Cannabis use before, during early pregnancy may increase nausea, vomiting

ByRegina Schaffer

Fact checked byCarol L. DiBerardino, MLA, ELS

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Key takeaways:

Cannabis use before or during early pregnancy was tied to first-trimester nausea and vomiting.
The increase in nausea and vomiting could be linked to cannabis withdrawal or cannabinoid hyperemesis syndrome.

Women who reported using cannabis before or during early pregnancy were more likely to be diagnosed with mild or severe nausea and vomiting in pregnancy, with the strongest association seen among daily cannabis users, researchers reported.

“From what we’ve seen in prior research, some pregnant individuals turn to cannabis to help with nausea, but our new findings suggest that frequent cannabis use, especially daily use, even prior to pregnancy is associated with nausea and vomiting during pregnancy,” Kelly C. Young-Wolff, PhD, MPH, a senior research scientist at Kaiser Permanente Northern California Division of Research, told Healio. “We know that stopping regular cannabis use can trigger withdrawal symptoms, including nausea and vomiting, which could be mistaken for pregnancy-related nausea.”

Odds for severe nausea and vomiting during pregnancy with: — Data derived from Young-Wolff KC, et al. *Obstet Gynecol.* 2025;doi:10.1097/AOG.00000000000005884.

For the cross-sectional study, researchers analyzed data from 356,343pregnant women in the Kaiser Permanente Northern California system, which universally screens for cannabis use at entry to prenatal care through self-report and urine toxicology. Researchers classified nausea and vomiting during pregnancy as severe, mild or none, and assessed the relationship between cannabis use measures and nausea and vomiting during pregnancy.

The findings were published in a research letter in Obstetrics & Gynecology.

Kelly C. Young-Wolff

Overall, 11.3% of women reported preconception cannabis use, including 2.7% reporting daily use, 2.4% reporting weekly use and 6.3% reporting monthly or less use; 6.5% screened positive for prenatal use. Among women reporting prenatal cannabis use, 1% self-reported use, 3.7% had a positive toxicology test without self-report and 1.8% were positive for cannabis use by both measures.

Within the cohort, 3.6% developed severe nausea and vomiting during pregnancy and 16% developed mild nausea.

Researchers found that any preconception cannabis use was associated with greater odds of mild nausea (adjusted OR = 1.21; 95% CI, 1.17-1.24) and severe nausea and vomiting during pregnancy (aOR = 1.65; 95% CI, 1.57-1.75). Odds for nausea and vomiting were higher for women who self-reported daily preconception use (aOR = 2.61; 95% CI, 2.4-2.84) or weekly preconception use (aOR = 1.73; 95% CI, 1.57-1.9) when compared with nonusers.

Researchers also found that any cannabis use during pregnancy was also associated with higher odds of mild nausea and vomiting (aOR = 1.74; 95% CI, 1.68-1.8) or severe nausea and vomiting during pregnancy (aOR = 3.02; 95% CI, 2.85-3.19), with a stronger association observed among those who reported daily cannabis use.

“While we cannot determine causality in this cross-sectional study, our findings suggest that while some pregnant individuals might use cannabis for its antiemetic properties, frequent cannabis use — even preconception — might also contribute to nausea and vomiting,” Young-Wolff told Healio.

Young-Wolff noted that it is important for women’s health clinicians to distinguish between cannabis withdrawal symptoms and pregnancy-related nausea and vomiting to guide appropriate care, especially if the patient has a history of frequent cannabis use.

“For some patients, what appears to be morning sickness might actually be the result of withdrawal from cannabis, in which case, symptoms could remit on their own following a week or two of abstinence,” Young-Wolff told Healio. “Clinicians can recommend medically approved treatments for pregnancy-related nausea and vomiting and advise patients to avoid cannabis use during pregnancy due to potential harms to both mother and child, consistent with guidelines from the American College of Obstetricians and Gynecologists.”

The research follows related work published by Young-Wolff and colleagues in November

assessing how cannabis legalization in California was tied to an increase in cannabis use during early pregnancy. As Healio previously reported, the implementation of recreational cannabis legalization in California in 2018 was associated with an immediate rise in rates of prenatal cannabis use in jurisdictions that permitted adult-use retailers, highlighting how variation in local policy shapes cannabis use behaviors.