{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,3]],"date-time":"2026-06-03T00:09:41Z","timestamp":1780445381179,"version":"3.54.1"},"reference-count":43,"publisher":"Wiley","issue":"3","license":[{"start":{"date-parts":[[2017,9,12]],"date-time":"2017-09-12T00:00:00Z","timestamp":1505174400000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"funder":[{"DOI":"10.13039\/100004427","name":"Center for Global Partnership","doi-asserted-by":"publisher","id":[{"id":"10.13039\/100004427","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["J of Obstet and Gynaecol"],"published-print":{"date-parts":[[2018,3]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:sec><jats:title>Aim<\/jats:title><jats:p>Secular trends of preterm birth in Japan between 1979 and 2014 were examined to determine whether changes could be explained by a shift in the distribution of maternal age at delivery and parity and\/or by changes in age\u2010specific preterm birth rates.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>Live birth data for 1979 to 2014 were obtained from the Japanese Ministry of Health, Labour and Welfare. Analyses were limited to singleton children born in Japan (<jats:italic>n<\/jats:italic>\u00a0=\u00a043\u2009632\u2009786). Preterm birth was defined using two cut\u2010offs at &lt; 37 or &lt; 34\u00a0weeks of gestation. Crude and standardized rates of preterm birth were calculated for firstborn and later\u2010born singletons by maternal age at delivery for specific time periods.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>Throughout the study period, the rates of preterm birth (both at &lt; 37 and &lt; 34\u00a0weeks of gestation) were higher among mothers aged 20 and younger, and mid\u201030s and older, compared to mothers in their 20s or early 30s. The rates of preterm birth at &lt; 37 (but not at &lt; 34)\u00a0weeks decreased for mothers aged in their late 30s and 40s, and increased for mothers in their 20s and early 30s. Standardized rates of preterm birth showed a secular increase for preterm births at &lt; 37\u00a0but not &lt; 34 weeks of gestation.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusion<\/jats:title><jats:p>The rates of preterm birth among mothers aged in their 20s and early 30s increased between 1979 and 2014, which contributed to the secular increase in rates of preterm birth at &lt; 37\u00a0weeks.<\/jats:p><\/jats:sec>","DOI":"10.1111\/jog.13460","type":"journal-article","created":{"date-parts":[[2017,9,13]],"date-time":"2017-09-13T02:31:44Z","timestamp":1505269904000},"page":"390-396","source":"Crossref","is-referenced-by-count":37,"title":["Preterm birth rates in Japan from 1979 to 2014: Analysis of national vital statistics"],"prefix":"10.1111","volume":"44","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-9597-0178","authenticated-orcid":false,"given":"Soyoko","family":"Sakata","sequence":"first","affiliation":[{"name":"Department of Human Ecology, Graduate School of Medicine The University of Tokyo  Tokyo Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7282-0863","authenticated-orcid":false,"given":"Shoko","family":"Konishi","sequence":"additional","affiliation":[{"name":"Department of Human Ecology, Graduate School of Medicine The University of Tokyo  Tokyo Japan"},{"name":"Department of Anthropology University of Washington  Seattle WA USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1025-0807","authenticated-orcid":false,"given":"Chris Fook Sheng","family":"Ng","sequence":"additional","affiliation":[{"name":"Department of Pediatric Infectious Diseases, Institute of Tropical Medicine Nagasaki University  Nagasaki Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chiho","family":"Watanabe","sequence":"additional","affiliation":[{"name":"Department