Warning-Sign Evidence, Evaluation, and Dissemination (WEED) Study

As states in the U.S. legalize recreational cannabis, some have enacted policies mandating point-of-sale warning signs with information on harms of using cannabis during pregnancy (MWS-cannabis). The Warning Sign Evidence, Evaluation and Dissemination (WEED) Study is an ongoing multi-pronged research project that seeks to understand the public health impact of MWS-cannabis. Previous research from ANSIRH has found that Mandatory Warning Signs policies for alcohol use during pregnancy contribute to increases in preterm birth and low birthweight and decreases in prenatal care use. As a strategy to ensure that MWS-cannabis policies do not have adverse consequences on public health,  research is needed to understand effects of MWS-cannabis and experiences and perspectives on MWS-cannabis of pregnant and recently pregnant people who use cannabis.

Research Aims

Examine the relationship between enacting MWS-cannabis and subsequence changes in birth outcomes such as preterm birth and low birthweight.
Examine pregnant people’s beliefs and behaviors related to cannabis use during pregnancy and whether these beliefs and behaviors vary across policy environments
Explore pregnant people’s perspectives on MWS-cannabis, including what messages pregnant people would want the signs to say

Study Design

Data for this study were collected from multiple sources. First, investigators used data from Vital Statistics records from Washington State and nearby states to examine relationships between Washington’s MWS-cannabis policy and birth outcomes.

Second, investigators conducted a cross-sectional survey with a nationally representative sample of over 3,500 pregnant and recently pregnant people to assess their beliefs and behaviors related to cannabis use during pregnancy and if their beliefs and behaviors varied by whether they lived in a state with a MWS for cannabis policy.

Lastly, researchers conducted in depth interviews with a sample of 35 people who completed the cross-sectional survey. These in-depth interviews asked participants about their perspectives on MWS-cannabis in general, and their reactions to specific sample MWS-cannabis messages.  

Key Findings

  • Relationship between mandatory warning signs for cannabis use during pregnancy policies and birth outcomes in the US: After Washington State enacted their MWS-cannabis policy, birthweight decreased and the proportion of babies born low birthweight increased, in comparison to other states that did not enact an MWS-cannabis policy
  • Living in a state with a MWS cannabis policy is not associated with decreased cannabis use during pregnancy or with pregnant and recently pregnant people who use cannabis believing that cannabis use during pregnancy is less safe.  Less than 1/3 of people who used cannabis during pregnancy reported that they trust the information in MWS-cannabis and half reported being tired of hearing how cannabis use during pregnancy is bad for the baby’s health.
  • Among the broader community of pregnant and recently pregnant people who do not use cannabis, living in a state with a MWS policy was associated with perceiving more stigma towards people who use cannabis during pregnancy and expressing more support for punishment of people who use cannabis during pregnancy.

Implications

Mandatory Warning Signs for cannabis use during pregnancy do not appear to have intended effects and may relate to adverse consequences. Evidence does not support further adoption of MWS for cannabis use during pregnancy.

Areas of Research