{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,11,11]],"date-time":"2026-11-11T21:58:30Z","timestamp":1794434310124,"version":"4.9.1"},"reference-count":39,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2016,5,20]],"date-time":"2016-05-20T00:00:00Z","timestamp":1463702400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Nutrients"],"abstract":"<jats:p>There are disagreements among researchers about the association between vitamin D deficiency during pregnancy and preterm birth (PTB). Therefore, we conducted a meta-analysis of observational studies to evaluate this association. We performed a systematic literature search of PubMed, MEDLINE and the Cochrane Library through August 2015 with the following keywords: \u201cvitamin D\u201d or \u201ccholecalciferol\u201d or \u201c25-hydroxyvitamin D\u201d or \u201c25(OH)D\u201d in combination with \u201cpremature birth\u201d or \u201cpreterm birth\u201d or \u201cPTB\u201d or \u201cpreterm delivery\u201d or \u201cPTD\u201d or \u201cprematurity\u201d. Our meta-analysis of 10 studies included 10,098 participants and found that pregnant women with vitamin D deficiency (maternal serum 25 (OH) D levels &lt; 20 ng\/mL) experienced a significantly increased risk of PTB (odds ratio (OR) = 1.29, 95% confidence intervals(CI): 1.16, 1.45) with low heterogeneity (I2 = 25%, p = 0.21). Sensitivity analysis showed that exclusion of any single study did not materially alter the overall combined effect. In the subgroup analyses, we found that heterogeneity was obvious in prospective cohort studies (I2 = 60%, p = 0.06). In conclusion, pregnant women with vitamin D deficiency during pregnancy have an increasing risk of PTB.<\/jats:p>","DOI":"10.3390\/nu8050301","type":"journal-article","created":{"date-parts":[[2016,5,21]],"date-time":"2016-05-21T19:24:37Z","timestamp":1463858677000},"page":"301","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":135,"title":["Does Maternal Vitamin D Deficiency Increase the Risk of Preterm Birth: A Meta-Analysis of Observational Studies"],"prefix":"10.3390","volume":"8","author":[{"given":"Lu-Lu","family":"Qin","sequence":"first","affiliation":[{"name":"Department of Prevention Medicine and Pathogenic Biology, Medical School, Hunan University of Chinese Medicine, Changsha 410208, China"},{"name":"Department of Social Medicine and Health Management, Xiangya School of Public Health, Central South University, Changsha 410078, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fang-Guo","family":"Lu","sequence":"additional","affiliation":[{"name":"Department of Prevention Medicine and Pathogenic Biology, Medical School, Hunan University of Chinese Medicine, Changsha 410208, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sheng-Hui","family":"Yang","sequence":"additional","affiliation":[{"name":"Department of Prevention Medicine and Pathogenic Biology, Medical School, Hunan University of Chinese Medicine, Changsha 410208, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hui-Lan","family":"Xu","sequence":"additional","affiliation":[{"name":"Department of Social Medicine and Health Management, Xiangya School of Public Health, Central South University, Changsha 410078, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bang-An","family":"Luo","sequence":"additional","affiliation":[{"name":"Department of Mental Health, Brain Hospital of Hunan Province, Changsha 410007, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2016,5,20]]},"reference":[{"key":"ref_1","unstructured":"March of Dimes, PMNCH, Save the Children, and WHO Born Too Soon: The Global Action Report on Preterm Birth. 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