Endometrial thickness does not dictate embryo transfer outcome

The chances of a live birth following either fresh or frozen-thawed embryo transfer (ET) cycles cannot be predicted by endometrial thickness alone, according to a study.

The analysis included a total of 560 ET cycles, of which 273 were fresh and 287 were frozen-thawed. Regardless of the endometrial thickness, blastocyst transfer was scheduled in the absence of increased serum progesterone level on the trigger day in fresh ET cycles or before commencing progesterone treatment in artificially prepared frozen-thawed ET cycles.

Live birth and miscarriage rates per ET cycle were assessed for each millimetre of endometrial thickness and stratified according to fresh and frozen-thawed ET cycles. Receiver operator characteristic curve was applied to determine the predictive value of endometrial thickness for live birth.

Results showed no significant differences in relevant patient characteristics and endometrial thickness between women who achieved a live birth and those who did not following fresh or frozen-thawed ET.

Endometrial thickness had a linear association with neither live birth nor miscarriage rates. Area under the curve values for predicting live birth after fresh, frozen-thawed, and all ETs were 0.56, 0.47, and 0.52, respectively.

In light of the present data, women with thinner endometrium should not be denied their potential for live birth once intracavitary pathology and inadvertent progesterone exposure were excluded because the outcome is comparable to those with thicker endometrium.