title: Seasonal Pattern of Preterm Births in Korea for 2000-2012.
abstract: The aim of this study was to investigate a seasonal pattern of preterm births in Korea. Data were obtained from the national birth registry of the Korean Statistics Office and included all births in Korea during the period 2000-2012 (n = 6,310,800). Delivery dates were grouped by month of the year or by season (winter [December, January, February], spring [March, April, May], summer [June, July, August], and autumn [September, October, November]). The seasonal patterns of prevalence of preterm births were assessed. The rates of preterm births at 37 weeks were highest twice a year (once in winter and again in summer). The rates of preterm births increased by 13.9% in summer and 7.5% in winter, respectively, than in spring (OR, 1.139; 95% CI, 1.127-1.152, and OR, 1.075; 95% 1.064-1.087, respectively) after controlling for age, the educational level of the parents, maternal parity, and neonatal gender. The pattern for spontaneous preterm births < 34 weeks was similar. In Korea, a seasonal pattern of preterm births was observed, with peak prevalence in summer and winter. A seasonal pattern of preterm births may provide new insights for the pathophysiology of preterm births.
authors.affiliation: Department of Obstetrics and Gynecology, Korea University Guro Hospital, Korea University College of Medicine, Seoul, Korea.
authors.forename: Yoonmi
authors.initials: Y
authors.lastname: Woo
authors.affiliation: Department of Obstetrics and Gynecology, Korea University Guro Hospital, Korea University College of Medicine, Seoul, Korea.
authors.forename: Yung Taek
authors.identifier: http://orcid.org/0000-0001-5887-4497
authors.initials: YT
authors.lastname: Ouh
authors.affiliation: Department of Obstetrics and Gynecology, Korea University Guro Hospital, Korea University College of Medicine, Seoul, Korea.
authors.forename: Ki Hoon
authors.initials: KH
authors.lastname: Ahn
authors.affiliation: Department of Obstetrics and Gynecology, Korea University Guro Hospital, Korea University College of Medicine, Seoul, Korea. md_cho@hanmail.net.
authors.forename: Geum Joon
authors.identifier: http://orcid.org/0000-0001-6761-0944
authors.initials: GJ
authors.lastname: Cho
authors.affiliation: Department of Obstetrics and Gynecology, Korea University Guro Hospital, Korea University College of Medicine, Seoul, Korea.
authors.forename: Soon Cheol
authors.initials: SC
authors.lastname: Hong
authors.affiliation: Department of Obstetrics and Gynecology, Korea University Guro Hospital, Korea University College of Medicine, Seoul, Korea.
authors.forename: Min Jeong
authors.initials: MJ
authors.lastname: Oh
authors.affiliation: Department of Obstetrics and Gynecology, Korea University Guro Hospital, Korea University College of Medicine, Seoul, Korea.
authors.forename: Hai Joong
authors.initials: HJ
authors.lastname: Kim
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D016015:Logistic Models; D008297:Male; D016017:Odds Ratio; D047928:Premature Birth / Q000453:epidemiology*; D015995:Prevalence; D056910:Republic of Korea / Q000453:epidemiology; D012621:Seasons; D055815:Young Adult
keywords: Preterm Birth; Seasonal Variation; Summer; Winter, Korea