Changes in measured endometrial thickness predict in vitro fertilization success.

OBJECTIVE: To assess the predictive ability of endometrial thickness and changes in endometrial thickness on pregnancy outcomes in patients undergoing IVF.
DESIGN: Retrospective cohort analysis.
SETTING: Academic IVF center. PATIENT(S): Infertile patients undergoing 132 fresh autologous IVF cycles. INTERVENTION(S): Transvaginal ultrasound to assess endometrial thickness at three defined points during IVF (after pituitary suppression, on the sixth day of gonadotropin stimulation, and on the day of hCG administration). MAIN OUTCOME MEASURE(S): Primary outcome variables included endometrial lining thickness at baseline, on day 6 of gonadotropins, the day of hCG administration, and the change in endometrial thickness during gonadotropin stimulation. RESULT(S): Patients attaining pregnancy had significantly greater endometrial thickness on day 6 and endometrial thickness on day of hCG administration. Pregnant patients had a greater change in endometrial thickness from the baseline to day 6 when compared to nonpregnant patients. Threshold analysis and receiver-operator characteristic curves noted significant endometrial thickness levels for implantation and pregnancy rates. CONCLUSION(S): Endometrial responsiveness and thickness during the early IVF stimulation seem to be better prognostic predictors of success than endometrial thickness at the start or the end of the IVF cycle.