Journal of Epidemiology
Online ISSN : 1349-9092
Print ISSN : 0917-5040
Original Article
Prevalence and Risk of Birth Defects Observed in a Prospective Cohort Study: The Hokkaido Study on Environment and Children’s Health
Tomoyuki HanaokaNaomi TamuraKumiko ItoSeiko SasakiAtsuko ArakiTamiko IkenoChihiro MiyashitaSachiko ItoHisanori MinakamiKazutoshi ChoToshiaki EndoTsuyoshi BabaToshinobu MiyamotoKazuo SengokuReiko Kishiother members of the Hokkaido Study on Environment and Children’s Health
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ジャーナル オープンアクセス

2018 年 28 巻 3 号 p. 125-132

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Background: Prevalence rates of all anomalies classified as birth defects, including those identified before the 22nd gestational week, are limited in published reports, including those from the International Clearinghouse for Birth Defects Surveillance and Research (ICBDSR). In our birth cohort study, we collected the data for all birth defects after 12 weeks of gestation.

Methods: Subjects in this study comprised 19,244 pregnant women who visited one of 37 associated hospitals in the Hokkaido Prefecture from 2003 through 2012, and completed follow-up. All birth defects after 12 weeks of gestation, including 55 marker anomalies associated with environmental chemical exposures, were recorded. We examined parental risk factors for birth defects and the association between birth defects and risk of growth retardation.

Results: Prevalence of all birth defects was 18.9/1,000 births. The proportion of patients with birth defects delivered between 12 and 21 weeks of gestation was approximately one-tenth of all patients with birth defects. Among those with congenital malformation of the nerve system, 39% were delivered before 22 weeks of gestation. All patients with anencephaly and encephalocele were delivered before 22 weeks of gestation. We observed different patterns of parental risk factors between birth defect cases included in ISBDSR and cases not included. Cases included in ISBDSR were associated with an increased risk of preterm birth. Cases not included in ISBDSR were associated with an increased risk of being small for gestational age at term.

Conclusions: Data from our study complemented the data from ICBDSR. We recommend that birth defects not included in ICBDSR also be analyzed to elucidate the etiology of birth defects.

著者関連情報
© 2017 Tomoyuki Hanaoka et al. This is an open access article distributed under the terms of Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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