Hypertension in Pregnancy

Original Editor - Manisha Shrestha Top Contributors - Manisha Shrestha, Kirenga Bamurange Liliane, Nupur Smit Shah, Kim Jackson and Lucinda hampton

Original Editor - User Name

Top Contributors - Manisha Shrestha, Kirenga Bamurange Liliane, Nupur Smit Shah, Kim Jackson and Lucinda hampton  

Introduction

Hypertensive disorders of pregnancy is a leading cause of maternal and neonatal morbidity and mortality. Hypertension in pregnancy should be defined as a hospital systolic blood pressure (SBP) ⩾ 140 mmHg and/or dystolic blood pressure (DBP) ⩾ 90 mmHg, based on the average of at least two measurements, taken at least 15 min apart, using the same arm.

Classification

A. Pre-existing (chronic) hypertension	This is defined as hypertension that was present either pre-pregnancy or that develops at <20 weeks of gestation
• With comorbid condition(s)	Comorbid conditions (e.g., pre-gestational type I or II diabetes mellitus or kidney disease) warrant tighter BP control outside of pregnancy because of their association with heightened cardiovascular risk
• With evidence of preeclampsia	This is also known as ‘superimposed preeclampsia’ and is defined by the development of one or more of the following at ⩾ 20 weeks: Resistant hypertension, or New or worsening proteinuria, or One/more adverse condition(s) or One/more severe complication(s) Severe preeclampsia is defined as preeclampsia with one or more severe complication(s)
B. Gestational hypertension	This is defined as hypertension that develops for the first time at ⩾ 20 weeks of gestation.
• With comorbid condition(s)	Comorbid conditions (e.g., pregestational type I or II diabetes mellitus or kidney disease) warrant tighter BP control outside of pregnancy because of their association with heightened cardiovascular risk
• With evidence of preeclampsia	Evidence of preeclampsia may appear many weeks after the onset of gestational hypertension.
C. Preeclampsia	Preeclampsia is defined by gestational hypertension and one or more of the following: New proteinuria, or One/more adverse conditions, or One/more severe complication(s)
	Severe preeclampsia is defined as preeclampsia with one or more severe complication(s)
’Other hypertensive effects’∗
Transient hypertensive effect	Elevated BP may be due to environmental stimuli or the pain of labour, for example
White coat hypertensive effect	BP that is elevated in the office (sBP ⩾ 140 mmHg or dBP ⩾ 90 mmHg) but is consistently normal outside of the office (<135/85 mmHg) by ABPM or HBPM
Masked hypertensive effect	BP that is consistently normal in the office (sBP < 140 mmHg or dBP < 90 mmHg) but is elevated outside of the office (⩾135/85 mmHg) by ABPM or repeated HBPM

ABPM, ambulatory BP monitoring; BP, blood pressure; HBPM, home BP monitoring.

Adverse conditions and severe complications of preeclampsia.

Organ system affected	Adverse conditions (that increase the risk of severe complications)	Severe complications (that warrant delivery)
CNS	Headache/visual symptoms	Eclampsia PRES Cortical blindness or retinal detachment Glasgow coma scale < 13 Stroke, TIA, or RIND
Cardiorespiratory	Chest pain/dyspnoea Oxygen saturation < 97%	Uncontrolled severe hypertension (over a period of 12hr despite use of three antihypertensive agents), Oxygen saturation < 90%, need for ⩾ 50% oxygen for > 1hr, intubation (other than for Caesarean section), pulmonary oedema Positive inotropic support Myocardial ischaemia or infarction
Haematological	Elevated WBC count ○ Elevated INR or aPTT [80] ○ Low platelet count	Platelet count < 50x109/L ○ Transfusion of any blood product
Renal	Elevated serum creatinine [81] ○ Elevated serum uric acid	Acute kidney injury (creatinine > 150 μM with no prior renal disease) ○ New indication for dialysis
Hepatic	Nausea or vomiting ○ RUQ or epigastric pain ○ Elevated serum AST, ALT, LDH, or bilirubin ○ Low plasma albumin	Hepatic dysfunction (INR > 2 in absence of DIC or warfarin) ○ Hepatic haematoma or rupture
Feto-placental	Non-reassuring FHR ○ IUGR [83], [84] ○ Oligohydramnios ○ Absent or reversed end-diastolic flow by Doppler velocimetry	Non-reassuring FHR ○ IUGR [83], [84] ○ Oligohydramnios ○ Absent or reversed end-diastolic flow by Doppler velocimetry

ST, aspartate aminotransferase; ALT, alanine aminotransferase; DIC, disseminated intravascular coagulation; FHR, fetal heart rate; LDH, lactate dehydrogenase; PRES, posterior reversible leukoencephalopathy syndrome; RIND, reversible neurological deficit < 48hr; RUQ, right upper quadrant; TIA, transient ischaemic attack.

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