{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,4]],"date-time":"2026-06-04T10:49:03Z","timestamp":1780570143700,"version":"3.54.1"},"reference-count":33,"publisher":"SAGE Publications","issue":"4","license":[{"start":{"date-parts":[[2021,4,1]],"date-time":"2021-04-01T00:00:00Z","timestamp":1617235200000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.sagepub.com\/page\/policies\/text-and-data-mining-license"}],"content-domain":{"domain":["journals.sagepub.com"],"crossmark-restriction":true},"short-container-title":["Thyroid\u00ae"],"published-print":{"date-parts":[[2021,4]]},"abstract":"<jats:sec>\n                    <jats:title>Background:<\/jats:title>\n                    <jats:p>Compared with singletons, a twin pregnancy is associated with a larger thyroid hormone demand and an increased stimulation of gestational thyroid function due to higher concentrations of human chorionic gonadotropin. However, such effects have been sparsely quantified. The aim of this study was to evaluate thyroid function and thyroid function test abnormalities in twin pregnancies during early and late pregnancy compared with singletons.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods:<\/jats:title>\n                    <jats:p>We included 1208 twin pregnancies and 46,834 singleton pregnancies with thyroid function tests available. Thyroid function test abnormalities were defined using population-based reference ranges. The analyses were adjusted for potential confounders including maternal age and body mass index.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results:<\/jats:title>\n                    <jats:p>\n                      Compared with singletons, a twin pregnancy was associated with a lower thyrotropin (TSH) (\u03b2\u2009=\u2009\u22120.46 [95% confidence interval, CI \u22120.49 to \u22120.44],\n                      <jats:italic toggle=\"yes\">p<\/jats:italic>\n                      \u2009&lt;\u20090.001) and a higher free thyroxine (fT4) (\u03b2\u2009=\u20090.91 [CI 0.69\u20131.16],\n                      <jats:italic toggle=\"yes\">p<\/jats:italic>\n                      \u2009&lt;\u20090.001) during early pregnancy. During late pregnancy, a twin pregnancy was associated with a higher TSH (\u03b2\u2009=\u20090.35 [CI 0.29\u20130.42],\n                      <jats:italic toggle=\"yes\">p<\/jats:italic>\n                      \u2009&lt;\u20090.001) while fT4 did not differ (\u03b2\u2009=\u2009\u22120.11 [CI \u22120.22 to 0.01],\n                      <jats:italic toggle=\"yes\">p<\/jats:italic>\n                      \u2009=\u20090.065). During early pregnancy, a twin pregnancy was associated with a higher risk of overt hyperthyroidism (odds ratio, OR\u2009=\u20097.49 [CI 6.02\u20139.33],\n                      <jats:italic toggle=\"yes\">p<\/jats:italic>\n                      \u2009&lt;\u20090.001), subclinical hyperthyroidism (OR\u2009=\u20095.26 [CI 4.17\u20136.64],\n                      <jats:italic toggle=\"yes\">p<\/jats:italic>\n                      \u2009&lt;\u20090.001), and isolated hypothyroxinemia (OR\u2009=\u20091.89 [CI 1.43\u20132.49],\n                      <jats:italic toggle=\"yes\">p<\/jats:italic>\n                      \u2009&lt;\u20090.001), but with a lower risk of subclinical hypothyroidism (OR\u2009=\u20090.27 [CI 0.13\u20130.54],\n                      <jats:italic toggle=\"yes\">p<\/jats:italic>\n                      \u2009&lt;\u20090.001). In late pregnancy, a twin pregnancy was associated with a higher risk of subclinical hypothyroidism (OR\u2009=\u20094.05 [CI 3.21\u20135.11],\n                      <jats:italic toggle=\"yes\">p<\/jats:italic>\n                      \u2009&lt;\u20090.001), isolated hypothyroxinemia (OR\u2009=\u20091.48 [CI 1.04\u20132.10],\n                      <jats:italic toggle=\"yes\">p<\/jats:italic>\n                      \u2009=\u20090.028), and subclinical hyperthyroidism (OR\u2009=\u20091.76 [CI 1.27\u20132.43],\n                      <jats:italic toggle=\"yes\">p<\/jats:italic>\n                      \u2009&lt;\u20090.001).