There are now more pregnant women using marijuana in the United States than ever before, a new study suggests.

Researchers with the National Institute on Drug Abuse (NIDA) recently discovered that the rate for which pregnant women admit to smoking marijuana has increased by around 62 percent in the past 12 years.

The study suggests the relaxed attitude these days regarding the safety of the cannabis plant seems to have prompted more women to stay high prior to giving birth.

However, while the increase is significant, the main takeaway from the study is that a whopping majority of women do not smoke marijuana during pregnancy. In 2014, the study shows that only around 4 percent of the nation's expecting mothers smoked weed  – an increase from the almost 2.5 percent that responded in 2002.

Researchers say that while 4 percent "is not high, the increases over time and potential adverse consequences of prenatal marijuana exposure suggest further monitoring and research are warranted.”

The study, conducted using data from the National Survey on Drug Use and Health, included more than 200,000 women between the ages of 18 and 44. Researchers also found more prenatal pot smoking in women aged 18 to 25 than those 26-44.

"Although the evidence for the effects of marijuana on human prenatal development is limited at this point, research does suggest that there is cause for concern,” the study authors wrote.

Some health professionals speculate that more soon-to-be-mothers may now be throwing caution to the wind when it comes to smoking weed because they feel it is safer than the chemical emissions from cigarettes. However, medical experts say “smoking” in general is hazardous to the respiratory and heart health of newborns.

While there is very little evidence to support the claim that marijuana causes developmental issues in newborns, researchers believe there is enough for concern.

Researchers also admit that more studies are needed in order to determine whether marijuana actually has a negative impact on a baby's development. Although previous studies from NIDA have suggested, “children prenatally exposed to marijuana are more likely to show gaps in problem-solving skills, memory, and the ability to remain attentive,” those reports also specify that other important factors, like a mother’s diet, need to be considered before marijuana can be branded as the primary culprit.