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Published on: October 23, 2020
Comparison of risk factors for major obstetric complications between Western countries and Japan: a case-cohort study
Arihiro Shiozaki1, Yoshio Matsuda, Kunihiko Hayashi
1Department of Obstetrics and Gynecology, University of Toyama, Sugitani, Toyama. s33shio@med.u-toyama.ac.jp
Aim:
The aim of this study was to demonstrate the differences in risk factors for obstetrical complications between Japan and Western countries.
Material And Methods:
Using the Perinatal Database of the Japan Society for Obstetrics and Gynecology, we studied singleton deliveries after 22 weeks of gestation (n = 242 715) at 125 centers of the perinatal network in Japan from 2001 through 2005 as a base cohort. In total, 3749 births (1.5% of the base cohort) were randomly selected as a subcohort. We compared the rate of risk factors in the cases with ten obstetrical complications with that in the subcohort (case-cohort study).
Results:
Almost all of the evaluated risk factors were common between Western countries and Japan. Older age at pregnancy was a common risk factor for pregnancy-induced hypertension, placental abruption, placenta previa, and placenta accreta/increta/percreta. On the other hand, younger age at pregnancy was a common risk factor for eclampsia and preterm delivery. Smoking during pregnancy was a common risk factor for pregnancy-induced hypertension, preterm premature rupture of the membranes, preterm delivery, cervical insufficiency, chorioamnionitis, and placental abruption. In vitro fertilization and embryo transfer was a common risk factor for cervical insufficiency, placenta previa, and placenta accreta/increta/percreta.
Conclusion:
This case-cohort study in Japan clarified the common risk factors between Western countries and Japan as well as the risk factors indigenous to Japanese women. To identify the risk factors for a disease in a specific country, we should use data derived from its population.
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