\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions:<\/jats:title>\n                    <jats:p>During early pregnancy, a twin pregnancy was associated with a higher thyroid function and a higher risk of (subclinical) hyperthyroidism, as well as a higher risk of isolated hypothyroxinemia. During late pregnancy, a twin pregnancy was associated with a higher TSH concentration and a higher risk of subclinical hypothyroidism, as well as a persistently higher risk of isolated hypothyroxinemia and subclinical hyperthyroidism. The study was approved by Chinese Clinical Trial Registry (registration no. ChiCTR1800014394).<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1089\/thy.2020.0348","type":"journal-article","created":{"date-parts":[[2020,8,4]],"date-time":"2020-08-04T04:21:42Z","timestamp":1596514902000},"page":"572-579","update-policy":"https:\/\/doi.org\/10.1177\/sage-journals-update-policy","source":"Crossref","is-referenced-by-count":15,"title":["Thyroid Function Test Abnormalities in Twin Pregnancies"],"prefix":"10.1177","volume":"31","author":[{"given":"Zhirou","family":"Chen","sequence":"first","affiliation":[{"name":"Department of Obstetrics, International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xi","family":"Yang","sequence":"additional","affiliation":[{"name":"Department of Obstetrics, International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chen","family":"Zhang","sequence":"additional","affiliation":[{"name":"Department of Obstetrics, International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China."},{"name":"Shanghai Key Laboratory of Embryo Original Diseases, Shanghai, China."},{"name":"Shanghai Municipal Key Clinical Specialty, Shanghai, China."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zheng","family":"Ding","sequence":"additional","affiliation":[{"name":"Department of Obstetrics, International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yong","family":"Zhang","sequence":"additional","affiliation":[{"name":"Department of Obstetrics, International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China."},{"name":"Shanghai Key Laboratory of Embryo Original Diseases, Shanghai, China."},{"name":"Shanghai Municipal Key Clinical Specialty, Shanghai, China."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tim I.M.","family":"Korevaar","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine, Academic Center for Thyroid Diseases, Erasmus Medical Center, Rotterdam, The Netherlands."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jianxia","family":"Fan","sequence":"additional","affiliation":[{"name":"Department of Obstetrics, International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China."},{"name":"Shanghai Key Laboratory of Embryo Original Diseases, Shanghai, China."},{"name":"Shanghai Municipal Key Clinical Specialty, Shanghai, China."}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"179","published-online":{"date-parts":[[2021,4,12]]},"reference":[{"key":"e_1_3_5_2_2","doi-asserted-by":"publisher","DOI":"10.1080\/10408363.2016.1269309"},{"key":"e_1_3_5_3_2","doi-asserted-by":"publisher","DOI":"10.1089\/thy.2016.0457"},{"key":"e_1_3_5_4_2","doi-asserted-by":"publisher","DOI":"10.1001\/jama.2019.10931"},{"key":"e_1_3_5_5_2","doi-asserted-by":"publisher","DOI":"10.1210\/er.2009-0041"},{"key":"e_1_3_5_6_2","doi-asserted-by":"publisher","DOI":"10.1210\/edrv.18.3.0300"},{"key":"e_1_3_5_7_2","doi-asserted-by":"publisher","DOI":"10.1089\/thy.2012.0537"},{"key":"e_1_3_5_8_2","doi-asserted-by":"publisher","DOI":"10.1097\/CM9.0000000000000381"},{"key":"e_1_3_5_9_2","doi-asserted-by":"publisher","DOI":"10.1002\/jcla.22405"},{"key":"e_1_3_5_10_2","doi-asserted-by":"publisher","DOI":"10.1097\/01.AOG.0000175836.41390.73"},{"key":"e_1_3_5_11_2","doi-asserted-by":"publisher","DOI":"10.1046\/j.1365-2265.1997.2011011.x"},{"key":"e_1_3_5_12_2","doi-asserted-by":"publisher","DOI":"10.1007\/s10654-015-0039-0"},{"key":"e_1_3_5_13_2","first-page":"69","article-title":"Thyroid autoimmunity impairs the thyroidal response to human chorionic gonadotropin: two population-based prospective cohort studies","volume":"102","author":"Korevaar TI","year":"2017","unstructured":"Korevaar TI, , Steegers EA, , Pop VJ, , Broeren MA, , Chaker L, , de Rijke YB, , Jaddoe VW, , Medici M, , Visser TJ, , Tiemeier H, , Peeters RP. 2017. 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