Hypertension Research
In Pregnancy
3
SOCIETY STATEMENT
Outline of Definition and
Classification of “Pregnancy induced
Hypertension (PIH)”
K. Watanabe et al.
Key words:
definition, pregnancy induced
hypertension, preeclampsia
Kazushi Watanabe1, Katsuhiko Naruse2, Kanji Tanaka3,
Hirohito Metoki4, Yoshikatsu Suzuki5
1
Department of Obstetrics and Gynecology, Aichi Medical University School of Medicine,
2
Department of Obstetrics and Gynecology, Nara Medical University, 3Department of
Obstetrics and Gynecology, Hirosaki University, 4Department of Obstetrics and
Gynecology and Tohoku Medical Megabank Organization, Tohoku University, 5Department
of Obstetrics and Gynecology, Nagoya City West Medical Center
In this report, we present the terminology, definition and classification of pregnancy induced hypertension (PIH) by the
Japan Society for the Study of Hypertension in Pregnancy (JSSHP). PIH is classified as gestational hypertension (GH),
preeclampsia (PE), superimposed preeclampsia (S-PE) or eclampsia (E). Subclassifications by symptoms (severity and
gestational age at onset) are also shown.
Terminology
but both symptoms normalize by 12 weeks postpartum.
In 2004, “Toxemia of Pregnancy” was revised to
“Pregnancy induced Hypertension (PIH)” in Japan.1,2)
Superimposed preeclampsia (S-PE)
Definition
PIH is defined as hypertension (blood pressure ≥ 140/90
mmHg) with or without proteinuria ( ≥ 300 mg/24 hours)
emerging after 20 weeks gestation, but resolving up to 12
weeks postpartum.1–10) PIH is also defined as new onset
proteinuria ( ≥ 300 mg/24 hours) in hypertensive women
who exhibit no proteinuria before 20 weeks gestation.
Classification
Gestational hypertension (GH)
GH is diagnosed in women whose blood pressure reaches
≥ 140/90 mmHg for the first time during pregnancy
(after 20 weeks gestation), but without proteinuria. Blood
pressure normalizes by 12 weeks postpartum.
Preeclampsia (PE)
Hypertension (blood pressure ≥ 140 / 90 mmHg)
accompanied with proteinuria exceeding 300 mg/24
hours emerges for the first time after 20 weeks gestation,
Superimposed preeclampsia is diagnosed in the following
three cases. (1) New onset proteinuria ( ≥ 300 mg/24
hours) in hypertensive women who exhibit no proteinuria
before 20 weeks gestation. (2) Hypertension and
proteinuria documented antecedent to pregnancy and/or
detected before 20 weeks gestation, one or both of which
progressing after 20 weeks gestation. (3) Renal disease
with proteinuria documented antecedent to pregnancy
and/or detected before 20 weeks gestation, which is
accompanied with new onset hypertension after 20 weeks
gestation.
Eclampsia (E)
Eclampsia is defined as the onset of convulsions in a
woman with PIH that cannot be attributed to other causes.
The seizures are generalized and may appear before,
during, or after labor.
Subclassification by symptoms
*Severity*
The severity of PIH is assessed by the extent of
symptoms. Both blood pressure and proteinuria are
dependable indicators of severity.
© 2013 The Authors
Hypertension Research in Pregnancy © 2013 Japan Society for the Study of Hypertension in Pregnancy
Hypertens Res Pregnancy 2013; 1: 3–4
3
Definition of PIH in JSSHP
Mild PIH
Blood pressure is ≥ 140/90 mmHg but < 160/110
mmHg after 20 weeks gestation, and proteinuria is ≥ 300
mg/24 hours without exceeding 2.0 g/24 hours or 3 +
dipstick.3,4,10,11)
Severe PIH
Blood pressure is ≥ 160/110 mmHg, and proteinuria
exceeds 2.0 g/24 hours or 3 + dipstick.11,12)
*Classification by onset*
PIH that emerges earlier than 32 weeks gestation is
referred to as early onset (EO) type, and PIH that emerges
after 32 weeks gestation is referred to as late onset (LO)
type.13–15)
Appendix
• Pulmonary edema, stroke, and HELLP syndrome are
considered severe variants, and are excluded from the
definition or classification of PIH.
• Gestational proteinuria and edema are excluded from
PIH symptoms.
References
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