dHealth, Apple Inc., Cupertino, CA, USA

Overview

This source page is a mechanical bulk-ingest record for a PDF in the research-pulls corpus. It preserves source-level identity, routeable product/analyte scope, and exact extracted numeric lines for later human or fresh-context audit. It does not derive HMTc thresholds, percentiles, or brand-by-brand comparisons.

Key numbers

The worker extracted the full PDF text with layout preservation twice and compared extraction hashes before commit. The following lines are copied from numeric/table-bearing regions of the PDF and retain the source units and wording where legible:

and either reported their usual menstrual cycle length (<21, 21–39, ≥40 days/too irregular) (n =
et al., 2022; Wang et al., 2024). Globally, menstrual irregularity impacts around 10–30%
(details described in Table S1) and reproductive, sociodemographic, medical, and lifestyle
We used two analytical datasets for our analyses: (1) Dataset #1 (n = 4,155 participants)
participants in both datasets (n = 2,240).
Supplemental Table S1. Those who indicated “I don’t know” or “I prefer not to answer” for
long cycles based on individual thresholds (3% of all logged cycles) were also excluded
relevant questions (Cohen et al., 1983), with a total PSS-4 score (range 0–16); (10) typical
and 95% confidence intervals (CIs) of very short cycles (<21 vs. 21–39 days) and very
the differences and 95% CIs in MCL by changes in PCP frequency, age at initiation,
within-individual standard deviations (SDs) of cycles (in days) and 95% CIs in each PCP
and current state-level legislations as detailed in Supplemental Table S2 (U.S. GAO
with 95% CIs. In the main analyses, p-value cutoffs of 0.05 were used to determine
(Dataset #1), median (IQR) age at enrollment was 34 (27–40) years. The majority self-
evaluated as in the medium–high SES categories (71%). Around 33% had a BMI of 18.5–
to Dataset #1, the 4,482 participants with 61,079 logged cycles (per person range: 3–83;
per person median (IQR): 9 (5 – 18) cycles) from mobile applications (Dataset #2) were
dataset reported a PCOS, fibroids, or endometriosis diagnosis, respectively (Table S2); when
very long or irregular MCL had higher prevalence of PCOS (31% vs. 12%), while those with
very short MCL had higher prevalence of fibroids (8% vs. 6%).
Datasets #1 and #2 are available in Supplemental Tables S3 and S4). Percentages (95% CIs)
(similarly in Dataset #2, these percentages were 19%, 39%, 25%, and 17%).
categories in Dataset #1 and mean MCL and within-individual cycle variability in Dataset
1/2 are available in Supplemental Table S5). Using perms/relaxers ≥ 4 times/year (vs.
never in the past year) was associated with 2.63 (95% CI: 0.75, 9.26) times higher odds of
3 days/week yielded a 12% higher cycle variability compared to never in the past year to a
few/year (estimated within-individual SD: 5.39 (95% CI: 5.18, 5.61) days vs. 4.83 (95% CI:
of top coats) vs. never in the past year to a few/year was associated with both 1.76 (95%
higher odds of very long/irregular cycles, as well as yielding a 19% higher cycle variability
(estimated within-individual SD: 5.51 (95% CI: 5.18, 5.83) days vs. 4.63 (95% CI: 4.59,
in Dataset #1 and mean MCL and within-individual cycle variability in Dataset #2 are
1/2 are available in Supplemental Table S6). In Dataset #1, the strongest association was
never), resulting in a 2.49 (95% CI: 1.23, 5.02) times higher odds of very long/irregular
had a 30% or 17% higher cycle variability compared to those who initiated ≥ 19 years old
or never used dry shampoo (estimated within-individual SD: 6.16 (95% CI: 5.09, 7.23) days,
5.55 (95% CI: 5.34, 5.76) days, vs. 4.73 (95% CI: 4.69, 4.76) days). Those who initiated
using permanent dye/coloring at home ≤ 12 years old also yielded a 24% higher cycle
within-individual SD: 5.76 (95% CI: 5.33, 6.20) days vs. 4.66 (95% CI: 4.62, 4.69) days).
categories in Dataset #1 and mean MCL and within-individual cycle variability in Dataset
Models 1/2 are available in Supplemental Table S7). Notably, in Dataset #1, avoiding
ingredients such as formaldehyde (OR (95% CI): 0.78 (0.63, 0.96)) or mercury (OR (95%
PFAS (OR (95% CI): 0.65 (0.44, 0.97)) or petroleum propellants (OR (95% CI): 0.65

Methods (brief)

by relatively small to moderate sample sizes and reliant on one-time exposure biomarker
life course. The large, geographically and demographically diverse sample with > 61,000

Implications

This page makes the source discoverable for category-level evidence routing. Values remain source-native and should be used only with the stated matrix, species, basis, geography, and censoring context from the paper. The page does not convert total mercury to methylmercury or use total arsenic as inorganic arsenic.

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Verification notes

Identity check: DOI, raw handle, candidate cite-key, and SHA-256 were compared against existing wiki/sources/ pages before creation.
Full-PDF read: pdftotext -layout was run on the full PDF twice; extracted text hashes matched before the page was written.
Numeric verification: numeric/table-bearing lines were selected mechanically from the verified extraction and preserved without unit conversion or rounding.
Brand firewall: the worker skips PDFs when extracted numeric lines appear brand/manufacturer-sensitive; this page contains category-level or species-level evidence only.
HMTc firewall: no threshold, percentile, pass/fail, clean/dirty, or certification math is stated.

Update history

The five most recent substantive edits to this page, classified major (evidence or structure moved), correction (a published value or statement was wrong and has been fixed), or minor (narrative rewritten without changing the underlying evidence). Each description is derived from what the edit did to this page; the linked commit is the authoritative record, routine regeneration passes are excluded, and 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.

Commit	Date	Change	Description
b01ec52c	2026-08-04	major	2 sections added
d49e450f	2026-08-03	major	5 sections added; narrative text revised