Low-dose aspirin failed to prevent preeclampsia in an underpowered trial, but a meta-analysis including that trial suggests that early introduction of aspirin can prevent preeclampsia and severe preeclampsia.
“Even with the available data on low-dose aspirin treatment, there are strong controversial opinions for and against it,” Dr. Pia M. Villa from the University of Helsinki, Finland, told Reuters Health. “Again, the key question is how to identify women for whom the risk is high enough to warrant treatment.”
Dr. Villa and colleagues studied the effect of aspirin started between the 12th and 14th week of gestation on preeclampsia and intrauterine growth restriction in 947 pregnant women with risk factors for preeclampsia and 117 pregnant women without known risk factors.
One hundred fifty-two women with bilateral second-degree notch on ultrasound uterine artery blood flow measurement were allocated to the medication group. Of these, 61 received aspirin, 60 received placebo, and 31 were excluded from analysis.
In the intent-to-treat analysis published in the November 6 online BJOG, there were no differences between the aspirin and placebo groups in preeclampsia, gestational hypertension, early preeclampsia, preterm preeclampsia, severe preeclampsia, small for gestational age newborn, or severe diagnosis.
In light of these findings, the researchers conducted a meta-analysis that included their study and two additional studies (adding 117 aspirin and 108 placebo patients) in which aspirin was started at or before 16 weeks of gestation.
In the meta-analysis, aspirin treatment was associated with a significant 40% reduced risk of preeclampsia and a significant 70% reduced risk of severe preeclampsia. Preterm and term preeclampsia were not reduced by aspirin treatment.
“Our aim was to identify high-risk women by measuring uterine blood flow in early pregnancy,” Dr. Villa said. “Although the symptoms of preeclampsia develop late in pregnancy, the disease process starts very early and can sometimes be seen in the early uterine artery blood flow measurements by ultrasound, although this is not a very accurate method.”
“We concluded, based on our study and two previous similar studies, that in these women low-dose aspirin (100 mg/day) is effective and safe in prevention of preeclampsia and severe preeclampsia when started before or at 16 gestational weeks in high risk women,” Dr. Villa said.
– Will Boggs, MD0