Human reproductive exposure to microplastics: A multi-technique analytical study of menstrual and amniotic fluids

Microplastics (MPs) have emerged as a significant public health concern due to their widespread presence in the environment and potential for human exposure through ingestion, inhalation, and dermal contact. Although MPs have been previously detected in human tissues such as the placenta, blood, and breast milk, their presence in menstrual blood has not been investigated until now. This study aimed to explore the presence and characteristics of MPs in menstrual blood and amniotic fluid, with a focus on their presence in the human reproductive system. Samples were collected using a rigorous plastic-free protocol to avoid contamination. Organic matters in the samples were digested using 30% potassium hydroxide (KOH). Initial screening was conducted via microscopic examination and hot needle testing to identify suspected MPs. Confirmatory analyses were performed using Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and pyrolysis GC/MS to determine polymer types and morphology. MPs were identified in all menstrual blood and amniotic fluid samples, with a higher concentration found in menstrual blood. A total of 136 particles were characterized, including common polymers such as polyethylene terephthalate (PET), polypropylene (PP), polymethyl methacrylate (PMMA), polyethylene (PE), polystyrene (PS) and polycarbonates (PC). The detected MPs exhibited varying shapes, including fragments and fibers, and were of diverse colors, indicating multiple environmental sources and extensive human exposure. These findings provide the first evidence of MPs in menstrual blood and contribute to growing concerns about their accumulation in the human reproductive system, underscoring the need for further investigation into potential health implications.