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:

1. 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.
2. 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.
3. 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. More on methods

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

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)?

Data extraction

We asked a large language model to extract each data column below from each paper. We gave the model the extraction instructions shown below for each column.

• Study Design: Describe the specific type of experimental design used in the study.

• Participant Characteristics: Extract specific details about the study subjects.

• Microplastic Characteristics: Capture detailed information about the microplastics used.

• Primary Outcomes Measured: List all primary outcomes examined in the study related to pregnancy and microplastic exposure.

• Key Findings: Summarize the most significant findings of the study.

Results

Characteristics of Included Studies

The extracted data indicates that many of the included studies were animal experiments, often using mice models, and frequently examining polystyrene nano- and microplastics. The diversity in exposure routes reflects the complex nature of microplastic exposure in biological systems.