[Aspirin and prevention of pre-eclampsia]

Aspirin is used in pregnant women in order to obviate the imbalance of prostanoids caused by a defective placentation, and also to counteract the widespread thrombotic tendency related to endothelial dysfunction. After a series of controlled trials which showed a very consistent effect of aspirin t prevent preeclampsia and fetal growth retardation, several recent large trials have cast the doubt, and even unbelief. Their results are analyzed in an explicative way. Discrepancies seem largely related to either studying very low-risk populations, or strong differences in aspirin dosage and/or term of introduction. In the last few years, several works have shown the critical importance of an early treatment, and also of a measurable biologic effect, which requires larger dosages than those used in the most recent trials. The doubt largely remains as for the adequate indications of this treatment. New data in the physiology of placentation suggest that it would be logical to give aspirin as early as the first wave of throphoblastic invasion. The effect of so an early treatment need to be evaluated. The search for early markers should be pursued. The combination of aspirin and heparin is under investigation. Finally, other ways of prevention, such as anti-oxidants, are also being studied.