Is Marijuana Use While Pregnant Safe? Here's What We Know so Far

There is still no conclusive evidence on how marijuana use during pregnancy may effect a fetus. RAUL ARBOLEDA/AFP/Getty Images

A new study published in JAMA this week shows that more pregnant women are using marijuana than previously noted. According to the report, in the state of California, nearly a quarter of pregnant teenagers and about one in five pregnant women between the ages of 18 and 24 admitted to using the drug. However, the jury is still out on whether a pregnant woman's marijuana use is really that dangerous to her unborn baby's health, and if so, how.

Marijuana is a drug derived from the cannabis plant. The main psychoactive component in marijuana is THC (delta-9-tetrahydrocannabinol ). When THC enters the bloodstream, whether this is through the stomach by eating an edible, or inhaled in a joint or bong, it soon enters the brain. Here, it triggers the release of large amounts of dopamine, Healthline reported. This release leads to a number of pleasurable symptoms, but can also impair judgment.

Related: Cannabis: Pregnant Women Are Using More Marijuana, Posing Unknown Danger To Babies

Overall, there are 66 cannabinoids, or natural components found in cannabis, each of which may have different effects on the body. For example, while THC is noted for its psychoactive effects, others such as cannabidiol (CBD) are noted for their potential use in therapeutic medicine. Marijuana affects other parts of the body as well, from inducing hunger, to reducing nausea and inflammation.

Related: Smoking During Pregnancy Can Increase Chances Of Children Becoming Substance Abuser

During pregnancy, the placenta is designed to buffer the fetus from any potential harm from within the mother's body, but research is still unclear if marijuana components are able to pass through the placenta and reach the fetus. For example, a 1987 study on rhesus monkeys suggests that THC could not readily cross the placenta, but more recent research suggests otherwise.

"While the placenta serves as a filter of sorts, pretty much everything in the mother's body gets shared with the baby," Dr. Ira Jaffe, DO, FACOG, a leading board certified high risk maternal fetal medicine and OB/GYN at the Rosh Maternal Fetal in NYC told Newsweek.

Even if marijuana does pass through the placenta to reach the fetus, scientists don't really don't know what effect this could have.

"Everyone is saying the same thing, we don't know. There's a lot of things we don't know, human health is complicated," said Jaffe.

Jaffe likened marijuana use to alcohol use in terms of our understanding precisely how much of the drug is needed to affect fetal development. Although U.S. regulations state that there is no safe level of alcohol use during pregnancy, a landmark English study from 2010 showed that dosage does make a difference.

Children of mothers who admitted to light drinking during pregnancy were nearly identical to children born to mothers who abstained completely, as in completely free of any health problems. How much of a drug mothers use appears to make a difference. Doctors are just not sure where that difference starts when it comes to marijuana.

Some physicians suggest a better-safe-than-sorry approach to marijuana use during pregnancy.

"I don't ever recommend it," Dr. James Betoni, DO, leading board certified high risk maternal fetal medicine and OB/GYN in Boise, ID, and creator of the Pregnancy Power app and workbook told Newsweek. "There are not enough studies."

According to Betoni, there are numerous factors that could potentially contribute to how marijuana may affect a fetus if used during pregnancy, such as how often the mother uses the drug and whether or not her overall health is good. For example, women with low folic acid levels may be more vulnerable to problems associated with marijuana use during pregnancy than healthy women, Betoni explained. Whether mothers use marijuana with other substances, such as cigarettes, could also play a role.

"As with everything else in healthcare, you try and take the best evidence that science can provide, but you're always limited." added Jaffe.

Regardless of physicians' opinions, it's only their duty to advise patients, not judge or police them. Ultimately, it's up the to the mother to use available information to determine whether or not she should use marijuana during her pregnancy. If the latest poll is a correct reflection of the national consensus, it seems more American moms are less concerned about possible consequences.