title: Fertility knowledge and the timing of first childbearing: a cross-sectional study in Japan.
abstract: Although fertility educational initiatives have increased in developed countries to prevent infertility and to broaden fertility choices, the relationship between knowledge and behaviour is still poorly understood. In order to investigate the association between fertility knowledge and timing of childbearing, we investigated male and female participants between 35 and 44 years of age who had children (n = 640) from an online survey conducted in Japan in 2013. The age at which participants actually gave birth to or fathered their first child was compared between those who were aware for at least a decade of age-related decline in female fertility (hereinafter, those with past fertility knowledge) and those without. Age at first birth was significantly younger and more narrowly distributed among women with past fertility knowledge than among those without: 28.2 ± 3.4 vs. 29.8 ± 4.6 (mean ± SD). A multivariate linear regression analysis showed that women with past fertility knowledge gave birth to their first child 2.34 [95% confidence interval (CI): 1.09-3.59] years earlier compared to those without such knowledge. No significant relation existed among men. Being informed in young adulthood about the facts of fertility might be related to starting a family at an earlier age, although further longitudinal evaluation will be necessary.
authors.affiliation: a Department of Public Health, Graduate School of Medicine , The University of Tokyo , Tokyo , Japan.|b Department of Environmental Health Sciences , Akita University Graduate School of Medicine , Akita , Japan.|c Research Fellow of Japan Society for the Promotion of Science.
authors.forename: Eri
authors.initials: E
authors.lastname: Maeda
authors.affiliation: a Department of Public Health, Graduate School of Medicine , The University of Tokyo , Tokyo , Japan.
authors.forename: Fumiaki
authors.initials: F
authors.lastname: Nakamura
authors.affiliation: d Cardiff Fertility Studies Research Group , School of Psychology Cardiff University , Cardiff , UK.
authors.forename: Jacky
authors.initials: J
authors.lastname: Boivin
authors.affiliation: a Department of Public Health, Graduate School of Medicine , The University of Tokyo , Tokyo , Japan.
authors.forename: Yasuki
authors.initials: Y
authors.lastname: Kobayashi
authors.affiliation: e Department of Preventive Medicine, Graduate School of Sports and Health Sciences , Daito Bunka University , Saitama , Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Sugimori
authors.affiliation: f Center of Maternal-Fetal, Neonatal and Reproductive Medicine , National Center for Child Health and Development , Tokyo , Japan.
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Saito
mesh_terms: D000328:Adult; D000367:Age Factors; D003430:Cross-Sectional Studies; D005260:Female; D005298:Fertility; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D007564:Japan; D008297:Male; D008423:Maternal Age; D012959:Socioeconomic Factors
keywords: Cardiff Fertility Knowledge Scale; Fertility awareness; Japan; delayed childbearing; education