Exposure to microplastics and human reproductive outcomes: A systematic review

Abstract

BackgroundMicroplastics, produced through degradation of environmental plastic pollution, have been detected in human tissues including placenta and fetal meconium. Cell culture and animal studies have demonstrated potential reproductive toxicity of these particles; however, their association with adverse fertility or pregnancy outcomes in humans is not known.ObjectivesTo synthesise evidence for the presence of microplastics in human reproductive tissue and their associations with environmental exposures and reproductive outcomes.Search StrategyMEDLINE, Embase, Emcare, CINAHL, ClinicalTrials.gov and ICTRP were searched from inception to 03/02/2023.Selection CriteriaStudies of human participants, assessing presence of microplastics in reproductive tissues, environmental exposures to microplastics, and fertility‐ or pregnancy‐related outcomes.Data Collection and AnalysisTwo independent reviewers selected studies and extracted data on study characteristics, microplastics detected, environmental exposures and reproductive outcomes. Narrative synthesis was performed due to methodological heterogeneity.Main ResultsOf 1094 citations, seven studies were included, covering 96 participants. Microplastics composed of 16 different polymer types were detected in both placental and meconium samples. Two studies reported associations between lifestyle factors (daily water intake, use of scrub cleanser or toothpaste, bottled water and takeaway food) and placental microplastics. One study reported associations between meconium microplastics and reduced microbiota diversity. One reported placental microplastic levels correlated with reduced birthweights and 1‐minute Apgar scores.ConclusionsThere is a need for high‐quality observational studies to assess the effects of microplastics on human reproductive health.

Impact of Microplastics on Pregnancy and Fetal Development: A Systematic Review

“…People across the world come into close, daily contact with plastics and the byproducts of their disintegration, especially nano-and microplastics. The discovery of microplastics in the placenta has sparked worries that plastics might affect fetal growth during pregnancy [16,[21][22][23][24][25][26][27][28][29]. Plastic pollution is a serious and growing worldwide issue; by 2060, the amount of plastic that leaks into the environment is expected to have doubled to 44 million tons annually from 22 million tons in 2019 [30][31][32].…”

“…Research has demonstrated that MPs cause harm to reproductive systems in several animal species and significantly affect the anomalies of development and metabolism in progeny [2,8,10,11,28,37]. A worldwide health concern, female reproductive disorders may have a direct correlation to the state of the environment [16]. Furthermore, prenatal exposure to these chemicals is especially concerning for the health and development of the unborn child because pregnancy is a critical time for the development of newborn organs [37].…”

“…Studies investigating the possible harmful effects of microplastics on reproduction at the cellular level and in animal models have increased recently. The first reports of microplastics found in human placenta and meconium were reported in 2021 [12,[16][17][18][19]. Chronic MP particle ingestion in mice can cause metabolic disorders, intestinal barrier failure, and dysbiosis of the gut microbiota [7].…”

“…Based on research on animals and in vitro cultures, there is growing proof that plastic particles are hazardous to fetuses and the placenta. According to studies, maternal exposure to microplastics during breastfeeding and pregnancy altered the neural cell compositions and the histology of the offspring's brains [16,18,20,21]. Studies have shown that exposure to MPs during pregnancy and the first few months of life may result in permanent alterations to the reproductive axis and central nervous system in the offspring of different species [16,21,22].…”

“…According to studies, maternal exposure to microplastics during breastfeeding and pregnancy altered the neural cell compositions and the histology of the offspring's brains [16,18,20,21]. Studies have shown that exposure to MPs during pregnancy and the first few months of life may result in permanent alterations to the reproductive axis and central nervous system in the offspring of different species [16,21,22]. A lack of evidence has prompted scientists and regulatory bodies to express concerns over the presence of MPs in food, possible human consumption, and potential health effects.…”