{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,2]],"date-time":"2026-06-02T06:59:36Z","timestamp":1780383576774,"version":"3.54.1"},"reference-count":31,"publisher":"Public Library of Science (PLoS)","issue":"10","license":[{"start":{"date-parts":[[2025,10,30]],"date-time":"2025-10-30T00:00:00Z","timestamp":1761782400000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"JST, PRESTO","award":["JPMJPR21RC"],"award-info":[{"award-number":["JPMJPR21RC"]}]},{"DOI":"10.13039\/501100000646","name":"Japan Society for the Promotion of Science London","doi-asserted-by":"publisher","award":["21K17292"],"award-info":[{"award-number":["21K17292"]}],"id":[{"id":"10.13039\/501100000646","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["www.plosone.org"],"crossmark-restriction":false},"short-container-title":["PLoS One"],"abstract":"<jats:sec id=\"sec001\">\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Japan\u2019s low infant mortality rates (IMR) reflect advancements in neonatal care. However, a comprehensive understanding of factors influencing long-term infant mortality nationwide is lacking. We examined the 1-year relationships between gestational age (GA), birth weight, small-for-gestational-age (SGA) status, and infant mortality risk.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec id=\"sec002\">\n                    <jats:title>Objective<\/jats:title>\n                    <jats:p>This study aimed to estimate the 1-year survival probability of infants stratified by GA, birth weight and SGA status.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec id=\"sec003\">\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>This study is an observational study using Japan\u2019s vital registration data between 2012 and 2018. Whole national birth and death registration data was analyzed. 6,918,305 births and 12,440 deaths within the first year of age were included. The main outcome is 1-year infant mortality and survival curve.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec id=\"sec004\">\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Infants born preterm, and SGA exhibited elevated mortality rates (15 and 8.5 per 1,000, respectively). Survival probability varied significantly based on GA, birth weight, and SGA status. Overall 1-year mortality risk was 1.8 per 1,000 live births with survival probabilities notably increasing with GA. Late preterm and early term births also exhibited increased mortality risks compared to full term infants (e.g., 2.2 per 1,000 live births if born at 37 weeks vs 0.76 at 39 weeks). Notably, late preterm births constituted the majority of preterm births and were associated with major mortality risks.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec id=\"sec005\">\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>This study, extending beyond previous short-term research, provides insights into long-term infant mortality risks in Japan, underscoring the importance of gestational age, birth weight, and SGA status in infant mortality risk among live births. Further study to elucidate the reasons behind pregnancy termination decisions and the specifics of antenatal and neonatal care is needed to better understand the factors influencing infant mortality.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1371\/journal.pone.0335191","type":"journal-article","created":{"date-parts":[[2025,10,30]],"date-time":"2025-10-30T17:41:35Z","timestamp":1761846095000},"page":"e0335191","update-policy":"https:\/\/doi.org\/10.1371\/journal.pone.corrections_policy","source":"Crossref","is-referenced-by-count":2,"title":["Gestational age, birth weight, and infant 1-year mortality risk: A large-scale analysis of 6.9 million births from the Japanese National registry"],"prefix":"10.1371","volume":"20","author":[{"given":"Miho","family":"Sassa","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ayaka","family":"Monoi","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yayoi","family":"Murano","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Utako","family":"Kondo","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2532-8910","authenticated-orcid":true,"given":"Hiromichi","family":"Shoji","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3525-5092","authenticated-orcid":true,"given":"Daisuke","family":"Yoneoka","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"340","published-online":{"date-parts":[[2025,10,30]]},"reference":[{"issue":"5","key":"pone.0335191.ref001","doi-asserted-by":"crossref","DOI":"10.1371\/journal.pmed.1001415","article-title":"Measuring coverage in MNCH: indicators for global tracking of newborn care","volume":"10","author":"AC Moran","year":"2013","journal-title":"PLoS Med"},{"issue":"3","key":"pone.0335191.ref002","doi-asserted-by":"crossref","first-page":"149","DOI":"10.1016\/j.pedneo.2014.07.006","article-title":"Nationwide Birth Weight and Gestational Age-specific Neonatal Mortality Rate in Taiwan","volume":"56","author":"S-T Hsu","year":"2015","journal-title":"Pediatr Neonatol"},{"key":"pone.0335191.ref003","unstructured":"OECD. Infant mortality rates [Internet]. [cited 2024 Mar 13]. https:\/\/www.oecd.org\/en\/data\/indicators\/infant-mortality-rates.html"},{"issue":"2","key":"pone.0335191.ref004","doi-asserted-by":"crossref","first-page":"317","DOI":"10.1038\/pr.2017.63","article-title":"Growth