Researchers studied how common environmental chemicals called PFAS affect the placenta—the organ that feeds a developing baby. They examined placental tissue from 147 pregnancies and found that one type of PFAS chemical may change how genes work in the placenta, but in different ways for boys and girls. The changes they found involve genes related to vitamin D, which is important for bone and immune health. While this is early research, it helps scientists understand how these chemicals might harm babies before birth and could lead to better ways to protect pregnant people and their babies.

The Quick Take

  • What they studied: How PFAS chemicals (man-made substances found in many products) affect the placenta and whether these effects differ between male and female babies
  • Who participated: 147 placentas from pregnancies in the GLOWING study, representing a diverse group of pregnancies
  • Key finding: One PFAS chemical called PFNA showed a connection to changes in placental genes, and this connection was different for male versus female babies. The genes affected are involved in processes related to vitamin D and how cells control their DNA.
  • What it means for you: This research suggests PFAS chemicals may harm fetal development by changing how genes work in the placenta, but more research is needed to understand the real-world health impact. If you’re pregnant, reducing exposure to PFAS (found in non-stick cookware, water-resistant fabrics, and some food packaging) may be wise, though this study doesn’t prove it prevents problems.

The Research Details

Scientists collected placental tissue samples from 147 pregnancies and measured how much PFAS chemicals were present in each sample. They then used advanced genetic testing to read which genes were turned on or off in the placenta. Instead of looking at individual genes, they grouped genes that work together into teams called ‘modules.’ They used statistical methods to see which gene modules were associated with higher PFAS levels and whether these associations differed between male and female babies.

This approach is like looking at how different departments in a company work together rather than studying individual employees. By grouping related genes, researchers can understand bigger patterns in how PFAS affects the placenta. They carefully controlled for other factors that might affect gene activity, like maternal age and smoking, to make sure PFAS was really the cause of the changes they observed.

This research matters because the placenta is the critical connection between a pregnant person and their developing baby. Understanding how PFAS chemicals change placental function could explain why babies exposed to these chemicals sometimes have lower birth weights or other health problems. By identifying specific genes and biological pathways affected by PFAS, scientists can develop better screening tests and interventions to protect babies.

This study has several strengths: it used actual human placental tissue rather than lab experiments, measured PFAS chemicals precisely using advanced technology, and examined a large number of genes systematically. However, it’s a relatively small sample size (147 placentas), and it’s observational—meaning researchers observed associations but cannot prove PFAS directly caused the gene changes. The findings need to be confirmed in other studies before drawing firm conclusions.

What the Results Show

The researchers identified 20 different groups of genes that work together in the placenta. One of these groups showed a clear connection to PFNA (a type of PFAS chemical)—as PFNA levels increased, activity in this gene group decreased. This finding was statistically significant, meaning it’s unlikely to be due to chance.

Importantly, this relationship between PFNA and gene activity was different for male and female babies. While both sexes showed the same general pattern (higher PFNA linked to lower gene activity), the strength and specific details of this relationship varied. This sex-specific difference is important because it suggests boys and girls may be affected differently by these chemicals.

The genes in the PFNA-associated group were particularly involved in ‘histone modification’—a process that controls how tightly DNA is wrapped and which genes can be read. These genes were also enriched for targets of the Vitamin D Receptor, a master control switch in cells that regulates many important functions including bone development and immune response.

While the study focused on PFNA, researchers measured several other PFAS chemicals as well. The other PFAS chemicals showed less clear associations with the gene modules, suggesting PFNA may be particularly important in affecting placental gene activity. The researchers also noted that the gene module associated with PFNA is involved in fundamental cellular processes, suggesting that PFAS exposure could have broad effects on placental function beyond just one pathway.

Previous research has shown that PFAS chemicals can harm fetal development and lead to lower birth weights, but the exact biological mechanisms were unclear. This study provides a potential explanation by identifying specific genes and pathways that PFAS affects. The finding that vitamin D receptor pathways are involved aligns with earlier research suggesting PFAS may interfere with vitamin D function. The sex-specific differences observed here are consistent with growing evidence that boys and girls respond differently to environmental exposures during pregnancy.

The study examined only 147 placentas, which is a relatively small sample for genetic research. The researchers couldn’t directly measure whether the changes in gene activity actually affected how the placenta functioned or whether babies were harmed. The study is observational, so while it shows associations between PFAS and gene changes, it cannot prove PFAS caused these changes—other factors could be involved. Additionally, the study measured PFAS at one point in time, so researchers couldn’t track how exposure changed during pregnancy. Finally, the findings need to be replicated in other populations to confirm they apply broadly.

The Bottom Line

Based on this research, pregnant people may want to reduce PFAS exposure by: avoiding non-stick cookware, choosing products labeled ‘PFAS-free,’ limiting consumption of processed foods and fast food (which often come in PFAS-containing packaging), and using water filters if local water contamination is a concern. However, this is early-stage research, so these recommendations should be discussed with your healthcare provider. The evidence is moderate—the research is promising but not yet definitive enough to make strong clinical recommendations.

This research is most relevant to pregnant people and those planning pregnancy, as it focuses on fetal development. Healthcare providers caring for pregnant patients should be aware of this research. Parents of young children may also be interested, as PFAS exposure can occur throughout childhood. People living in areas with known PFAS contamination in water supplies should pay particular attention. However, this study doesn’t change current medical care recommendations—it’s foundational research that helps explain how PFAS might cause harm.

This research doesn’t directly address how quickly PFAS affects the placenta or how long it takes for health effects to appear. Based on other research, PFAS accumulates in the body over time, so reducing exposure during pregnancy may help, but benefits wouldn’t be immediate. Long-term follow-up studies of the babies in this research will help determine whether the gene changes observed actually lead to health problems and whether reducing PFAS exposure prevents these problems.

Want to Apply This Research?

  • Track PFAS exposure sources weekly: record non-stick cookware use, processed food consumption, water source, and product types used (checking labels for ‘PFAS-free’ designation). Rate exposure level 1-10 based on estimated PFAS contact.
  • Replace one PFAS-containing product per week with a PFAS-free alternative. Start with the most frequently used item (e.g., non-stick cookware or food storage containers). Log the replacement and note any challenges to build sustainable habits.
  • Monthly review of PFAS exposure reduction progress. Track cumulative product replacements and identify remaining high-exposure areas. Set quarterly goals to reduce overall PFAS contact, particularly important during pregnancy planning and pregnancy itself.

This research is preliminary and identifies potential biological mechanisms by which PFAS may affect fetal development—it does not prove that PFAS causes health problems in babies. This study was conducted in laboratory conditions analyzing placental tissue and cannot directly predict health outcomes. Pregnant people should not make major changes to their diet or lifestyle based solely on this research. Consult with your healthcare provider before making decisions about PFAS exposure reduction or any other pregnancy-related health matters. This information is for educational purposes and should not replace professional medical advice. If you have concerns about PFAS exposure, discuss them with your obstetrician or midwife.