Preeclampsia: A Pregnancy Complication that Puts Mothers at Risk of a Later Stroke

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Last month, we introduced a new series in which we’ll focus on medical problems during pregnancy that increase the risk of problems for the mother later in life. Within this theme, today, we’ll discuss the pregnancy complication preeclampsia, which appears to increase a mother’s risk of suffering a stroke later in life, yet earlier than old age, which is when it usually occurs. In the introduction, we noted that, of mothers who die on account pregnancy complications, only approximately 31 percent die actually during pregnancy. A substantial fraction of deaths, illness, and disability occur much later, including many years later. While strokes are notorious for striking mostly older individuals, women who suffered preeclampsia carry an elevated risk of suffering a stroke as early as in their forties and fifties.

Preeclampsia is a condition characterized by elevated blood pressure developing in a pregnant woman beyond the 20th gestational week, the halfway point of pregnancy. Along with high blood pressure, preeclampsia includes dysfunction of an organ, usually the kidneys, so the urine must be tested, plus there are various blood tests. Preeclampsia endangers both the mother and the fetus and the only cure is to deliver the fetus as soon as possible. Factors that put you at risk of developing preeclampsia include having a previous case of preeclampsia, having a relative who suffered preeclampsia, carrying a male fetus if you are not Asian, carrying a fetus with a genetic mutation called sFlt-1, having type 2 diabetes, being obese, being in your first pregnancy, and certain health problems. Fathers may also contribute to the preeclampsia risk and there is some evidence of connections between living at high altitude and preeclampsia that we will explore in a future post

Connections between preeclampsia and stroke may relate to abnormalities of the inner lining of blood vessels, which is present in both conditions. Both conditions also share risk factors, including high blood pressure.

A stroke is a sudden loss of function in the central nervous system, due to a problem with a blood vessel. Strokes are classified either as hemorrhagic (a blood vessel has ruptured), or ischemic, meaning that there is a shortage of blood supply to the tissues, due to blood vessel obstruction. A stroke can produce temporary or permanent disability and even can be fatal. Disabilities that often occur in strokes include problems with speech or understanding of speech, paralysis of particular parts of the body, such as the face, arms, or legs. Typically, one side of the body or face is affected.

In cases of stroke, blood flow must be restored to the affected area of the brain and new strokes must be prevented. Quick recognition of the stroke is extremely important and is a major factor in determining the treatment. For ischemic strokes, the gold standard treatment consists of drugs of a category called fibrinolytic (or thrombolytic) agents, which are given to break up clots that are causing the ischemia, the interruption of blood flow. In particular, a blood clot busting agent called tissue plasminogen activator (tPA) is given, but it is effective only if the patient receives it within approximately 4.5 hours of the onset of the stroke. The drug can be given intravenously, or endovascularly, meaning through an instrument in what doctors call catheter that is inserted into a vein. While clot busting medications such as tPA are effective if given within 4.5 hours of the onset of ischemic stroke symptoms, researchers are investigating whether and how endovascular delivery of the drugs can improve the effectiveness. A procedure known as mechanical thrombectomy, in which endovascular techniques are used to remove the clot from the blood vessel, can be effective up to 24 hours after the stroke symptoms have begun. For long term treatment following ischemic stroke, patients take medications that make it harder for blood to form clots. Often this includes aspirin (which interferes with clotting cells called platelets) and medicines that interfere with the blood’s clot forming system.

In cases of hemorrhagic stroke, the treatment is very different. Surgery is sometimes needed to relieve pressure building on the brain as a result of bleeding, and sometimes also for blood vessel repair.

Some stroke centers have the capability to cool down your body, and especially your brain, ever more rapidly. Known as therapeutic hypothermia, this procedure is showing effectiveness in improving stroke recovery, but generally it is performed only by specialized groups of doctors who are researching it (this is likely to change in the years to come). As with the other treatments, hypothermia must be initiated very early.

David Warmflash
Dr. David Warmflash is a science communicator and physician with a research background in astrobiology and space medicine. He has completed research fellowships at NASA Johnson Space Center, the University of Pennsylvania, and Brandeis University. Since 2002, he has been collaborating with The Planetary Society on experiments helping us to understand the effects of deep space radiation on life forms, and since 2011 has worked nearly full time in medical writing and science journalism. His focus area includes the emergence of new biotechnologies and their impact on biomedicine, public health, and society.

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