The chemicals in your body today may reach your baby before birth. Here's what the research shows.
Pregnancy is one of the most remarkable biological processes — and also one of the most vulnerable. While new life is growing in the womb, mom’s body is acting as a gateway between the outside world and the developing child. It’s critical that nutrients and oxygen, your hormones and antibodies all come from mom, but unfortunately, that’s not all that makes it through.
One of the most powerful ways scientists measure prenatal exposures is through umbilical cord blood, which reflects what actually crossed the placenta to reach baby. Recent research has indicated that these factors can influence lifelong health.
“Forever Chemicals”: What They Are and Why They Matter
Per- and polyfluoroalkyl substances (PFAS) — often called “forever chemicals” — are a large family of human-made compounds used in everyday products like nonstick cookware, stain-resistant fabrics, waterproof clothing, and food packaging. They’ve earned their nickname because they don’t break down easily in the environment or in the human body, meaning exposure can accumulate over time.
In a new 2026 study, scientists discovered 42 different PFAS compounds (forever chemicals) in cord blood — far more than traditional tests had ever captured.
The lead author, Dr. Shelley Liu, commented, “When we look more comprehensively, we see that babies are exposed to far more PFAS chemicals before birth than we previously realized.
Why PFAS Cross h Placenta
The placenta isn’t a perfect barrier. Its job is to allow nutrients and oxygen to reach your baby while keeping many harmful substances out — but it doesn’t block everything. Many synthetic chemicals are small enough or chemically suited to travel across the placental membrane and enter the fetal bloodstream via the umbilical cord.
Once in your baby’s circulation, these persistent chemicals can accumulate in developing tissues at a time when organs, hormones, and the immune system are rapidly forming. That’s why prenatal exposure — especially early in pregnancy — can be so problematic.
The Mount Sinai study isn’t the first to document this phenomenon — it expands on an emerging body of research showing that maternal chemical exposures do cross the placenta:
- - Earlier research detected PFAS in newborn blood samples shortly after birth, indicating prenatal transfer and associated risks like preterm birth and hormonal disruption.
- - Multiple studies have found that a variety of environmental contaminants — including pesticides, plastics chemicals, and other PFAS — show up in umbilical cord blood and placental tissue across populations worldwide.
These findings reinforce a key biological truth: your baby is not isolated from your environment — they share it with you. That’s why minimizing chemical exposure before and during pregnancy is such an important part of preconception care.
Pregnancy isn’t just the beginning of a child’s life — it’s a window of opportunity to set the stage for lifelong health. Taking thoughtful steps now doesn’t just reduce risks — it promotes resilience, wellness, and thriving for a new generation.
Taibl, K. R. et al. (2023). Newborn metabolomic signatures of maternal per- and polyfluoroalkyl substance exposure and reduced length of gestation. Nature Communications, 14, Article 3120. https://doi.org/10.1038/s41467-023-38710-3
Liu, S. H. et al. (2026). Quantifying PFAS-omics burden scores for nontargeted analysis using multidimensional item response theory: An exploratory analysis of novel and legacy PFAS in cord blood.Environmental Science & Technology. Advance online publication. https://doi.org/10.1021/acs.est.5c06490
Environmental Working Group. (2005). Body burden: The pollution in newborns. https://www.ewg.org/research/body-burden-pollution-newborn
