ICA 2024 - FDA CDRH systematic review of tampon contaminants

International Consulting Associates prepared this systematic literature review for FDA CDRH to summarize evidence on additives, chemicals, and contaminants in vaginal tampons, including metals. The review is secondary evidence: it transports study-level summaries from included bench and clinical studies and does not itself test tampons. Its metals value is mainly as an FDA-commissioned evidence map around the primary Shearston et al. tampon-metal dataset and the BioCycle tampon-use blood-metal biomonitoring study.

Key numbers

The report states that electronic database searches were conducted on August 9, 2024. It reports 1,171 records identified, 247 duplicates excluded, 924 records screened, 880 records excluded at screening, 44 full texts assessed, 35 full texts excluded, and 9 studies included. The included set comprised 4 bench/laboratory tampon studies and 5 clinical or human-sample studies.

Table 2 assigns included studies to key questions: KQ1 contaminants and biomarkers in individuals (4 studies), KQ2 health outcomes associated with vaginal tampon use (1 study), and KQ3 laboratory testing of vaginal tampons (4 studies). The review notes that the largest laboratory sample size was 60 samples and the smallest was 22 samples; among clinical studies other than the two-patient case series, the largest sample size included 851 women and the smallest included 25 women who provided 100 urine samples.

For laboratory tampon metals, the review summarizes Shearston et al. 2024 as n = 60 tampon samples representing 30 unique tampons and 24 unique brand-product-line-absorbency combinations. The report gives geometric mean and geometric standard deviation values in ng/g:

The review also states that Shearston et al. detected mercury above the MDL in 5/60 samples (8.3%) and chromium above the MDL in 6/60 samples (10%) even though the grouped GM rows for mercury and chromium are shown as below MDL.

For BioCycle blood-metal biomonitoring, the report summarizes Singh et al. 2019 as tampon users (n = 158) and non-tampon users (n = 97). Geometric mean and GSD values were cadmium 0.26 (1.90) versus 0.33 (1.90) µg/L, mercury 1.08 (2.75) versus 1.01 (2.47) µg/L, and lead 0.85 (1.53) versus 1.01 (1.62) µg/dL for tampon users versus non-users, respectively. Adjusted model ratios were cadmium 0.94 (0.78, 1.14), lead 0.91 (0.80, 1.05), and mercury 1.24 (0.92, 1.67); the review states that none of these associations were statistically significant.

For non-metal laboratory tampon evidence, the review summarizes Gao et al. 2020 (n = 12 tampons) for phthalates, parabens, bisphenols, and TCC; Lin et al. 2020 (n = 22 tampons) for VOCs; and Archer et al. 2005 for dioxins in seven tampon brands. These data are useful tampon-context evidence but are not heavy-metal occurrence values.

The report’s evidence assessment states that ICA rated the group of studies as low quality, citing limited sample sizes, incomplete reporting of tampon brands/materials, common pooling of different tampon brands as one tampon group, and limited ability to stratify by product or participant characteristics.

Methods (brief)

ICA searched PubMed and Embase on August 9, 2024, covering literature from 2004 through 2024, using tampon/exposure/contaminant search terms and PICOTS eligibility criteria. One ICA reviewer screened titles/abstracts and full texts, abstracted data from primary studies, and classified study quality using NHLBI study-quality assessment tools. Eligible evidence included randomized trials, cohort studies, case-control studies, cross-sectional studies, case series, and laboratory bench studies of vaginal tampon samples; narrative/non-systematic reviews and toxic-shock-syndrome-only studies were excluded.

Implications

Certification: This source should be used as an FDA-CDRH evidence map for the menstrual-tampons row, not as an independent primary metals dataset. Shearston et al. 2024 remains the primary tampon-metal occurrence page for the transported ng/g values; downstream pooling must avoid double-counting the same 60-sample Shearston dataset via this review.

Courses: The report is useful for teaching evidence hierarchy in product-contaminant review work: a regulator-commissioned SLR can identify gaps, methods, and included-study quality, while primary measurements still control concentration values.

App: The report can support a tampon evidence-card note that FDA CDRH commissioned a review through December 2024 and found limited, low-quality evidence, with metals covered chiefly by one primary tampon dataset and one blood-biomonitoring cohort.

Microbiome: Not directly addressed. The review mentions vaginal microenvironment biomarkers as a target evidence domain, but it reports that the identified literature did not compare contaminant exposures in the vaginal microenvironment versus systemic circulation.

Wiki pages this source may touch

• menstrual-tampons
• arsenic-total
• barium
• cadmium
• cobalt
• chromium
• copper
• iron
• mercury-total
• manganese
• nickel
• lead
• selenium
• strontium
• vanadium
• zinc

Verification notes

Identity checks before drafting found no existing wiki/sources/ hit for raw handle MFK_paper-21-fda-2025-tampons-systematic-review, candidate cite keys ica2024-tampon-contaminants-review or fda2024-tampon-contaminants-review, exact title, or “International Consulting Associates” tampon-review wording. The local filename says FDA_2025, but the PDF cover date is December 5, 2024, so year: 2024 is used. No DOI is printed in the report; doi: null and no_doi_assigned: true are retained. The raw PDF SHA-256 is 80cda8138ffbd37ea159e544d55ffdba9aec603fd5b37d9cf137dc191bb1c548. Key numbers were checked against the PRISMA/results narrative, Tables 2-5, the Discussion, and Evidence Assessment sections in /tmp/hmi-fem-013.txt. Arsenic and mercury values transported from Shearston/Singh are total-element values, not iAs or MeHg; chromium is total Cr, not Cr-VI. Brand firewall is clean: the report explicitly states that brands/manufacturers were generally not disclosed and this page reports no brand-linked values. The near_duplicates entries point to primary/companion sources already represented in the wiki; they are not true duplicate source pages. npm run evidence:source-routes exited 0 and generated one menstrual-tampons product route; routing_malformed.csv contains an advisory-only missing-ingredients warning.

Page history

The five most recent substantive edits to this page. The full version history lives in git; when DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.