{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,26]],"date-time":"2026-06-26T22:36:30Z","timestamp":1782513390283,"version":"3.54.5"},"reference-count":49,"publisher":"Wiley","issue":"8","license":[{"start":{"date-parts":[[2018,7,10]],"date-time":"2018-07-10T00:00:00Z","timestamp":1531180800000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"funder":[{"DOI":"10.13039\/100000002","name":"National Institutes of Health","doi-asserted-by":"publisher","id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Intl Journal of Cancer"],"published-print":{"date-parts":[[2018,10,15]]},"abstract":"<jats:p>Epithelial ovarian cancer is a fatal disease of largely unknown etiology. Higher parity is associated with reduced risk of ovarian cancer. However, among parous women, the impact of pregnancy\u2010related factors on risk is not well understood. This population\u2010based case\u2013control study included all parous women with epithelial ovarian cancer in Denmark, Finland, Norway and Sweden during 1967\u20132013 (<jats:italic>n<\/jats:italic>\u2009=\u200910,957) and up to 10 matched controls (<jats:italic>n<\/jats:italic>\u2009=\u2009107,864). We used conditional logistic regression to estimate odds ratios (ORs) with 95% confidence intervals (CIs) for pregnancy\u2010related factors and ovarian cancer risk by histological subtype. Preterm delivery was associated with an increased risk [pregnancy length (last pregnancy) \u226430 <jats:italic>vs<\/jats:italic>. 39\u201341 weeks, OR 1.33 (95% CI 1.06\u20131.67), adjusted for number of births]; the OR increased as pregnancy length decreased (<jats:italic>p<\/jats:italic> for trend\u2009&lt;\u20090.001). Older age at first and last birth was associated with a decreased risk [first birth: 30\u201339 <jats:italic>vs<\/jats:italic>. &lt;25 years: adjusted OR 0.76 (95% CI 0.70\u20130.83); last birth 30\u201339 <jats:italic>vs<\/jats:italic>. &lt;25 years: adjusted OR 0.76 (95% CI 0.71\u20130.82)]. Increasing number of births was protective [\u22654 births <jats:italic>vs<\/jats:italic>. 1; OR 0.63 (95% CI 0.59\u20130.68)] for all subtypes, most pronounced for clear\u2010cell tumors [OR 0.30, (95% CI 0.21\u20130.44), <jats:italic>p<jats:sub>heterogeneity<\/jats:sub><\/jats:italic>\u2009&lt;\u20090.001]. No associations were observed for multiple pregnancies, preeclampsia or offspring size. In conclusion, in addition to high parity, full\u2010term pregnancies and pregnancies at older ages were associated with decreased risk of ovarian cancer. Our findings favor the cell clearance hypothesis, i.e. a recent pregnancy provides protection by clearing of precancerous cells from the epithelium of the ovary\/fallopian tubes, mediated by placental or ovarian hormones.<\/jats:p>","DOI":"10.1002\/ijc.31581","type":"journal-article","created":{"date-parts":[[2018,5,8]],"date-time":"2018-05-08T09:17:35Z","timestamp":1525771055000},"page":"1858-1867","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":17,"title":["Preterm delivery is associated with an increased risk of epithelial ovarian cancer among parous women"],"prefix":"10.1002","volume":"143","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-8212-0003","authenticated-orcid":false,"given":"Camilla","family":"Sk\u00f6ld","sequence":"first","affiliation":[{"name":"Department of Immunology, Genetics and Pathology Uppsala University Uppsala 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