Recurrent miscarriages are extremely traumatic and stressful for women, and, according to the American Society for Reproductive Medicine, the cause is unknown in more than 50% of cases. Though treatments to avoid these tragedies remain elusive, some practitioners suspect that abnormal clots in the blood vessels that nourish the placenta are responsible for many recurrent miscarriages, and thus they have increasingly used aspirin and low-molecular-weight heparin to prevent further miscarriages, even though evidence to support their use is not available.Both medications are blood thinners and are used to prevent clots in the placenta that could cut off the supply of nutrients to a growing baby, or to decrease the risk of other pregnancy complications that might be causing the miscarriages.To test the effectiveness of these controversial treatments, a team of researchers from the Netherlands conducted a multicenter, randomized clinical trial of 364 women between the ages of 18 and 42 who were attempting to conceive or were less than six weeks pregnant. The women had previously experienced at least two unexplained miscarriages by the 20th week of pregnancy. Because the researchers were focused on miscarriages with unexplained causes, women with previous venous or arterial thromboembolism (clotting disorders), endocrine disorders, or other indications for anticoagulant treatment during pregnancy were excluded from the study.?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 lead study author Stef P. Kaandorp, MD, research fellow in the Department of Obstetrics and Gynecology at the University of Amsterdam Academic Medical Center in The Netherlands. ?These results are extremely important because they will likely change the way some women at high risk for another miscarriage have been treated.?During the study, three treatment groups were compared: aspirin and nadroparin (a low-molecular-weight heparin), aspirin alone, and placebo. Oral medication was administered once a day beginning on the day of inclusion in the study through 36 weeks of gestational age, or until miscarriage, ectopic pregnancy, or premature delivery. Patients on the oral regimens received either placebo pills or 100 mg of calcium carbasalate (a salt formulation of aspirin equivalent to 80 mg of aspirin). Women who were to receive low-molecular-weight heparin received subcutaneous injections once a day of 2,850 international units of nadroparin from six weeks of gestational age through 12 hours before delivery.The intention-to-treat analysis of the study showed that the live birth rate did not differ significantly among the three treatment groups: 54.5% of those in the aspirin and nadroparin group had a live birth (67 women), compared with 50.8% in the aspirin group (61 women), and 57% of the placebo group (69 women). Side effects, most notably skin reactions, also occurred more often in women assigned to the aspirin and nadroparin group.Dr. Kaandorp will present the results of this study, Aspirin and Aspirin Combined With Low-Molecular-Weight Heparin in Women with Unexplained Recurrent Miscarriage: A Randomized Controlled Multicenter Trial (ALIFE Study; Abstract #488), on Monday, December 7, at 3:00 p.m.(Room 275-277) during an oral session of the 51st Annual Meeting of the American Society of Hematology.For more information seeKaandorp SP, Goddijn M, Van der Post JAM, Hutten BA, et al Aspirin and Aspirin Combined with Low-Molecular-Weight Heparin in Women with Unexplained Recurrent Miscarriage: a Randomized Controlled Multicenter Trial (ALIFE Study) Abstract 488:Also read PubMed AbstractCoppens M, Kaandorp SP, Middeldorp S. Inherited thrombophilias. Obstet Gynecol Clin North Am. 2006 Sep;33(3):357-74.