Hypertensive diseases of pregnancy accounts for 15% of maternal deaths.

Hypertensive disorders complicate 5-7 % of all pregnancies.

The complex aetiology (Cause) of hypertension in pregnancy has led to confusion in both its definition and management.

Approximately 70% of women diagnosed with hypertension during pregnancy have gestational hypertension and pre-eclampsia.

Chronic (Pre- existing) hypertension complicates 1 to 3% of all pregnancies. Hypertensive disorders in pregnancy have a wide range of presentation ranging from mild elevation of blood pressure to severe organ failure.

Definition

Hypertension is defined as changes of blood pressure recorded on at least two occasions at least six hours apart, either:

i) Diastolic blood pressure greater than 90mm Hg or

ii) Systolic blood pressure greater than 140mm Hg or

iii)A rise in diastolic pressure of at least 15mm Hg or

iv)A rise in systolic blood pressure of at least 30mm Hg

Classification of Hypertensive Disorders in Pregnancy

a) Gestational hypertension (Previously known as pregnancy induced hypertension).

b) Pre eclampsia

c) Chronic hypertension

d) Chronic hypertension with superimposed pre-eclampsia.

Gestational Hypertension

Hypertension which develops as a direct result of the gravid state  is referred to as gestational hypertension (previously known as pregnancy induced hypertension).

Gestational hypertension is defined as systolic blood pressure of at least 140mm Hg and a diastolic B.P of at least 90mm Hg on at least two occasions at least 6 hours apart after the 20 th week of gestation in women known to be normotensive before pregnancy and before 20 weeks of gestation.The B. P recordings should not be greater than 7 days apart.

Sever gestational hypertension is defined as sustained elevation is systolic B.P. of at least 160mm Hg and/or in diastolic B.P to at least 110mm Hg for at least 6 hours. Approximately 25% of women with gestational hypertension will develop proteinuria (Means proteins in the urine, a feature of pre- eclampsia).

Features of Gestational Hypertension

i) Confined to pregnancy

ii) Blood pressure becomes normal usually 24 to 48 hours after delivery or following death in utero.

iii)Occurs usually after the 20th week of pregnancy .

iv)More common in primigravida (Mothers who are pregnant for the first time).

v) Common in situations where there is an increase in placental mass eg. Multiple pregnancies  and  trophoblastic disease. There is also a higher incidence of hydrops fetalis due to Rh incompatibility or non-immune hydrops fetalis.

vi) Associated with diseases affecting the vascular system eg Diabetes Mellitus.

vii) Non- dependent oedema and proteinuria are accompaning features.

Pre- Eclampsia

Pre -Eclampsia is a triad of oedema, hypertension and proteinuria (Presence of proteins in the urine) , which usually occurs in a nulliparous female after the 20th week of gestation, other common signs and symptoms in pre- eclampsia include oedema, visual disturbances, headache and epigastric pain.

Lab tests may show increased liver enzymes, haemolysis and low platelet counts.

The proteinuria in pre-eclampsia is defined as the presense of 0.3 gram (300mg) or more of protein in a 24 hour urine collection.

Eclampsia

Eclampsia is defined as the presense of new onset grand mal seizures( also known as fit,ie like epilepsy) in a woman with pre-eclampsia.

Gestational hypertension ,pre- eclampsia and eclampsia will be dealt with in more detailed in subsequent posts dedicated to each. I do not want to overwhealm our readers who are mostly non-medical people.

As usual if you have any questions/comments you may either post it below or discuss it in my forums.

References

Obstetrics by Ten Teachers, edited by Stuart Campbell and Christoph Lees, 17th Edition.

Medical Disorders in Pregnancy-an update edited by Hiralal Konar and Pralhad Kushtagi 1st edition- Federation of Obstetric and Gynaecological Societies of India.

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