Women with higher levels of PFAS in their system may be 20% more likely to stop breastfeeding early, according to a new study published in the Endocrine Society’s Journal of Clinical Endocrinology & Metabolism.

Per- and polyfluoroalkyl substances (PFAS) are manmade chemicals used as oil and water repellents and coatings for common products including cookware, carpets and textiles. These endocrine-disrupting chemicals do not break down when they are released into the environment, and they continue to accumulate over time. PFAS chemicals can affect pregnancy outcomes, the timing of puberty and other aspects of reproductive health.

“Our findings are important because almost every human on the planet is exposed to PFAS. These man-made chemicals accumulate in our bodies and have detrimental effects on reproductive health,” said the study’s first author Clara Amalie Gade Timmermann, PhD, assistant professor of the University of Southern Denmark in Copenhagen, Denmark. “Early unwanted weaning has been traditionally attributed to psychological factors, which are without a doubt important, but hopefully our research will help shift the focus and highlight that not all mothers can breastfeed despite good intentions and support from family and healthcare professionals.”

The researchers analyzed blood samples for PFAS and prolactin concentrations from up to 1,286 pregnant women from the Odense Child Cohort. The women provided information about the duration of breastfeeding in weekly text messages or questionnaires at three and eighteen months postpartum. The researchers found women with higher levels of PFAS in their system were 20% more likely to stop breastfeeding early.

“Because breastfeeding is crucial to promote both child and maternal health, adverse PFAS effects on the ability to breastfeed may have long-term health consequences,” Timmermann said.

Other authors of the study include: Marianne Skovsager Andersen and Henriette Boye of the Odense University Hospital in Denmark; Esben Budtz-Jørgensen of the University of Copenhagen; Flemming Nielsen of the University of Southern Denmark; Richard Christian Jensen, Steffen Husby and Tina Kold Jensen of the University of Southern Denmark and the Odense University Hospital; Signe Bruun of the Odense University Hospital, the University of Southern Denmark and Arla Foods Ingredients Group; and Philippe Grandjean of the University of Southern Denmark and the Harvard T.H. Chan School of Public Health in Boston, Mass.

The study received funding from the Independent Research Fund Denmark, the Odense University Hospital, the Region of Southern Denmark, the Municipality of Odense, the Mental Health Service of the Region of Southern Denmark, the Odense Patient data Explorative Network, Novo Nordisk and the National Institute of Environmental Health Sciences.

The manuscript, “Pregnancy Exposure to Perfluoroalkyl Substances, Prolactin Concentrations and Breastfeeding in the Odense Child Cohort,” was published online, ahead of print.