The use of cannabis or marijuana during pregnancy is associated with complications like fetal growth restriction, preterm birth, low birth weight and long-term brain development issues in children. In a new study, researchers have found a link between cannabis use in pregnancy and the risk of certain childhood cancers.

Researchers from Duke Health found that children born to mothers exposed to illicit drugs, particularly cannabis, are at an increased risk of tumors of the central nervous system such as medulloblastomas and supratentorial primitive neuroectodermal tumors (PNETS), and retinoblastoma.

The findings were based on a survey conducted among parents of children diagnosed with cancer before the age of 18. The study was published in the journal Cancer Epidemiology, Biomarkers and Prevention.

Researchers hope the findings will have a meaningful impact, particularly given the recent spike in cannabis usage, often used as a remedy for severe morning sickness and nausea.

"Alcohol and tobacco use during pregnancy has declined, but gestational cannabis use has risen in the last decade," lead author Kyle Walsh said in a news release.

"The psychoactive compounds of cannabis are capable of crossing the placental barrier and may interfere with normal neuronal development in the fetal brain. We examined 15 different types of childhood cancer and identified an association that was quite specific to cancers of the central nervous system," Walsh explained.

The survey was conducted among 3,145 families, of which 92% identified as the child's biological mother. The participants were asked about their usage of tobacco, alcohol and illicit drugs during pregnancy.

"About 14% of families reported gestational use of tobacco products, 4% reported using illicit drugs such as marijuana or cocaine, and 2% reported drinking more than a moderate amount of alcohol," the researchers wrote.

In addition to the observations related to illegal substances, researchers noticed a significant association between moderate to heavy alcohol consumption and an increased risk of non-Hodgkin lymphoma. Newborns born to mothers who smoked tobacco during pregnancy faced a higher risk of low birth weight. However, there was no elevated risk of specific cancers associated with smoking.

"We hope that our findings can promote increased provider-patient dialogs about the potential effects of prenatal substance use, and cannabis use in particular. This has implications for public health messaging. We also stress the need for further research into the risk-benefit profile of cannabis use among expectant mothers," Walsh said.

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