Microplastics & Fertility
A research digest — compiled ahead of Netflix's documentary "The Plastic Detox"
Over the past few years, researchers have begun detecting microplastics inside some of the most protected tissues in the human body. The science doesn’t yet prove that microplastics cause infertility. But researchers are finding plastic in places we never expected — inside the very tissues responsible for creating life. Here’s what the studies actually show.
I. Microplastics in the Human Placenta
They’re right there in the placenta
The first big reveal came in 2021, when Italian researchers published what they called Plasticenta — the first detection of microplastics using Raman microspectroscopy in human placental tissue. They found particles in 4 out of 6 placentas from healthy, normal pregnancies. Three years later, a team at the University of New Mexico used a more sensitive method and found MPs in all 62 placentas they tested — with concentrations varying wildly from person to person, and polyethylene as the most prevalent polymer (54% of total NMPs and consistently found in nearly all samples).
• Ragusa et al. (2021) Plasticenta: first evidence of microplastics in human placenta. Environ Int. 146:106274.
• Garcia, Nihart et al. (2024) Quantitation and identification of microplastics in human placental specimens using pyrolysis GC/MS. Toxicol Sci. 199(1):81–88.
Preterm births show even higher levels
A striking 2025 study from Baylor College of Medicine and Boston Children’s Hospital, in collaboration with the University of New Mexico, analyzed 175 placentas — 100 delivered at term, 75 preterm — and found that preterm placentas contained significantly higher MP concentrations than term ones. This was counterintuitive: one might expect a longer pregnancy to accumulate more plastic, not less. The finding suggests MPs may play a role in preterm birth, not just passively accumulating.
• Barrozo, Aagaard et al. (2025) Higher concentrations of microplastics and nanoplastics in placentae of infants born prematurely. Presented at SMFM Annual Meeting, 2025.
• Jochum et al. (2025) Elevated Micro- and Nanoplastics Detected in Preterm Human Placentae. Res Sq [Preprint]. 2025 Feb 3:rs.3.rs-5903715. doi: 10.21203/rs.3.rs-5903715/v1. PMID: 39975889; PMCID: PMC11838745.
II. Microplastics in the Ovary & Female Fertility
First detection in human ovarian fluid — and it correlates with hormone disruption
Until 2023, only a few studies had looked for microplastics directly inside the ovarian tissues or ovarian follicular fluid. Then a German study found MPs in both human and bovine follicular fluid and showed that polystyrene MPs directly compromised oocyte (egg) function in lab conditions. Soon after, an Italian team studying 18 women undergoing IVF found MPs in 14 of their 18 follicular fluid samples — the fluid that surrounds and nourishes eggs. Average concentration was over 2,000 particles per milliliter. Critically, higher MP levels correlated significantly with elevated FSH (follicle-stimulating hormone), a marker often associated with diminished ovarian reserve.
• Grechi et al. (2023) Microplastics are present in women’s and cows’ follicular fluid and polystyrene microplastics compromise bovine oocyte function in vitro. eLife12:RP86791.
• Montano et al. (2025) First evidence of microplastics in human ovarian follicular fluid: An emerging threat to female fertility. Ecotoxicol Environ Saf. 2025. PMID: 39947063.
Animal studies: ovarian damage, hormone disruption, and multigenerational effects
While human ovarian data is still emerging, the animal literature is extensive and consistently alarming. Rat cell studies show polystyrene MPs induce programmed cell death in ovarian granulosa cells through the NLRP3/Caspase-1 signaling pathway. Other studies also indicate that MP exposure can potentially disrupt estrogen and progesterone production. In the uterus, MP exposure is associated with a thinner endometrial lining and reduced uterine glands. Most troublingly, the harm doesn’t stop at the exposed generation — one mouse study showed reproductive toxicity passed on to offspring, and a 2025 study found that gestational MP exposure caused cardiac changes in rat offspring, suggesting the damage extends beyond the reproductive system entirely. A 2025 systematic review covering 15 studies concluded that MP exposure significantly affects ovarian function and decreases fertility rates.
• Hou et al. (2021) Polystyrene microplastics lead to pyroptosis and apoptosis of ovarian granulosa cells via NLRP3/Caspase-1 pathway in rats. Ecotoxicol Environ Saf. 212:112012.
• Zhang et al. (2023) Reproductive toxicity of microplastics in female mice and their offspring from induction of oxidative stress. Environ Pollut. 327:121482.
• Geng et al. (2023) Toxicity of microplastics and nanoplastics: invisible killers of female fertility and offspring health. Front Physiol. 14:1254886.
• Zurub et al. (2024) Microplastics exposure: implications for human fertility, pregnancy and child health. Front Endocrinol. 14:1330396.
• Cary et al. (2025) Gestational exposure to micro and nanoplastics differentially impacts cardiac development and function in male and female rats throughout the lifespan. Toxicology and Applied Pharmacology, 504, 117507.
• Inam Ö. (2025) Impact of microplastics on female reproductive health: insights from animal and human experimental studies: a systematic review. Arch Gynecol Obstet. 2025 Jul;312(1):77-92. doi: 10.1007/s00404-024-07929-w. Epub 2025 Jan 16. PMID: 39821449; PMCID: PMC12176963.
