The use of cannabis, including CBD products, during pregnancy has seen a significant surge in recent years. Its rise in popularity is partly fueled by the perception that cannabis is a safer, more natural alternative to pharmaceutical interventions. However, emerging research highlights severe risks associated with cannabis use during pregnancy. Complications such as restricted fetal growth, preterm birth, long-term behavioral and metabolic issues in offspring, and, as new evidence suggests, disruptive behavioral disorders (DBDs) are critical concerns that must be addressed.

A recent study using a murine model sheds light on how oral cannabis consumption, specifically CBD and THC, impairs maternal health, gestational processes, and offspring development. Additionally, groundbreaking cohort research underscores the link between maternal cannabis use disorder (CUD) and significant neurobehavioral challenges in children, reinforcing the urgent need for education and intervention.

What Is Cannabis Use During Pregnancy and Why Is It a Concern?

Cannabis consumption during pregnancy includes the use of THC- or CBD-containing products by expecting mothers. These products may be smoked, vaped, or ingested via oils, edibles, or tinctures. Cannabis is often marketed as natural and risk-free, but this perception dangerously overlooks its potential to disrupt fetal development.

Both THC and CBD cross the placental barrier, directly exposing the developing fetus to substances that can impede growth and neurological development. The early stages of pregnancy, in particular, represent a critical window for placental and fetal development. Emerging evidence reveals that not only does cannabis use disrupt these processes, but the consequences extend beyond gestation, profoundly affecting offspring into adolescence and adulthood.

While oral cannabis consumption might avoid the risks associated with smoke inhalation, research finds it can still be harmful. The murine study adds critical insights into how oral cannabis use alters maternal and fetal outcomes. This is compounded by human cohort evidence that highlights stark consequences, such as a threefold or greater risk of DBDs in offspring from cannabis-exposed pregnancies.

Disruption of Early Pregnancy Processes by Cannabis Use

Impaired Maternal-Fetal Interface

The placenta is essential for nutrient delivery and waste removal between the mother and fetus. Findings show that oral CBD consumption reduces placental size, while both CBD and THC negatively impact vascular remodeling in the placenta, leading to restricted nutrient and oxygen exchange. Maternal spiral artery remodeling is hindered, resulting in thicker vessel walls and less effective blood flow. This increases risks for conditions like preeclampsia and intrauterine growth restriction, placing both the fetus and mother in danger.

The murine study also found elevated levels of uterine natural killer (uNK) cells in the decidua with CBD exposure. These cells play a critical role in immune regulation and vascular remodeling. Their overactivity, however, compromised reproductive processes, raising red flags about fetal development risks.

Maternal Cannabis Use and Disruptive Behavioral Disorders in Offspring

Findings from a comprehensive human cohort study show that maternal cannabis use disorder (CUD) significantly heightens the risk of developing DBDs in offspring, which include issues like oppositional defiant disorder (ODD) and conduct disorder (CD). These risks were notably elevated during key periods:

• Antenatal CUD exposure: A 3.56 times higher risk of DBDs.
• Perinatal CUD exposure: A 3.55 times higher risk of DBDs.
• Postnatal CUD exposure: A 2.95 times higher risk of DBDs.

Even after adjusting for confounding factors like socioeconomic status, tobacco use, and maternal mental health conditions (e.g., anxiety and depression), the association between maternal cannabis use and DBDs in children persisted strongly. This indicates that maternal cannabis use during pregnancy is an independent risk factor for significant neurobehavioral outcomes in offspring.

Impairments in Fetal Growth Due to Cannabis

Fetal Weight and Size

Cannabis exposure reduces fetal weight and body length, with THC treatment leading to significant reductions in both. CBD-treated dams showed high variability in fetal weights, with a disturbing percentage falling below growth benchmarks.

Brain and Head Development

Fetal head size and brain development were markedly affected. THC exposure reduced head length, and trends in lowered brain mass were noted for both THC and CBD exposure. These physical markers of impaired growth are reflections of deeper neurological disruptions likely to manifest later in life.

Increased Risk of Pregnancy Loss

Both studies observed troubling trends of increased fetal resorption rates in pregnancies exposed to cannabis. This might signal an elevated risk of miscarriage in human pregnancies involving cannabis use.

Long-Term Impacts of Prenatal Cannabis Exposure

Behavioral Impacts in Offspring

The effects of cannabis use during pregnancy do not stop at birth. Behavioral changes in offspring linked to prenatal cannabis exposure are concerning and often sex-dependent:

• Male offspring: THC-exposed males displayed aggressive behavior and heightened hyperactivity, echoing trends seen in human studies linking prenatal cannabis exposure with externalizing behaviors.
• Female offspring: Cognitive impairments like poor spatial learning were more pronounced, raising concerns about lifelong cognitive deficits.

Metabolic Changes

Cannabis exposure also affects offspring metabolism. Male offspring from THC-exposed pregnancies demonstrated lower metabolic activity and basal metabolic rates, potentially setting them up for metabolic syndrome in later life.

Mechanisms Behind Cannabis-Driven Impairments

Both THC and CBD cross the placental barrier, directly affecting fetal tissues. One emerging mechanism involves the suppression of VEGF (vascular endothelial growth factor) production by uterine natural killer cells. VEGF is crucial for proper blood vessel development. Its suppression compromises placental vascular remodeling, leading to reduced nutrient and oxygen exchange between mother and fetus.

Similar mechanisms underlie the behavioral and cognitive changes seen in offspring. Alterations in hippocampal connectivity documented in both murine and human studies suggest that cannabis compounds disrupt neural circuitry during critical windows of brain development.

Dispelling Myths and Raising Awareness

Safety Perception vs Reality

The notion that cannabis is a natural, safe alternative during pregnancy is dangerously misleading. The findings from these studies decisively confirm the risks, even with oral consumption. No mode of cannabis use is free of harm for the developing fetus.

Critical Importance of Avoidance

Cannabis poses the greatest risks during the early trimesters, when organs and critical structures like the placenta are forming. Given the long-lasting impacts observed on offspring health, it is vital that public health campaigns target these critical gestational periods to educate expecting mothers.

Healthcare Interventions

Clearer guidelines and more proactive health counseling around cannabis use during pregnancy are essential. Healthcare providers must engage in open, evidence-based conversations with pregnant individuals to ensure they understand the risks.

Protecting Future Generations

The message couldn’t be clearer—using cannabis during pregnancy is dangerous. It disrupts critical processes for both mother and baby, leading to risks like restricted fetal growth, long-term behavioral and cognitive issues, and even metabolic problems. On top of that, the increased likelihood of disruptive behavioral disorders in children makes the stakes even higher.

We need to talk about this. Too many people still believe the myth that cannabis is “natural” and safe, but the science says otherwise. It’s time for public health campaigns to step up and spread the word. If you or someone you know is pregnant and using cannabis, don’t wait. Talk to a healthcare provider and make choices that protect your baby’s future. The health of the next generation depends on the decisions we make today.

Source: Science Direct