Herbert CM, Hill GA, Maxson WS, Wentz AC, Osteen KG. Use of a sensitive urine pregnancy test before endometrial biopsies taken in the late luteal phase. Fertility and sterility. 1990 Jan;53(53). 162-4. PMID: 2295336 [PubMed]
Endometrial biopsies for evaluation of the luteal phase should be taken within 2 days of the onset of menses. When these guidelines are followed and patients present at least 12 days after the thermogenic shift on BBT, the ICON pregnancy test is extremely rapid, sensitive, specific, and has predictive values close to 100%. If a biopsy is undertaken before this time there may be an increased risk of false negative results (i.e., a decreased sensitivity). The improved technology in urine pregnancy tests has now made it feasible to obtain accurate urine pregnancy tests before endometrial instrumentation with an increased level of confidence. It is recommended that this technology be used in the management of patients undergoing endometrial biopsies in the late luteal phase.