Received December 28, 2007
Accepted January 25, 2008

Premature luteinization is defined as a rise in serum progesterone levels on the day of human chorionic gonadotrophin administration for final oocyte maturation, during in vitro fertilization (IVF) cycles, above a threshold level. It is a frequent event of uncertain aetiology. Studies have been made trying to look for an association between premature luteinization and IVF outcome. Significant reduction in pregnancy rates has been reported by many authors. Alternative treatment to the couple who present with premature luteinization has been suggested for several researches, but it remains controversial. The aim of this review is to verify the literature data trying to find if the elevated progesterone levels at the end of the follicular phase have an association with IVF outcome in cycles using GnRH analogs.