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
Paper search
Using your research question “What are the effects of microplastic exposure during pregnancy?”, we searched across over 126 million academic papers from the Semantic Scholar corpus. We retrieved the 499 papers most relevant to the query.
Screening
We screened in sources based on their abstracts that met these criteria:
- Study Population: Does the study include pregnant humans or animals AND report clear pregnancy-related outcomes?
- Exposure Assessment: Does the study examine microplastic (not macroplastic) exposure through any route (ingestion, inhalation, or dermal) using clear assessment methodology?
- Outcome Measures: Does the study measure specific maternal, fetal, or pregnancy outcomes during any stage of pregnancy?
- Study Design: Is the study either a primary research study (experimental or observational) or systematic review with a sample size of at least 10?
- Exposure Quantification: Does the study include biological measurements or outcomes related to microplastic exposure (not just environmental concentrations)?
We considered all screening questions together and made a holistic judgement about whether to screen in each paper.
Data extraction
We asked a large language model to extract each data column below from each paper.
- Study Design: Animal experimental, observational, or systematic review.
- Participant Characteristics: Species, strain, pregnancy stage, number of animals per group.
- Microplastic Characteristics: Type, particle size, concentration, method of administration, duration of exposure.
- Primary Outcomes Measured: Maternal outcomes, fetal outcomes, biochemical markers.
- Key Findings: Statistically significant changes, observed biological mechanisms, dose-dependent effects.
Results
Characteristics of Included Studies
| Study | Study Design | Microplastic Type/Size | Exposure Route | Species/Model |
|---|---|---|---|---|
| Aghaei et al., 2022 | Animal experimental | Polystyrene, 5 μm and 50 nm | Drinking water | Mice |
| Amereh et al., 2022 | Observational cross-sectional | Polyethylene, Polystyrene, <5 mm | Not applicable (detected in placenta) | Human |
| Barrozo et al., 2024 | Observational | Polyethylene, < 20 μm | Not applicable (detected in placenta) | Human |
| Cary et al., 2024 | Animal experimental | Polystyrene nanoplastic | Intratracheal instillation | Rats |
| Chen et al., 2022 | Animal experimental | Polystyrene, 100 nm | Drinking water | Mice |
| Chen et al., 2024a | Animal experimental | Polystyrene, 6-154 μm | Oral gavage | C57BL/6J mice |
| Chen et al., 2024b | Animal experimental | Polystyrene, 50 nm | Oral gavage | Rats |
| Dibbon et al., 2023 | Animal experimental | Polystyrene, 5 µm and 50 nm | Drinking water | CD-1 mice |
| Dou et al., 2024 | Animal experimental | Polystyrene | Lactational exposure | Mice |
| Fournier et al., 2020 | Animal experimental | Polystyrene, 20 nm | Intratracheal instillation | Sprague Dawley rats |
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 | No mention found | Not applicable | No mention found |
| Barrozo et al., 2024 | Not applicable | No mention found | Not applicable | No mention found |
| Cary et al., 2024 | Cardiovascular | Increased heart weight, vascular dysfunction | 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 | No significant body weight changes | 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 | 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 | Not applicable | 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 & function | No mention found | Significant cardiovascular effects in fetuses |
| Chen et al., 2022 | Fetal growth, Metabolism | Reduced fetal weights, 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 | 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.
- Inflammation: Elevated levels of monocyte chemoattractant protein-1 and TNF-α.
- Metabolic Alterations: Disturbances in cholesterol metabolism and metabolic pathways.
- Gene Expression Changes: Upregulation of genes involved in lipid metabolism.
- Hormonal Changes: Alterations in testosterone levels.
- Neurotransmitter Alterations: Reduced levels of GABA.
- Cellular Apoptosis: Increased apoptosis in placental tissues.
- Epigenetic Changes: Dysregulation of DNA methylation pathways.
Conclusions
Due to potential degradation of placental endocrine, metabolic, and immune systems, microplastics may have a negative impact on a growing fetus. To comprehend the impact of microplastic exposure on the growing fetus and the gestational parent, further high-quality research involving larger cohorts of pregnant women is needed.