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Developmental Biology - Drugs In Pregnancy

Daily Cannabis Use Before and During Pregnancy?

Current advice from Kaiser Permanente is to avoid cannabis exposure during pregnancy...

The number of women using cannabis in the year before they get pregnant and early in their pregnancies is increasing, and their frequency of use is also rising, according to new data from Kaiser Permanente.

The research, published in JAMA Network Open, examined self-reported cannabis use among 276,991 pregnant women (representing 367,403 pregnancies) in Northern California over 9 years and found that cannabis use has increased.

From 2009 to 2017, the adjusted prevalence of self-reported cannabis use in the year before pregnancy increased from 6.8% to 12.5%, and the adjusted prevalence of self-reported cannabis use during pregnancy increased from 1.9% to 3.4%. Annual rates of change in self-reported daily, weekly, and monthly - or less - use of cannabis increased significantly, though daily use increased the most rapidly.

Among women who self-reported cannabis use in the year before pregnancy, daily users increased from 17% to 25%, and weekly users increased from 20% to 22%, while monthly (or less) users decreased from 63% to 53% in the study period. Similarly, among women who self-reported cannabis use during pregnancy, daily users increased from 15% to 21%, and weekly users from 25% to 27%, while monthly users decreased from 60% to 52%.
"These findings should alert women's health clinicians to be aware of potential increases in daily and weekly cannabis use among their patients. The actual numbers are likely higher, as women may be unwilling to disclose their substance use to a medical professional."

Kelly Young-Wolff PhD MPH, Research Scientist, Kaiser Permanente Research.

The prevalence of daily and weekly cannabis use may have risen even further in the past year and a half following legalization of cannabis for recreational use in California in 2018, Young-Wolff adds.

The data come from women's initial prenatal visits at Kaiser Permanente in Northern California, which usually take place at around 8 weeks gestation, and do not reflect continued use throughout pregnancy. Investigators were unable to differentiate whether self-reported cannabis use during pregnancy occurred before or after women were aware that they were pregnant.

While the current findings are based on women's self-reporting, the results are supported by the Kaiser Permanente research team's December 2017 JAMA Research Letter showing an increase in prenatal cannabis use via urine toxicology testing. In this newer study, the authors focus on trends in frequency of use in the year before and during pregnancy.
Some women may use cannabis during pregnancy to manage morning sickness, the authors noted. The authors' previous work published in JAMA Internal Medicine in 2018 found women with severe nausea and vomiting in pregnancy were nearly 4 times more likely to use cannabis during the first trimester of pregnancy.

Women may get the impression from cannabis product marketing and online media that cannabis use is safe during pregnancy, said Young-Wolff. However, there is substantial evidence that exposure to cannabis in pregnancy is associated with having a low-birthweight baby, and the American College of Obstetricians and Gynecologists recommends women who are pregnant or contemplating pregnancy discontinue cannabis use because of concerns about impaired neurodevelopment and exposure to the adverse effects of smoking.

More research is needed to offer women better, specific advice, said study senior author Nancy Goler MD, Obstetrician/Gynecologist and Associate Executive Director, Permanente Medical Group.
"There is still much that is unknown on the topic, including what type of cannabis products pregnant women are using and if health consequences differ based on mode of cannabis administration and frequency of prenatal cannabis use. There is an urgent need to better understand the effects of prenatal cannabis exposure as cannabis becomes legalized in more states and more widely accepted and used."

Nancy Goler MD, Obstetrician/Gynecologist, Associate Executive Director, Kaiser Permanente Medical Group.

"Until such time as we fully understand the specific health risks cannabis poses for pregnant women and their fetuses, we are recommending stopping all cannabis use prior to conceiving and certainly once a woman knows she is pregnant."

Kelly Young-Wolff PhD MPH.

As the overall prevalence of prenatal cannabis use rises, it is vital to also monitor trends in the frequency of cannabis use in the period leading up to and during pregnancy because more frequent use may confer greater health risks for mothers and their children.

To examine trends in the frequency of self-reported cannabis use among pregnant women in the year before and during pregnancy.

