Low-dose aspirin shows potential for preterm pre-eclampsia prevention
Low-dose aspirin appears to confer a protective effect against preterm pre-eclampsia in high-risk pregnant women, according to a team of international researchers.
In a trial of women with singleton pregnancies who were at increased risk of preterm pre-eclampsia, significantly fewer women treated with once-daily aspirin 150 mg until 36 weeks of gestation delivered with pre-eclampsia before 37 weeks of gestation, the primary study outcome, as compared with those who received placebo (1.6 vs 4.3 percent). [N Engl J Med 2017;doi:10.1056/NEJMoa1704559]
Aspirin was particularly associated with a more than 60-percent reduction in the odds of having preterm pre-eclampsia (odds ratio [OR], 0.38; 95 percent CI, 0.20 to 0.74; p=0.004).
“Results were materially unchanged in a sensitivity analysis that took into account participants who had withdrawn or were lost to follow-up,” researchers said.
Among 1,777 women initially randomized, only 798 and 822 remained in the aspirin and placebo groups, respectively. There were no significant between-group differences in baseline characteristics (median age, 31.5 vs 31.4 years; median gestational age at enrolment, 12.7 vs 12.6 weeks).
Likewise, safety was comparable between the two treatment groups, with no difference in the incidence of other pregnancy complications or of adverse foetal or neonatal outcomes. Treatment adherence was good in majority (79.9 percent) of the women overall, with a reported intake of ≥85 percent in the required number of tablets. These assessments were performed at 16 and 28 weeks of gestation and 30 days after the last tablet was taken.
An important cause of death and complications for both the mother and infant, pre-eclampsia is a pregnancy-specific systemic vascular disorder characterized by new-onset hypertension and proteinuria after 20 weeks of gestation. The risk of complications increases considerably when the disorder is severe and of early onset, leading to preterm birth at <37 weeks of gestation. [Hypertens Res 2017:40;305–310]
Researchers noted that identifying women at high risk for preterm pre-eclampsia early in pregnancy, during which intervention may reduce the prevalence of such disease, is a major challenge in modern obstetrics.
“In the United Kingdom, the National Institute for Health and Clinical Excellence recommends the identification of the high-risk group on the basis of 10 factors, including maternal characteristics and features of the medical and obstetrical histories. However, the performance of such screening is poor, with detection of approximately 40 percent of cases of preterm pre-eclampsia and 33 cases of cases of term pre-eclampsia, at a screen-positive rate of 11 percent,” they continued.
The present data provide evidence that the administration of aspirin at a dose of 150 mg per day from 11 to 14 weeks of gestation until 36 weeks of gestation among women with singleton pregnancies, who were identified by means of first-trimester screening as being at high risk for preterm pre-eclampsia, may result in a significantly lower incidence of preterm pre-eclampsia than that with placebo, researchers said.
“Professional associations now recommend the prophylactic use of low-dose aspirin (60 to 80 mg per day) in women who are considered to be at high risk for pre-eclampsia,” they added.
However, aspirin does not show any benefit in terms of the incidence of term pre-eclampsia, researchers said.