Following successful sperm-egg fusing (fertilization), the fertilized eggs (embryos) are maintained in laboratory for a variable period of time before being transferred to the uterus. Commonly, embryos are replaced in the uterus after three (3) day culture in laboratory. In case of blastocyst transfer, the embryos are maintained in laboratory for five (5) or six (6) days. If tubal embryo transfer is planned, the embryos are placed in the fallopian tube by laparoscopy 24 to 48 hours after egg aspiration.
Embryos are commonly replaced to the endometrium of uterus through the cervix (trans-cervical transfer) under the guidance of a trans-abdominal ultrasound.
At this time, patient’s bladder must be completely full for a better viewing of the sonography.
This procedure is similar to the technique of intra-uterine insemination (IUI). For IUI, a catheter is used to negotiate the cervix and place sperm sample in the uterus, instead of embryos. The transferred embryos will be maintained in the uterine cavity by surface tension.
The embryo transfer process is crucial to the success of IVF cycle. Good morphology embryos placed into a well-prepared uterus may fail to implant during IVF procedure if these embryos are not placed in an optimal location or if uterine contraction (cramp) causes the transferred embryos to move away from the original proper location.
Dr. Wang et al at the American Fertility Center are well-experienced for this delicate, yet critical procedure.
Also our Center uses the full-bladder technique (to help straighten the axis of uterus), a special soft catheter to minimize possible trauma to the uterus, and simultaneous ultrasound to visualize the optimal location for the transferred embryos.
The embryo transfer is practiced at least twice, the first time at the time of egg retrieval (or at the time of endometrial biopsy for recipients of egg donation), a second time just before practicing embryo transfer. In rare instances, we may recommend laparoscopic tubal embryo transfer.