Environmental Contaminants in Breast Milk

Krista Nickerson, CNM, MSN


J Midwifery Womens Health. 2006;51(1):26-34. 

In This Article

Abstract and Introduction

Toxic environmental contaminants can be transferred from mother to infant via breastfeeding. Persistent organic pollutants (POPs) are a family of lipophilic stable chemicals that bioaccumulate in adipose tissue and create a lasting toxic body burden. Breastfeeding provides a significant source of exposure to POPs early in human life, the effects of which are unknown, and is the subject of a growing body of research. Despite the possibility of harm from environmental contaminants in breast milk, breastfeeding is still recommended as the best infant feeding method. This article reviews what is known about POPs in breast milk and their effect on infant development to inform clinicians about the issue, provide recommendations for practice, and promote environmental and public health policies that reduce human exposure to harmful pollutants.

We are what we eat. The interconnectedness of humans with their environment is illustrated by this familiar maxim. Substances that enter the human body from our external environment—food, water, and air—are the source for our biologic composition. Now imagine the breastfeeding maternal-infant dyad. A mother's body becomes the environment for her children throughout pregnancy and through breastfeeding. Over the past several decades, the public has grown increasingly aware that chemicals in the environment are entering our bodies and sometimes causing harm. Recently, this awareness has extended to concern about what effect(s) toxic contaminants have on breastfeeding women and their children.

The issue of environmental pollution and breastfeeding was brought to light by Sandra Steingraber, a mother and an ecologist, an author and public spokesperson in 2001. Her book Having Faith: An Ecologist's Journey to Motherhood[1] has fueled a growing concern over this issue. It is a fascinating and well-researched personal account of her own pregnancy, birth, and breastfeeding experience, emphasizing the environmental influences on her own developing child. In a recent issue of the popular magazine Mothering,[2] the lead article addressed breastfeeding and environmental contaminants. Newspapers, radio programs, and other mainstream media are bringing this particular issue to the lay public. Obstetric providers need to recognize and confront the issue of pollutants in breast milk for several reasons. 1) As clinicians, we need to be aware of the research and guidelines promoted by leading experts to counsel our clients appropriately. 2) As caretakers of women's reproductive health, we need to promote progressive public health policy concerning this issue to prevent future harm.

The benefits of breastfeeding are clear. Breast milk is nutritionally balanced and biologically appropriate for human infants. The species-specific components present in breast milk protect infants against infections; promote immune and neurologic system development; and may decrease the risk of disease, including allergies, obesity, insulin-dependent diabetes mellitus, inflammatory bowel disease, and sudden infant death syndrome (SIDS).[3] Breastfeeding also facilitates maternal-infant attachment. However, there is unambiguous data that breast milk accumulates and harbors persistent organohalogens, including persistent organic pollutants (POPs), heavy metals, and volatile solvents.[4] The effect of these contaminants on the breastfeeding infant is the subject of a growing body of research. As a category of pollutants, POPs include chemicals that can be very toxic to humans, are found in relatively high quantities in breast milk, and have been fairly well studied. Although all breast milk contaminants are important to consider, this article focuses on the evidence about the effects of POPs in breast milk.


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