Endometrial evaluation by aspiration biopsy on the day of oocyte retrieval in the embryo transfer cycles in patients with serum progesterone rise during the follicular phase.

OBJECTIVE: To investigate the effect of subtle serum P rise before hCG administration on endometrial maturation in stimulated cycles.
DESIGN: Case-control study.
SETTING: Tertiary referral center. PATIENT(S): Twenty patients with serum P < or = 0.9 ng/mL (group I) (conversion to SI unit, 3.180), 20 patients with premature P rise (> or = 1.1 ng/mL, group II), and 20 patients with normal serum P (group III). INTERVENTION(S): Patients in groups I and II underwent endometrial aspiration biopsies on the day of oocyte retrieval in the ET cycles themselves. Patients in group III, without endometrial biopsies, were chosen as controls. MAIN OUTCOME MEASURE(S): Comparison of endometrial maturation, correlation between endometrial dating and cumulative P exposure, and/or number of days of P > or = 1.1 ng/mL and comparison of clinical outcome. RESULT(S): Groups I and II showed a secretory activity of the endometrium. In group II, the endometrial dating correlated neither with P exposure nor with the number of days of subtle P rise. Clinical pregnancies were observed in both groups but none in cases with endometrium advanced > 3 days. Similar pregnancy and implantation rates were observed between groups I and III. CONCLUSION(S): These data suggest that an endometrial aspiration biopsy performed on the day of oocyte retrieval may be used to assess endometrial receptivity in patients with serum P rise.