The luteinized unruptured follicle and other ovulatory dysfunctions

In theory, several aberrations of the process of ovulation-luteinization can occur at the gonadal level: (1) Failure of the follicle to rupture with entrapment of the oocyte and subsequent luteinization of the surrounding granulosa cells. The resulting structure has been termed 'luteinized unruptured follicle'. (2) Rupture of the follicle without release of the oocyte. (3) Maturation of an 'empty' follicle (one that when mature does not contain an oocyte). (4) Ovulation with inadequate luteinization (luteal phase defect). (5) Incomplete maturation of a follicle (one that fails to ovulate and luteinize) resulting in atresia. This article reviews the clinical literature and addresses the animal data on the first aberration, namely, the 'luteinized unruptured follicle' (LUF). Furthermore, the limited literature addressing the second and third aberrations will be succinctly mentioned.