Marijuana and Pregnancy: 5 Key Takeaways from the New Official Guidelines

More than half of Americans support the legalization of marijuana, but questions remain about how the drug affects our health.

Those questions are especially important for one group: pregnant women. Marijuana use during pregnancy is becoming more common, despite the lack of clarity about its possible effects.

But today (Aug. 27), the American Academy of Pediatrics (AAP) released its first-ever guidelines on marijuana use for pregnant and breast-feeding women. The new recommendations are based on an analysis of the existing research on how marijuana affects pregnancy, breast-feeding and childhood development, and they touch on a range of questions that expectant parents might have. [7 Ways Pregnant Women Affect Babies]

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Here are the most important takeaways from the report.

Don't use marijuana, in any form, during pregnancy.

The AAP report concludes that completely avoiding marijuana use during pregnancy is best.

That's in part because THC, or tetrahydrocannabinol — the compound responsible for marijuana's psychoactive effects — can cross the placenta. Several long-term studies have found relationships between marijuana use by pregnant women and slightly shorter gestational periods and lower birth weights, according to the report. Other studies looking at newborns have found that babies who were exposed to marijuana in utero had some other irregularities compared with other babies, such as unusual sleep patterns.

Ultimately, based on the available evidence, the AAP decided to recommend against the use of marijuana during pregnancy, said Dr. Seth Ammerman, a pediatrics professor at Stanford University and a co-author of the AAP report.

Dr. Torri Metz, a high-risk obstetrician at University of Utah Health, who wasn't involved with the report, said this stance from pediatricians falls in line with what experts in other medical specialties, such as obstetrics and gynecology, have concluded.

"This is not a paradigm shift but something we should continue to emphasize," Metz told Live Science.

Don't use marijuana while breast-feeding.

Breast-feeding moms should avoid marijuana use, because THC, along with some other potentially psychoactive compounds in pot, gets into breast milk, Ammerman told Live Science.

In fact, a new study published alongside the report in the journal Pediatrics looked at breast milk from 50 women who used marijuana and found THC in 63 percent of the samples up to six days after they reported using the drug. Other cannabinoids, such as cannabidiol (CBD), showed up in just 5 percent of the samples.

Because other research found that these compounds could impact fetal development, it's possible that they could also affect a breast-feeding child, the researchers noted. But that specific link hasn't been explored, and breast-feeding is the still recommended option for a child's milk, Ammerman said. "The goal is to encourage breast-feeding," he said, "but if you're breast-feeding and using marijuana, you should cut down or stop" marijuana use.

There's no research showing that marijuana helps to treat morning sickness.

The new report acknowledges that some pregnant women may use marijuana because they've heard that it eases morning sickness. But "there are no research studies that say marijuana is effective for nausea in pregnancy," Metz told Live Science. If nausea during pregnancy is a problem, there are several treatments approved for use, including vitamin B6 and doxylamine, she added. [Battle Morning Sickness with 5 Science-Approved Remedies]

Doctors who treat sexually active women should talk to them about drug use.

Accidental pregnancies happen, and if someone is using drugs in the weeks before they know they're pregnant, that could cause problems for a fetus in its most critical stages, Ammerman said.

"One of the hopes of our recommendations is that pediatricians will take a more proactive role in counseling their patients who are sexually active about these issues, because it is really important," he said. In addition to discussing these recommendations with patients, doctors should be careful to avoid judging women regarding drug use, Ammerman added.

There are still a lot of questions that need be answered.

Despite the publication of the guidelines, there's still a lot of research that needs to be done.

For example, researchers have worked primarily with marijuana compounds, like THC and CBD, that people hear about most, but there are dozens more that deserve studies, Ammerman said.

There's also a lot of room for research on what, if any, complications marijuana can cause for pregnant women themselves, Metz noted.

And researching marijuana's impact on child development can also be difficult. It's unethical to give marijuana to pregnant individuals, so researchers mostly rely on data from parents who report using the drug. What's more, researchers have to account for the different ways pot is used, and decipher the dose concentrations, which are changing — THC concentrations in marijuana increased from about 4 percent in the 1990s to about 12 percent in 2014.

And, of course, the U.S. Drug Enforcement Administration still classifies marijuana as a Schedule I drug, which puts up a lot of barriers for researchers, Ammerman said.

Originally published on Live Science.