More women are using marijuana during pregnancy, but doctors say no amount of the drug is known to be safe for mums-to-be

sruilk/ShutterstockExperts say there’s potential that marijuana use during pregnancy could be harmful.
  • As more US states legalise marijuana, research indicates that more pregnant people are using the drug.
  • Research in this area is very limited, but some studies suggest marijuana use during pregnancy may restrict a baby’s growth, disrupt brain development, or result in learning or behavioural problems as a child grows up.
  • A doctor told INSIDER no amount of the drug is known to be safe during pregnancy.

In November 2018, a research letter published in JAMA Pediatrics offered some encouraging news: Between 2002 and 2016, the use of alcohol and cigarettes during pregnancy has declined. But the researchers also found that use of marijuana is on the rise.

The letter evaluated responses from more than 12,000 women taking the National Survey on Drug Use and Health. In 2002, 2.9% of women reported using cannabis while pregnant. In 2016, 5% of women said they’d used the drug during pregnancy.

That increase comes amid a wave of marijuana legalization and acceptance in the US. To date, 33 states and Washington, D.C. have legalised medical marijuana and 10 states and Washington, D.C. have legalised the drug for recreational use, with New York and New Jersey expected to soon follow suit. A recent Pew Research poll found that 62% of Americans favour legalizing marijuana, up from just 31% in 2000.

Despite rising access and acceptance, however, experts maintain that pregnant people should not use marijuana.

Right now, there’s very little research on the drug’s safety during pregnancy, two doctors explained to INSIDER. In fact, they added, the evidence we do have suggests that the drug may have risks for developing babies.

“I think a misconception is that [marijuana] probably doesn’t do any harm, and we simply don’t know the answer for that,” Dr. Kjersti Aagard, maternal-fetal medicine specialist and professor at Baylor College of Medicine and Texas Children’s Hospital, told INSIDER. “No amount of marijuana is known to be safe in pregnancy. Not for the mum, not for the baby.”

The research on marijuana use during pregnancy is limited, but experts have concerns

Marijuana is the most commonly used illicit drug during pregnancy, according to the American College of Obstetricians and Gynecologists’ (ACOG) 2017 committee opinion on marijuana use in pregnancy. Some studies show that as many as 34 to 60% of marijuana users continue using the drug in pregnancy, with some mums-to-be believing that it’s “relatively safe,” the committee opinion said.

But right now, there’s not much data on pot’s safety for pregnant people and their babies. It can be difficult to research because results of human studies are often confounded by other substance use or lifestyle factors, according to the ACOG, but existing studies suggest that it may have health risks.

“What we know today is pretty sparse,” Aagaard said. “When we’ve looked, there is evidence of harm. And we haven’t looked at all the different avenues where that harm may occur and we don’t have the long term studies to really examine that carefully from a public health perspective.”

So far, research suggests that marijuana use may disrupt a foetus’s normal brain development and that babies born to mothers who used marijuana during pregnancy may be smaller at birth, according to the ACOG. The organisation also adds that pot use during pregnancy may lead to an increased risk of stillbirth, but it’s not clear if that’s due to marijuana use or other substances.

“Probably the most consistent data we have is related to the growth of the baby – that marijuana [use] might relate to growth restriction,”Dr. Cynthia Gyamfi-Bannerman, a maternal-fetal medicine specialist at Columbia University’s department of obstetrics and gynecology, told INSIDER.

Read more:Marijuana use could potentially lower a person’s sperm count, making it more difficult to have children

Some research also suggests that kids whose mothers used weed during pregnancy could have learning and behavioural problems as they get older, according to the ACOG.

“There is some early data to look at adverse neurodevelopment, and there have been a handful of studies showing lower visual-motor coordination, visual analyses, lower neurodevelopmental test scores,” Gyamfi said. “That might be a huge downstream problem that we’re underappreciating at this point.”

For now, according to a 2017report on cannabis and health from National Academies of Sciences, Engineering, and Medicine, there’s still “insufficient evidence to support or refute” a link between mothers smoking cannabis and later outcomes for their children.

Aagaard also added that there’s no good data on the safety or potential harms of exposure to secondhand marijuana smoke.

Further complicating things is that not all marijuana is exactly the same.

“Marijuana is not highly regulated,” Gyamfi-Bannerman said. “One person’s marijuana might be completely different from somebody else’s and it’s not like there’s a standardised formulation, so it’s something that is just so experimental.”

Some women may turn to marijuana to deal with pregnancy symptoms

Some reports suggest pregnant people may turn to the drug hoping it will combat unpleasant pregnancy symptoms. In 2015, two mothers told Vice they used marijuana to cope with morning sickness, and, some mums-to-be have reported using cannabis to help with back pain and depression, according to NPR. One small 2006 study also found that women reported using medical marijuana to help with nausea and vomiting while pregnant.

But Aagaard said she’s seen no evidence to suggest that marijuana has health benefits in the context of pregnancy. Additionally, Gyamfi-Bannerman noted that there are typically safer options available to address issues that pregnant people may seek to address with marijuana.

“If you want to protect the developing foetus, there are alternatives to what you think you might be treating [with marijuana],” she said. “If you’re pregnant, ask your doctor before you start some new treatment – and don’t assume that it’s’ going to be safe for pregnancy.”

The bottom line: Experts say pregnant people should not use marijuana

“I think that, partially because [marijuana is] becoming legal everywhere, it’s thought to be less harmful than other drugs and alcohol, but it’s still a substance that has harm,” Gyamfi-Bannerman said. ” [Pregnant people] should not use marijuana. There’s really no data to say that it’s safer than smoking.”

Given current scant evidence, the ACOG recommends that expecting mothers not use the drug and the American Academy of Pediatrics (AAP) also recommends they avoid it.

“We should know whether there are long term risks for mothers and for their children before we can make a statement in any direction, and until that time our statement should remain, ‘There’s no amount of marijuana use that’s known to be safe in pregnancy,'” Aagaard said.

“Once upon a time we thought it was fine to drink wine in pregnancy, once upon a time we thought it was fine to smoke cigarettes. And our thinking evolved as we studied the issues carefully,” she added. “I don’t want this to be another stop on the highway littered with assumptions without evidence.”


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