Acetylsalicylic acid ( Aspirin; ASA ) and low-molecular-weight Heparin are prescribed for women with unexplained recurrent miscarriage, with the goal of improving the rate of live births, but limited data from randomized, controlled trials are available to support the use of these drugs.
In this randomized trial, researchers enrolled 364 women between the ages of 18 and 42 years who had a history of unexplained recurrent miscarriage and were attempting to conceive or were less than 6 weeks pregnant.
The women were then randomly assigned to receive daily 80 mg of Acetylsalicylic acid plus open-label subcutaneous Nadroparin ( at a dose of 2850 IU, starting as soon as a viable pregnancy was demonstrated ), 80 mg of Acetylsalicylic acid alone, or placebo.
The primary outcome measure was the live-birth rate. Secondary outcomes included rates of miscarriage, obstetrical complications, and maternal and fetal adverse events.
Live-birth rates did not differ significantly among the three study groups. The proportions of women who gave birth to a live infant were 54.5% in the group receiving Acetylsalicylic acid plus Nadroparin ( combination-therapy group ), 50.8% in the Acetylsalicylic acid-only group, and 57.0% in the placebo group ( absolute difference in live-birth rate: combination therapy vs. placebo, -2.6 percentage points; 95% confidence interval [CI], -15.0 to 9.9; Acetylsalicylic acid only vs. placebo, -6.2 percentage points; 95% CI, -18.8 to 6.4 ).
Among 299 women who became pregnant, the live-birth rates were 69.1% in the combination-therapy group, 61.6% in the Acetylsalicylic acid-only group, and 67.0% in the placebo group ( absolute difference in live-birth rate: combination therapy vs. placebo, 2.1 percentage points; 95% CI, -10.8 to 15.0; Acetylsalicylic acid alone vs. placebo -5.4 percentage points; 95% CI, -18.6 to 7.8 ).
An increased tendency to bruise and swelling or itching at the injection site occurred significantly more frequently in the combination-therapy group than in the other two study groups.
In conclusion, neither Acetylsalicylic acid combined with Nadroparin nor Acetylsalicylic acid alone improved the live-birth rate, as compared with placebo, among women with unexplained recurrent miscarriage. ( Xagena )
Kaandorp SP et al, N Engl J Med 2010;362:1586-1596