of Human Ecology, Graduate School of Medicine The University of Tokyo  Tokyo Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2017,9,12]]},"reference":[{"key":"e_1_2_8_2_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0140-6736(12)60820-4"},{"key":"e_1_2_8_3_1","doi-asserted-by":"crossref","first-page":"S1","DOI":"10.1186\/1471-2393-10-S1-S1","volume":"10","author":"Lawn JE","year":"2010","journal-title":"BMC Pregnancy Childbirth"},{"key":"e_1_2_8_4_1","first-page":"12","article-title":"Prevention of preterm birth (2) Bacterial vaginitide: Actual condition and countermove","volume":"61","author":"Saito S","year":"2010","journal-title":"Boshi Hoken Joho"},{"key":"e_1_2_8_5_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0029-7844(03)00617-3"},{"key":"e_1_2_8_6_1","doi-asserted-by":"crossref","first-page":"4","DOI":"10.1111\/j.1471-0528.2006.01117.x","article-title":"The cost of preterm birth: The low cost versus high value of tocolysis","volume":"113","author":"Gilbert WM","year":"2006","journal-title":"BJOG"},{"key":"e_1_2_8_7_1","doi-asserted-by":"publisher","DOI":"10.1136\/fn.88.5.F415"},{"key":"e_1_2_8_8_1","doi-asserted-by":"crossref","first-page":"372","DOI":"10.1542\/peds.114.2.372","article-title":"Clinical outcomes of near term infants","volume":"114","author":"Wang ML","year":"2004","journal-title":"Pediatrics"},{"key":"e_1_2_8_9_1","doi-asserted-by":"publisher","DOI":"10.1542\/peds.2006-0860"},{"key":"e_1_2_8_10_1","doi-asserted-by":"publisher","DOI":"10.1542\/peds.113.5.1230"},{"key":"e_1_2_8_11_1","doi-asserted-by":"publisher","DOI":"10.3109\/14767058.2014.941799"},{"key":"e_1_2_8_12_1","doi-asserted-by":"publisher","DOI":"10.1001\/jama.284.7.843"},{"key":"e_1_2_8_13_1","doi-asserted-by":"publisher","DOI":"10.1038\/jp.2015.91"},{"key":"e_1_2_8_14_1","doi-asserted-by":"publisher","DOI":"10.1111\/ppe.12085"},{"key":"e_1_2_8_15_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.infbeh.2016.05.002"},{"key":"e_1_2_8_16_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.ejpn.2016.04.011"},{"key":"e_1_2_8_17_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1365-3016.2007.00823.x"},{"key":"e_1_2_8_18_1","first-page":"1","article-title":"Infant mortality statistics from the 2005 period linked birth\/infant death data set","volume":"57","author":"Mathews TJ","year":"2008","journal-title":"Natl Vital Stat Rep"},{"key":"e_1_2_8_19_1","first-page":"274","article-title":"The trend of preterm birth in Japan","volume":"69","author":"Oba T","year":"2015","journal-title":"Clin Obstet Gynaecol"},{"key":"e_1_2_8_20_1","unstructured":"SaitoS.[Premature delivery and threatened premature delivery.] In:OkaiT AyabeT(eds). [Standard Textbook of Obstetrics and Gynacology 3rd edn.]Tokyo:Igaku shoin 2013;348\u2013355. (In Japanese)"},{"key":"e_1_2_8_21_1","first-page":"158","volume-title":"Disease: An Illustrated Reference Guide","author":"Saito S","year":"2016"},{"key":"e_1_2_8_22_1","doi-asserted-by":"publisher","DOI":"10.2105\/AJPH.2013.301523"},{"key":"e_1_2_8_23_1","doi-asserted-by":"publisher","DOI":"10.1136\/bmj.38751.524132.2F"},{"key":"e_1_2_8_24_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.0001-6349.2005.00765.x"},{"key":"e_1_2_8_25_1","doi-asserted-by":"publisher","DOI":"10.3109\/00016349.2010.486827"},{"key":"e_1_2_8_26_1","unstructured":"National Institute of Population and Social Security Research. [Table 4\u201017 Mean maternal age at first birth among member nations of UNECE: 1980\u20132012.] (In Japanese) (2016). [Cited 11 Mar 2017.] Available from URL:http:\/\/www.ipss.go.jp\/syoushika\/tohkei\/Popular\/P_Detail2016.asp?fname=T04\u201017.htm"},{"key":"e_1_2_8_27_1","unstructured":"Ministry