Cannabis Use Disorder During the Perinatal Period, Martha L. Velez et al., 2019

Cannabis Use Disorder During the Perinatal Period

Martha L. Velez, Chloe J. Jordan, and Lauren M. Jansson

Chapter 17, in : I. D. Montoya, S. R. B. Weiss (eds.), Cannabis Use Disorders, 2019,

© Springer Nature Switzerland AG 2019 177


Cannabis use in the perinatal period has been increasing in recent years, coincident with increasing legalization in the USA for medical or recreational purposes [1]. Marijuana is the most commonly used illicit drug during pregnancy [2], and among some populations, it is used more frequently than tobacco [3, 4]. Although the prevalence of cannabis use during pregnancy is difficult to ascertain with accuracy, rates of marijuana use range from 2.6% to 28% or higher [3, 5] depending on the population studied and/or screening practices.

According to the 2013 National Survey on Drug Use and Health, the rate of marijuana and hashish use among pregnant women in the USA was 5.2% [6].Marijuana use is more prevalent among nonpregnant than pregnant women of child-bearing age in the general population.

However, among past-year users, near daily use rates are higher in pregnant versus nonpregnant women (16.2% versus 12.8%), as is the percentages of women meeting criteria for cannabis abuse and dependence (18.1% versus 11.4%) [7]. These statistics indicate that for the population of women using marijuana during pregnancy, many are chronic users who are likely to have a cannabis use disorder (CUD). Young adolescents (ages 15–17) have the highest rate of marijuana use during pregnancy (16.5%), more than double the rate for 18- to 25-year-olds (7.5%) [6, 8]. During pregnancy, rates of marijuana use are higher during the first trimester than the second or third trimester (6.44% vs. 3.34% and 1.82%, respectively) [9]. Given that the percentage of unplanned pregnancies is very high (almost half of pregnancies in the general population and higher in substance using/ abusing populations), many fetuses are likely to be exposed to cannabis during the first trimester of pregnancy, before the mother is aware of being pregnant.

The effects of cannabis mainly depend on its major psychoactive cannabinoid (delta 9-tetrahydro-cannabinol or THC) content. Novel ways of cultivating the Cannabis sativa plant have produced more potent varieties of cannabis [10], and the legal cannabis market has implemented selective growing methods to boost psychoactive potency. In the USA, the potency of cannabis has increased steadily over the past 50 years [11], and this trend has translated to increased fetal THC exposure. For example, tetrahydrocannabinolic acid concentrations were significantly increased in marijuana-positive meconium samples originating from Colorado hospitals compared with specimens sent from the rest of the USA during the first 9 months post legalization in Colorado [12]. The proportion of THC in the commonly used herbal cannabis (marijuana) and its resin (hashish) was 3% or less in the 1960s but reached a potency of 12% by 2014 [10, 13].

This means that marijuana today is at least 4 times more potent than it was 4 decades ago [14], which has implications for the interpretation of older studies on the effects of prenatal marijuana exposure on child development that form the large bulk of our current knowledge.

The emergence on the drug market of synthetics cannabinoids (SCBs) in the early 2000s represents a new public health challenge. Whereas THC generally acts as a partial cannabinoid receptor agonist, SBCs are often full cannabinoid receptor agonists and can have greater cellular actions and behavioral effects. The concentrations of SCBs can vary widely, even within batches of the same product [15]. Some SCBs have extremely high potency, ranging from 40- to 660-fold higher than Δ9-THC in cannabis strains [16]. SCBs are cheap and easily purchased on the Internet, potent, and addictive and possess different toxicity profiles from naturally grown marijuana [17]. These substances appear to produce multiple dose-dependent congenital anomalies in rodents [18], and there is no current information on the effects of SCBs in exposed human fetuses or infants.

Despite its controversial nature, the use of medical marijuana and cannabis-derived medicinal products is also becoming more popular in the USA. Nausea, a common complaint in pregnant women, is a medically approved indication for marijuana in all states where medical use of this drug has been legalized [19]. A study carried out in Hawaii, a state where marijuana is legal, found that women with
severe nausea during pregnancy, compared with other pregnant women, were significantly more likely to use marijuana (3.7% vs 2.3%, respectively) [20].

Taking this information together, the current landscape of the risks of marijuana use during the perinatal period is not clear because of the recent changes in the patterns of marijuana use, the increase in prevalence of cannabis use in women during the perinatal period, the production and use of more potent forms of cannabis, and the introduction of synthetic cannabinoids. It is well-established that THC crosses the placental barrier, and while a preponderance of studies have established harmful effects of prenatal cannabinoid exposure in animal (e.g., rodent) models, further research is urgently needed to determine the effects of the increased fetal THC exposure.