Diagnosis of luteal phase defect (LPD) is controversial and complicated. In the past, serum progesterone levels above 3 in the mid luteal phase indicated proficient ovulation. Performing an endometrial biopsy in the mid luteal phase and sending it to the pathologist for dating was the previous gold standard in diagnosing LPD, with 2 biopsies in different cycles showing two or more days discrepancy from the cycle day being diagnostic.
This is no longer the case, and reproductive endocrinologists are getting away from doing endometrial biopsies to diagnose LPD because the test is invasive, painful, and not always accurate. There are women who have endometrial biopsies that are discrepant by 2 or more days that get pregnant with no problem, and the reverse is also true.
The most reliable current diagnostic regime involves simple charting of a consistently short luteal phase of less than 13 days is the best criteria for clinical practice. (Speroff page 1036).
Ovulation Test Strips - test for your cycles LH Surge.