A new study on cannabis consumption and pregnant women has identified certain obesity risks for babies exposed to cannabis in the womb. Published in The Journal of Clinical Endocrinology & Metabolism, researchers set out to measure the potential impact of fetal exposure to cannabinoids. Their findings suggest a few different associations between adiposity (the condition of having too much fatty tissue in the body) and glucose-insulin traits and being exposed to cannabis in the womb. 
Fetal Exposure to Cannabis and Obesity Risk Study
A group of pregnant women who consumed cannabis gave consent to participate in the study. The study involved three visits during pregnancy and one follow-up after. Tests during pregnancy took place at 17 weeks, 27 weeks, and after delivery. In-person follow-ups were conducted when children were an average age of four and a half years old.
Urine samples were used to measure cannabinoid content. A total of 12 cannabinoids and cannabis metabolites were detected in the mothers consuming cannabis while pregnant. Later, at the in-person follow-up, blood samples were taken from the children after an overnight fast to measure glucose and insulin levels. Fat mass was also measured using whole-body air displacement plethysmography, and it was measured twice for accuracy.
After analyzing all of the data, the researchers found three main conclusions.
Fetal Exposure to Cannabis is Associated With
- Increased fat mass, fat-free mass, and adiposity. 0.7-kg higher fat mass at age ~4.7 years.
- Higher fasting glucose levels. Average of 8.0 mg/dL higher at age 4.7 years.
- Higher fasting insulin. 
Yes, the study did have sufficient evidence to “suggest that fetal exposure to cannabis is associated with increased adiposity and fasting glucose levels in early childhood”. However, the study sample was very small with only 103 mothers participating. There are also a few other holes in the research that are important to point out. 
Childhood diet and physical activity are the two most influential factors on metabolism, and they “were not included in our fully adjusted models because many of mother-child pairs were missing information about childhood diet and physical activity”. Furthermore, the study suggests tobacco consumption may be the hidden catalyst influencing their test results. “Fetal exposure to tobacco has been independently linked to insulin resistance in the offspring. Given that many participants in our cohort had both exposures, this raises the concern that tobacco, rather than cannabis, is driving these associations.”
Considering all of the negative health effects we already know about tobacco, it’s hard to give this study much credit. This goes double-fold for not being able to properly measure childhood diet and physical activity. CBD has even been shown to help with weight loss in adults. Given the study’s critical limitations, it’s still very hard to say if there are obesity risks for babies exposed to cannabis in the womb as more research is required.
- Moore, A. et al. Fetal Exposure to Cannabis and Childhood Metabolic Outcomes: The Healthy Start Study, The Journal of Clinical Endocrinology & Metabolism, 2022;, dgac101, https://doi.org/10.1210/clinem/dgac101. Times Cited: 1 Journal Impact Factor: 5.958