ABSTRACT
The role of progesterone in the mammalian reproductive cycle is well described and undisputed. Its pharmaco-dynamics have been extensively studied and progesterone has been synthesized and commercially available since 1935. However, despite the putative role of progesterone in ameliorating unexplained recurrent pregnancy loss, the evidence base for its use in this setting is lacking, despite decades of clinical use. With this in mind, we argue that the use of progesterone supplementation for women, in whom no identifiable cause for three or more successive pregnancy losses before 20 weeks of gestation has been identified, is currently unjustified.
