A new study has uncovered alarming evidence that cannabis use may cause significant damage to human egg cells, potentially leading to infertility, miscarriage, and genetic abnormalities in unborn children.

Published in the prestigious journal Nature Communications, the research represents the first comprehensive investigation into how marijuana impacts female reproductive cells at a chromosomal level. The findings have prompted fertility experts to urge caution amongst women planning to conceive.

Understanding the Cannabis Fertility Risks

The study analysed over 1,000 ovarian fluid samples from patients undergoing fertility treatment, revealing a troubling connection between THC exposure and egg cell abnormalities. Tetrahydrocannabinol (THC), the psychoactive compound that causes marijuana’s euphoric effects, interferes with the delicate process of egg maturation.

Dr Jamie Lo, an associate professor of obstetrics, gynaecology and urology at Oregon Health & Science University, described the findings as “concerning” and emphasised the need for a cautious approach when using marijuana whilst planning pregnancy.

“The findings of this study are concerning and highlight the importance of a cautious approach in using cannabis when planning to conceive,” Dr Lo stated.

How Cannabis Damages Reproductive Cells

Researchers discovered that higher THC levels were associated with accelerated egg maturation rates, a phenomenon that initially appears positive but actually creates significant problems. When oocytes (unfertilized eggs) mature too rapidly, chromosomes lack sufficient time to align correctly for fertilisation.

Lead study author Cyntia Duval, who conducted the research at the University of Toronto, explained the critical nature of this timing: “Chromosomes need time to align perfectly to be ready to be fertilised by sperm and create healthy embryos. So yes, we have more oocytes that are mature, but at what price if they don’t have the right number of chromosomes?”

The investigation also examined immature egg cells in laboratory conditions. When exposed to THC for 24 hours, these cells showed altered spindles, the structures essential for proper chromosome separation. Such abnormalities can lead to embryonic development failures.

Rising Cannabis Use Amongst Pregnant Women

The research arrives at a crucial moment, as marijuana use during pregnancy has risen dramatically. A June study revealed that self-reported cannabis consumption amongst pregnant women in the United States more than tripled between 2002 and 2020.

Many women, believing cannabis to be a safe natural remedy, turn to the drug to manage pregnancy-related nausea and discomfort. However, numerous studies have already linked marijuana use during pregnancy to autism, poor foetal development, low birth weight, premature deliveries, and infant mortality.

The new findings on marijuana and egg health add another dimension to these concerns, suggesting that harm may occur even before conception takes place.

The Hidden Danger of THC Potency

A particularly worrying aspect of cannabis fertility risks involves the dramatic increase in THC potency over recent decades. According to the National Institute on Drug Abuse, THC concentrations quadrupled between 1995 and 2022, with some dispensary products now containing over 40% THC.

This surge in potency may not be apparent to consumers. Whilst legal dispensaries provide product labels detailing THC content, those purchasing marijuana through illegal channels often lack access to reliable potency information.

Tom Freeman, a professor of psychology at the University of Bath, noted that even when consumers attempt to adjust their intake based on potency, such as using less product or inhaling less deeply, these efforts typically fail to compensate fully. Consequently, higher potency products deliver substantially larger THC doses than lower potency alternatives.

Women may inadvertently expose themselves to damaging THC levels without realising it, potentially compromising their reproductive health before they even attempt to conceive.

Expert Recommendations for Women Planning Pregnancy

Dr Lo emphasised that whilst the study demonstrates an association rather than definitive causation, the implications warrant serious consideration. For women who struggle to abstain from cannabis entirely, the research offers valuable guidance for harm reduction.

“The finding that exposure to higher levels of THC could be associated with worsened fertility and increased reproductive complications may help patients that cannot abstain from cannabis with a harm-reduction strategy,” Dr Lo explained. “With this information, these patients can consider reducing the amount of cannabis that they are using to mitigate adverse outcomes to their babies.”

Duval stressed the need for additional research to verify the findings and determine the full extent of cannabis’s impact on reproduction. “This is a hypothesis, and the worst thing I would want is for the public to read this and become fearful,” she said. “More studies are needed to verify our findings.”

Nevertheless, experts unanimously recommend that women planning to conceive explore safer alternatives for managing symptoms they might otherwise treat with marijuana, or at minimum reduce their frequency of use.

A Call for Awareness

The study fills a critical gap in scientific understanding. Whilst previous research has examined marijuana’s effects on male sperm, this investigation represents the first examination of cannabis’s impact on human eggs and ovarian follicles.

As cannabis legalisation expands globally and social acceptance grows, understanding the full spectrum of health implications becomes increasingly vital. For women of reproductive age, the emerging evidence on cannabis fertility risks provides important information for making informed decisions about their health and future families.

The message from researchers is clear: when it comes to planning pregnancy, caution regarding cannabis use isn’t merely advisable—it may be essential for protecting both fertility and the health of future children.

Source: CNN