Health outcome · disease
Infertility
Also: sterility, subfertility, time to pregnancy, involuntary childlessness
Failure to conceive after twelve months of regular unprotected intercourse. It is defined by time rather than by a mechanism, so it covers male and female causes together and is the endpoint that population studies of reproductive exposures can actually count.
Not reviewed by a clinician. This entry describes a disease or a symptom. We are introducing clinical review for pages of this kind; until that reviewer is in place, this page has been written and checked by the Coridum team but not reviewed by a clinician. It is general information and not medical advice. How this library is built is described in How we build this library.
Why it matters indoors
The twelve-month definition makes infertility measurable in surveys that could never measure a hormone or a semen sample, which is why it is the outcome through which indoor exposures reach the reproductive literature at population scale.
It is also the outcome that loses the most information. A couple is the unit, so a result cannot be attributed to one partner; and the mechanisms that might be at work — reduced semen quality, disrupted ovulation, impaired implantation — are collapsed into a single yes or no.
Indoor exposures studied against it are those with a plausible endocrine or oxidative mechanism: phthalates and other semi-volatile compounds released by materials, combustion products from cooking and heating, and tobacco smoke, whose effect on fertility is long established. Confounding by age is severe and dominates every other variable, so an estimate that has not handled it carries little weight.
Indoor factors with evidence
| Factor | Effect | Population | Study design | Source | Checked |
|---|---|---|---|---|---|
| Ozone (O₃) | difference 52 | women aged 15 to 60 · city (ambient) | cohort of women aged 15 to 60 in Taiwan drawn from the National Health Insurance Research Database between July 2003 and December 2013: concentrations of sulfur dioxide, carbon monoxide, ozone, particulate matter, nitrogen oxides, total and non-methane hydrocarbons and methane estimated at the insurance registration address and related to incident infertility per standard deviation of ten-year exposure | F-1296 Long-term exposure to ambient air pollutants and female infe… (2025) | machine |
| Tobacco smoke (secondhand smoke) | OR 1.64 (1.14–2.36) | women aged 18 to 50 | analysis of the United States National Health and Nutrition Examination Survey 2013 to 2018: women aged 18 to 50 with a recorded serum cotinine level and infertility information, with weighted multivariate logistic regression of infertility against environmental tobacco smoke exposure | F-1326 Peng Unraveling the link: environmental tobacco smoke exposure an… (2024) | machine |
Each row is one Finding — a sentence as printed in one study, recorded with its page in the Coridum Knowledge Base. Follow the Finding number for the exact wording and the citation. Checked says who verified the row: machine means every automatic check passed and the surrounding text was read; person means someone read the sentence in the document. Rows are re-checked by a person over time. The studies are curated in the Coridum Knowledge Base; the reading of them together is a Claim, shown separately.
Cite this page
Coridum Research. Infertility. Coridum Knowledge G-0185, 16 September 2026. https://coridum.com/k/G-0185/