July 13, 2024

Cannabis Exposure Associated with Higher Risk of Unhealthy Pregnancy Outcomes, Study Finds

 The study, which involved over 9,000 pregnant individuals from across the United States, revealed that cannabis exposure was associated with a composite measure of negative pregnancy outcomes, particularly low birth weight. Additionally, the study demonstrated that higher levels of cannabis exposure corresponded to higher risks of adverse outcomes.

The researchers emphasized that cannabis use is not safe for pregnant individuals, and they discourage its use during pregnancy. According to Dr. Robert Silver, a professor of obstetrics and gynecology at U of U Health and last author on the study, cannabis increases the risk of pregnancy complications. Therefore, if possible, pregnant individuals should avoid using cannabis.

The motivation behind this study stems from the conflicting information surrounding the health effects of cannabis use during pregnancy. Dr. Torri Metz, the lead author of the study and vice chair of research of obstetrics and gynecology at U of U Health, pointed out that there is a vast amount of information available on cannabis use during pregnancy, making it challenging for patients to discern what they should be concerned about. Previous studies on this topic have yielded inconsistent results, partially due to differences in the characteristics of individuals who use cannabis during pregnancy and those who do not. Factors such as rates of anxiety and depression could influence the outcomes, making it difficult to isolate the consequences specifically related to cannabis use.

However, the large study population, comprising participants from eight medical centers across the U.S., allowed the researchers to address these issues. The researchers were able to statistically analyze the impacts of cannabis use by comparing pregnancy outcomes for a significant number of participants, 610 of which had detectable levels of cannabis exposure. This approach enabled them to differentiate the effects of cannabis from other factors such as pre-existing health conditions, nicotine exposure, and socioeconomic status.

The findings of the study revealed that cannabis exposure was associated with a 1.5-fold increase in the risk of negative pregnancy outcomes. Approximately 26% of pregnant individuals exposed to cannabis experienced unhealthy pregnancy outcomes, compared to 17% of non-exposed pregnant individuals. Furthermore, higher levels of cannabis exposure throughout pregnancy were linked to higher risks.

A significant aspect of this study was the accurate measurement of cannabis exposure. While previous studies relied on self-reporting of cannabis use, which can underestimate the actual rate of use, the researchers measured the levels of a metabolic byproduct of cannabis in participants’ urine samples, providing more accurate measurements.

To assess the impacts on pregnancy, the researchers examined various negative health outcomes, including low birth weight, pregnancy-related high blood pressure, stillbirth, and medically indicated preterm birth. The association between cannabis use and low birth weight was found to be the strongest. All of these conditions have been linked to reduced placental function, which supplies the growing fetus with oxygen and nutrients.

Although this type of study cannot determine why cannabis is associated with negative pregnancy outcomes, previous research conducted on non-human primates has shown that long-term cannabis exposure can disrupt the blood supply to the placenta. The correlation observed in this study suggests a similar effect on the human placenta.

Dr. Silver expressed concern over the higher risk observed with higher levels of cannabis exposure, particularly due to the increased potency of newer cannabis products. The study data was collected from 2010 to 2014, a timeframe when these concentrated products started becoming available. The health effects of these highly potent products are still largely unknown.

The researchers advocate for open conversations between pregnant individuals considering cannabis use and their healthcare providers. While some individuals may turn to cannabis to alleviate symptoms such as nausea or anxiety, there are alternative therapies that have been proven to be safe. Dr. Silver emphasizes the need for further research on the health impacts of cannabis, allowing individuals to make informed decisions about their health.

This research was conducted in collaboration with several other institutions, including ARUP Laboratories, University of California, Irvine, The Ohio State University, Indiana University, Case Western Reserve University, University of Pennsylvania, Columbia University, Eastern Virginia Medical School, and the University of Pittsburgh.

1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it