Design, Setting, and Participants
Cross-sectional study using data from 367?403 pregnancies among 276?991 women 11 years or older who completed a self-administered questionnaire on cannabis use during standard prenatal care in Kaiser Permanente Northern California from January 1, 2009, to December 31, 2017. The annual prevalence of self-reported daily, weekly, and monthly cannabis use among women before and during pregnancy was estimated using Poisson regression with a log link function, adjusting for sociodemographics. Data analyses were conducted from February to May 2019.

Calendar year.

Main Outcomes and Measures
Self-reported frequency of cannabis use in the year before pregnancy and during pregnancy assessed as part of standard prenatal care (at approximately 8 weeks’ gestation).

Among the overall sample of 367?403 pregnancies among 276?991 women, 35.9% of the women self-reported white race/ethnicity; 28.0%, Hispanic; 16.6%, Asian; 6.0%, African American; and 13.5%, other. In the sample, 1.2% of the women were aged 11 to 17 years; 15.3%, 18 to 24 years; 61.4%, 25 to 34 years; and 22.0%, older than 34 years. Median (interquartile range) neighborhood household income was $70?472 ($51?583-$92?643). From 2009 to 2017, the adjusted prevalence of cannabis use in the year before pregnancy increased from 6.80% (95% CI, 6.42%-7.18%) to 12.50% (95% CI, 12.01%-12.99%), and the adjusted prevalence of cannabis use during pregnancy increased from 1.95% (95% CI, 1.78%-2.13%) to 3.38% (95% CI, 3.15%-3.60%). Annual relative rates of change in self-reported daily cannabis use (1.115; 95% CI, 1.103-1.128), weekly cannabis use (1.083; 95% CI, 1.071-1.095), and monthly or less cannabis use (1.050; 95% CI, 1.043-1.057) in the year before pregnancy increased significantly, with daily use increasing most rapidly (from 1.17% to 3.05%). Similarly, annual relative rates of change in self-reported daily cannabis use (1.110; 95% CI, 1.089-1.132), weekly cannabis use (1.075; 95% CI, 1.059-1.092) and monthly or less cannabis use (1.044; 95% CI, 1.032-1.057) during pregnancy increased significantly from 2009 to 2017, with daily use increasing most rapidly (from 0.28% to 0.69%).

Conclusions and Relevance
Results of this study demonstrate that frequency of cannabis use in the year before pregnancy and during pregnancy has increased in recent years among pregnant women in Northern California, potentially associated with increasing acceptance of cannabis use and decreasing perceptions of cannabis-associated harms.

Kelly C. Young-Wolff PhD MPH, Varada Sarovar PhD, Lue-Yen Tucker BA, Amy Conway MPH, Stacey Alexeeff PhD, Constance Weisner DrPH, Mary Anne Armstrong MA and Nancy Goler MD.

The study was supported by a grant from the National Institute on Drug Abuse.

Young-Wolff and Kaiser Permanente Division of Research colleague Lindsay Avalos, PhD, MPH, have received a new 5-year grant from NIDA to support further research on maternal cannabis use during pregnancy. They plan to study whether prenatal cannabis use is associated with increased risk of adverse maternal, fetal, and neonatal outcomes using data from urine toxicology testing, self-reported frequency of prenatal cannabis use, and mode of cannabis administration. They will also test whether legalization of cannabis for recreational use in 2018 and local regulatory practices (such as retailer bans) are associated with variation in prenatal cannabis use.

Conflict of Interest Disclosures: Dr Young-Wolff, Mr Tucker, Dr Alexeeff, and Ms Armstrong report receiving grants from National Institutes of Health (NIH) National Institute on Drug Abuse (NIDA) during the conduct of the study. No other disclosures were reported.

Funding/Support: This study was supported by an NIDA K01 Award (DA043604) from the NIH.

Role of the Funder/Sponsor: The funder/sponsor had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

Additional Contributions: Agatha Hinman, BA (Kaiser Permanente California), assisted with manuscript preparation. She was not compensated for her contibutions beyond her salary as an administrative professional.

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Jul 25 2019   Fetal Timeline   Maternal Timeline   News  

Women are getting the impression from cannabis marketing that cannabis use is safe in pregnancy.
But, there is substantial evidence exposure to cannabis is associated with low-birth weight,
and impaired neuro-development. CREDIT Public Domain.

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