Elicit: Effects of Microplastics on Pregnancy
Effects of Microplastics on Pregnancy
What are the effects of microplastic exposure during pregnancy?
Research shows that maternal exposure to microplastics during pregnancy disrupts maternal physiology, compromises placental integrity, and impairs fetal growth and development.
Abstract
Microplastic exposure during pregnancy shows measurable impacts on maternal physiology, placental integrity, and fetal development. In rodent studies, exposure to primarily polystyrene and polyethylene particles via drinking water, oral gavage, or inhalation has been associated with the following outcomes:
- Maternal changes such as altered cardiovascular parameters (e.g., increased heart and spleen weight, vascular dysfunction), reproductive delays (e.g., disturbed estrous cyclicity and diminished fertility), metabolic disruptions, and shifts in liver weight or function.
- Placental findings that include accumulation of microplastics (with one report noting a mean concentration of 6.91 mg/g in 100% of placentae) and altered vascular flow—up to a 43% increase in umbilical artery flow in one study.
- Fetal effects marked by growth restriction—for example, a 12% reduction in fetal weight at 106 ng/L exposure—and neurodevelopmental disruptions, including hippocampal ferroptosis, reduced myelin formation, and altered neurotransmitter levels.
Biochemical assessments reveal increased oxidative stress, inflammation, and modulated gene expression linked to lipid metabolism and angiogenesis. In several experiments, higher doses (for instance, exposures equivalent to levels producing dose-dependent effects in mice) correspond with more pronounced adverse outcomes. These findings indicate that microplastic exposure during gestation may perturb maternal, placental, and fetal systems in measurable ways.
Methods
We analyzed 40 sources from an initial pool of 499, using 5 screening criteria. Each paper was reviewed for 5 key aspects that mattered most to the research question.
Papers identified with Elicit search
- n = 499
- Papers screened using: Study Population, Exposure Assessment, Outcome Measures, Study Design, Exposure Quantification
- n = 499
- Papers screened out
- n = 459
- Papers included for extraction
- n = 40
Data extraction
We asked a large language model to extract each data column from each paper. We gave instructions for each column:
Study Design
- Type of study (e.g., animal experimental study, in vivo experiment)
- Specific model used (e.g., pregnant mice, pregnant rats)
- Experimental groups (number and type)
Participant Characteristics
- Species used (e.g., ICR mice, rats)
- Strain or type of animal
- Pregnancy stage or gestational age at start of experiment
- Number of animals per group
- Age of animals (if reported)
- Sex (though likely all female for pregnancy studies)
Microplastic Characteristics
- Type of microplastic (e.g., polyethylene, polystyrene)
- Particle size (in μm or mm)
- Concentration of exposure (include units)
- Method of administration (e.g., intragastric intubation, pulmonary exposure)
- Duration of exposure
Primary Outcomes Measured
- Maternal outcomes (e.g., body weight, glucose homeostasis, organ function)
- Fetal/offspring outcomes (e.g., birth weight, organ weight, developmental markers)
- Biochemical markers (e.g., acetylcholinesterase, glutathione peroxidase)
Key Findings
- Statistically significant changes in maternal or fetal outcomes
- Observed biological mechanisms
- Dose-dependent effects
- Potential implications for pregnancy health
Results
Characteristics of Included Studies
| Study | Study Design | Microplastic Type/Size | Exposure Route | Species/Model | Full text retrieved |
|---|---|---|---|---|---|
| Aghaei et al., 2022 | Animal experimental | Polystyrene, 5 μm and 50 nm | Drinking water | Mice | No |
| Amereh et al., 2022 | Observational cross-sectional | Polyethylene, Polystyrene, <5 mm | Not applicable (detected in placenta) | Human | No |
| Barrozo et al., 2024 | Observational | Polyethylene, < 20 μm | Not applicable (detected in placenta) | Human | No |
| Cary et al., 2024 | Animal experimental | Polystyrene nanoplastic | Intratracheal instillation | Rats | No |
| Chen et al., 2022 | Animal experimental | Polystyrene, 100 nm | Drinking water | Mice | No |
| Chen et al., 2024a | Animal experimental | Polystyrene, 6-154 μm | Oral gavage | C57BL/6J mice | Yes |
| Chen et al., 2024b | Animal experimental | Polystyrene, 50 nm | Oral gavage | Rats | No |
| Dibbon et al., 2023 | Animal experimental | Polystyrene, 5 µm and 50 nm | Drinking water | CD-1 mice | No |
| Dou et al., 2024 | Animal experimental | Polystyrene | Lactational exposure | Mice | No |
| Fournier et al., 2020 | Animal experimental | Polystyrene, 20 nm | Intratracheal instillation | Sprague Dawley rats | Yes |
Effects of Microplastic Exposure
Maternal Effects
| Study | Effect Category | Observed Changes | Exposure Level | Significance |
|---|---|---|---|---|
| Aghaei et al., 2022 | No mention found | No mention found | 102, 104, or 106 ng/L | No mention found |
| Amereh et al., 2022 | Not applicable (observational) | No mention found | Not applicable | No mention found |
