Assessment of endometrial receptivity for gestation in patients undergoing in vitro fertilization, using endometrial thickness and the endometrium-myometrium relative echogenicity coefficient.

OBJECTIVE

To evaluate the outcome of in vitro fertilization (IVF) treatment in relation to the sonographic parameters of the endometrium.

DESIGN AND METHODS

Seventy-five patients with no uterine pathology (age 31.1 +/- 5.4 years) treated in our IVF clinic for various indications were assessed during 75 cycles in which good-quality (grades 1 and 2) embryos were transferred. Controlled ovarian stimulation was achieved by the long protocol (gonadotropin releasing hormone agonist and gonadotropins). The bilayered endometrial thickness (BET), estradiol, luteinizing hormone and progesterone serum levels were measured in 272 tests. A special computer program was used to measure endometrial echogenicity relative to myometrial echogenicity. The gray-level data were analyzed on the basis of the midsagittal sonographic uterine image. Endometrium-myometrium relative echogenicity coefficient (E/M REC) values were computed and displayed graphically along the anteroposterior axis of the endometrial layers in the upper part of the uterine cavity. The area under the E/M REC curve within the BET limits was defined as the relative echogenicity area (REA) and was used as a measure of endometrial echogenicity. Each cycle was sampled in six time segments representing desensitization, follicular and luteal phases. Assigning the day of ovum pick-up as day 0, the time segments of each cycle were: first, day -20 to day -11; second, day -10 to day -6; third, day -5 to day -2; fourth, day 0; fifth, day +7 to day +14; sixth, day +15 to day +21.

RESULTS

A total of 276 embryos were transferred (3.68 +/- 1.01 per cycle), of which 223 were of good quality (2.97 +/- 1.51 per cycle). An intrauterine pregnancy was diagnosed in 29 patients. All patients in this study had a BET of > 5 mm in the third and the fourth time segments. There was no significant difference in BET and REA between pregnant and non-pregnant patients tested in the first to the fifth time segments of the IVF cycles. Both BET and REA measured in the sixth time segment were significantly higher in pregnant compared to non-pregnant patients.

CONCLUSIONS

Our results suggest that the proposed sonographic assessment of the endometrium shows no benefit in characterization of uterine receptivity in IVF patients with a reactive endometrium. High BET and REA values can indicate pregnancy during the sixth time segment, when the decidualization of the endometrium is well established.