Women may be self-medicating with marijuana for nausea, vomiting in early pregnancy

Findings suggest that women who experience nausea and vomiting in early pregnancy may be self-medicating with marijuana, and obstetricians should be prepared to offer safe and effective treatment alternatives.

“We hear anecdotally that patients are using cannabis for the treatment of nausea and vomiting of pregnancy,” Torri D. Metz, MD, MSCR, associate professor of obstetrics and gynecology and vice chair of OB/GYN research at the University of Utah Health, told Healio. “Prior studies have evaluated this using billing codes or subjective recall of nausea. We wanted to examine this question using a validated instrument for assessment of nausea and with biologic sampling to measure cannabis use.”

Using a prospective cohort enrolled at eight U.S. centers between 2010 and 2013, Metz and colleagues analyzed 9,250 nulliparous pregnant women who had both a frozen urine sample and Pregnancy-Unique Quantification of Emesis (PUQE) Tool results available from their first study visit.

The primary outcome was PUQE scores — ranging from none to severe — which ranked nausea and vomiting severity over the last 12 hours. Secondary outcomes were individual components of the PUQE score and use of antiemetic drugs.

Marijuana use was determined by evaluating by 11-nor-9-carboxy-delta-9-THC (THC-COOH) presence in urine samples.

Nearly half the cohort (46%) reported experiencing nausea, whereas 38.2% reported mild nausea and 15.8% reported moderate or severe nausea. THC-COOH was found in 5.8% of participants (95% CI, 5.4%-6.3%).

“Those who had detected THC were more likely to be younger, of Black race, of higher BMI, have public insurance and to be below the poverty level,” Metz said in her presentation.

Higher PUQE scores were associated with detectable THC, and a multivariable analysis revealed that incrementally higher THC-COOH was associated with moderate to severe nausea, according to the presentation (adjusted OR = 1.6; 95% CI, 1.1-2.2).

Hours of nausea, episodes of vomiting and episodes of dry heaves were also associated with marijuana use. Incrementally higher THC-COOH was associated with episodes of vomiting (aOR = 1.9; 95% CI, 1.3-2.7) and dry heaving or retching (aOR = 1.6; 95% CI, 1.1-1.2); however, hours of nausea were not associated with incrementally higher THC-COOH (aOR = 1.3; 95% CI, 0.9-1.9), said Metz, who is also a maternal-fetal medicine subspecialist.

Antiemetic drugs were prescribed to 9.6% of the cohort, and those with marijuana exposure were more likely to use antiemetics than their counterparts (18% vs. 12%).

“What was surprising is that the majority of individuals who used cannabis were only using one prescription medication to treat nausea,” Metz told Healio. “This makes me wonder if perhaps we are not treating patients adequately for nausea in early pregnancy.”

Women in the study were not asked why they used marijuana — a limitation of the study, Metz noted. Additionally, PUQE scores only focused on symptoms in the last 12 hours, and the cohort was established before cannabidiol products became widely available.

Moving forward, Metz told Healio “it would be valuable to further explore why pregnant individuals are using cannabis in early pregnancy so that we can have open discussions about safe alternatives.”