IVF Pregnancy Outcomes Are Associated with the Stage of Embryo Transfer and Endometrial Ultrasonographic Parameters A Prospective Study

OBJECTIVE: To evaluate the relationship between pregnancy outcomes and embryo morphological stage at transfer combined with several endometrial ultrasonographic parameters. STUDY DESIGN: The subjects enrolled included 197 women undertaking in vitro fertilization (IVF) between December 2017 and February 2020. The transferred embryos were scored with the Gardner embryo morphology grading system. Endometrial ultrasonographic parameters were recorded on the day before embryo transfer (ET). RESULTS: The results showed that between the pregnant and nonpregnant groups, significant differences were observed in the percentage of blastocyst stage embryos (77.21% vs. 65.31%, p = 0.016), endometrial thickness (EMT) (9.64 +/- 2.13 mm vs. 8.70 +/- 2.04 mm, p =0.002), and endometrial volume (EMV) (3.71 +/- 1.62 cm(3) vs. 3.19 +/- 1.69 cm(3), p = 0.004) on the day before ET, while no significant differ- ence in embryo morphology score and other endometrial ultrasonographic variables was found. The cutoff value for EMT was 8.75 mm and for EMV was 2.84 cm(3). CONCLUSION: Compared with other parameters, the stage of ET and the EMT (or EMV) on the day before ET are more important variables in affecting pregnancy outcome. The blastocyst stage embryos combined with EMT of > 8.75 mm or EMV of >2.84 cm(3) on the day before ET seems to predict successful IVF pregnancy outcome.