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By Pamela Ferdinand
Glyphosate, the world’s most widely used herbicide, disrupts female hormones and damages the ovaries and uterus in ways that can make it more difficult for women to get pregnant, according to a new review of human and animal research.
The study, published in Reproductive Sciences on March 21, also found that glyphosate may be tied to polycystic ovary syndrome (PCOS) and endometriosis, due to its endocrine-disrupting capabilities and reproductive toxicity.
PCOS is a hormonal disorder that affects the ovaries, fertility and periods, among other symptoms. Endometriosis is an often painful condition when tissue similar to the uterine lining (endometrial tissue) grows outside the uterus. Both conditions are among the leading causes of infertility.
“Collectively, these findings raise concerns about potential associations between [glyphosate-based herbicide] exposure and female reproductive system diseases, including PCOS, endometriosis, and subfertility/infertility,” the researchers say.
The study highlights growing concerns about the long-term health effects of glyphosate and glyphosate-based herbicides (GBH), such as Roundup. Glyphosate use rose sharply in recent decades, with around 240 million pounds sprayed annually on U.S. farms.
People are exposed to glyphosate through skin contact, ingestion in food or water and inhalation of airborne particles. Studies have detected glyphosate and its breakdown product (aminomethylphosphonic acid, or AMPA) in blood, breast milk and urine.
A 2022 survey found glyphosate in more than 80% of urine samples from U.S. adults and children.
Multiple toxic effects of glyphosate exposure
Although the U.S. Environmental Protection Agency (EPA) considers glyphosate safe, recent studies have linked it to cancer, adverse early neurodevelopment, lower birth weight, liver inflammation and metabolic disorder, toxic effects on the nervous system, and diseases like Alzheimer’s and Parkinson’s.
Research has shown impacts on the male reproductive system, including hormonal changes, developmental delays and reductions in sperm count and quality, as well as in lab animals exposed to glyphosate.
Several studies also suggest that GBH, which contain additional chemicals, are more toxic than glyphosate alone.
For this review, researchers analyzed studies from PubMed up until March 2024 to explore how glyphosate impacts the female reproductive system and potential clinical implications on reproductive health outcomes.
The evidence indicates glyphosate can harm the female reproductive system and increase the risk of infertility and disease in multiple ways.
These include:
- Pregnancy risks: Glyphosate exposure may increase inflammation and disrupt key pregnancy hormones, including estrogen and progesterone. This potentially leads to poor pregnancy outcomes and fetal developmental issues, as seen in animal studies.
- Uterine abnormalities: Glyphosate and GBH can damage the uterus, altering its structure, harming tissue, and disrupting pregnancy processes like blood vessel formation and embryo implantation.
- “These GBH-induced alterations in uterine architecture and morphology may contribute to infertility, early pregnancy loss, and endometrial hyperplasia [abnormally thick uterine lining],” the researchers say.
- Ovarian damage: Glyphosate exposure has been linked to diminished ovarian function and a reduction in the number and quality of eggs. It can also damage ovarian follicles, essential for hormone production and egg development, making it harder to get pregnant.
- Oxidative stress: Glyphosate can cause stress in the body by increasing levels of harmful molecules (reactive oxygen species) that cause cellular, protein, and DNA damage. The chemical can make it difficult for the body to absorb zinc, which protects against oxidative stress and is important for proper egg (oocyte) development and growth. It can also reduce the activity of enzymes that protect cells from oxidative damage. This can disrupt immune function and reproduction, and affect hormones, brain function, metabolism and genes.
- Genetic changes: Glyphosate can alter gene expression (whether genes are turned “on” or “off”) without changing the actual DNA sequence itself (epigenetics). This means maternal exposure to glyphosate, especially during pregnancy or sensitive periods of fetal development, can lead to congenital abnormalities. The genetic changes also can be passed down to future generations, which promotes disease long after direct chemical exposure occurs.
- Hormone disruption: Glyphosate acts as a hormone (endocrine) disruptor, interfering with estrogen signaling and inhibiting an enzyme needed to produce estrogen. This affects ovary function, the structure and shape of the uterus and embryo implantation.
Understanding the full impact of glyphosate on human health, especially female reproductive health, is crucial for public policy decisions, the researchers say. Future studies should identify safer alternatives to GBH, they add.
Establishing the effects of GBH on female reproductive health and human fertility is a “pressing public health issue,” the researchers said.
To reduce your risk of exposure to glyphosate, experts recommend opting for organic produce, avoiding herbicide use in home gardens, and using protective gear when handling pesticides. Supporting non-herbicide weed control strategies and organic farming can also decrease reliance on chemical herbicides.
Originally published by U.S. Right to Know.
Pamela Ferdinand is an award-winning journalist and former Massachusetts Institute of Technology Knight Science Journalism fellow who covers the commercial determinants of public health.
