Endometrial dating in the conception cycle.

OBJECTIVE

To investigate endometrial dating during the conception cycle.

METHODS

Endometrial biopsies of the last half of the luteal phase of conception cycles were dated based on urinary luteinizing hormone (LH) surges.

METHODS

Endometrial samples were obtained from women attending the fertility clinic of the Department of Obstetrics and Gynecology at Gunma University Hospital.

METHODS

One hundred eighty-five women, of whom 15 (8.1%) conceived during this study.

METHODS

Urinary LH surge, serum progesterone (P) levels, and endometrial dating.

RESULTS

All 10 women who conceived showed 2 or within 2 days in-phase endometrial biopsies on days 7 to 11 after the LH surge. In 4 of 5 women biopsied on day 12, an unequivocally delay in the stroma was found, i.e., a persistence of edema and poor development of predecidual reaction. Since serum P levels in conception cycles were significantly higher than in nonconception cycles on days 10, 11, and 12, we interpreted this delay in the stroma as a consequence of conception.

CONCLUSIONS

Endometrial specimens during the last half of the luteal phase of conception cycles are in-phase until day 12. On day 12, gestational hyperplasia causes apparent out-of-phase.