Plastic levels ‘significantly’ higher in preterm placentas

Key takeaways:

• Preterm placentas had higher micro- and nanoplastic concentrations vs. term placentas.
• Concentrations differed based on fetal sex and race/ethnicity and were correlated with social deprivation indices.

Micro- and nanoplastics accumulate in preterm birth placentas, but not term placentas, and further investigation is needed to fully understand the impact on fetal development and pregnancy outcomes, findings show.

Researchers evaluated placental micro- and nanoplastic concentrations and species among women who gave birth at term and preterm, given the widespread presence of micro- and nanoplastics in the environment and within human tissues.

The findings were presented at The Pregnancy Meeting.

“Our study provides strong evidence that micro- and nanoplastics accumulate at significantly higher levels in the placentas of pregnancies that result in preterm birth,” Enrico R. Barrozo, PhD, assistant professor in the department of obstetrics and gynecology at the Baylor College of Medicine and Texas Children’s Hospital, told Healio. “This finding suggests that micro- and nanoplastics may be an underappreciated environmental exposure impacting pregnancy outcomes, warranting further investigation.”

Barrozo and colleagues analyzed human placentas collected from 175 women, of which 100 delivered at term and 75 delivered preterm. Researchers conducted pyrolysis-gas chromatography-mass spectrometry on all placental specimens to quantify micro- and nanoplastics as polyethylene, polypropylene, acrylonitrile butadiene styrene, styrene-butadiene rubber, polymethyl methacrylate, polycarbonate, polyvinyl chloride, polyurethane, polyethylene terephthalate, nylon 6 or nylon 66.

Researchers observed higher levels of polycarbonate, polyvinyl chloride and nylon 66 micro- and nanoplastics in preterm vs. term placentas. In addition, despite having shorter gestations, cumulative micro- and nanoplastic concentrations were higher in preterm vs. term placentas (mean 203 µg/g vs. 129.8 µg/g; P < .0001).

Micro- and nanoplastic concentrations differed based on fetal sex and race/ethnicity and were significantly correlated with social deprivation indices.

“While this study does not establish causation, this study raises important questions about how environmental pollutants, including micro- and nanoplastics, may contribute to pregnancy complications,” Barrozo told Healio. “If future research confirms a mechanistic link between micro- and nanoplastic exposure and adverse pregnancy outcomes, this could inform public health policies aimed at reducing plastic exposure during pregnancy and lead to the development of biomarkers for environmental risk assessment in obstetric care.”

According to Barrozo, researchers observed 121.9 times higher cumulative levels in placental tissue compared with data from published reports on micro- and nanoplastic concentrations in the blood of nonpregnant adults (P < .0001).

“We need mechanistic studies to determine how micro- and nanoplastics interact with the placenta, whether they alter immune signaling, disrupt endocrine function or induce oxidative stress,” Barrozo told Healio. “Longitudinal human studies tracking micro- and nanoplastic exposure across pregnancy and experimental models assessing dose-response relationships will be critical for clarifying their role in pregnancy complications such as preterm birth.”

For more information:

Enrico R. Barrozo, PhD, can be reached at enrico.barrozo@bcm.edu; X (Twitter): @BarrozoPhD.