Ultrasound tracking of the movement of embryo-associated air bubbles on standing after transfer.

The aim of this study was to investigate whether standing upright shortly after embryo transfer has any potential to affect the position of embryos transferred to the uterine cavity during treatment with in-vitro fertilization (IVF). This was assessed by ultrasound-guided tracking of embryo-associated air within the uterine cavity. A prospective study of 93 patients undergoing 101 consecutive embryo transfers in an IVF programme was carried out. Transvaginal ultrasound guided embryo transfer was performed with a second ultrasound in standing position immediately after transfer, allowing the movement of embryo-associated air to be assessed. No movement occurred in 94.1% (95/101) of transfers, movement of <1 cm in 4.0% (4/101) of transfers and movement of 1-5 cm in 2.0% (2/101) transfers. No movement of embryo-associated air out of the uterine cavity, either into the cervix or the intramural portion of the Fallopian tube, was seen. Standing shortly after embryo transfer does not play a significant role in the final position of embryo-associated air and is unlikely to be a factor in determining the position of embryos transferred to the uterine cavity during treatment with IVF.