of Internal Affairs and Communications. [Table 4\u201024 Number of birth and percentage by gestational age and year.] (In Japanese) (2015). [Cited 28 Oct 2016.] Available from URL:https:\/\/www.e\u2010stat.go.jp\/SG1\/estat\/eStatTopPortal.do"},{"key":"e_1_2_8_28_1","doi-asserted-by":"publisher","DOI":"10.1038\/srep31396"},{"key":"e_1_2_8_29_1","doi-asserted-by":"publisher","DOI":"10.1111\/jog.12120"},{"key":"e_1_2_8_30_1","unstructured":"Ministry of Internal Affairs and Communications. [Historical data 3 (3) Employed person and employment rate by age group \u2010 Whole Japan.] (In Japanese) (2017). [Cited 8 Feb 2017.] Available from URL:http:\/\/www.stat.go.jp\/data\/roudou\/longtime\/03roudou.htm"},{"key":"e_1_2_8_31_1","doi-asserted-by":"publisher","DOI":"10.1097\/00001648-199907000-00015"},{"key":"e_1_2_8_32_1","doi-asserted-by":"publisher","DOI":"10.2105\/AJPH.86.6.825"},{"key":"e_1_2_8_33_1","doi-asserted-by":"publisher","DOI":"10.5271\/sjweh.56"},{"key":"e_1_2_8_34_1","doi-asserted-by":"publisher","DOI":"10.1056\/NEJM199010113231506"},{"key":"e_1_2_8_35_1","first-page":"148","article-title":"Fetal death and work in pregnancy","volume":"45","author":"McDonald AD","year":"1988","journal-title":"Br J Ind Med"},{"key":"e_1_2_8_36_1","doi-asserted-by":"crossref","first-page":"1007","DOI":"10.2105\/AJPH.81.8.1007","article-title":"Characteristics of maternal employment during pregnancy: Effects on low birthweight","volume":"81","author":"People\u2010Sheps MD","year":"1991","journal-title":"Am J Public Health"},{"key":"e_1_2_8_37_1","first-page":"236","article-title":"Pregnant women's working conditions and their changes during pregnancy: A national study in France","volume":"44","author":"Saurel\u2010Cubizolles MJ","year":"1987","journal-title":"Br J Ind Med"},{"key":"e_1_2_8_38_1","doi-asserted-by":"publisher","DOI":"10.1136\/jech.45.1.29"},{"key":"e_1_2_8_39_1","doi-asserted-by":"publisher","DOI":"10.1097\/00001648-199605000-00009"},{"key":"e_1_2_8_40_1","doi-asserted-by":"publisher","DOI":"10.1186\/1471-2393-14-245"},{"key":"e_1_2_8_41_1","doi-asserted-by":"publisher","DOI":"10.5271\/sjweh.1832"},{"key":"e_1_2_8_42_1","doi-asserted-by":"publisher","DOI":"10.1136\/oem.51.7.470"},{"key":"e_1_2_8_43_1","doi-asserted-by":"publisher","DOI":"10.1111\/apa.12616"},{"key":"e_1_2_8_44_1","unstructured":"Ministry of Health Labour and Welfare. [Trends in Prevalence of Obesity (BMI\u226725) and Underweight (BMI\u226620) 1973\u20132014 (subjects aged 15 years and over by Gender and Age Regrouped).] (In Japanese) [Cited 10 Feb 2017.] Available from URL:http:\/\/www.mhlw.go.jp\/seisakunitsuite\/bunya\/kenkou_iryou\/kenkou\/kenkounippon21\/download_files\/keinen_henka\/shintai\/07.xlsx"}],"container-title":["Journal of Obstetrics and Gynaecology Research"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/api.wiley.com\/onlinelibrary\/tdm\/v1\/articles\/10.1111%2Fjog.13460","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/obgyn.onlinelibrary.wiley.com\/doi\/pdf\/10.1111\/jog.13460","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,9,25]],"date-time":"2023-09-25T15:22:09Z","timestamp":1695655329000},"score":1,"resource":{"primary":{"URL":"https:\/\/obgyn.onlinelibrary.wiley.com\/doi\/10.1111\/jog.13460"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2017,9,12]]},"references-count":43,"journal-issue":{"issue":"3","published-print":{"date-parts":[[2018,3]]}},"alternative-id":["10.1111\/jog.13460"],"URL":"https:\/\/doi.org\/10.1111\/jog.13460","archive":["Portico"],"relation":{},"ISSN":["1341-8076","1447-0756"],"issn-type":[{"value":"1341-8076","type":"print"},{"value":"1447-0756","type":"electronic"}],"subject":[],"published":{"date-parts":[[2017,9,12]]}}}