One of the most serious health problems that can affect pregnant women is preeclampsia, a condition that causes high blood pressure and kidney problems, among other possible complications. Without treatment, preeclampsia can progress to a more serious, potentially fatal condition called eclampsia. Although there are treatments for some of the signs of preeclampsia, such as hypertension drugs for high blood pressure, the only cure for the condition is delivery of the child. But a new report...
One of the most serious health problems that can affect pregnant women is preeclampsia, a condition that causes high blood pressure and kidney problems, among other possible complications. Without treatment, preeclampsia can progress to a more serious, potentially fatal condition called eclampsia. Although there are treatments for some of the signs of preeclampsia, such as hypertension drugs for high blood pressure, the only cure for the condition is delivery of the child. But a new report suggests there may be a preventive treatment.
The report, by the U.S. Preventive Services Task Force (USPSTF) — an independent group of health experts supported by the federal government — was released in April 2014 and published in the journal Annals of Internal Medicine. In the report, the USPSTF makes new recommendations regarding the use of low-dose aspirin to reduce the risk of developing preeclampsia and its complications.
Preeclampsia is a complex condition that affects 2 to 8 percent of pregnant women worldwide. It usually occurs during the second half of pregnancy (after 20 weeks) and is characterized by a blood pressure reading of 140/90 or higher and kidney problems that can lead to high protein levels in the urine. Evidence of severe forms of preeclampsia includes blood pressure values exceeding 160/110, low numbers of platelets (the blood cells that help with clotting), kidney failure, liver problems, accumulation of fluid in the lungs, vision problems and neurological symptoms. Regardless of severity, preeclampsia can worsen quickly, resulting in eclampsia (convulsions) and possibly death.
Fetal complications of preeclampsia include intrauterine growth restriction (IUGR) — poor growth of the baby while in the mother’s womb — and low birth weight.
Preeclampsia and eclampsia are linked directly to about 12 percent of deaths among pregnant women and 15 percent of preterm births. The two conditions are the leading causes of medically initiated preterm births in the U.S.
Risk Levels for Preeclampsia
Evidence on low-dose aspirin
The April 2014 USPSTF recommendations update the 1996 guidelines, in which the task force found insufficient evidence for or against using aspirin to prevent preeclampsia or its complications.
The task force based its new recommendations on a review of research that included 21 randomized clinical trials. In the reviewed studies, women 12 to 28 weeks pregnant and at risk of preeclampsia were given low doses of aspirin ranging from 50 to 150 milligrams (mg).
The task force found that low-dose aspirin was associated with a 24 percent reduction in the risk of preeclampsia, a 14 percent reduction in the risk of preterm birth and a 20 percent reduction in the risk of IUGR. However, the task force could not evaluate maternal complications among pregnant women taking low-dose aspirin because these outcomes rarely occurred in the reviewed studies.
The task force acknowledged a lack of evidence on long-term outcomes in infants exposed to low-dose aspirin during pregnancy. However, it reported that a large study found no developmental harms among infants followed until 18 months of age.
Task force recommendations
The task force concluded with moderate certainty that there is a substantial net benefit of low-dose aspirin use to prevent preeclampsia among women at high risk. Therefore, it recommended low-dose aspirin for women with high risk and suggested it for women with moderate risk. (See table, page 7, for a summary of risk levels.) The USPSTF suggested an 81 mg daily dose of aspirin beginning after 12 weeks of pregnancy.
These recommendations do not apply to women with low risk for preeclampsia, those who have already developed the condition in their current pregnancy, or those who have a history of allergic reactions to or other serious side effects from aspirin.
Given the evidence from the updated USPSTF report, we recommend that pregnant women discuss the recommendations regarding aspirin use to prevent preeclampsia with their obstetricians. The treatment decision should be based on the woman’s risk level for preeclampsia, risk for bleeding and personal preferences.
Patients taking aspirin should be alert for the following side effects of aspirin, which generally occur infrequently: nausea, abdominal pain or discomfort, inflammation of the stomach, ulcers of the stomach or small intestine, and bleeding. If these side effects develop, patients should contact their health care providers and discuss whether use of the drug should be continued.
 Henderson JT, Whitlock EP, O’Connor E, et al. Low-Dose Aspirin for the Prevention of Morbidity and Mortality From Preeclampsia: A Systematic Evidence Review for the U.S. Preventive Services Task Force. Rockville, MD: Agency for Healthcare Research and Quality; 2014. Evidence Synthesis No. 112. AHRQ Publication No. 14-05207-EF-1.
 LeFevre ML. Low-dose aspirin use for the prevention of morbidity and mortality from preeclampsia: U.S. Preventive Services Task Force recommendation statement. Annals of Internal Medicine. 2014;161(11):819-826.
 U.S. Preventive Services Task Force. Aspirin prophylaxis in pregnancy. In: Guide to Clinical Preventive Services. 2nd ed. Washington, DC: U.S. Department of Health and Human Services; 1996.