Understanding the surge in cannabis use among pregnant and postpartum women in the US

Pregnant and recently postpartum women who suffer with mental health disorders may be vulnerable to using cannabis to self-medicate, according to a Rutgers-led study.

In a nationally representative survey, Qiana L. Brown, an assistant professor at the Rutgers School of Social Work, examined the relationship between mental health disorders, cannabis use and cannabis use disorder (CUD) among pregnant and postpartum women in the US. The findings were published in the journal Drug and Alcohol Dependence.

"Before this study, we didn't know much about the associations between cannabis use, CUD and specific mental health disorders, such as bipolar disorder or specific phobia, among pregnant and postpartum women in the US," Brown said.

"Most prior research grouped mental health disorders into general classes, such as any mood disorder or any anxiety disorder, without examining the relationship between specific types of mood and anxiety disorders and cannabis use and CUD during and after pregnancy."

Despite public health messaging encouraging women to abstain from using cannabis during pregnancy and while breast feeding, the prevalence of cannabis use by women of reproductive age has been increasing.

In a previous study by Brown and colleagues published in the Journal of the American Medical Association, the prevalence of past month cannabis use increased 62 percent among pregnant women and 47 percent among nonpregnant women of reproductive age from 2002 to 2014.

In studies using smaller sample sizes, "pregnant and postpartum women used cannabis to relieve stress, anxiety and cope with mental health symptoms, which may indicate that they are self-medicating mental health conditions," the researchers noted.

"However, little is known about the mental health correlates of cannabis use and CUD among pregnant and postpartum women at the national level." Given that most states have legalized cannabis for medical or recreational use, Brown said it's important to understand mental health correlates of cannabis use and CUD among this population at the national level.

To address this research gap, Brown and colleagues from Columbia University, Washington University in St. Louis and École Polytechnique Fédérale de Lausanne in Switzerland analyzed the responses of 1,316 women in a national survey focused on drug and alcohol use and associated physical and mental disabilities. The sample included 414 women who were pregnant at the time of the interview and 902 postpartum women (pregnant in the past year).

What they found was a clear association between general classes of mental health disorders, cannabis use and CUD. For instance, pregnant and postpartum women who had any mood, anxiety or posttraumatic stress disorders in the past year or any lifetime history of personality disorder had higher odds of cannabis use and higher odds of CUD in the past year than women without a history of a given mental health disorder.

However, when mental health disorders were disaggregated into specific types, some mental health disorders were associated with cannabis use, but not CUD and vice versa. For example, while persistent and major depressive disorders were associated with both past year cannabis use and CUD, bipolar disorder was only associated with past year cannabis use, and not CUD (after accounting for potential confounding factors).

Additionally, cannabis use and CUD didn't share common correlates regarding anxiety disorders. Social anxiety and panic disorders were associated with increases in cannabis use, but not CUD, while specific phobia was associated with increases in CUD and not cannabis use.

Previous studies that have examined the relationship between mental health disorders, cannabis use and CUD among pregnant or postpartum women primarily focused on patient- samples, not women from the general US population, used smaller samples sizes or focused on a limited number of mental health disorders.

In total, the researchers examined three general classes of mental health disorders and 12 specific types of mental health disorders and their relationship with cannabis use and CUD.

"This level of specificity and the generalizability of our results can help inform tailored treatment and population-level preventive interventions," said Brown.