Early abortion: natural failure or lack of a critical spirit?

The existence of spontaneous, clinically inapparent early abortions seems to be generally acknowledged in the scientific literature. The lack of scientific criticism about the limitations and inconsistencies on the quantitative estimation of these early losses is however striking. This study examines critically the published primary scientific evidence about early spontaneous clinically inapparent abortions. Three main methods are disclosed: 1) Direct inspection of the uterus and fallopian tubes; 2) Theoretical assumptions, and, 3) Estimates of 'biochemical abortions'. Estimates ranging from 7.6% to 56.8% of all pregnancies are obtained by experimental studies. Actual methodological shortcomings and inter-group variability in results provide no scientific ground for a quantitative agreement. The results of this study preclude the utilization of a precise quantitative estimate of early spontaneous clinically inapparent abortions in any rational discussion, unless new experimental evidence could be provided.