Task Force Recommends Low-Dose Aspirin for Women at High Risk for Preeclampsia
Draft statement supports 81 mg/day after 12 weeks of pregnancy
The U.S. Preventive Services Task Force has posted a draft recommendation statement and has published a final evidence summary on low-dose aspirin for the prevention of morbidity and mortality from preeclampsia.
The Task Force recommends the use of low-dose aspirin (81 mg/day) after 12 weeks of pregnancy in women who are at high risk for preeclampsia. This recommendation applies to pregnant women who are at high risk for preeclampsia and who do not show signs or symptoms of the condition and have not had any health problems from using aspirin in the past.
According to the Task Force, preeclampsia is one of the most serious health problems affecting pregnant women in the world. It is a complication in 2% to 8% of pregnancies worldwide and contributes to both maternal and infant morbidity and mortality. Preeclampsia also accounts for 15% of preterm births in the U.S.
The disorder is defined by the onset of hypertension (blood pressure of > 140/90 mm Hg) and proteinuria (the presence of ≥ 0.3 g of protein in the urine within a 24-hour period) during the second half of pregnancy (> 20 weeks). In the absence of proteinuria, preeclampsia is classified as hypertension with any of the following: thrombocytopenia, impaired liver function, renal insufficiency, pulmonary edema, or cerebral or visual disturbances.
“Preeclampsia can cause serious health problems for both expectant mothers and their babies,” said Task Force member Jessica Herzstein, MD, MPH. “The good news is that pregnant women who are at high risk for developing preeclampsia can take a low dosage of aspirin daily to help to prevent the condition. This can result in better health outcomes for both the mother and the baby.”
The Task Force found that the use of low-dose aspirin (between 50 and 160 mg) reduced the occurrence of preeclampsia, preterm birth, and intrauterine growth restriction (IUGR) — when a baby grows more slowly than expected in the mother’s womb — in women at increased risk for preeclampsia in several randomized trials. The most commonly used aspirin dose was 100 mg, but the two largest trials contributing to the estimates of benefit used 60 mg. In the U.S., low-dose aspirin is available as 81-mg tablets, which is a reasonable dosage for prophylaxis for women at high risk for preeclampsia, the Task Force says.
In 15 randomized controlled trials, low-dose aspirin was initiated at between 12 and 28 weeks’ gestation. None of the trials initiated aspirin before 12 weeks. Eight trials initiated low-dose aspirin before 16 weeks’ gestation. The evidence did not suggest additional benefit when starting aspirin earlier (12 to 16 weeks) rather than later (≥ 16 weeks) in pregnancy in women at increased risk for preeclampsia.
“Only a small percentage of pregnant women are at high risk for preeclampsia,” said Task Force chair Michael L. LeFevre, MD, MSPH. “Before taking aspirin, pregnant women should talk to their doctor or nurse to determine their risk and discuss if taking aspirin is right for them.”