Objective To explore the correlation between endometrial receptivity ultrasound parameters and pregnancy outcomes in in vitro fertilization-embryo transfer (IVF-ET) patients during fresh embryo transfer cycle. Methods A total of 98 patients undergoing IVF-ET in Handan Central Hospital were enrolled between July 2020 and January 2023. According to pregnancy outcomes within 12-14d after transfer

they were divided into pregnancy group (59 cases) and non-pregnancy group (39 cases). The general data in the two groups were compared. On the day of transfer

endometrial volume

vascularization index (VI)

flow index (FI)

vascularization flow index (VFI) and blood flow parameters of endometrial spiral artery near the uterine fundus in the two groups were compared by three-dimensional reconstruction technology. The predictive value of endometrial receptivity ultrasound parameters for pregnancy outcomes was analyzed by receiver operating characteristic (ROC) curves. Results There was no significant difference in endometrial thickness

volume or morphology between the two groups (P>0.05). S/D

PI and RI under endometrium in pregnancy group were significantly lower than those in non-pregnancy group (P<0.05)

while VI

FI and VFI in endometrium and under endometrium were significantly higher than those in non-pregnancy group (P<0.05). The area under curve (AUC) values of S/D

PI

RI

VI

FI and VFI under endometrium

VI

FI and VFI in endometrium

and combined detection were 0.796

0.736

0.617

0.735

0.711

0.717

0.780

0.611

0.725 and 0.978

respectively (P<0.05). Conclusion S/D

PI

VI

FI and VFI under endometrium

VI and VFI in endometrium can all predict pregnancy outcomes of IVF-ET patients

and the combined detection has the highest predictive value.