First, an empty catheter passes to the level of the lower uterine segment under ultrasound guidance to a point where the inner catheter enters the endometrial cavity. The inner sheath is removed slowly, leaving the outer sheath just beyond the internal os. After verifying the catheter's position on the TA ultrasound scan, the physician gives the signal to the embryologist to start the embryo loading. The embryologist brings the loaded inner catheter and inserts it into the outer sheath, which is maintained in its position by the physician.

First a trial transfer is performed using both the inner catheter and outer sheath connected together in standard configuration, just before the actual embryo transfer. It is passed up to and just through the the internal os. When it appears that the actual transfer will be possible without great difficulty ,the trial catheter is withdrawn. An embryo transfer catheter is loaded and the actual transfer is performed

Embryo transfer is done by using "afterload transfer" method

the presence of gestational sac on ultrasound

the number of gestational sacs divided by the number of embryos transferred