Women using a common, injectable form of birth control showed increased levels of potentially hazardous lead in their blood, a study led by a Michigan State University researcher found.
The study reported that women who were currently using the contraceptive depot medroxyprogesterone acetate, or DMPA, had 18% higher levels of lead in their blood on average than those who were not using it.
Kristen Upson, an assistant professor of epidemiology and biostatistics in MSU College of Human Medicine and lead author of the study, said she suspected DMPA, sold under the brand name Depo-Provera, could be associated with higher levels of blood lead because of its effect on bone. A known possible side effect is loss of bone mineral density during its use. With bone loss there can be a release of lead that is stored in bone. About 90% of lead that enters the body is stored in the bones.
“We do not know how 18% translates to adverse health effects. What we do know is that the widespread scientific consensus is that there is no safe blood lead level,” Upson said.
The study, published in the journal Environmental Health Perspectives, included 1,548 African American women participating in research to learn more about the development of uterine fibroids, a condition that disproportionately affects African American women. The project was initiated and data is collected through the Detroit Study of Environment, Lifestyle, and Fibroids, sponsored by the National Institute of Environmental Health Sciences, part of the National Institutes of Health.
Upson said that since current DMPA users and those not using DMPA were compared at one time point, it is possible that other differences between current users and nonusers could explain the result. “However, our finding persisted even after conducting additional analyses to account as best we could for these differences,” Upson said.
The U.S. Food and Drug Administration approved DMPA for birth control in 1992, and one in five sexually active women in the United States have used it. A single injection provides three months of contraceptive coverage to prevent pregnancy. Worldwide, some 74 million women use injectable contraception.
“While lead exposure in children commonly is associated with neurodevelopmental problems, it can affect all organ systems even in adulthood,” Upson said. “That’s why it’s so important to do further research.”
The latest findings do not suggest that DMPA should be banned. “It is such an important form of contraception that we really need to do more research to make sure that other studies confirm this finding,” she said.
Upson said she hopes to conduct further research following women from when they start using DMPA until after they stop using it to further assess the drug’s potentially adverse health effects.
Data collection for this investigation was funded by NIEHS, NIH, and from funds allocated for health research by the American Recovery and Reinvestment Act. Additional support came from the National Institute of Nursing Research and the Office of Disease Prevention. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
(Note for media: Please include a link to the original paper in online coverage: https://doi.org/10.1289/EHP7017)