Transfer of Inhaled Cannabis Into Human Breast Milk

Obstet Gynecol. 2018 May;131(5):783-788. doi: 10.1097/AOG.0000000000002575.

Abstract

Objective: To evaluate the transfer of delta-9-tetrahydrocannabinol and its metabolites into human breast milk after maternal inhalation of 0.1 g cannabis containing 23.18% delta-9-tetrahydrocannabinol.

Methods: In this pilot pharmacokinetic study, breast milk samples were collected from mothers who regularly consumed cannabis, were 2-5 months postpartum, and exclusively breastfeeding their infants. Women were anonymously recruited for the study. After discontinuing cannabis for at least 24 hours, they were directed to obtain a baseline breast milk sample, then smoke a preweighed, analyzed, standardized strain of cannabis from one preselected dispensary, and collect breast milk samples at specific time points: 20 minutes and 1, 2, and 4 hours. Quantification of delta-9-tetrahydrocannabinol and its metabolites in these collected breast milk samples was performed by high-performance liquid chromatography tandem mass spectrometry.

Results: A total of eight women were enrolled. Most were occasional cannabis smokers and one a chronic user. Delta-9-tetrahydrocannabinol was detected at low concentrations at all the time points beyond time zero. No metabolites were detected at any time point. Delta-9-tetrahydrocannabinol was transferred into mother's milk such that exclusively breastfeeding infants ingested an estimated mean of 2.5% of the maternal dose (the calculated relative infant dose=2.5%, range 0.4-8.7%). The estimated daily infant dose was 8 micrograms per kilogram per day.

Conclusion: This study documents inhaled delta-9-tetrahydrocannabinol transfer into the mother's breast milk. Low concentrations of delta-9-tetrahydrocannabinol were detected. The long-term neurobehavioral effect of exposure to delta-9-tetrahydrocannabinol on the developing brain is unclear. Mothers should be cautious using cannabis during pregnancy and breastfeeding.

MeSH terms

  • Adult
  • Breast Feeding*
  • Cannabis*
  • Dronabinol / analogs & derivatives*
  • Dronabinol / analysis
  • Dronabinol / pharmacokinetics
  • Female
  • Food Contamination / analysis
  • Food Contamination / prevention & control
  • Humans
  • Infant
  • Infant, Newborn
  • Marijuana Abuse* / complications
  • Marijuana Abuse* / diagnosis
  • Marijuana Smoking / adverse effects*
  • Milk, Human / chemistry*
  • Puerperal Disorders / diagnosis

Substances

  • delta-8-tetrahydrocannabinol
  • Dronabinol