Cannabis

Can I use marijuana if I am breastfeeding?

There is little research on the effect that a mother’s use of cannabis has on her baby but its use during pregnancy and breastfeeding is not recommended. Experts are concerned that its use at these times may harm the baby’s rapidly developing nervous system and brain. Use during pregnancy may also increase the risk of premature birth and withdrawal symptoms. When breastfeeding, cannabis has been shown to decrease the levels of two hormones that a mother needs for breastfeeding. It can also affect her ability to parent. Researchers have found THC can remain in milk for up to six weeks after a mother uses cannabis and babies take even longer to remove the drug from their bodies.

A) Cannabis

Cannabis (marijuana) comes from the Indian hemp plant. The main psychoactive chemical is tetrahydrocannabinal (THC). The plants contains more than 400 other chemicals including about 60 that are chemically related to THC (cannabinoids) and may have effects on the brain (Schneider 2009). A further 2000 chemicals are produced during smoking (Joseph 2020). THC connects with receptors in the brain, nerves, and the rest of the body.

Cannabis can be smoked or consumed in other forms. The smoke may be breathed in by a baby. THC also reaches the baby through the placenta and through breast milk.

Researchers estimate that babies who are exclusively breastfed receive 2.5% of the mother’s THC dose and that THC can remain in milk for as along as six weeks after a mother’s last use (Bertrand 2018; NIH; Wymore 2021). The highest concentration of THC in breast milk is one hour after consumption (NAS 2020).

It takes babies longer than it takes adults to remove THC from their blood and tissues.  

Please discuss any concerns about cannabis with your health-care providers and consider using additional resources for more information.

B) Risks of cannabis

There is little research on the short- and long-term effects on babies of mothers who use cannabis (Mourh 2017; Ryan 2018) but experts are concerned that cannabis use during pregnancy and breastfeeding may harm the baby’s rapidly developing nervous system and brain (Anderson 2017; Fernandez-Ruiz 2000).

1. Cannabis use by the mother during pregnancy

Studies have shown cannabis use during pregnancy increases the risk of a baby  (Brar 2019; Crume 2018; Joseph 2020; Navarrete 2020):

  • Being born premature.
  • Being born small.
  • Having a smaller head.
  • Experiencing withdrawal symptoms after being born. 

Children may have  (Joseph 2020; Navarrete 2020):

  • Poorer memory.
  • Poorer visual problem solving
  • Decreased attention span
  • Poorer sleep.
  • More impulsivity, hyperactivity and aggression.

Effects on the brain have been found to continue to young adulthood.

2) Cannabis use by the mother while breastfeeding

a) Effect on the mother

Cannabis has been shown to decrease levels of the hormones prolactin and oxytocin, which are essential for normal breastfeeding, but cannabis does not appear to affect the age of weaning (Mourh 2017). It can affect parenting ability and may increase the risk of depression and anxiety (Joseph 2020).

b) Effect on the baby

There is a small amount of evidence that shows cannabis use while breastfeeding resulted in babies (Navarrete 2020):

  • Being sleepy.
  • Growing slowly.
  • Having low resting muscle tension (tone).
  • Not sucking well.

C) Recommendations

As there is little information about the safety of using cannabis while pregnant or breastfeeding, cannabis use is discouraged by organizations concerned with the health of mothers and babies (ACOG 2017; Ordean 2019; Ryan 2018).

If you cannot stop using cannabis, you can reduce your baby’s exposure to it by:

  • Reducing your consumption.
  • Not exposing the baby to second-hand smoke.
  • Preventing the baby from being in contact with clothing contaminated with cannabis.
  • Not breastfeeding within one hour of inhaled use (Ordean 2019).

References

Anderson PO. Cannabis and Breastfeeding. Breastfeed Med. 2017 Oct 24
 
Bertrand KA, Hanan NJ, Honerkamp-Smith G, et al. Marijuana Use by Breastfeeding Mothers and Cannabinoid Concentrations in Breast Milk. Pediatrics Aug 2018 Sep;142(3). pii: e20181076
 
Brar BK, Patil PS, Jackson DN, et al. Effect of intrauterine marijuana exposure on fetal growth patterns and placental vascular resistance. J Matern Fetal Neonatal Med. 2019;1–5
 
Committee on Obstetric Practice (American College of Obstetricians and Gynecologists (ACOG). Committee Opinion No. 722: Marijuana Use During Pregnancy and Lactation. Obstet Gynecol. 2017 Oct;130(4):e205-e209
 
Crume TL, Juhl AL, Brooks-Russell A, et al. Cannabis Use During the Perinatal Period in a State With Legalized Recreational and Medical Marijuana: The Association Between Maternal Characteristics, Breastfeeding Patterns, and Neonatal Outcomes. J Pediatr. 2018 Mar 28. pii: S0022-3476(18)30181-1
 
Fernandez-Ruiz J, Berrendero F, Hernandez ML, et al. The endogenous cannabinoid system and brain development. Trends Neurosci. 2000;23(1):14–20

Joseph P, Vettraino IM. Cannabis in Pregnancy and Lactation - A Review. Mo Med. 2020 Sep-Oct;117(5):400-405

Mourh J, Rowe H. Marijuana and Breastfeeding: Applicability of the Current Literature to Clinical Practice. Breastfeeding Medicine. December 2017, 12(10): 582-596

National Academies of Sciences, Engineering, and Medicine; Health and Medicine Division; Board on Population Health and Public Health Practice; Committee on the Health Effects of Marijuana: An Evidence Review and Research Agenda (NAS et al). The Health Effects of Cannabis and Cannabinoids: The Current State of Evidence and Recommendations for Research. Washington (DC): National Academies Press (US); 2017 Jan 12

Navarrete F, García-Gutiérrez MS, Gasparyan A, et al.  Cannabis Use in Pregnant and Breastfeeding Women: Behavioral and Neurobiological Consequences. Front Psychiatry. 2020 Nov 2;11:586447

Ordean A, Kim G. Cannabis Use During Lactation: Literature Review and Clinical Recommendations. J Obstet Gynaecol Can. 2020 Jan 25:S1701-2163(19)30984-3

Ryan SA, Ammerman SD, O'Connor ME; Committee On Substance Use And Prevention; Section On Breastfeeding. Marijuana Use During Pregnancy and Breastfeeding: Implications for Neonatal and Childhood Outcomes. Pediatrics. 2018 Sep;142(3)
 
Schneider M. Cannabis use in pregnancy and early life and its consequences: animal models. Eur Arch Psychiatry Clin Neurosci. 2009 Oct;259(7):383-93

United States National Institute of Health (NIH). National Library of Medicine, Toxnet, Drugs and Lactation Database (LactMed) [Internet]. Bethesda: U.S. National Library of Medicine 

Wymore EM, Palmer C, Wang GS, et al. Persistence of Δ-9-Tetrahydrocannabinol in Human Breast Milk. JAMA Pediatr. 2021 Jun 1;175(6):632-634