Cannabis Use During Pregnancy Was Linked to Significantly Lower Birth Weight in Aboriginal Babies
In a study of 344 Aboriginal women in South Australia, 20.5% used cannabis during pregnancy, and their babies were on average 565 grams lighter with 3.9 times higher odds of low birth weight even after adjusting for social factors.
Quick Facts
What This Study Found
Researchers surveyed 344 Aboriginal women giving birth in South Australia to assess whether cannabis use during pregnancy was associated with adverse birth outcomes.
One in five women (20.5%) used cannabis during pregnancy, and 52% smoked cigarettes. Compared to mothers who used neither cannabis nor cigarettes, mothers who used cannabis had babies that were on average 565 grams lighter, were 6.5 times more likely to have low birth weight, and 3.8 times more likely to be small for gestational age.
After adjusting for education, social characteristics, and exposure to stressful life events, the odds of low birth weight remained elevated at 3.9 times higher for cannabis-using mothers. The persistence of this association after controlling for social determinants suggests a biological effect of cannabis on fetal growth.
Key Numbers
344 women surveyed. 20.5% used cannabis during pregnancy. 52% smoked cigarettes. Cannabis users' babies were 565g lighter on average. Unadjusted OR for low birth weight: 6.5. Adjusted OR: 3.9. OR for small for gestational age: 3.8.
How They Did This
Cross-sectional, population-based survey of women giving birth to Aboriginal babies in South Australia from July 2011 to June 2013. Data included cannabis use, cigarette smoking, stressful events, social health issues, and birth outcomes (weight and gestational age). Sample of 344 women representative of the broader population.
Why This Research Matters
Indigenous communities already experience rates of stillbirth, preterm birth, and low birth weight two to three times higher than other populations. The finding that cannabis use is independently associated with reduced birth weight even after accounting for social factors highlights an additional, potentially modifiable risk factor.
The Bigger Picture
This study adds to the evidence on cannabis and birth outcomes while highlighting the complex interplay between substance use, social determinants, and health disparities in Indigenous communities. The researchers emphasized the need for integrated responses developed collaboratively with Aboriginal communities.
What This Study Doesn't Tell Us
Self-reported cannabis use may undercount actual use. The cross-sectional design limits causal inference. Cannabis and cigarette use overlapped substantially, making it difficult to fully separate their effects. The sample represented one geographic region and may not generalize to all Aboriginal communities.
Questions This Raises
- ?What mechanisms drive the association between cannabis use and reduced fetal growth?
- ?Would culturally appropriate prenatal programs reduce cannabis use and improve birth outcomes in Aboriginal communities?
Trust & Context
- Key Stat:
- Babies of cannabis users were 565 grams lighter on average, with 3.9x higher odds of low birth weight
- Evidence Grade:
- This is a population-based cross-sectional study with statistical adjustment for multiple confounders, providing moderate-quality evidence on the association between cannabis and birth outcomes.
- Study Age:
- Published in 2016. Research on cannabis and birth outcomes has continued, with most studies supporting an association with reduced fetal growth.
- Original Title:
- Use of cannabis during pregnancy and birth outcomes in an Aboriginal birth cohort: a cross-sectional, population-based study.
- Published In:
- BMJ open, 6(2), e010286 (2016)
- Authors:
- Brown, Stephanie J, Mensah, Fiona K, Ah Kit, Jackie, Stuart-Butler, Deanna, Glover, Karen, Leane, Cathy, Weetra, Donna, Gartland, Deirdre, Newbury, Jonathan, Yelland, Jane
- Database ID:
- RTHC-01113
Evidence Hierarchy
A snapshot of a population at one point in time.
What do these levels mean? →Frequently Asked Questions
Does cannabis use during pregnancy cause low birth weight?
This study found a strong association between cannabis use and lower birth weight that persisted after controlling for social factors. While this suggests a biological effect, the study design cannot definitively prove causation. However, the consistency of this finding across multiple studies strengthens the evidence.
Is it safe to use cannabis during pregnancy?
Based on this and other research, cannabis use during pregnancy is associated with reduced fetal growth and higher odds of low birth weight. Major medical organizations generally advise against cannabis use during pregnancy.
Read More on RethinkTHC
Cite This Study
https://rethinkthc.com/research/RTHC-01113APA
Brown, Stephanie J; Mensah, Fiona K; Ah Kit, Jackie; Stuart-Butler, Deanna; Glover, Karen; Leane, Cathy; Weetra, Donna; Gartland, Deirdre; Newbury, Jonathan; Yelland, Jane. (2016). Use of cannabis during pregnancy and birth outcomes in an Aboriginal birth cohort: a cross-sectional, population-based study.. BMJ open, 6(2), e010286. https://doi.org/10.1136/bmjopen-2015-010286
MLA
Brown, Stephanie J, et al. "Use of cannabis during pregnancy and birth outcomes in an Aboriginal birth cohort: a cross-sectional, population-based study.." BMJ open, 2016. https://doi.org/10.1136/bmjopen-2015-010286
RethinkTHC
RethinkTHC Research Database. "Use of cannabis during pregnancy and birth outcomes in an Ab..." RTHC-01113. Retrieved from https://rethinkthc.com/research/brown-2016-use-of-cannabis-during
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.