| Barrozo et al., 2024 | Not applicable (observational) | No mention found | Not applicable | No mention found |
| Cary et al., 2024 | Cardiovascular | Increased heart weight, vascular dysfunction in aorta and uterine artery | No mention found | No mention found |
| Chen et al., 2022 | No mention found | No mention found | 1 and 10 mg/L | No mention found |
| Chen et al., 2024a | Body weight, Mammary gland development | No significant body weight changes, potential mammary gland alterations | Equivalent to 0.3, 3.3, 33.3 cups/day | No mention found |
| Chen et al., 2024b | No mention found | No mention found | No mention found | No mention found |
| Dibbon et al., 2023 | No mention found | No mention found | 106 ng/L | No mention found |
| Dou et al., 2024 | Reproductive | Delayed puberty, disturbed estrous cyclicity, diminished fertility, elevated testosterone, abnormal follicle development | No mention found | No mention found |
| Fournier et al., 2020 | Organ deposition | Nanopolystyrene particles in lung, heart, spleen | 2.64 × 10^14 particles | No mention found |
Placental and Fetal Effects
| Study | System Affected | Observed Changes | Exposure Level | Key Findings |
|---|---|---|---|---|
| Aghaei et al., 2022 | Fetal growth | 12% decrease in fetal weight | 106 ng/L | Significant fetal growth restriction at highest exposure |
| Amereh et al., 2022 | Fetal growth, Development | Reduced birth weight, length, head circumference, 1-min Apgar score | Not applicable (observational) | Inverse associations between microplastic exposure and birth outcomes |
| Barrozo et al., 2024 | Placenta | Microplastic accumulation | Mean 6.91 mg/g | Microplastics detected in 100% of placentae |
| Cary et al., 2024 | Fetal growth, Cardiovascular | Reduced fetal and placental weight, dysregulated fetal heart, aorta, and umbilical artery function | No mention found | Significant cardiovascular effects in fetuses |
| Chen et al., 2022 | Fetal growth, Metabolism | Reduced fetal weights, abnormal cell morphologies, metabolic disturbances | 10 mg/L | Significant fetal growth restriction and metabolic changes |
| Chen et al., 2024a | Fetal growth, Development | Fetal growth restriction, compromised mammary gland development | Equivalent to 3.3 cups/day | Dose-dependent harmful effects on fetal development |
| Chen et al., 2024b | Neurodevelopment | Ferroptosis in hippocampus, cognitive deficits | No mention found | Significant neurodevelopmental effects in offspring |
| Dibbon et al., 2023 | Placental function, Fetal growth | Altered umbilical artery blood flow, fetal growth restriction | 106 ng/L | Significant placental dysfunction and fetal effects |
| Dou et al., 2024 | Reproductive (offspring) | Decreased sperm count and viability in male offspring | No mention found | Transgenerational reproductive toxicity |
| Fournier et al., 2020 | Fetal growth, Organ deposition | Reduced fetal weight, nanoplastic particles in fetal organs | 2.64 × 10^14 particles | Significant fetal growth restriction and particle translocation |
Biochemical and Molecular Changes
The studies reported a range of biochemical and molecular changes associated with microplastic exposure during pregnancy:
- Oxidative Stress: Increased malondialdehyde generation and altered activities of antioxidants in offspring tissues.
- Inflammation: Increased levels of inflammatory markers in neonatal livers and fetal brain regions.
- Metabolic Alterations: Disturbances in lipid metabolism and metabolic pathways.
- Gene Expression Changes: Upregulation of genes involved in lipid metabolism, angiogenesis, and development.
- Hormonal Changes: Observed hormonal alterations, including elevated testosterone levels in exposed females.
- Neurotransmitter Alterations: Changes in neurotransmitter levels and related deficits in cognitive functions.
- Cellular Apoptosis: Indicators of increased apoptosis in various tissues.
- Epigenetic Changes: Modifications in DNA methylation and histone modifications reported.
Dose-Dependent Relationships
Several studies reported dose-dependent effects of microplastic exposure during pregnancy affecting various outcomes such as fetal growth, placental structure, hepatic effects, and neurodevelopmental implications. This suggests possible threshold levels of exposure that warrant further investigation.
Route-Specific Effects
Oral Exposure Outcomes
- Significant declines in fetal weights and alterations in placental function were observed following oral exposure to microplastics.
Respiratory Exposure Outcomes
- Inhalation resulted in various adverse effects including significant impact on maternal cardiovascular health and fetal growth.
References
- Impact of Microplastics on Pregnancy and Fetal Development: A Systematic Review
- Microplastics from disposable paper cups are enriched in the placenta and fetus, leading to metabolic and reproductive toxicity during pregnancy.
- Toxicities Demonstrated in Dams and Neonates following Intragastric Intubation of Polyethylene Microplastics to Pregnant Mice.
- Maternal Exposure to Polystyrene Micro- and Nanoplastics Causes Fetal Growth Restriction in Mice.
- Polystyrene micro- and nanoplastics cause placental dysfunction in mice.