III. Microplastics in Sperm, Testes & Male Fertility
MPs have now been found in human testes and semen — and they breach the blood-testis barrier
The blood-testis barrier is one of the tightest protective membranes in the human body. And yet microplastics are getting through. A 2023 Beijing study was the first to detect and characterize MPs in both human testis tissue and semen samples simultaneously, with polystyrene dominant in testes and PE/PVC dominant in semen. A concurrent Italian study using Raman spectroscopy confirmed 8 plastic polymer types in semen from men living in a high-pollution region. Then in 2024, a joint U.S. study (University of New Mexico) found MPs in 100% of both human and dog testicles — with human testes carrying nearly three times the concentration of the dogs. PE was the dominant type of polymer in both species.
• Zhao et al. (2023) Detection and characterization of microplastics in the human testis and semen. Sci Total Environ. 877:162713. PMID: 36948312.
• Montano et al. (2023) Raman Microspectroscopy evidence of microplastics in human semen. Sci Total Environ. 901:165922.
• Hu et al. (2024) Microplastic presence in dog and human testis and its potential association with sperm count and weights of testis and epididymis. Toxicol Sci. 200(2):235–240.
Human studies link specific plastics to lower sperm motility and quality
Three human observational studies have now connected specific plastic types to measurable sperm problems. A Shanghai fertility center study of 45 men found MPs in 76% of semen samples, with PET linked to reduced sperm progressive motility. The largest study to date — a 2024 multi-site Chinese study of 113 men — found PTFE (the non-stick coating on cookware) significantly associated with decreased semen quality. A Raman spectroscopy study of general semen samples further supported the theory that MPs appear widespread across the male population, not just in high-risk groups.
• Guo et al. (2025) The presence of microplastics in human semen and their associations with semen quality. Toxics. 13(7):566. PMC12299061.
• Zhang et al. (2024) Association of mixed exposure to microplastics with sperm dysfunction: a multi-site study in China. eBioMedicine. 108:105369.
• Li et al. (2024) Prevalence and implications of microplastic contaminants in general human seminal fluid: A Raman spectroscopic study. Sci Total Environ. 937:173522.
Direct Exposure Studies: Motility, DNA, and Fusion Genes
Beyond detecting MPs in semen, researchers have also exposed human sperm directly to polystyrene MPs in lab conditions. Human sperm exposed to polystyrene MPs showed declining motility and vitality over time, increased DNA fragmentation, and clumping that physically hindered movement. Most strikingly, all essential genes responsible for sperm-egg fusion were downregulated — suggesting PS-MPs may compromise sperm’s ability to fertilize an egg entirely. Adding further context, a 2022 review calculated that the minimum MP dose causing abnormal semen quality in animal models is close to exposure levels already being measured in humans in parts of Asia.
• Zhang et al. (2022) Microplastics May Be a Significant Cause of Male Infertility. American Journal of Men’s Health, 16(3), 15579883221096549
• Mottola et al. (2025) Impact of Polystyrene Microplastics on Human Sperm Functionality: An In Vitro Study of Cytotoxicity, Genotoxicity and Fertility-Related Gene Expression. Toxics. 13(7):605.
IV. The Bigger Picture: What Does This All Mean?
Where the science stands — and what’s still unproven
The evidence above paints a striking picture: microplastics have been found in human placentas, ovarian follicular fluid, testes, and semen. In controlled settings, they disrupt hormones, damage DNA, and impair the very mechanisms cells use to reproduce. Animal studies show consistent harm across multiple reproductive endpoints. The science is moving fast — and with each new study, the picture grows more concerning.
But a couple of things warrant caution before drawing firm conclusions.
The widely cited birthweight correlation study, for instance, analyzed MPs in pregnancies diagnosed with intrauterine growth restriction (IUGR) and compared them with 30 normal pregnancies. The study can’t tell us whether MPs contributed to the growth problem or whether compromised placentas accumulate more MPs. And when Hunt et al. conducted their 2024 systematic review, combing through over 1,000 citations in the literature, they found only 7 qualifying studies — covering just 96 total participants — and of those seven, only one reported a link to clinical birth outcomes. — and that was the same birthweight paper mentioned above.
It’s worth noting that many of the studies covered in this piece were published after that review was written, so the landscape is shifting. But as the field continues to grow and methodological standards are still being established, we are not yet at the point of drawing definitive conclusions about causation in humans.
• Amereh et al. (2022) Placental plastics in young women from general population correlate with reduced foetal growth in IUGR pregnancies. Environ Pollut. 314:120174.
• Hunt et al. (2024) Exposure to microplastics and human reproductive outcomes: A systematic review. BJOG. 131(5):675–683. doi: 10.1111/1471-0528.17756.
What’s coming next: the AURORA Project
What I’d encourage you to watch closely, however, is the AURORA Project — a large-scale EU-funded longitudinal study running from 2021 to 2026, designed specifically to track microplastic exposure and health outcomes across pregnancy and early childhood in real populations. Unlike the small, observational studies that currently dominate this field, AURORA is built to generate the kind of robust, long-term human data that could finally move the needle from correlation to conclusion. Results are expected from 2025 onward.
• AURORA Project Consortium (2024) Investigating Exposure and Hazards of Micro- and Nanoplastics During Pregnancy and Early Life (AURORA Project): Protocol for an Interdisciplinary Study JMIR Res Protoc. 13:e63176.
The bottom line: the evidence doesn’t yet prove that microplastics directly harm fertility or pregnancy outcomes in humans. But across ovaries, testes, placentas, and semen, MPs are consistently found — and animal and cell studies consistently show harm where MPs accumulate. The gap between ‘we find them everywhere’ and ‘we can prove they’re hurting us’ is real, and it’s exactly what the next generation of larger human studies needs to close. Watch that space.
Cannot wait for this film to go live! I’m glad we are finally talking about the impacts of microplastics and associated chemicals on fertility in mainstream.