SynthesisJournal of pregnancy2026
Hair Dyes in Pregnancy: A Systematic Review and Meta-Analysis.
Synthesis in Journal of pregnancy, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper, 1 of them a synthesis that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
1 citing paper in PubMed, 1 synthesis or guideline pooled it.
- Hair Dyes in Pregnancy: A Systematic Review and Meta-Analysis.Journal of pregnancy · 2026Pooled it
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
8 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
objectiveThe main objective is to investigate the association between periconceptional or pregnancy exposure to hair dyes and obstetric and pediatric outcomes.
methodsA systematic literature search was conducted in Scopus, PubMed/MEDLINE, Web of Science, and CINAHL Ultimate from database inception to August 31, 2024. Studies were included based on PECO criteria: pregnant women and their newborns (population), exposure to hair dyes during periconception or pregnancy (exposure), no exposure (comparator), and any obstetric or pediatric complication (outcome). After screening 311 records and removing duplicates, 179 abstracts were reviewed, 29 full texts assessed, and 20 observational studies included. Four reviewers assessed bias and extracted data. Meta-analyses were performed using a random-effects model when appropriate.
resultsFew studies distinguished hair dye types or exposure timing. Periconceptional or pregnancy hair dye exposure was reported to be associated with stillbirth, low birth weight (Pooled OR 2.30; 95% CI 1.24-4.25), and low hormone levels; in the offspring, with allergic rhinitis, leukemia, neuroblastoma (pooled OR 1.79; 95% CI 1.20-2.68), Wilms tumor (pooled OR 6.00; 95% CI 1.22-29.46), germ cell tumors, and membranous ventricular septal defect. No association was observed with asthma (pooled OR 1.19; 95% CI 0.86-1.65), childhood brain tumors (pooled OR 1.06; 95% CI 0.88-1.28), or mental retardation. Based on the GRADE assessment, the certainty of evidence was low or very low.
conclusionsCurrent observational evidence suggests a potential association between periconceptional or pregnancy exposure to hair dyes and some adverse obstetric and pediatric outcomes. However, given the low and very low certainty of evidence and the retrospective nature of most included studies, these findings are hypothesis-generating and preclude causal inference. Further prospective studies are needed to confirm these preliminary associations and define the specific chemicals involved.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.