Prenatal marijuana use linked to hyperemesis

October 9, 2018

Pregnant women with severe nausea are increasingly turning to cannabis. But it may expose their fetuses to health risks.

Pregnant women diagnosed with severe hyperemesis had nearly four times greater odds of using marijuana in the first trimester compared to those without the symptoms, according to data from a large California healthcare system.

Published in JAMA Internal Medicine, the results show that having mild nausea and vomiting more than doubled the odds that a woman had used marijuana in the first trimester over a pregnant counterpart who did not suffer from the condition.

“Our previous research found that the prevalence of marijuana use is rising among pregnant women,” said first author Kelly Young-Wolff, PhD, MPH, a research scientist at Kaiser Permanente Northern California in Oakland. “In addition, media reports and several small studies have recently indicated that pregnant women may be using marijuana to treat morning sickness. But there is a lack of epidemiologic data on this topic.”

One of the prior studies conducted between 2009 and 2011 found that among 4,735 pregnant women in Hawaii, the percentage of self-reported prenatal marijuana use was higher among women with severe nausea in pregnancy (3.7%) than in those who did not have severe nausea in pregnancy (2.3%).  

The current study was designed to directly address the literature gap by examining whether prevalence of use of marijuana in the first trimester was elevated among women with a diagnosis of hyperemesis in pregnancy. 

The investigators reviewed data from 279,457 pregnancies screened for prenatal marijuana use by both self-report and urine toxicology testing at roughly 8 weeks’ gestation in members of Kaiser Permanente Northern California between 2009 and 2016.

The patient sample was 36.7% white, 27.1% Hispanic, 16.8% Asian, 5.7% black and 13.7% other. 

Age-wise, 1.2% of patients were aged 12 to 17, 15.3% were aged 18 to 24, 62.7% were aged 25 to 34, and 20.9% were aged 35 years or older.

A total of 8.3% of study patients self-reported marijuana use in the 12 months prior to pregnancy.

Prevalence of prenatal marijuana use among women with severe nausea and vomiting in pregnancy was 11.3% and prevalence of prenatal marijuana use among women with mild nausea and vomiting in pregnancy was 8.4%, compared to 4.5% among those without diagnosed nausea and vomiting in pregnancy. 

“These study findings are in line with our hypotheses,” Dr. Young-Wolff told Contemporary OB/GYN.

The authors noted, however, that their findings may be different than in a population of females without healthcare coverage or those who delay prenatal care.

Clinicians also may not diagnose very mild nausea and vomiting in pregnancy, hence the study sample may reflect a subset of patients with more severe nausea and vomiting during pregnancy.

Still, the authors hope that their findings will alert clinicians to the elevated prevalence of marijuana use among women diagnosed with nausea and vomiting in pregnancy.

Further research on the health effects of prenatal marijuana use is critically needed. “However, given concerns about the health risks of marijuana use in pregnancy, which may include lower offspring birth weight and increased risk of developmental problems, it is important that clinicians connect pregnant women experiencing nausea and vomiting in pregnancy with safe and effective medically recommended interventions,” Dr. Young-Wolff said. “Likewise, these women should be advised not to use marijuana during pregnancy.”

Women who are experiencing nausea and vomiting in pregnancy “should also talk to their doctor about medically approved ways to reduce nausea and vomiting in pregnancy that are safe for their babies,” Dr. Young-Wolf said.

Disclosures:

Dr. Young-Wolff reports no relevant financial disclosures.