Validation of the gestational week division border for subclassification of pregnancy induced hypertension

Abstract

Aim: Classification of pregnancy induced hypertension (PIH) according to the Japan Society of Obstetrics andGynecology 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.

Nocturnal oxygen desaturation in the late third trimester of uncomplicated pregnancy for prediction of late‐onset gestational hypertension

“…In both patients A and B, GH was diagnosed at 37 weeks of gestation, when they developed hypertension without proteinuria and other symptoms concerning maternal organ damage or uteroplacental insufficiency. 17 Patient A had a blood pressure of 122/77 mmHg at the time of recruitment (36 weeks of gestation), but this increased to 148/89 mmHg at 37 weeks of gestation. Because her blood pressure continued to rise, labor was induced at 39 weeks of gestation.…”

“…16 However, recent metaanalyses have established OSA as a risk factor for the development of preeclampsia or GH. 13,14 Blood pressure often becomes elevated after 37 weeks of gestation in women with late-onset GH, 17 and overlooked OSA may be closely associated with the pathogenesis of hypertension. If such late-onset GH can be predicted in advance using pulse oximetry, which is a simple tool for screening nocturnal oxygen desaturation caused by OSA, 18 then reasonable preventive interventions could help bring about safe deliveries.…”

Evaluation of the relationship between gestational week and the incidence of preeclampsia

“…Based on the time of onset, The International Society for the Study of Hypertension in Pregnancy (ISSHP) has defined EO-PE and LO-PE as PE occurring before and after 34 weeks gestation, respectively. However, in Japan, the EO and LO types of PE are defined as an onset time before and after 32 weeks of gestation, respectively [1]. The ISSHP classification is based on expert consensus, whereas the Japanese classification is based on previous reports of dual peaks of PE onset in Japan.…”