pattern and final height of very preterm vs. very low birth weight infants","volume":"82","author":"JJ Hollanders","year":"2017","journal-title":"Pediatr Res"},{"issue":"2","key":"pone.0335191.ref005","doi-asserted-by":"crossref","first-page":"97","DOI":"10.1111\/j.1475-097X.1983.tb00681.x","article-title":"Lung surfactant for replacement therapy","volume":"3","author":"B Robertson","year":"1983","journal-title":"Clin Physiol"},{"key":"pone.0335191.ref006","first-page":"73s","article-title":"Neonatal respiratory distress syndrome and surfactant therapy; a brief review","volume":"3","author":"B Robertson","year":"1989","journal-title":"Eur Respir J Suppl"},{"key":"pone.0335191.ref007","first-page":"89","article-title":"Lung-protective ventilatory 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The Effect of Early Term Birth on Maternal and Infant Health","volume":"36","author":"K Buckles","year":"2017","journal-title":"J Policy Anal Manage"},{"key":"pone.0335191.ref021","doi-asserted-by":"crossref","DOI":"10.1016\/j.jpeds.2017.09.007","article-title":"Neonatal and infant mortality risk associated with preterm and small for gestational age births in Tanzania: individual level pooled analysis using the Intergrowth standard","volume":"192","author":"A Sania","year":"2018","journal-title":"The Journal of Pediatrics"},{"key":"pone.0335191.ref022","doi-asserted-by":"crossref","first-page":"105321","DOI":"10.1016\/j.earlhumdev.2021.105321","article-title":"Changes in mortality rates among extremely preterm infants born before 25 weeks\u2019 gestation: Comparison between the 2005 and 2010 nationwide surveys in Japan","volume":"155","author":"K Itabashi","year":"2021","journal-title":"Early Human Development"},{"key":"pone.0335191.ref023","first-page":"1271","article-title":"Introduction of new gestational age-specific standards for birth size","volume":"114","author":"K Itabashi","year":"2010","journal-title":"J Jpn Pediatr Soc"},{"key":"pone.0335191.ref024","doi-asserted-by":"crossref","first-page":"17","DOI":"10.1186\/1471-2431-12-17","article-title":"Population based trends in mortality, morbidity and treatment for very preterm- and very low birth weight infants over 12 years","volume":"12","author":"Swiss Neonatal Network","year":"2012","journal-title":"BMC Pediatr"},{"issue":"9890","key":"pone.0335191.ref025","doi-asserted-by":"crossref","first-page":"417","DOI":"10.1016\/S0140-6736(13)60993-9","article-title":"Mortality risk in preterm and small-for-gestational-age infants in low-income and middle-income countries: a pooled country analysis","volume":"382","author":"J Katz","year":"2013","journal-title":"Lancet"},{"issue":"4","key":"pone.0335191.ref026","doi-asserted-by":"crossref","first-page":"741","DOI":"10.1542\/peds.2013-1131","article-title":"Late preterm infants: near term but still in a critical developmental time period","volume":"132","author":"A Kugelman","year":"2013","journal-title":"Pediatrics"},{"issue":"1","key":"pone.0335191.ref027","doi-asserted-by":"crossref","first-page":"234","DOI":"10.1542\/peds.2008-3232","article-title":"Delivery indications at late-preterm gestations and infant mortality rates in the United States","volume":"124","author":"UM Reddy","year":"2009","journal-title":"Pediatrics"},{"issue":"4","key":"pone.0335191.ref028","article-title":"Committee opinion no. 561: Nonmedically indicated early-term deliveries","volume":"121","year":"2013","journal-title":"Obstetrics & Gynecology"},{"issue":"9947","key":"pone.0335191.ref029","doi-asserted-by":"crossref","first-page":"980","DOI":"10.1016\/S0140-6736(14)60696-6","article-title":"Global, regional, and national levels and causes of maternal mortality during 1990-2013: a systematic analysis for the Global Burden of Disease Study 2013","volume":"384","author":"NJ Kassebaum","year":"2014","journal-title":"Lancet"},{"issue":"8","key":"pone.0335191.ref030","doi-asserted-by":"crossref","first-page":"1255","DOI":"10.1007\/s00431-020-03613-8","article-title":"Comorbidities in childhood associated with extrauterine growth restriction in preterm infants: a scoping review","volume":"179","author":"MD Mart\u00ednez-Jim\u00e9nez","year":"2020","journal-title":"Eur J Pediatr"},{"issue":"4","key":"pone.0335191.ref031","doi-asserted-by":"crossref","first-page":"235","DOI":"10.1111\/j.1469-8749.2000.tb00078.x","article-title":"Identification of neonates at risk of developing feeding problems in infancy","volume":"42","author":"JM Hawdon","year":"2000","journal-title":"Dev Med Child Neurol"}],"container-title":["PLOS One"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/dx.plos.org\/10.1371\/journal.pone.0335191","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,30]],"date-time":"2025-10-30T17:41:41Z","timestamp":1761846101000},"score":1,"resource":{"primary":{"URL":"https:\/\/dx.plos.org\/10.1371\/journal.pone.0335191"}},"subtitle":[],"editor":[{"given":"Kazumichi","family":"Fujioka","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"editor"}]}],"short-title":[],"issued":{"date-parts":[[2025,10,30]]},"references-count":31,"journal-issue":{"issue":"10","published-online":{"date-parts":[[2025,10,30]]}},"URL":"https:\/\/doi.org\/10.1371\/journal.pone.0335191","relation":{},"ISSN":["1932-6203"],"issn-type":[{"value":"1932-6203","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,10,30]]}}}