Detecting Microplastics in Human Amniotic Fluid

A recent study investigated the presence of microplastics (MPs) in human amniotic fluid using both chromatography and spectroscopy. The study, which was led by Lin Zhang of the Clinical Medical Research Center for Women and Children Diseases at the Shandong Provincial Maternal and Child Health Care Hospital, at Qingdao University (Jinan, China), demonstrated the utility of using Raman spectroscopy with pyrolysis gas chromatography–mass spectrometry (Py-GC/MS) to identify MPs in this environment. The study’s findings, which were published in the Journal of Hazardous Materials, demonstrate how this new dual-approach could help improve prenatal care (1).

What are microplastics?

MPs are small bits of plastic, usually no more than 5 mm in size. Thanks to anthropogenic activities, microplastics are becoming more pervasive in society, finding their way in our food and water supplies (2–4). Ultimately, this is how MPs find their way back in human digestive systems.

Numerous studies have examined analyzing MPs in biological matrices, such as human fluids, but they have it several roadblocks. One of these roadblocks is that single-method identification techniques often lacked either the sensitivity or the specificity required to confirm the presence and composition of microplastics within complex biological systems.

In the pictures of the ultrasound 4 weeks of pregnancy and 20 weeks is a phonendoscope. The concept of the study of pregnancy. Observation Selective focus. | Image Credit: © Natalya Lys - stock.adobe.com

What did the researchers test in their study?

Given the limitations of single-method identification techniques, the research team experimented with a new dual-technique method to see if it can lead to better identification success. They combined the molecular-level resolution of Py-GC/MS with the spatial identification capabilities of Raman spectroscopy. By using both techniques, the research team was able to conduct a multidimensional analysis of 48 amniotic fluid samples collected from pregnant women (1).

What were the results?

Using their method, the research team detected MPs in 39 out of 48 samples. They were also able to identify six different polymer types (1). The average size of the MP particles was 3.05 ± 1.05 micrometers, suggesting the possibility that these particles may traverse the placental barrier (1). The most common polymer detected was polytetrafluoroethylene (PTFE). PTFE was discovered in 31.25% of positive samples, followed by polystyrene (20.83%) and acrylonitrile-butadiene-styrene (ABS) at 14.58% (1).

How did Raman spectroscopy and Py-GC/MS work together?

Py-GC/MS was crucial in validating the results obtained using Raman spectroscopy. By identifying pyrolytic markers such as fluoroethylene and styrene, the research team was able to confirm the presence of these materials beyond visual or spectral inference (1).

Although the researchers did not find a statistically significant link between microplastic presence and immediate adverse pregnancy outcomes, they emphasized that the presence of these foreign particles in the amniotic fluid raises serious questions about long-term developmental risks (1). The amniotic fluid serves as a critical protective and nutritional environment for the developing fetus; the infiltration of synthetic polymers into this area is cause for concern (1).

What were the limitations of this study?

There were two key limitations regarding this study. The first limitation was the sample size. The researchers acknowledge that having only 48 samples is small, which means that broad conclusions should be taken with a grain of salt (1). The cross-sectional design of the study also limits its ability to assess how microplastic accumulation changes throughout pregnancy or impacts health outcomes after birth (1).

The second key limitation is that it only detected six polymer types, which means that there were a lot of polymers overlooked in the study. Additionally, although the dual-technique approach improves detection reliability, the sensitivity threshold may still miss particles below certain size or concentration levels (1).

The detection of MPs in amniotic fluid indicates that these pollutants can reach the most sensitive stages of human development. Although the research team did not observe any immediate adverse outcomes, the long-term implications remain unknown. As a result, the research team calls for more work to be conducted in this space, which will help them fully understand how prenatal exposure to microplastics may affect fetal development and postnatal health (1).

References

1. Tian, J.; Liang, L.; Li, Q.; et al. Association Between Microplastics in Human Amniotic Fluid and Pregnancy Outcomes: Detection and Characterization Using Raman Spectroscopy and Pyrolysis GC/MS. J. Hazard Mater. 2025, 482, 136637. DOI: 10.1016/j.jhazmat.2024.136637
2. Utecht, S.; Krause, S.; Schuetz, T. Quantitative and Qualitative Differences of Common Microplastic Detection Procedures: Nile Red-assisted Fluorescence Microscopy and Confocal Micro-Raman Spectroscopy. Research Square 2025, ASAP. DOI: 10.21203/rs.3.rs-5803470/v1
3. Wetzel, W. Measuring Microplastics in Remote and Pristine Environments. Spectroscopy. Available at: https://www.spectroscopyonline.com/view/measuring-microplastics-in-remote-and-pristine-environments (accessed 2025-07-25).
4. Wetzel, W. Quantifying Microplastics and Anthropogenic Particles in Marine and Aquatic Environments. Spectroscopy. Available at: https://www.spectroscopyonline.com/view/quantifying-microplastics-and-anthropogenic-particles-in-marine-and-aquatic-environments (accessed 2025-07-25).