Chemical Effects on Mammary Gland Development

Pregnant women already know that consuming alcohol, caffeine, and tobacco can be harmful to their babies’ health.  But they may be surprised to learn that some chemicals women are exposed to in their daily lives—from their food packaging to their drinking water—could affect their children’s development and health later on.

Our new review, published in the peer-reviewed journal Environmental Health Perspectives, reports the conclusions of an international workshop on ways to improve chemicals safety testing for effects on the breast. Studies reviewed by the scientists show that exposures to common chemicals during critical windows of development—such as in the womb and during infancy and puberty—may lead to changes that cause problems later in life with breast-feeding and increase the risk of breast cancer.  Exposures may also lead to enlarged breasts in boys and men.

The review and a related editorial identify a major gap in chemicals safety testing, which currently does not assess how chemicals may affect breast development. The scientists recommend that future chemical safety testing evaluate these effects. By studying how environmental chemicals influence breast development, scientists can help government, manufacturers, and consumers make better decisions about chemicals in consumer products and air and water pollution. In the meantime, there are steps moms can take now to reduce their exposures.


Review in Environmental Health Perspectives

Editorial in Environmental Health Perspectives

Press Release: Scientists call for safety testing of chemicals to include prenatal exposures

Study Fact Sheet

Tips Card: Five Tips for Moms and Moms-To-Be

Table: Common Chemicals May Harm Breast Development

The study was authored by scientists from Silent Spring Institute, the National Institute of Environmental Health Sciences (NIEHS), the US Environmental Protection Agency (EPA), and the California Breast Cancer Research Program (CBCRP). This work was supported by the CBCRP, US EPA, NIEHS, National Toxicology Program, and the Susan S. Bailis Breast Cancer Research Fund at Silent Spring Institute.