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Study breakdown

Most pregnant Canadians know cannabis reaches the fetus, but some keep using anyway

Cross SectionalModerate evidence
The takeaway

Among 478 pregnant Canadian women, 94% knew cannabis is transmitted to the fetus, legalization did not influence most women's cannabis decisions, and women who continued using were paradoxically more likely to have received information from a healthcare provider.

Obstetric care providers, midwives, and pregnant women.

94% knew cannabis reaches fetus; 4.2% kept using

What the researchers found

94.3% perceived cannabis is transmitted to the fetus and 91.2% to the infant via breastmilk. 99% said legalization did not influence their choice to use cannabis in pregnancy. 4.2% continued using during pregnancy. Surprisingly, women who continued using were more likely to have received cannabis information from a provider (52%) than those who quit (35%, p=0.035).

Why it matters

The finding that provider counseling was associated with continued use challenges assumptions about the effectiveness of current clinical messaging approaches.

The numbers in context

478 women surveyed. 94.3% knew cannabis reaches fetus. 91.2% knew it reaches infant via breastmilk. 99% said legalization was not a factor. 4.2% continued use. Providers: 52% of users vs 35% of quitters received provider information (p=0.035).

How the study worked

Anonymous survey of 478 pregnant women at obstetrical, midwifery, and family practice clinics in the greater Hamilton, Ontario area.

What this study cannot tell us

Cross-sectional survey from one region. Self-reported data. Small number who continued use. Cannot determine direction of the counseling association.

How to read the evidence

Regional cross-sectional survey with reasonable sample size but self-reported data and potential selection bias.

When this study was published

2020 survey from Canada.

The bigger picture

The paradoxical provider counseling finding may mean that women who use cannabis are more likely to disclose and receive counseling, not that counseling causes continued use.

Questions still open

  • Why does provider counseling appear associated with continued use? Are current counseling approaches effective, or do they need to be redesigned?

Common questions

Do pregnant women know cannabis affects the baby?
In this Canadian survey, 94.3% of pregnant women knew cannabis is transmitted to the fetus, yet 4.2% continued using during pregnancy.
Did cannabis legalization increase use in pregnancy?
99% of the 478 women surveyed said legalization did not influence their decision about cannabis use during pregnancy.

Read the original research

Pregnant Canadians' Perceptions About the Transmission of Cannabis in Pregnancy and While Breastfeeding and the Impact of Information From Health Care Providers on Discontinuation of Use.

Journal of obstetrics and gynaecology Canada : JOGC = Journal d'obstetrique et gynecologie du Canada : JOGC, 42(11), 1346-1350

Citation

Bartlett, Katelyn; Kaarid, Kaija; Gervais, Nicole; Vu, Nancy; Sharma, Sapna; Patel, Tejal; Shea, Alison K. (2020). Pregnant Canadians' Perceptions About the Transmission of Cannabis in Pregnancy and While Breastfeeding and the Impact of Information From Health Care Providers on Discontinuation of Use.. Journal of obstetrics and gynaecology Canada : JOGC = Journal d'obstetrique et gynecologie du Canada : JOGC, 42(11), 1346-1350. https://doi.org/10.1016/j.jogc.2020.04.015

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