Risk factors for eclampsia in Japan between 2005 and 2009.

Objective: To determine risk factors for eclampsia among Japanese women with singleton pregnancies.

Methods: A retrospective observational study was carried out among patients with and those without eclampsia who were registered on the Japan Society of Obstetrics and Gynecology registry system and who gave birth to singleton infants at 22 weeks or more between 2005 and 2009. Multivariate logistic regression analyses were performed to determine independent risk factors for eclampsia.

Results: One-third (75/225) of eclampsia patients developed the condition in the absence of hypertension. Maternal age, nulliparity, and pregnancy-induced hypertension (PIH) were all independent risk factors for eclampsia. The risk of eclampsia decreased by 3.0% per 1-year increase in maternal age, and increased 2.6-fold and 35.4-fold in nulliparous women and women with PIH, respectively. Among teenaged girls with hypertension, the prevalence of eclampsia was 1 case per 28 teenagers.

Conclusion: Hypertension alone was not a reliable predictor of eclampsia. More intensified monitoring of nulliparous women and teenaged girls with hypertension is needed in order to prevent eclampsia.