Should we warn women against using marijuana during pregnancy?

Abstract

Prevention and public education are the best tools for addressing the spread of many diseases and their consequences. For example, public education and other measures have led to the reduction of tobacco use and mortality rates attributable to tobacco-related cancers. It took a long time to achieve this, but as evidence of the negative effects of tobacco piled up, we acted resolutely and effectively. We now face a similar problem of epidemic proportion with the use of marijuana. Marijuana is portrayed as a mostly harmless substance compared with other drugs of abuse. We continued to hear about its possible beneficial effects for numerous conditions, yet the evidence of its benefits is frequently of low quality. Nevertheless, the drumbeat of positive press has led many states to legalize marijuana production, distribution, and use, perhaps because it brings substantial tax revenues. The marijuana industry has been skillful in marketing “medical marijuana” and in promoting its presumed benefits. This has happened despite mounting evidence of the negative consequences of marijuana use, which are not “just” psychiatric. The latest warning has come from a Scientific Statement from the American Heart Association: “Patients with underlying ischemic disease could see an increase in angina, particularly when cannabis is smoked.” Some evidence suggests that cannabis use may be a trigger for acute myocardial infarction and may be linked to a “higher risk of cerebrovascular accident and heart failure.” Reports of the negative consequences of and warnings about marijuana use have focused on those who make a personal choice to use the substance. But what about those who are exposed to marijuana unwillingly, namely children who are exposed to it at home by relatives and others who are users, or fetuses exposed to marijuana prenatally? We do not know much about the consequences of second-hand exposure to marijuana. However, the negative consequences of prenatal marijuana exposure are becoming evident. Several studies have reported evidence for negative consequences such as fetal growth reduction, or the development of delinquent behavior at age 14 years. One scientific review reported on the alterations of endocannabinoid neurotransmission at critical developmental ages (based on rodent studies). Another review reported that marijuana use during pregnancy and lactation Richard Balon, MD Departments of Psychiatry and Behavioral Neurosciences and Anesthesiology Wayne State University Detroit, Michigan, USA