Conclusions: Results of this study show that the frequency with which women in California use cannabis in the year before and during pregnancy has increased over time, corresponding with increasing acceptance of cannabis use and decreasing perceptions of cannabis-associated harms. Future studies are critically needed to determine whether and how the adverse outcomes of maternal perinatal cannabis use on the health and development of infants and children vary with daily vs less frequent use. (July 2019)
Academic review-commentary posted 21/7/19
Unrolling and Unravelling Far-Reaching Implications of Cannabis Use in Pregnancy Study
Albert Stuart Reece, MBBS, FRCS(Ed.), MD | University of Western Australia and Edith Cowan University
The recent paper by Young-Wolff and colleagues reports several major findings relating to cannabis use in pregnancy 1. The data are particularly noteworthy as they were compiled in the northern counties of California which is known to be one of the highest areas of cannabis use in the nation, and has also been identified as a hotspot of both autism and gastroschisis 2. Amongst the authors’ major findings are a marked rise in high intensity use of daily use both before and during pregnancy; the striking differentials in cannabis use by age group, race and income which are seven-fold, twenty-fold and four-fold respectively; and the rate of self-admitted cannabis use in pregnancy reaching almost 4% in 2017, a finding particularly notable in terms of these authors’ prior report that 80% of patients falsely under-report cannabis use 3.Together these data indicate that cannabis is used differentially and disproportionately by the young, the poor and racial minorities – the same epidemiological profile as gastroschisis, an anomaly which has been uniformly linked with cannabis use in all seven studies on this issue 4. Indeed, a recent CDC paper documented a threefold increase in gastroschisis in minority teenage mothers a disparity which quickly collapsed with increasing age 5, just as the pregnancy-cannabis use data of Young-Wolff does. Such data leave open the possibility that small groups of high intensity cannabis users might be contributing disproportionately to adverse neurodevelopmental neonatal and other paediatric outcomes; and suggest that integral-cumulative exposure and intensity of exposure may be paramount. Indeed, cannabis was recently linked with autism rates across US states and shown to be significantly higher under cannabis-liberal regimes 6,7.Nor is it just neurodevelopmental outcomes which are at risk. Cardiovascular defects have also been implicated 8 with atrial septal defect rising substantially in Colorado, Hawaii, Kentucky, Canada and Queensland in association with cannabis 4,9 which further implies that our list of cannabis-related sequalae remains incomplete.Interestingly several national surveys show that the historically low rate of cannabis use amongst African-Americans has risen in recent years. Cannabis acts epigenomically and heritably by altering DNA methylation, histone modification and reduction in total histones 10. Most importantly as agreed by both authors 1,11 the situation is readily amenable to education both of our patients and the public in general, and, since cannabis use in pregnancy closely parallels that in the general community, carry wider implications for cannabis legalization worldwide.
