How Common Is Unintentional Cannabis Ingestion?

Patient Presentation
A full-term female was born to a 26 year old G4P4 female by vaginal delivery without complications. She was given routine care and was doing well at 24 hours after delivery. The social history revealed that the mother was known to smoke marijuana frequently, and had a positive urine drug testing for marijuana during this pregnancy. A male sibling had also been admitted for an unintentional cannabis exposure after the toddler had ingested his mother’s unfinished marijuana cigarette. The father of the baby smoked cigarettes and smokeless tobacco, and had some beers on the weekend. He denied any substance abuse. Both parents were employed and all of the children were living with them.

The pertinent physical exam showed a healthy female with normal vital signs. She had a weight and head circumference at the 10% and length of 50%. She had no physical anomalies noted and had a normal exam. The diagnosis of a healthy female with prenatal cannabis exposure was made. A urine toxicology screening was sent on the infant and eventually was positive for cannabis only. The state’s Department of Human Services was contacted and continued to follow the family over the next year. The mother had entered a substance abuse treatment program but was inconsistent in going to the program.

The patient’s clinical course showed her to continue to grow appropriately but she still was at the 10-15% for head circumference and weight over the next year. She also had normal development. The family was lost to followup after the 12 month appointment.

“[Cannabis] is a genus of flowering plant with three main varieties: sativa, indica and ruderalis.” It has been used for hundreds of years for hemp or fiber and also for psychoactive and medicinal effects. The active compounds are collectively called cannabinoids, of which delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) are the most abundant. The floral buds or calyxes of the plant have the most cannabinoids, but other parts of the plant are also used such as leaves. Hash oil, hashish (or resin) and marijuana (dried leaves) are the common products from strongest to least strongest products. (Hash oil is not the same as Hemp oil. Hemp oil is often sold over the counter and contains little cannabinoids). Cannabis is smoked (like or with tobacco) or vaporized (like an e-cigarette) or ingested in drinks or food. Cannabis like many psychoactive drugs is lipophilic which allows it to easily cross the blood-brain or placental barriers and to remain within the fat tissue and therefore can be concentrated and its effects can last up to weeks. THC half-life is several days to a week. Cannabis’s “[a]cute effects include … Relaxation, euphoria, heightened perception, sociability, sensation of time slowing, increased appetite and decrease pain, and on the other hand paranoia, anxiety, irritability, impaired short-term memory, poor attention and judgment, and poor coordination and balance. Physiologic effects include tachycardia, hypertension, dry mouth and throat, and conjunctival injection.”

Cannabis is used by about 3.9% of the world’s population. For drug users, it is the most commonly abused drug. Up to ~40% of adults have used cannabis at some time in their lifetime. It is commonly used in pregnant and lactating women (~2.5 – 5.0% depending on the population). Marijuana use is on the increase for teens with an overall use of ~7% and ~23% of 12th graders in the U.S. have used it in the past month (Data from 2013).

Cannabis research has been difficult because different definitions (such as defining what is regular or significant use) or confounding factors such as concurrent substance abuse (e.g. tobacco, alcohol, other), poor nutrition, lifestyle, and parenting effects. Infants, whose mother’s used cannabis, have an increased associated with low birth weight and growth restriction, smaller head growth (that continues through adolescence), cognition, visual-perceptual skills, verbal-reasoning skills, language skills, specific learning problems, attention and depression. Regular cannabis use by adolescents has been linked to a decline in intelligence quotient through age 38 that is not reversed with discontinuation of cannabis use. Adolescent cannabis use has also been linked to depression (but not suicide) and possibly anxiety disorders. Cannabis use during times of critical brain development such as fetal and young children and adolescence, increases the risk of neurological impairment.

Medical use has been proposed and mainly studied in adult populations. Potential indications include cancer-related nausea, appetite enhancement, neurogenic pain, glaucoma and epilepsy. In pediatrics some of the most common use is for seizures, but also chronic pain and muscle spasms. CBD is the more common form of cannabis used for seizures. Currently available data for developmental or behavioral conditions such as ADHD, oppositional defiant disorder, or autism spectrum disorder are case-studies or small series. Research agendas have been proposed to try to answer many of the important but unclear or not available research voids.

Learning Point
Unintentional ingestion by young children is increasing as cannabis is available legally or illegally within their environments. When comparing data from states where cannabis is not legal or legal, the numbers of phone calls to poison control centers from 2005-2011, showed an increase of 1.5% in non-legal states, but a 38.5% increase in legal states. In legal states, there was also an increase in the number of moderate or major effects and hospital admissions (overall admission = 16%). There was also a small number but increased admissions to intensive care settings.

Young children are more likely to orally ingest cannabis as resin, food (cookies) or unfinished marijuana cigarettes (joints). They can also be exposed through candies and beverages or other food products which are often marketed to look like non-cannabis food products. Hash resin itself looks similar to a chocolate candy bar. There is little data about passive exposure to cannabis smoke exposure but cannabis smoke has been shown to have similar components to nicotine/tobacco smoke including potential carcinogens. Cannabis products such as hash oil or resin are being used by some though vaporization (similar to e-cigarettes). The most common symptoms of unintentional ingestion were lethargy, followed by tachycardia, mydriasis and hypotonia.
“The unintentional ingestion of cannabis by children is a serious public health concern and is well-documented in numerous retrospective studies, case-series, and case reports. Clinicians should consider cannabis toxicity in any child with a sudden onset of lethargy or ataxia. Hypotonia, mydriasis, tachycardia, and hyperventilation represent other common clinical findings of cannabis toxicity. As cannabis legalization, availability, and potency increases so does the possibility for the rising incidence of unintentional pediatric cannabis intoxication, which frequently requires hospitalizations, and, in some cases, admission to the PICU for airway support.”

Questions for Further Discussion
1. What types of body fluids or tissues can be tested for cannabis?
2. What is the legal status of cannabis in your state or country? If legal in some form, how is medical cannabis prescribed and distributed?

Related Cases

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Evidence-based medicine information on this topic can be found at and the Cochrane Database of Systematic Reviews.
Information prescriptions for patients can be found at MedlinePlus for these topics: Marijuana and Pregnancy and Substance Abuse.

To view current news articles on this topic check Google News.

To view images related to this topic check Google Images.

To view videos related to this topic check YouTube Videos.

Jaques SC, Kingsbury A, Henshcke P, Chomchai C, Clews S, Falconer J, Abdel-Latif ME, Feller JM, Oei JL. Cannabis, the pregnant woman and her child: weeding out the myths. J Perinatol. 2014 Jun;34(6):417-24.

Hadland SE, Knight JR, Harris SK. Medical marijuana: review of the science and implications for developmental-behavioral pediatric practice. J Dev Behav Pediatr. 2015 Feb-Mar;36(2):115-23.

Richards JR, Smith NE, Moulin AK. Unintentional Cannabis Ingestion in Children: A Systematic Review. J Pediatr. 2017 Nov;190:142-152.

Wang GS. Pediatric Concerns Due to Expanded Cannabis Use: Unintended Consequences of Legalization. J Med Toxicol. 2017 Mar;13(1):99-105.

Donna M. D’Alessandro, MD
Professor of Pediatrics, University of Iowa