Pregnant women should take low-dose aspirin daily to reduce their chance of developing pre-eclampsia if they are at high risk for the life-threatening disorder, an influential government panel said on Monday.
The United States Preventive Services Task Force’s draft recommendation follows a growing scientific consensus that low doses may be beneficial to some high-risk women and their offspring. Low-dose aspirin reduced the risk of pre-eclampsia by 24 percent in clinical trials, according to a systematic review underpinning the new recommendation, which was published in Annals of Internal Medicine.
Low-dose aspirin also reduced the risk of premature birth by 14 percent and of intrauterine growth restriction — a condition in which the fetus doesn’t grow as fast as expected — by 20 percent.
“For every four women who would have gotten pre-eclampsia, one case is prevented,” said Dr. Ira M. Bernstein, the chair of department of obstetrics, gynecology and reproductive sciences at the University of Vermont. “The ability to prevent a quarter of disease is substantial.”
Pre-eclampsia is a condition usually occurring in the second half of pregnancy and characterized by high blood pressure, protein in the urine, liver disease and blood-clotting abnormalities.
It is a leading complication for expectant mothers and their infants, affecting roughly 4 percent of pregnancies nationwide. The only “cure” is delivery. When a pregnant women develops pre-eclampsia in the second trimester, her infant often must be delivered prematurely to avoid severe maternal complications, like stroke.
The task force recommended that women at high risk for pre-eclampsia take 81 milligrams of low-dose aspirin daily after 12 weeks of gestation. High-risk women include those who have had pre-eclampsia in a prior pregnancy, especially those who have had to deliver preterm; women carrying multiple fetuses; and women who had diabetes or high blood pressure at conception.
But the task force also advised that expectant women with multiple moderate-risk factors “may also benefit from low-dose aspirin.” These risks include obesity, a family history of pre-eclampsia, women older than 35, and African-American women.
A single high-risk factor merits low-dose aspirin use, but “it’s a judgment call between physicians and patients as to whether a combination of moderate-risk factors is enough to justify taking low-dose aspirin,” said Dr. Michael L. LeFevre, the chair of the task force and a professor of family medicine at the University of Missouri in Columbia.
Low-dose aspirin appears to cause no short-term harm during pregnancy, according to the new review of 19 clinical trials and two observational studies. However, potential rare or long-term harms could not be ruled out.
The largest trial followed infants 18 months after birth, and “found no differences in development outcomes,” said Jillian T. Henderson, the lead author of the review and an investigator at Kaiser Permanente Center for Health Research in Portland, Ore.
The researchers also found that use of low-dose aspirin doesn’t increase the risk of excessive bleeding after delivery, placental abruption (when the placenta detaches from the uterus before it should) or bleeding inside the baby’s cranial vault.
Dr. Phyllis August, a professor of medicine in obstetrics and gynecology at Weill Cornell Medical College, praised the careful appraisal of the potential risks of taking aspirin. “They critically reviewed the risks, and well,” said Dr. August, who for 20 years has had selected high-risk patients use low-dose aspirin.
In recent months, medical organizations like the American College of Obstetricians and Gynecologists and the American Heart Association also have advised that high-risk women use low-dose aspirin, with slight variations in who qualifies.
Still, “our general impression is it’s being used infrequently,” said Dr. LeFevre.
It’s not currently possible to predict which women will develop pre-eclampsia or its complications. Some women classified as low risk still get the syndrome out of the blue. Effective prevention of pre-eclampsia has been difficult to pinpoint, experts said, but a remedy that could prevent a quarter of the cases is a significant step forward.
“We’d like to be able to prevent four out of four cases, obviously,” Dr. Bernstein said. “There’s still a lot to learn about why the other three are still getting it, and how to prevent their disease.”
By CATHERINE SAINT LOUIS, APRIL 7, 2014, 5:24 PM