New analyses of maternal cannabis use during early pregnancy have found no evidence of increased risk of early developmental delays up to age 5 or of autism spectrum disorder (ASD). The studies, published in JAMA Network Open, offer reassuring data for pediatricians and parents, though researchers still recommend caution.
Absence of Increased Risk
The first study, focusing on developmental delays, retrospectively examined 119,976 mother-child pairs from Kaiser Permanente Northern California (KPNC). Children born between 2015 and 2019 were followed for up to five-and-a-half years. Researchers looked for diagnoses of speech and language disorders, motor delays, or global delays based on KPNC's standard surveillance. Maternal cannabis use was assessed through questionnaires and urine toxicology tests during early prenatal care (around 8 to 10 weeks' gestation). The study found no increased risk of early childhood developmental delays related to maternal prenatal cannabis use.
The second study included 178,948 children born between 2011 and 2019 to 146,296 KPNC patients, focusing on autism risk. Child ASD diagnoses were obtained from medical records based on KPNC’s universal pediatric autism screening. Maternal cannabis use was assessed through prenatal care screening. The study found that 3.6% of children were diagnosed with ASD, but there was no relationship found with maternal prenatal cannabis use.
Expert Commentary
"Our study on developmental delays is the first to examine clinical diagnoses of speech and language disorders, motor delays, and global developmental delays and we looked up to age 5, longer than other studies have done," said lead author Lyndsay Avalos, PhD, MPH, a research scientist with the Kaiser Permanente Division of Research (DOR).
Kelly Young-Wolff, PhD, MPH, senior author and DOR Research Scientist, noted, "We recommend that pregnant individuals avoid cannabis use during pregnancy, consistent with guidelines from national medical organizations," despite the reassuring findings.
Meghan Davignon, MD, a developmental pediatrician with The Permanente Medical Group and KPNC’s regional medical director of pediatric developmental disabilities, stated the findings suggest that currently recommended universal screening practices may be adequate.
Significance of Null Findings
Lyndsay Avalos emphasized the importance of reporting null findings to focus healthcare resources where they are most needed and to alleviate unnecessary parental worry.
Study Context and Future Research
The studies provide updated evidence based on current cannabis use, reflecting the strength of cannabis products being used today, according to Young-Wolff. The research team intends to explore other health outcomes that can appear later in childhood or adolescence, such as mental health problems, substance use, and cardiovascular disease, as the children in the study grow older. Additional research is needed to explore if use of cannabis later in pregnancy could be related to increased risk of developmental delays or autism spectrum disorder.
Deborah Ansley, MD, regional medical director of KPNC’s Early Start prenatal health program, noted that the findings are helpful for providing women with specific information about health risks to make informed decisions about substance use in pregnancy. The studies were funded by the National Institute on Drug Abuse.
