Study Links Cannabis Use Disorder in Pregnancy to Higher Risk of Postpartum Psychiatric ER Visits

Women diagnosed with cannabis use disorder during pregnancy were more likely to end up in an emergency room for a psychiatric crisis in the year after giving birth, according to a large California study published in the Annals of Epidemiology. After the researchers adjusted for other factors, the diagnosis was tied to a 39 percent higher risk of a postpartum psychiatric emergency visit compared with women who had neither a cannabis nor an alcohol use disorder.

The study was led by Sidra Goldman-Mellor, a public health professor at the University of California, Merced, and graduate student LaMecia De Alba, working with researchers from Michigan State University and UCLA, NTD reported. The work is part of a broader project funded by the National Institutes of Health.

The team examined linked hospital and emergency department discharge records covering 2,036,016 deliveries in California from 2016 through 2021. Of those mothers, 25,697 had a prenatal cannabis use disorder diagnosis and 2,358 had a prenatal alcohol use disorder diagnosis.

In the first year after delivery, 10.4 percent of women with cannabis use disorder had a psychiatric emergency visit, compared with 2.7 percent of women with neither diagnosis and 15.6 percent of women with alcohol use disorder. The adjusted risk ratio for cannabis use disorder was 1.39, with a 95 percent confidence interval of 1.32 to 1.47. For alcohol use disorder, used as a benchmark, it was 1.80. The share of delivering women diagnosed with cannabis use disorder rose from 1.0 percent to 1.4 percent over the six years, a relative increase of roughly 40 percent, while alcohol use disorder rates held steady.

Goldman-Mellor told NTD the study was not designed to prove that cannabis use disorder causes psychiatric emergencies. The findings apply to women with a clinical diagnosis, a condition marked by trouble controlling use and continuing despite health or social problems, not to every woman who used cannabis while expecting. She said pregnant women who are addicted to cannabis "are not a neutral group" and described them as a high-risk population. The research is a retrospective review of hospital records. The authors concluded that the elevated risk supports consistent screening, diagnosis and treatment of women with cannabis use disorder during pregnancy and after delivery.

The study adds to research showing more expectant mothers are using cannabis, often believing it is safe. A University of Georgia study of 4,338 pregnant women, reported by HealthDay, found 5.7 percent had used cannabis in the past month, and 70.9 percent of those users believed it posed little or no risk to themselves or their babies. A 2021 JAMA Psychiatry study of more than 20 million U.S. hospital discharges found the share of hospitalized pregnant patients with cannabis use disorder rose 150 percent from 2010 to 2018, and that patients with the disorder alone had depression and anxiety rates about three times higher than patients with no substance use disorder, according to Weill Cornell Medicine. Co-lead researcher Claudia Lugo-Candelas of Columbia University called it "a red flag that patients may not be getting the treatment they need".

The Centers for Disease Control and Prevention warns that cannabis "may be bad for your baby no matter how you use it" and notes that THC passes from mother to baby, with some research linking prenatal use to lower birth weight and later problems with attention, memory and behavior. The CDC advises pregnant women not to use cannabis and encourages breastfeeding mothers to avoid it.

The American College of Obstetricians and Gynecologists issued updated guidance in September 2025 stating there is no medical reason to use cannabis during pregnancy or after birth and advising women to stop, according to Contemporary OB/GYN. ACOG recommends asking every patient about cannabis before, during and after pregnancy through conversation and validated questionnaires rather than relying on urine or hair tests. The group cites links to preterm birth, low birth weight, newborn intensive care admission and perinatal death, with risk appearing to rise with dose, and notes that THC potency has climbed nearly fourfold since 1995. ACOG also notes that many women resume or increase use within six to 12 months after delivery, overlapping the window the California study examined.

For families, the message is care, not fear. Cannabis use in pregnancy often peaks in the first trimester, frequently to ease nausea, and the University of Georgia researchers urged women to ask their obstetricians about prescription options for morning sickness before turning to cannabis. ACOG points clinicians toward supportive help, including motivational counseling, home visits and cognitive behavioral therapy, while noting there is no FDA-approved medication for cannabis use disorder. It also asks doctors to understand what a positive screen can trigger locally, such as child protective services involvement.

A healthy start for a newborn depends on a healthy mother. Goldman-Mellor said that as cannabis becomes more socially accepted, the health care system must make sure pregnant and postpartum women receive the care they need.