New research for the first time links prenatal exposure to Pfas “forever chemicals” with the development of polyendocrine metabolic ovarian syndrome (PMOS) later in life.

PMOS, formerly known as polycystic ovarian syndrome (PCOS), is estimated to impact about 13% of women. Many cases are undiagnosed, and the disease’s cause largely remains a mystery.

The new peer-reviewed study, led by Harvard University, looked at about 325 mother-daughter pairs and found that mothers with higher Pfas levels in their blood during pregnancy were more likely to have a daughter with PMOS and moderate-to-severe acne by their later teenage years.

The findings suggest chemical exposure may be a main driver of the disease, the authors say, though they stressed that more research is needed. The paper builds on studies that previously linked Pfas to PMOS, and a range of hormonal and developmental problems. But it is the first to examine the impacts of prenatal exposure and development of PMOS later in life, which provides a key piece of evidence, public health advocates say.

“This is another piece that fits in that larger body of evidence of these specific harms, like hormonal disruption,” said Tasha Stoiber, a senior scientist with the Environmental Working Group non-profit who reviewed the study, but was not an author.

Pfas are a class of at least 16,000 compounds most frequently used to make products water-, stain- and grease-resistant. They have been linked to cancer, birth defects, decreased immunity, high cholesterol, kidney disease and a range of other serious health problems. They are dubbed “forever chemicals” because they can persist for thousands of years in the environment, and are designed to be indestructible.

PMOS causes symptoms like irregular periods, excessive hair growth, acne and infertility. The disease is not actually caused by a problem with the ovary or ovaries themselves, but is more like a response to dysregulated hormonal signals and endocrine messaging miscommunication within the body. In May, PCOS was renamed PMOS to better reflect that the issues affected the broader system, and not just ovaries.

The mothers and daughters in the study live in the Boston area and are part of Project Viva, a study started in 1999 that examines how early life experiences impact mothers and their children later in life.

Teens with mothers who had higher levels of the Pfas compounds in their blood at birth were 2.3 to 2.7 times more likely to develop PMOS or acne later in life.

While the study’s length provides valuable insight, the authors cautioned that it has a small sample size and was overrepresented by white and college-educated women.

A correlation was found between the disease and elevated levels of the N-EtFOSAA compound, which is widely found in stain guards, pesticides, water repellents for textiles, or as coatings for paper products. Once in the environment, the compound can break down into Pfos, which is considered to be among the most toxic Pfas chemicals.

Another compound, PFNA, which is used in many of the same applications, was associated with higher odds of moderate-to-severe acne.

“It’s not just PFOA and Pfos that we’re worried about – it’s the precursors and all the chemicals along the way,” Stoiber said.

Pfas are difficult to avoid because they are so widely used. Still, mothers can protect themselves by avoiding stain guards, and checking with textile or clothing producers to ensure that their waterproof products are free from Pfas. Stoiber also recommended eating organic, whole foods cooked at home as much as possible, because those tend to have less Pfas from packaging and processing equipment.