According to data published in the journal Hospital Pediatrics, patients selected to undergo drug screening during the labor and delivery process for cannabis are disproportionately Hispanic or African American and were also more likely to be on subsidized health insurance plans.
The team of researchers from the American Academy of Pediatrics looked to describe the characteristics of people undergoing toxicology testing at delivery solely for the indication of cannabis use along with evaluating the rate of unexpected positive testing results among the cohort to identify additional social risk factors and clinical outcomes.
The Disproportionate Impact of Perinatal Drug Testing
The retrospective cohort study included dyads with a maternal history of cannabis use who were given peripartum toxicology testing between 2016 and 2020 at five Massachusetts birthing hospitals.
Researchers reviewed a total of 60,608 live births, of which 1,924 dyads underwent toxicology testing. Of that group, 614 (31.9%) were tested for the sole indication of cannabis use. The data revealed that significantly greater patients in the cannabis cohort were less than 25 years old, non-Hispanic Black, Hispanic or Latino and publicly insured.
Specifically, Hispanic patients were twice as likely to be mandated to undergo testing (30.5% vs. 15.5% of the birthing population) and Black patients were four times as likely (32.4% vs. 8.1%). Patients under 25 were more than five times as likely to be mandated for testing (32.4% vs. 6.1%), and those on public healthcare plans were more than twice as likely to be tested for past cannabis exposure (39.9% vs. 15.6%).
Regarding positive results, eight of the 614 dyads (1.3%) had an unexpected positive toxicology test result, including two (0.3%) who unexpectedly tested positive for opioids. Seven dyads (1.1%) also had false positive test results for unexpected substances.
Doctors also rarely took any follow up actions or made changes to the clinical management of patients after they tested positive for cannabis, as just a single test result changed clinical management: monitoring and no medication for neonatal opioid withdrawal syndrome.
“Toxicology testing of patients for a sole indication of cannabis use, without other risk factors, may be of limited utility in elucidating other substance use and may exacerbate existing disparities in perinatal outcomes,” the study’s authors concluded.
Echoes of Previous Research
The findings are consistent with previous studies. Namely, one study released just last month published in Academic Pediatrics similarly found that younger individuals and people of color were more likely to be tested for cannabis use or maternal medical complications compared to white, non-Hispanic individuals. This study found the disproportionality ratios were greater than 1.0 for individuals under 25 years old (3.8), Hispanic individuals (1.6), non-Hispanic Black individuals (1.8) individuals of other races (1.8) and those with public insurance (Medicaid 2.6; Medicare 10.6).
While this is one of the most recent studies investigating the topic, a number of studies from years past have found similar figures. One study published in the Journal of Women’s Health reported that Black women and their newborns were 1.5 times more likely to be tested for illicit drugs than non-Black women.
Another published in the New England Journal of Medicine showed that, even though Black and White women had similar rates of illicit drug consumption during pregnancy, Black women were “reported [to health authorities] at approximately 10 times the rate of white women.”
Drug Use, Drug Testing and Childbirth: A Complex Issue
False positive test results of THC are generally uncommon in adults, they can be fairly prevalent among newborns. For example, a 2012 study found that commonly used soap and wash products used for newborn and infant care, like Johnson’s Head-to-Toe Baby Wash and CVS Baby Wash, often cross-react with the immunoassay test and can cause false positive results for carboxy THC.
“[The] addition of Head-to-Toe Baby Wash to drug-free urine produced a dose dependent measurable response in the THC immunoassay,” the investigators concluded. “Addition of other commercially available baby soaps gave similar results, and subsequent testing identified specific chemical surfactants that reacted with the THC immunoassay. … Given these consequences, it is important for laboratories and providers to be aware of this potential source for false positive screening results and to consider confirmation before initiating interventions.”
Even though the Hospital Pediatrics study had few follow up actions after positive testing, that’s not always the case. Another study from 2018 notes the importance of considering a number of technical, medical, ethical, legal and social issues when screening pregnant people for drug use.
Specifically, it cites that birthing people “can and have been arrested for positive drug screens with even preliminary results used to remove children from custody, before rigorous confirmatory testing is completed. Balancing the scientific, medical, public health, legal, and ethical aspects of screening tests for drugs in pregnancy is critical for helping to address this crisis at all levels.”
The study concludes that the medical field largely lacks a good understanding of the pharmacokinetics of drugs in pregnancy. While there is a clear need for testing, authors note that there is a lack of pharmacological knowledge, compounded by a “general misunderstanding of addiction and substance use/misuse within the medical profession” that is further complicated when working with pregnant people and their children.
