New USPSTF, AAFP Guidance

Daily Low-dose Aspirin Recommended for Pregnant Women at High Risk for Pre-eclampsia

September 10, 2014 07:53 pm Chris Crawford

Pre-eclampsia is one of the leading causes of health complications for pregnant women and their infants, affecting almost 4 percent of all deliveries (about 160,000 each year) in the United States, according to a U.S. Preventive Services Task Force (USPSTF) news release(www.uspreventiveservicestaskforce.org). This complex condition is diagnosed in the presence of a rise in blood pressure and excess protein in the urine after 20 weeks of pregnancy.

[Pregnant woman sitting on a bench in park setting]

To help family physicians and other health care professionals who care for pregnant women better treat this condition, the USPSTF published a recommendation(www.uspreventiveservicestaskforce.org) on Sept. 9 that women at high risk for pre-eclampsia should use low-dose aspirin (81 mg/day) after 12 weeks of pregnancy to prevent the condition and its related health problems. The AAFP issued a parallel recommendation the same day. This is a B recommendation(www.uspreventiveservicestaskforce.org) and applies only to pregnant women who do not show signs or symptoms of pre-eclampsia but who are at high risk for the condition and can safely take aspirin.

"Pre-eclampsia is a condition that puts both mother and infant at risk for serious complications, including death," said Jennifer Frost, M.D., medical director for the AAFP Health of the Public and Science Division. "The evidence shows that low-dose aspirin use in high-risk women reduces the risk of pre-eclampsia by 24 percent, premature birth by 14 percent and intrauterine growth restriction by 20 percent."

Frost added that the condition occurs more often in certain populations, including blacks, and overall rates among women continue to increase as the incidences of chronic hypertension and diabetes increase.

Story highlights
  • The U.S. Preventive Services Task Force (USPSTF) has recommended that women at high risk for pre-eclampsia use low-dose aspirin (81 mg/day) after 12 weeks of pregnancy.
  • This recommendation updates a 1996 USPSTF recommendation that concluded evidence was insufficient to recommend for or against aspirin use for the prevention of pre-eclampsia.
  • The USPSTF provided a table of risk factors to help physicians determine which patients should receive aspirin.

Recommendation Overview

This recommendation updates a 1996 USPSTF recommendation that concluded evidence was insufficient to recommend for or against aspirin use for the prevention of pre-eclampsia. Evidence produced since then on the effectiveness and harms of low-dose aspirin on maternal and perinatal health outcomes led to the current USPSTF recommendation.

Previously, other organizations, including the American Congress of Obstetricians and Gynecologists, had recommended low-dose aspirin for women at high risk for pre-eclampsia, Frost said. "This recommendation from the USPSTF reinforces these other recommendations, backing them up with a rigorous review of the evidence," she said. "The recommendation from the USPSTF also broadens the definition of 'high-risk,' therefore, recommending low-dose aspirin for more women."

The USPSTF, in fact, provided a table of risk factors(www.uspreventiveservicestaskforce.org) to help physicians determine which patients should receive aspirin. The highest-risk women are those with a history of pre-eclampsia in a previous pregnancy. Women with chronic hypertension, type 1 or type 2 diabetes, kidney disease or autoimmune disease (e.g., lupus) also are at higher risk. The final high-risk category is women with multifetal pregnancies.

"Aspirin should be considered in women with any of these risk factors," Frost said. "There also is a list of moderate risk factors, and physicians may consider aspirin if a woman has several of these risk factors, as well."

According to the USPSTF evidence report(www.uspreventiveservicestaskforce.org), investigators reassessed the studies from the 1996 review for this recommendation and additionally reviewed studies published between January 2006 and June 2013. The group also examined an individual-patient data meta-analysis published by the Perinatal Antiplatelet Review of International Studies Collaboration and a 2007 Cochrane review.

Fifteen randomized, controlled trials (RCTs) met inclusion criteria for evaluation of maternal and perinatal health benefits from aspirin chemoprevention and 13 RCTs reported preeclampsia incidence with and without low-dose aspirin among women at high risk. In all, 23 studies met inclusion criteria.

Overall, women in the trials were young (mean age from 20.3 to 31) and predominantly white, although three trials reported majorities of black women in their samples. None of the trials initiated treatment before 12 weeks' gestation; eight trials initiated treatment before 16 weeks. Daily aspirin doses ranged from 60 mg to 150 mg, with one trial reporting a dose of 0.5 mg/kg of body weight. Most trials used doses of 60 mg or 100 mg.

In the Office

Family physician and USPSTF Chair Michael LeFevre, M.D., M.S.P.H., of Columbia, Mo., said in the news release that most women are not at high risk for pre-eclampsia. Therefore, physicians should determine what their pregnant patients' risk level for pre-eclampsia is and discuss whether taking aspirin is right for them.

Additionally, Frost pointed out that low-dose aspirin use in high-risk expectant mothers can help decrease the incidence of pre-eclampsia, but it doesn't eliminate it.

"(These women) still need to be managed as a high-risk pregnancy, with increased surveillance," she said, "and pre-eclampsia will still occur in women who do not fit into this category. It can be a rapidly progressive and devastating disease."

Physicians need to continue to monitor blood pressure and symptoms in all women, with a low threshold for the suspicion of pre-eclampsia, Frost concluded.

More From AAFP
American Family Physician: "POEMs: Aspirin in Low Doses Decreases Preeclampsia Risk"
(Sept. 1, 2014)

American Family Physician: "Diagnosis and Management of Preeclampsia"
(Dec. 15, 2004)

American Family Physician: "ACOG Practice Bulletin on Diagnosing and Managing Preeclampsia and Eclampsia"
(July 15, 2002)


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