抄録
Aim: Classification of pregnancy induced hypertension (PIH) according to the Japan Society of Obstetrics and Gynecology defines early onset PIH as that which develops before 32 weeks of gestation, and late onset PIH as that which occurs thereafter. The present study aimed to validate this cut-off point.Methods: Clinical characteristics of the patients from 59 domestic tertiary settings of perinatal medicine were analyzed. Women with multiple pregnancies and/or any medical complications were excluded. Subgroups of mild and severe PIH were created according to the severity of hypertension.Results: Numbers of patients with preeclampsia (PE) and gestational hypertension (GH) were 619 and 194, respectively. Severe cases accounted for 379 (333 for PE and 46 for GH) and mild cases accounted for 434 (286 for PE and 148 for GH). The difference in patterns of distribution of onset time between severe and mild cases of PIH was more remarkable than those between PE and GH. Discriminate analysis showed 32.3 weeks of gestation to be the optimal cut-off point at which severe forms of PIH were distinguishable from mild forms. Receiver operating characteristic (ROC) curve analysis of assumptive diagnostic efficacy for predicting severe hypertension with time of disease onset was most predictive at 32 weeks of gestation.Statistical analyses revealed that the cases presenting before 32 weeks were not significantly different from the severely hypertensive cases in terms of maternal and offspring outcomes. Comparison of PIH cases occurring after 32 weeks with cases of mild hypertension were also very similar.Conclusions: It is considered appropriate to regard 32 weeks of gestation as an optimal cut-off point for subclassification of early and late onset types of PIH.
