{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,25]],"date-time":"2026-10-25T00:55:44Z","timestamp":1792889744811,"version":"4.5.0"},"reference-count":58,"publisher":"Wiley","issue":"10","license":[{"start":{"date-parts":[[2014,10,16]],"date-time":"2014-10-16T00:00:00Z","timestamp":1413417600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"funder":[{"DOI":"10.13039\/100000066","name":"National Institute of Environmental Health Sciences","doi-asserted-by":"publisher","award":["UO1 NS 047537-01"],"award-info":[{"award-number":["UO1 NS 047537-01"]}],"id":[{"id":"10.13039\/100000066","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["obgyn.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["BJOG"],"published-print":{"date-parts":[[2015,9]]},"abstract":"<jats:sec>\n                    <jats:title>Objective<\/jats:title>\n                    <jats:p>To evaluate whether hormonal contraceptives, used before or in early pregnancy, confer increased risk of preterm birth or reduced fetal growth.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Design<\/jats:title>\n                    <jats:p>Population\u2010based cohort study conducted by the Norwegian Institute of Public Health (Mother and Child Cohort Study, 1998\u20132008) with linkage to the Norwegian Prescription Registry and to the Medical Birth Registry of Norway.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Setting<\/jats:title>\n                    <jats:p>Norway.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Population<\/jats:title>\n                    <jats:p>Of the 48\u00a0615 pregnancies meeting study inclusion criteria, 44\u00a0734 pregnancies were included in the complete case analysis.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>We characterised hormonal contraception by type (combination oral, progestin\u2010only oral, vaginal ring, transdermal, and injectable) and specific progestin component. We used generalised estimating equations to estimate the odds of adverse outcome according to formulation used. Several sensitivity analyses were conducted.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Main outcome measures<\/jats:title>\n                    <jats:p>Preterm birth, small for gestational age.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>We observed a positive association between use of a combination oral contraceptive and preterm birth for all exposure periods (e.g. adjusted odds ratio 1.21, 95% confidence interval 1.04\u20131.41 for last use 12 to &gt;4\u00a0months before conception); combination contraceptives containing the progestin norethisterone were consistently related to risk. Other types of hormonal contraception were generally not associated with preterm birth; none were related to small for gestational age. Observed associations were robust to sensitivity analyses.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>Hormonally active agents may exert dose\u2010, agent\u2010, and timing\u2010specific effects on growth and development. We found that the particular progestin component is important when assessing the potential for adverse effects among former users of hormonal contraceptives.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1111\/1471-0528.13114","type":"journal-article","created":{"date-parts":[[2014,10,16]],"date-time":"2014-10-16T04:33:53Z","timestamp":1413434033000},"page":"1349-1361","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":11,"title":["Hormonal contraceptive use before and after conception in relation to preterm birth and small for gestational age: an observational cohort study"],"prefix":"10.1111","volume":"122","author":[{"given":"ET","family":"Jensen","sequence":"first","affiliation":[{"name":"National Institutes of Health National Institute of Environmental Health Sciences Research Triangle Park NC USA"},{"name":"Department of Epidemiology Gillings School of Global Public Health University of North Carolina Chapel Hill NC USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"JL","family":"Daniels","sequence":"additional","affiliation":[{"name":"Department of Epidemiology Gillings School of Global Public Health University of North Carolina Chapel Hill NC USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"T","family":"St\u00fcrmer","sequence":"additional","affiliation":[{"name":"Department of Epidemiology Gillings School of Global Public Health University of North Carolina Chapel Hill NC USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"WR","family":"Robinson","sequence":"additional","affiliation":[{"name":"Department of Epidemiology Gillings School of Global Public Health University of North Carolina Chapel Hill NC USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"CJ","family":"Williams","sequence":"additional","affiliation":[{"name":"National Institutes of Health National Institute of Environmental Health Sciences Research Triangle Park NC USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"K","family":"Vejrup","sequence":"additional","affiliation":[{"name":"National Institute of Public Health Oslo Norway"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"P","family":"Magnus","sequence":"additional","affiliation":[{"name":"National Institute of Public Health Oslo Norway"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"MP","family":"Longnecker","sequence":"additional","affiliation":[{"name":"National Institutes of Health National Institute of Environmental Health Sciences Research Triangle Park NC USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2014,10,16]]},"reference":[{"key":"e_1_2_7_2_1","doi-asserted-by":"publisher","DOI":"10.1586\/17474108.2013.811939"},{"key":"e_1_2_7_3_1","doi-asserted-by":"publisher","DOI":"10.1080\/10937404.2013.775048"},{"key":"e_1_2_7_4_1","doi-asserted-by":"publisher","DOI":"10.1007\/s11356-013-1753-3"},{"key":"e_1_2_7_5_1","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0080398"},{"key":"e_1_2_7_6_1","doi-asserted-by":"publisher","DOI":"10.1093\/humrep\/dep477"},{"key":"e_1_2_7_7_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.taap.2012.07.006"},{"key":"e_1_2_7_8_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.mce.2009.02.024"},{"key":"e_1_2_7_9_1","doi-asserted-by":"publisher","DOI":"10.1177\/0960327108092290"},{"key":"e_1_2_7_10_1","doi-asserted-by":"crossref","first-page":"795","DOI":"10.1093\/oxfordjournals.aje.a116152","article-title":"In utero exposure to steroid contraceptives and outcome of pregnancy","volume":"134","author":"Pardthaisong T","year":"1991","journal-title":"Am J Epidemiol"},{"key":"e_1_2_7_11_1","doi-asserted-by":"publisher","DOI":"10.1002\/tera.1420270210"},{"key":"e_1_2_7_12_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1471-0528.1979.tb10808.x"},{"key":"e_1_2_7_13_1","volume-title":"Managing Contraceptive Pill Patients\/Drug Patients","author":"Dickey RP","year":"2010"},{"key":"e_1_2_7_14_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.maturitas.2003.09.014"},{"key":"e_1_2_7_15_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.tips.2004.09.005"},{"key":"e_1_2_7_16_1","doi-asserted-by":"publisher","DOI":"10.1210\/jc.2007-2599"},{"key":"e_1_2_7_17_1","first-page":"43","article-title":"Pharmacodynamic effects of oral contraceptive steroids on biochemical markers for arterial thrombosis. 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