Introduction: Continuing story of premature progesterone elevation.

Since the late 1980s premature progesterone elevation has repeatedly caught the attention of investigators, not only for its importance, but also because studies have shown differing results and conclusions, constituting an unexplainable sequence of doubts and uncertainties. This issue's Views and Reviews section seeks to present a sequence of short and complementary papers summarizing the whole story and updating the reader on the current information and perspectives on premature progesterone elevation.