Cardiac disease in pregnancy and hypertension


 * ; Stacie Zelman, M.D. [mailto:szelman@wfumbc.edu]

Overview
Hypertension in pregnancy can be broadly classified as chronic hypertension, pregnancy-induced hypertension (or gestational hypertension), and pre-eclampsia/eclampsia. All of these conditions are the source of significant maternal morbidity and mortality.

Chronic Hypertension in Pregnancy
This condition is defined as hypertension (blood pressure ≥140 mm Hg systolic or ≥90 mm Hg diastolic) present before pregnancy or that is diagnosed before the 20th week of gestation. In general, antihypertensive medications are effective in treating this condition, in contrast to pre-eclampsia.

Safe anti-hypertensive drugs that can be used during pregnancy include;
 * Calcium channel blockers
 * Diuretics
 * Beta-blockers
 * Hydralazine
 * Methyldopa

For a more broad discussion of chronic hypertension, click here.

Pregnancy Induced Hypertension
Pregnancy-induced hypertension (PIH) (or gestational hypertension) is defined as the development of new arterial hypertension in a pregnant woman after 20 weeks gestation. There is no specific treatment, but is monitored closely to rapidly identify pre-eclampsia and its life-threatening complications (HELLP syndrome and eclampsia). Treatment options are limited, as many antihypertensives may negatively affect the fetus; methyldopa and labetalol are most commonly used for severe pregnancy hypertension.

For a more broad discussion of pregnancy induced hypertension, click here.

Pre-eclampsia
Pre-eclampsia (US: preeclampsia) is a medical condition where hypertension arises in pregnancy (pregnancy-induced hypertension) in association with significant protein in the urine. Its cause remains unclear, although the principal cause appears to be a substance or substances from the placenta causing endothelial dysfunction in the maternal blood vessels. While blood pressure elevation is the most visible sign of the disease, it involves generalized damage to the maternal endothelium and kidneys and liver, with the release of vasopressive factors only secondary to the original damage.

Pre-eclampsia may develop at varying times within pregnancy and its progress differs among patients; most cases are diagnosed pre-term. It has no known cure apart from ending the pregnancy (induction of labor or abortion). It may also occur up to six weeks post-partum. Of dangerous pregnancy complications, it is the most common; it may affect both the mother and the fetus.

For a more detailed discussion of pre-eclampsia, click here.

Eclampsia
Eclampsia, an acute and life-threatening  complication of pregnancy,  is  characterized by the appearance of tonic-clonic seizures in a patient who had developed  preeclampsia;  rarely  does eclampsia  occur without  preceding  preeclamptic symptoms. Hypertensive disorder of pregnancy and toxemia of pregnancy are terms used to encompass both preeclampsia and eclampsia. Seizures and coma that happen during pregnancy but are due to preexisting or organic brain disorders are not eclampsia.

The term is derived from the Greek and refers to a flash, a term used by Hippocrates to designate a fever of sudden onset.

Typically patients show signs of pregnancy-induced hypertension and proteinuria prior to the onset of the hallmark of eclampsia, the  eclamptic convulsion. Other cerebral signs may precede the convulsion such as nausea, vomiting, headaches, and cortical blindness. In addition, with the advancement of the pathophysiological process, other organ symptoms may be present including abdominal pain, liver failure, signs of the HELLP syndrome, pulmonary edema, and oliguria. The fetus may have been already compromised by intrauterine growth retardation, and with the toxemic changes during eclampsia may suffer fetal distress. Placental bleeding and placental abruption may occur.

The treatment of eclampsia requires prompt intervention and aims to prevent further convulsions, control the elevated blood pressure and deliver the fetus.

For a more detailed discussion of eclampsia, click here.