Prevalence of out-of-phase endometrial biopsy specimens.

OBJECTIVE: We attempted to determine the prevalence of out-of-phase endometrial biopsy specimens among fertile and infertile women and women with recurrent pregnancy loss, histologic dating of biopsies was compared with four reference points for expected ovulation. These reference points included last menstrual period, next menstrual period, luteinizing hormone testing, and ultrasonographic documentation of ovulation.

STUDY DESIGN: Four hundred eighty-five endometrial biopsies were performed 7 days after documented ovulation-based ultrasonographic evidence for follicle collapse. The histologic dating was referenced to the last menstrual period, next menstrual period, and ultrasonographic documentation of ovulation. One hundred thirty-two of these women also performed urinary luteinizing hormone surge testing before ovulation and serum progesterone determinations. A comparison of the prevalence of out-of-phase biopsy specimens among groups was determined with the chi 2 test and Fisher's exact test.

RESULTS: The prevalence of out-of-phase endometrial biopsy specimens ranged from 42% when last menstrual period was used to 26% with next menstrual period, to 21% with luteinizing hormone testing, and to 4% with ultrasonographic documentation of ovulation. Serum progesterone values among women with a diagnosis of out-of-phase biopsy specimens by any of the reference dates progesterone were similar to those with in-phase biopsy specimens.

CONCLUSION: The accuracy of histologic endometrial dating was best determined by ultrasonographic monitoring rather than by last menstrual period, next menstrual period, or luteinizing hormone testing in infertile populations and in those with recurrent pregnancy loss. Additionally, because no significant difference in out-of-phase biopsy specimens exists between fertile and infertile patients and recurrent pregnancy loss, those with the role of this procedure is called into question.