Clinical Newswire, December 6, 2009 (NEW ORLEANS, LOUISIANA, USA) - Aspirin and low-molecular-weight heparin are not effective in preventing unexplained recurrent miscarriages, according to research presented at the 51st Annual Meeting of the American Society of Hematology (ASH).
Recurrent miscarriages occur in 1-3% of women, and, according to the American Society of Reproductive Medicine, the cause is unknown in more than 50% of cases. Unexplained recurrent miscarriages are extremely traumatic and stressful for women, however there is a lack of effective treatments. Based on the belief among some practitioners that abnormal clots in placental blood vessels are responsible for many recurrent miscarriages, anticoagulants such as aspirin and low-molecular-weight heparin have been increasingly prescribed to prevent further miscarriages, despite lack of evidence to support their use.
To test the efficacy of these treatments, a team of researchers from the Netherlands conducted a multicenter, randomized controlled trial of 364 women in 8 centers in the Netherlands (the ALIFE study). The women, aged between 18 and 42 years, had previously experienced at least two unexplained miscarriages by the 20th week of pregnancy, and attempted to conceive or were less than 6 weeks pregnant. Women with previous venous or arterial thromboembolism, endocrine disorders, or other indications for anticoagulant treatment during pregnancy were excluded from the study.
The study compared three treatment groups: aspirin alone, aspirin and nadroparin (a low-molecular-weight heparin), and placebo. Oral medication (aspirin as calcium carbasalate 100mg or placebo) was administered once daily starting from the day of inclusion in the study through 36 weeks of gestational age, or until miscarriage, ectopic pregnancy or premature delivery. Women allocated to receive open-label nadroparin received oral aspirin and started nadroparin 2850 IU once daily subcutaneous injections when a viable intrauterine pregnancy was confirmed by ultrasound from 6 weeks of gestational age through 12 hours before delivery.
The live birth rate, which was the primary outcome measure of the study, did not differ significantly between women in the three treatment groups: 50.8% (61 women) in the aspirin only group, 54.5% (67 women) in the aspirin and nadroparin group and 57% (69 women) in the placebo group. Side effects, most notably skin reactions, were more common in the women assigned to the aspirin and nadroparin group.
“The study clearly demonstrates that aspirin combined with heparin and aspirin alone do not prevent recurrent, unexplained miscarriages and that we should not needlessly put these women through the inconvenience and risks associated with these blood-thinning medications”, said study lead author Stef P. Kaandorp, MD (Department of Obstetrics and Gynecology, Academic Medical Center, Amsterdam, Netherlands). According to Dr Kaandorp, there results are extremely important and will likely change the way some women at high risk for another miscarriage have been treated.
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