Health Outcomes of Cannabis Use During Pregnancy
For the pregnant or lactating person, negative health effects remain the same within and outside of pregnancy; harms include respiratory and cardiovascular disorders as well as mental health and addiction challenges 22-27. There is evidence that pregnant cannabis users are at greater risk for anemia than non-pregnant users28.
Evidence about fetal harms of cannabis use during pregnancy is not yet clear. There have been contradictory findings on whether the use of cannabis during pregnancy has effects on birth weight, stillbirth or miscarriage, preterm birth and neonatal effects 27-30. Meta-analyses have reported that some studies show a decrease in birth weight with cannabis use 28, 31, 32, while others report no association 27, 29. There are also inconsistencies about whether cannabis use increases the risk for preterm delivery 28, 29, 32-34, or if it poses an increased risk for neonatal intensive care unit admission28, 29, 33. Prenatal exposure to cannabis may also affect longer term neurodevelopmental outcomes including attention, hyperactivity, impulsivity in early childhood 34, 35, emotional and behaviour problems 35, and autism spectrum disorder 36. Very few studies have analyzed the harms of cannabis exposure through lactation; there is conflicting evidence about the potential for delays in infant motor development27, 37-39.
To help clinicians understand the decisional challenges about cannabis use faced by pregnant and lactating people, we conducted a systematic review to synthesize existing knowledge about how pregnant people’s experiences, attitudes, and beliefs about cannabis use in pregnancy and during lactation.