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USDTL Research

THCA Meconium State Law

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Originally published in NeoTox, Summer 2016.
A study of the impact of relaxing statewide marijuana laws on maternal marijuana use.

by Joseph Jones, MS, NRCC-TC

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Doctor performing ultrasound | Sourced by Freepik© stock


A November 2012 ballot initiative in the State of Colorado allowing full commercialization was passed.1 The new law went into effect in January of 2014. The law included large-scale production and statewide distribution. This new statewide marijuana policy was the most liberal marijuana law in recent US history, even more liberal than marijuana policies in The Netherlands.2

At this time, most states have adopted some form of relaxed marijuana law or they have legislation pending to relax their marijuana laws.3 At this time, there are four states that have legalized personal non-medical use. There are 10 states that have decriminalized personal nonmedical use of cannabis. Twenty-three (23) states have legalized medicinal use of marijuana. Seven states have legislation pending at this time.

Many are preoccupied with personal civil liberty concerns with respect to decriminalizing marijuana ( Many are concerned with adolescent marijuana use initiation, as they should be.4 Some are concerned with traffic safety issues5 and increased crime in neighborhoods where marijuana dispensaries are allowed.6 Some are concerned with the increased potency of marijuana now that growers are free to improve their product in a free market environment.7 Missing from this conversation is the effect of relaxing statewide marijuana laws on maternal marijuana use or more specifically prenatal marijuana exposure.8

The outcomes of studies that have evaluated the association between prenatal marijuana exposure and neonatal outcome deficits are not consistent.9 Some studies show deficits in birth weight, birth length, low Apgar scores, and increased NICU admissions, but just as many studies show no relationship. These inconsistent findings are perhaps responsible for the lack of perceived risk of maternal marijuana use. However, one must look further downstream to observe the damage caused by maternal marijuana; We must look for neurobehavioral deficits.10

Several constituents in cannabis are considered to be teratogens, which mean that they are foreign agents that do damage to the central nervous system.10 Unfortunately, the damage occurs during a period of time when crucial neural development is occurring. The damage has long and persistent effects including behavioral impairments that are observed only later in life. Such examples of these impairments are deficits in abstract reasoning, visual reasoning, and short term memory. Increased adolescent delinquency is significantly higher as well as increased marijuana use in young adulthood, thus repeating the cycle.

We conducted a simple study of the impact of relaxed marijuana policy on maternal marijuana use. The objectives of this study were two-fold. First, has there been an increase in the proportion of THCA (marijuana metabolite) positive meconium (the newborns first fecal matter) specimens? Second, has there been an increase in the concentrations observed for THCA in marijuana positive meconium originating from the State of Colorado?

We queried our database for meconium specimens originating from hospitals within the State of Colorado for the first 9 months of the years 2012 and 2014. The data were analyzed for changes in the proportion of positive outcomes for each time period and the mean concentrations of THCA, the primary metabolite of marijuana for each time period.


The THCA positivity rate for all specimens in our database originating in Colorado increased from 10.6% to 11.7%, representing a 10.4% increase of positive specimens (Figure 1, page 12). The median concentration of THCA in the meconium specimens more than doubled with medians of 108 ng/g and 277 ng/g for 2012 and 2014, respectively. A Mann-Whitney U Test showed that the concentration differences were statistically significant (p = 0.013) (Figure 2, page 12).


The data presented here shows that there was a slight increase (10.4% of maternal marijuana users between the years 2012 and 2014). Furthermore, it appears that the neonates that are exposed experience substantially more exposure to marijuana in utero as indicated by the significant increase in the concentrations of THCA reported in their meconium. The long-term effects of prenatal marijuana exposure and the impact of state-wide marijuana policy on maternal marijuana use are largely unknown. This study demonstrates the need for more research to fully describe the effects of prenatal marijuana exposure and the need for policy makers to be aware of the unintended consequences of state-level marijuana policy.

  1. Colorado Amendment 64: The Regulate Marijuana Like Alcohol Act of 2012.
  2. Hawken, A., Caulkins, J. P., Kilmer, B., & Kleiman, M. A. (2013). Quasi-legal Cannabis in Colorado and Washington [Editorial]. Addiction, 108, 837-838.
  3. National Alliance for Model State Drug Laws (NAMSDL, 2015). Retrived from
  4. Wall, M. M., Poh, E., Cerdá, M., Keyes, K. M., Galea, S., & Hasin, D. S. (2011). Adolescent marijuana use from 2002 to 2008: higher in states with medical marijuana laws, cause still unclear. Annals of Epidemiology, 21(9), 714-716.
  5. Rogeberg, O., & Elvik, R. (2016). The effects of cannabis intoxication on motor vehicle collision revisited and revised. Addiction. In Press.
  6. Mair, C., Freisthler, B., Ponicki, W. R., & Gaidus, A. (2015). The impacts of marijuana dispensary density and neighborhood ecology on marijuana abuse and dependence. Drug and Alcohol Dependence, 154, 111-116.
  7. ElSohly, M. A., Mehmedic, Z., Foster, S., Gon, C., Chandra, S., & Church, J. C. (2016). Changes in cannabis potency over the last two decades (1995-2014)-Analysis of current data in the United States. Biological Psychiatry. In Press.
  8. Warner, T. D., Roussos-Ross, D., & Behnke, M. (2014). It’s not your mother’s marijuana: Effects on maternal-fetal health and the developing child. Clinics in Perinatology, 41(4), 877-894.
  9. Conner, S. N., Carter, E. B., Tuuli, M. G., Macones, G. A., & Cahill, A. G. (2015). Maternal marijuana use and neonatal morbidity. American Journal of Obstetrics and Gynecology, 213(3), 422-e1.
  10. Minnes, S., Lang, A., & Singer, L. (2011). Prenatal tobacco, marijuana, stimulant, and opiate exposure: outcomes and practice implications. Addiction Science & Clinical Practice, 6(1), 57–70.
  11. Kondrad, E., & Reid, A. (2013). Colorado family physicians’ attitudes toward medical marijuana. The Journal of the American Board of Family Medicine, 26(1), 52-60.

Joseph Jones is the Senior Vice President for USDTL with more than 25 years of experience in the forensic toxicology industry. Jones has provided expert testimony in a variety of venues throughout the country and appears as an author on over a dozen peer-reviewed scientific articles. Jones, M.S., N.R.C.C.-T.C. is listed by The National Registry of Certified Chemists as a Toxicological Chemist, CAP Laboratory Inspector, and qualified as an expert in drug testing in several venues including union arbitration, unemployment hearings, family court, civil court, criminal court and Military courts-martial and frequently gives workshops, presentations and webinars.

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