Pregnant women using marijuana has increased while smoking cigarettes has decreased
A new report shows fewer women are drinking alcohol or smoking cigarettes while pregnant, but also found that more are using marijuana while pregnant.

In a study published in the JAMA Pediatrics, research shows that between 2002 and 2006, the number of women who smoked cigarettes while pregnant fell dramatically, from 17.% to about 10%. Additionally, the use of alcohol while pregnant also dropped from about 10% of pregnant women to 8.5%.

However, though still a low percentage, the women who used cannabis products while pregnant rose from 3% to almost 5%.

Related: More Pregnant Women Turning to Marijuana for Anxiety And Morning Sickness

The data came from responses on the National Survey of Drug Use and Health. The survey had about 12,000 pregnant women who were between 18- and 44-years-old respond and about 3,500 of the respondents were in their first trimester. Experts agree that the first trimester is a pivotal time for fetal development, particularly in the brain.

There was no clear causal relationship behind the increase but generally speaking, more relaxed marijuana laws across the country could have contributed in the rise. Medical marijuana is often used for nausea and is legal in the bulk of the United States, so perhaps more mothers are turning to medical marijuana to combat morning sickness and nausea. Recreational marijuana use is also legal in almost a fifth of the country, so that passive endorsement may add to the rise as well.

The paper's authors found that the decrease in pregnant women smoking fell in line with the decrease in Americans overall smoking. Recently, research found that the number of Americans who smoked dropped from 45.1 million in 2005 to 36.5 million in 2015, which is about 15% of the U.S. population. In a similar vein, alcohol consumption while pregnant dropped slightly, though experts still remain on various sides of the 'should I/shouldn't I' spectrum when it comes to drinking while pregnant, as well as how much is safe to drink.

Related: Pediatricians Say Absolutely No Marijuana While Pregnant and To Limit Use While Breastfeeding

There's much research on the effects of drinking while pregnant as well as smoking while pregnant, but the paper's authors voiced concern about the rise in the use of cannabis while pregnant as there is significantly less research on the health effects of prenatal cannabis exposure. The CDC cautions that expectant mothers should not use cannabis while pregnant, as there is potential harm for developing infants. The authors of the paper agree, saying that there needs to be a greater awareness in the public about the possible adverse effects of prenatal cannabis exposure.