Analysis of the guidance value of 3D ultrasound in evaluating endometrial receptivity for frozen-thawed embryo transfer in patients with repeated implantation failure

BACKGROUND: Repeated implantation failure (RIF) is currently believed by some scholars to be mainly related to the poor endometrial receptivity. Three-dimensional (3D) ultrasound, as a noninvasive examination, has attracted the most attention. This paper further discusses whether 3D ultrasound of the endometrial receptivity index has guidance value in the evaluation of pregnancy outcomes in patients with RIF following frozen-thawed embryo transfer. METHODS: A total of 79 patients with RIF were retrospectively analyzed. These 79 patients which were confirmed by the transvaginal ultrasonography detection comprised 36 cases of intrauterine pregnancy, which were included in the pregnancy group, and 43 cases with biochemical pregnancy (the HCG in blood or urine is only transient and can be detected by clinical biochemical methods. The pregnancy sac cannot be seen under ultrasound) or negative results of human chorionic gonadotropin (HCG) examination, which were included in the non-pregnancy group. The endometrial thickness, uterine volume, sub-endometrial blood flow type, pulsatility index (PI) and resistance index (RI) of the spiral artery; the RI and PI of the uterine artery; and the peak systolic velocity/end diastolic velocity (S/D) of the two groups were measured and analyzed. RESULTS: (I) There were no significant differences in the age, infertility years, body mass index (BMI), anti-Müllerian hormone (AMH), endometrial thickness on the hCG injection day, estradiol (E2), and progesterone (P) between the pregnant and non-pregnant groups (P>0.05). (II) There were no significant differences in the endometrial thickness, uterine volume, and RI and PI of the uterine artery on the day before the implantation between the two groups (P>0.05). (III) There was statistical difference in the sum of the S/D of the two uterine arteries between the two groups (P<0.05) with a cutoff value of 14.47 (P<0.05). (IV) The RI and PI of the spiral artery in the non-pregnancy group were lower than those in the pregnancy group, and the difference was statistically significant (P<0.05). (V) The differences in the endometrial classification and subendometrial blood flow classification between the two groups were statistically significant (P<0.05). CONCLUSIONS: Ultrasonographic endometrial blood flow classification, spiral artery blood flow parameters, and uterine artery blood flow parameters can be effective indexes for evaluating endometrial receptivity, and they have a certain clinical significance in evaluating the pregnancy outcome of RIF patients after retransplantation.