A Small Daily Dose of Aspirin Can Help Prevent Preeclampsia

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Preeclampsia is a serious complication of pregnancy. If it is left untreated, it can lead to serious problems for both you and your baby. But an inexpensive drug can help reduce the risk of developing preeclampsia for woman at high risk. A public health organization just reaffirmed its recommendation that an inexpensive treatment can reduce the risk of preeclampsia for women with high blood pressure.

Healthcare professionals should instruct pregnant woman who are at high risk for developing preeclampsia should take one low-dose tablet of aspirin every day starting after their third month of pregnancy. The U.S. Preventive Services Task Force originally made this recommendation several years ago but after analyzing more studies it reaffirmed its recommendation.

Women at high risk include those who had high blood pressure before their pregnancy, who had preeclampsia in a previous pregnancy or have a family history of preeclampsia, who are obese, or who are having a multiple birth. Black women are at greater risk for developing preeclampsia than are white women. Other factors that increase the risk of developing preeclampsia are being diabetic or having kidney disease.

Preeclampsia affects between 2% and 8% of all pregnancies. It is one of the leading causes of premature birth.

The Task Force evaluated 23 randomized controlled trials that involved more than 26,000 pregnant women who were at higher risk of developing preeclampsia. In these studies, the women were given either a low dose of aspirin or a placebo. By bringing together the data from all 23 studies, the Task Force found that the women who took a daily low-dose aspirin had about a 15% lower risk of developing preeclampsia. There were also less likely to have a premature baby or a small baby and there was a reduced risk of stillbirth.

The studies that were evaluated used doses of aspirin that ranged from 50 to 150 milligrams. However, the Task Force’s recommended dose for reducing the risk of preeclampsia is 81 milligrams because it is a dose that is readily available on drugstore shelves. This size tablet used to be called “baby aspirin,” but now it is usually taken by people to help prevent heart attacks and stroke. The usual size for aspirin tablets for headaches or other pain is 325 milligrams per pill, or 650 milligrams in the usual dose of two pills.

In renewing its recommendation, the Task Force note that the Food and Drug Administration issues a warning that the use of nonsteroidal anti-inflammatory drugs (NSAIDs), which includes aspirin, may cause a serious kidney problem in unborn infants. However, the FDA made an exception to this warning for low-dose aspirin for pregnant women at risk of preeclampsia, when used under the direction of a healthcare professional.

For this reason, do not start to take aspirin on your own during your pregnancy unless your doctor or midwife advise you to do so.

The U.S. Preventive Services Task Force is an independent panel of health experts who specialize in disease prevention and evidence-based medicine. Its purpose is to make recommendations for treatments or interventions that help prevent health problems based on evidence from clinical trials and other sources of research. These treatments or interventions can include health screenings, counseling services, or the use of medications that prevent a health problem. Although the task force is independent, it is funded by the Department of Health and Human Services through the Agency for Healthcare Research and quality.

The Task Force’s recommendation of low-dose aspirin to prevent preeclampsia in 2014 led to a similar recommendation by the American College of Obstetricians and Gynecologists. Obstetricians have been prescribing low-dose aspirin for women at risk for preeclampsia for several years.

No one knows exactly what causes preeclampsia. It appears to start during pregnancy when the placenta does not form as well as it should. The placenta needs to create new blood vessels as it grows that connect with the inside lining of the uterus. With preeclampsia, the blood vessels that form are smaller than they should be and don’t respond as well to changing hormone levels during the pregnancy.

Symptoms of preeclampsia include bad headaches, changes in vision, nausea or vomiting, and decreased urine output. Untreated preeclampsia can cause seizures. One reason you give regular urine samples during your prenatal visits with your doctor or midwife is to test for high levels of protein in the urine, which is another symptom of preeclampsia.

Treating preeclampsia can involve delivering the baby early, but this can’t be done too early. Your healthcare provider may treat you with drugs for high blood pressure or with corticosteroids, as well as drugs to prevent seizures.

Valerie DeBenedette
Valerie DeBenedette is an experienced health and medical writer who lives about an hour north of New York City with a dog that is smaller than her cat. Her work has appeared in magazines, newspapers, newsletters, and on websites. She is a member of the National Association of Science Writers.

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