As the professional voice of neonatal nurses, the National Association of Neonatal Nurses (NANN) recommends women abstain from marijuana consumption while breastfeeding or providing human milk for consumption. NANN has republished their 2020 position statement due to an increase in marijuana use during pregnancy and lactation. See the entire position statement here.
SOURCE: Wallman, C. , Baessler, C. & Hoffman, J. M. (2021). Marijuana, Breastfeeding, and the Use of Human Milk. Advances in Neonatal Care, 21(3), 176–177. doi: 10.1097/ANC.0000000000000904.
REFERENCE: Metz, T. D. & Borgelt, L. M. (2018). Marijuana Use in Pregnancy and While Breastfeeding. Obstetrics & Gynecology, 132(5), 1198–1210. doi: 10.1097/AOG.0000000000002878.