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From the Journals

Daily 150-mg aspirin dose slashes preterm preeclampsia risk

Publish date: July 6, 2017

By

Jennie Smith

FROM NEW ENGLAND JOURNAL OF MEDICINE

While low-dose aspirin has been shown for decades to decrease the risk of preterm preeclampsia, yet to be established are the optimal dose and time of day to administer aspirin; how preeclampsia risk is best assessed; and at what gestational week it is best to start aspirin.

New findings from a randomized, double-blind, placebo-controlled trial show that a daily 150-mg dose of aspirin, taken at night, significantly reduced incidence of preterm preeclampsia in women identified as being at high risk in the first trimester (N Engl J Med. 2017 June 28. doi: 10.1056/NEJMoa1704559).

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Daniel L. Rolnik, MD, of Kings College Hospital in London, and his colleagues, recruited 1,776 women with singleton pregnancies at 13 maternity hospitals in Belgium, Greece, Israel, Italy, Spain, and the United Kingdom. All were identified as being at high risk of preeclampsia by way of a sophisticated screening algorithm that combines maternal factors, mean arterial pressure, uterine-artery pulsatility index, maternal serum pregnancy–associated plasma protein A, and placental growth factor. The women were randomly assigned to aspirin or placebo, starting at between 11 and 14 weeks and continuing through week 36 of pregnancy.

After 156 women dropped out of the study or were lost to follow-up, investigators had results from 798 women in the aspirin group and 822 in the placebo group, with about 80% of subjects having taken aspirin or placebo as directed. The study’s primary outcome was delivery with preeclampsia before 37 weeks, seen in 13 women (1.6%) in the aspirin group, compared with 35 (4.3%) in the placebo group (odds ratio 0.38; 95% confidence interval, 0.20 to 0.74; P = .004).

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There were no significant between-group differences for other pregnancy complications or adverse fetal or neonatal outcomes, although the study was not powered to detect these. Dr. Rolnik and his colleagues noted in their analysis that unlike in prior trials to reduce the risk of preeclampsia risk, “we identified women at high risk for preterm preeclampsia by means of combined screening with maternal demographic characteristics and historical factors and biomarkers – a strategy that has been shown to be superior to other currently used methods.”

Other decisions incorporated into the study design, including those about aspirin dosage (higher than the currently recommended 60-80 mg for this population), taking aspirin at night, and the gestational age at which to start aspirin, were based on results from prior trials, studies, and meta-analyses, the researchers said.

Screening at 11-13 weeks’ gestation identifies less than 40% of term preeclampsia, studies have shown, and aspirin did not reduce term preeclampsia in this study, the investigators said.

The European Union Seventh Framework Program and the Fetal Medicine Foundation (UK) sponsored the study. None of the investigators had any relevant financial disclosures.

Daily 150-mg aspirin dose slashes preterm preeclampsia risk

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