{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,18]],"date-time":"2026-09-18T16:47:04Z","timestamp":1789750024806,"version":"4.0.1"},"reference-count":34,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2015,5,11]],"date-time":"2015-05-11T00:00:00Z","timestamp":1431302400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Samsung Medical Center Clinical Research Development Program grant","award":["CRO1121421"],"award-info":[{"award-number":["CRO1121421"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Nutrients"],"abstract":"<jats:p>We investigated the vitamin D status of Korean women during pregnancy and assessed the effects of vitamin D deficiency on two pregnancy outcomes; preterm births and the births of small for gestational age. We measured the serum 25-hydroxyvitamin D levels in 220 pregnant Korean women who were recruited prospectively and compared these levels with those of 500 healthy non-pregnant women. We analyzed vitamin D status according to patient demographics, season, and obstetrical characteristics; moreover, we also assessed pregnancy outcomes. The overall prevalence of vitamin D deficiency(&lt;20 ng\/mL) in pregnant women and healthy non-pregnant women was 77.3% and 79.2%; respectively; and the prevalence of severe vitamin D deficiency (&lt;10 ng\/mL) was 28.6% and 7.2%; respectively (p &lt; 0.05). Vitamin D deficiency was more prevalent in the winter (100%) than in the summer (45.5%) in pregnant Korean women. A higher risk of vitamin D deficiency was observed in the first trimester than in the third trimester (adjusted OR 4.3; p &lt; 0.05). No significant association was observed between vitamin D deficiency and any of the pregnancy outcomes examined. Further research focusing on the long-term consequences of vitamin D deficiency during pregnancy in Korean women is warranted.<\/jats:p>","DOI":"10.3390\/nu7053427","type":"journal-article","created":{"date-parts":[[2015,5,11]],"date-time":"2015-05-11T10:09:28Z","timestamp":1431338968000},"page":"3427-3448","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":70,"title":["High Prevalence of Vitamin D Deficiency in Pregnant Korean Women: The First Trimester and the Winter Season as Risk Factors for Vitamin D Deficiency"],"prefix":"10.3390","volume":"7","author":[{"given":"Rihwa","family":"Choi","sequence":"first","affiliation":[{"name":"Department of Laboratory Medicine and Genetics, Samsung Medical Center,  Sungkyunkwan University School of Medicine, 81 Irwon-Ro, Gangnam-Gu, Seoul 135-710, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Seonwoo","family":"Kim","sequence":"additional","affiliation":[{"name":"Biostatistics Team, Samsung Biomedical Research Institute, 81 Irwon-Ro, Gangnam-Gu,  Seoul 135-710, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4341-6906","authenticated-orcid":false,"given":"Heejin","family":"Yoo","sequence":"additional","affiliation":[{"name":"Biostatistics and Clinical Epidemiology Center, Samsung Medical Center, 81 Irwon-Ro,  Gangnam-Gu, Seoul 135-710, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yoon","family":"Cho","sequence":"additional","affiliation":[{"name":"Division of Endocrinology and Metabolism, Department of Medicine, Thyroid Center,  Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-Ro,  Gangnam-Gu, Seoul 135-710, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sun","family":"Kim","sequence":"additional","affiliation":[{"name":"Division of Endocrinology and Metabolism, Department of Medicine, Thyroid Center,  Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-Ro,  Gangnam-Gu, Seoul 135-710, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9563-5046","authenticated-orcid":false,"given":"Jae","family":"Chung","sequence":"additional","affiliation":[{"name":"Division of Endocrinology and Metabolism, Department of Medicine, Thyroid Center,  Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-Ro,  Gangnam-Gu, Seoul 135-710, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Soo-young","family":"Oh","sequence":"additional","affiliation":[{"name":"Department of Obstetrics and Gynecology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-Ro, Gangnam-Gu, Seoul 135-710, Seoul, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7595-4042","authenticated-orcid":false,"given":"Soo-Youn","family":"Lee","sequence":"additional","affiliation":[{"name":"Department of Laboratory Medicine and Genetics, Samsung Medical Center,  Sungkyunkwan University School of Medicine, 81 Irwon-Ro, Gangnam-Gu, Seoul 135-710, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2015,5,11]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"266","DOI":"10.1056\/NEJMra070553","article-title":"Vitamin D deficiency","volume":"357","author":"Holick","year":"2007","journal-title":"New Engl. 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