Incidence of the luteinized unruptured follicle syndrome in fertile women and in women with endometriosis

One-hundred normal fertile women with normal luteal phase and 118 women with endometriosis underwent luteal phase laparoscopy before day 22. The luteal phase was ascertained by the presence of secretory endometrium and serum progesterone levels higher than 3 ng/ml. The ovaries were carefully inspected for the presence or absence of an ovulation ostium. The percentage of ostii that was observed in fertile women (91%) was similar to that observed in women with mild endometriosis (85%). However, in women with moderate and severe endometriosis, significantly less ostii were noted, respectively 72 and 51%. It is therefore argued that the absence of an ovulation ostium (so-called luteinized unrupted follicle syndrome, LUF) is more frequent in women with moderate and severe endometriosis and may contribute to infertility in this group of women.