Heavy Metal Exposure Could Deplete Eggs in Ovaries

Exposure to toxic heavy metals can lead to various harmful effects on the body. New research featured in The Journal of Clinical Endocrinology & Metabolism suggests middle-aged women in particular may face heightened risks, reporting that women with higher heavy metal levels in their urine had indicators of lower ovarian reserve.

Endocrine disruptors

The menopause transition is a normal part of aging for women that typically occurs between 45–55 years of age. The process lasts around seven years and is often accompanied by symptoms such as changes in the menstrual cycle, hot flashes and night sweats.

A diminished ovarian reserve is characterized by having fewer eggs compared to others in the same age group. The condition is associated with health problems such as weak bones and a higher chance of heart disease.

Previous research has linked heavy metals, found in urine, to an increase in women’s reproductive aging and a diminished ovarian reserve. Arsenic, cadmium, mercury and lead are classified as endocrine-disrupting chemicals and can commonly be found in drinking water, air pollution and food contamination.

"Widespread exposure to toxins in heavy metals may have a big impact on health problems linked to earlier aging of the ovaries in middle-aged women, such as hot flashes, bone weakening and osteoporosis, higher chances of heart disease and cognitive decline,” said study author Dr. Sung Kyun Park, an associate professor of epidemiology and environmental health sciences at the University of Michigan.

Heavy metals and anti-Müllerian hormone

Park and the team studied 549 middle-aged perimenopausal women who tested positive for heavy metals in their urine samples. They used blood test results from up to 10 years before the woman's final menstrual period to analyze levels of anti-Müllerian hormone (AMH) – an indicator for how many eggs remain in a woman’s ovaries. AMH can be used to predict health risks for women in middle age and later in life.

The researchers found women with increased levels of heavy metals in their urine were more likely to have lower AMH levels and therefore were at risk of diminished ovarian reserve.

“Metals, including arsenic and cadmium, possess endocrine disrupting characteristics and may be potentially toxic to the ovaries,” Park said. “We need to study the younger population as well to fully understand the role of chemicals in diminished ovarian reserve and infertility.”

“Future studies are needed to confirm the reliability of our findings and explore these associations in a more diverse and extensive population,” the authors write.

Reference: Ding N, Wang X, Harlow SD, Randolph Jr JF, Gold EB, Park SK. Heavy metals and trajectories of anti-Müllerian hormone during the menopausal transition. J. Clin. Endocrinol. Metab. 2024. doi: 10.1210/clinem/dgad756

This article is a rework of a press release issued by The Endocrine Society. Material has been edited for length and content.