2 Studies Find Aspirin Helpful in Pregnancies
Low doses of aspirin can prevent pregnancy-induced hypertension and related toxemia in some women, according to two new studies that offer hope of the first effective method of averting a common and potentially fatal complication of pregnancy.
The studies, published today in the New England Journal of Medicine, found that small amounts of aspirin during late pregnancy reduced the women’s risk of high blood pressure and thus averted the need for sometimes-dangerous premature delivery.
The results are the latest in a string of recent findings on possible new benefits of the 90-year-old painkiller. Aspirin was shown recently to cut in half the risk of heart attack in men over 50. Researchers are also exploring its uses against stroke.
The authors of the pregnancy studies found no evidence that the aspirin harmed the babies or their mothers, even though pregnant women are usually advised against taking aspirin. The daily doses given--60 and 100 milligrams--were far less than the usual adult dose.
Specialists in the field said the findings were not unexpected and raise the possibility of reducing the rate of premature births and the medical problems that prematurity can cause. But they cautioned that the studies, done in Israel and Italy, were small and need confirmation.
Called Significant
“It’s very significant,” Dr. Khalil Tabsh, chief of obstetrics at the UCLA School of Medicine, said Wednesday of the new findings. “They’re encouraging. The effects are favorable. However, I think we need larger studies.”
Five to seven percent of all pregnant women experience pregnancy-induced hypertension during the latter stages of pregnancy. The condition is especially common--with an incidence as high as 20%--among women who are pregnant for the first time.
Pregnancy-induced hypertension is often accompanied by a condition known as preeclampsia or toxemia, a disorder characterized by fluid retention, tissue swelling and leakage of protein from the kidneys into the urine.
In rare cases, preeclampsia can progress into eclampsia, in which the woman suffers seizures sometimes followed by coma and death. Pregnancy-induced hypertension and preeclampsia can also result in retarded growth of the fetus, among other problems.
Currently, the only treatment is delivery of the baby; in some cases, delivery must be induced at as early as 28 weeks, raising the possibility of permanently disabling developmental problems or other consequences of premature birth.
In the first paper, researchers at the Chaim Sheba Medical Center in Tel Aviv studied 65 women at high risk of preeclampsia. Thirty-four received 100 milligrams of aspirin daily during their third trimester of pregnancy; 31 received an inert placebo.
Just 11.8% of those who received aspirin developed pregnancy-induced hypertension, compared to 35.5% of those on the placebo, a reduction of 67%. Similarly, the researchers found that aspirin reduced the risk of preeclampsia by 77%.
The women on aspirin delivered their babies on average 11 days later than the other women because they were less likely to require early delivery. The researchers found indications that aspirin might also help ensure increased weight of babies at birth.
The second paper, by researchers at several institutions in Italy, compared 17 high-risk women on 60 milligrams of aspirin daily to 16 on a placebo. The women on aspirin delivered their babies several weeks later than the others, and their babies weighed slightly more.
Precisely what causes pregnancy-induced hypertension and preeclampsia, and why aspirin might prevent it, remain somewhat unclear. Researchers suspect that the answers may involve hormone-like substances called prostaglandins that are involved in controlling blood pressure.
Researchers theorize that some pregnant women experience an imbalance between two types of prostaglandins that respectively dilate and constrict the blood vessels. Aspirin, through a complicated series of steps, appears to right that balance.
Pregnancy-induced hypertension occurs in women who previously had normal blood pressure.
Early evidence of the possible benefit of aspirin during pregnancy began emerging in the 1970s. But numerous studies have proved inconclusive. A 3,000-patient study is now being conducted by researchers at seven U.S. institutions, including USC.
Money Issue
“This (issue) is significant in terms of dollars and cents,” said Dr. Damon Masaki, an assistant professor of maternal-fetal medicine at the USC School of Medicine. “Prematurity and low birth weight are still a big problem in America, and one of the factors is preeclampsia.”
Aspirin’s benefits against heart attack have been reported over the last year after a study of 22,071 male physicians found it cut their heart attack risk in half. Other researchers have suggested it could be used against stroke and, in theory, against cataract formation.
But the drug is not without side-effects: In children, it has been linked to Reye’s syndrome, a rare brain and liver disorder. In adults, it irritates the stomach lining and over time can cause bleeding or peptic ulcers.
While the Israeli and Italian researchers detected no harm done by the aspirin to the women or fetuses in their studies, the Italian group noted, “The small numbers in the trial do not allow us to rule out completely (the possibility of) a small increase in fetal bleeding.”
