug. But Scialli said he suggests patients get over-the-counter versions of the two. Another option is a combination of vitamin B6 and ginger, he said.
The findings, published online Aug. 20 in the journal JAMA Internal Medicine, come at a time when a growing number of states are legalizing medical and recreational marijuana use. Young-Wolff pointed to a recent study that raised concerns about what some marijuana dispensaries are telling pregnant women.
In that study, researchers contacted 400 Colorado dispensaries, pretending to be pregnant women with morning sickness. Nearly 70 percent of the dispensaries recommended marijuana products -- from cigarettes to edibles -- as a morning sickness remedy. One-third of them told callers that marijuana was safe during pregnancy.
The American College of Obstetricians and Gynecologists has more on morning sickness.