Smoking pot while pregnant can harm the health of a woman’s unborn child, according to a new study.
Infants born to women who used cannabis regularly were more likely to have preterm births, low birth weight, smaller sizes, and possible other health issues later on, the study’s authors said.
Researchers at the University of California San Diego (UCSD) looked at 4.8 million births in the state from 2001 to 2012.
The study, published in the April issue of the journal Addiction, identified 20,237 women based on medical records at the time who were diagnosed with cannabis-use disorder — a term used to describe problematic marijuana use, whether the person is addicted or not — as compared to a control group of 40,474 mother-infant pairs.
“Because we are looking only at medical records, there is a lot we don’t know about the mothers and infants in this study, but our analysis supports the recommendation that health professionals screen for and address cannabis-use disorders in their pregnant clients — to protect both their health and potentially the health of their infants,” said lead author Yuyan Shi, associate professor at the Herbert Wertheim School of Public Health at UCSD.
The study authors also noted not every person who uses marijuana is diagnosed with cannabis-use disorder, so the numbers would likely be higher than what is reported.
In addition, the risk of infant mortality, while rare (less than 1%), was greater for infants born to women with cannabis-use disorder.
“These infants were 35% more likely to die within a year of birth than infants in the control group,” the school said.
Researchers also found the rate of cannabis-use disorder among expectant mothers increased from 2.8 to 6.9 per 1,000 deliveries from 2002 to 2012.
Despite the limitations of the research, an ongoing study at the University of Washington in Seattle is recruiting pregnant women who use marijuana regularly to get a better understanding of marijuana’s effects on pregnant women and their children.
“We are trying to track their marijuana uses pretty carefully, and we’re also doing drug testing to make sure the women aren’t using any other substances,” the study’s lead researcher, Natalia Kleinhans, an associate professor at the University of Washington, told NBC News.
Researchers are seeking women who use marijuana at least three times a week during the first trimester and are willing to keep a diary of the types of cannabis bought and how it was consumed.