The American College of Obstetricians and Gynecologists recommends that pregnant people not use cannabis. Studies suggest that using cannabis during pregnancy may be linked to lower birth weight, growth restriction of the baby in the uterus, increased risk of stillbirth, and may impact the baby's motor development and neurodevelopment. Research also suggests that children born to people who use cannabis during pregnancy may have problems with attention, memory, problem solving skills, and behavior later in life. For resources and information on the potential risks of cannabis use while pregnant or breastfeeding, please visit the Health Considerations for People who are Pregnant or Breastfeeding web page.
When interpreting these data, it is important to recognize that decisions about cannabis use during pregnancy occur within a balance of potential risks and perceived benefits, and within broader social and structural drivers that underlie cannabis use. Some individuals use cannabis as a means of self-medication, particularly within communities who have limited access to supportive or effective mental health care and may face longstanding biases in medical assessment and treatment; this context can influence both patient experience and data interpretation. Presenting a balanced context helps avoid stigmatization and supports clearer communication of the available evidence.
In California, cannabis use during pregnancy has remained relatively stable between 4% and 5% from 2017 to 2023; however, notable disparities exist across sociodemographic groups.
Cannabis use during pregnancy data were obtained from the 2017-2023 Maternal and Infant Health Assessment (MIHA). MIHA is an annual, statewide-representative survey of California residents with a recent live birth. MIHA collects self-reported information about maternal and infant experiences and about maternal attitudes and behaviors before, during, and shortly after pregnancy. For more information and data from MIHA please visit the MIHA Webpage.
Newborns affected by prenatal use of cannabis data were obtained from the 2019-2023 California Department of Health Care Access and Information (HCAI) Patient Discharge Data.
Cannabis use during pregnancy is defined as using marijuana or weed in any way (smoking, eating, or vaping) during pregnancy.
Only Californian newborns were included in the HCAI data analyses and ICD-10 code P04.81 was used to identify newborns affected by prenatal (maternal) use of cannabis.
Prevalence estimates obtained from MIHA do not distinguish between type of psychoactive cannabinoid (e.g., delta-9-tetrahydrocannabinol, delta-8-tetrahydracannabinol), potency, or source of cannabis (e.g., legal, illicit). Thus, prevalence estimates can only be applied to “cannabis" as a whole.
When analyzing MIHA data, Asian and Pacific Islander ethnicities are collapsed into one aggregate category to align with data de-identification best practices and maintain individual privacy. MIHA does not collect information on sexual orientation or gender identity.
Federal poverty guidelines (FPG) are set by the U.S. Department of Health and Human Services (HHS) and are mostly used to determine eligibility for public programs such as food assistance. FPGs are set based on poverty thresholds. More information can be found on the Office of the Assistant Secretary for Planning and Evaluation website.
The 2023 Statewide Live Birth Profile from the California Department of Public Health was used as the denominator for determining the proportion of live births affected by prenatal use of cannabis in California.
For questions, please contact us at cannabis@cdph.ca.gov.