Hypertension in Pregnancy & Preeclampsia
Hypertension (high blood pressure) complicates up to 10% of pregnancies worldwide.
Hypertensive disorders affecting pregnancies include several conditions:
- Chronic hypertension
- Gestational hypertension
- Preeclampsia superimposed on chronic hypertension
Chronic hypertension refers to a high blood pressure, which is either preceding the pregnancy or is detected within the first 20 weeks of gestation.
Gestational hypertension is defined as a new onset of hypertension after 20 weeks of gestation.
Preeclampsia or toxaemia of pregnancy is a pregnancy specific disorder defined as new onset of high blood pressure (hypertension) and protein leek in the urine after 20 weeks of gestation.
Preeclampsia complicates 3-8% of all pregnancies worldwide and is a major cause of mother and infant death and disease while the economic cost to society is substantial.
The cause(s) of this disorder remain elusive, but there is increasing evidence of widespread abnormalities in the small blood vessels called capillaries in this syndrome.
Furthermore women with a history of preeclampsia are at increased risk of hypertension, stroke, and death from heart disease in later life.
The mechanism(s) by which these disorders are associated with preeclampsia are not fully understood, but microcirculatory abnormalities including reduction in capillary density (i.e. capillary rarefaction) have been implicated in the pathogenesis.