The embryo transfer procedure is the last one of the in vitro fertilization process. The embryo is delicately placed at the proper location near the middle of the endometrial cavity. This has to be placed with as little trauma and manipulation as possible to the ideal location in the uterine cavity.
The woman is first stimulated with medications that are injected to develop multiple egg development. The eggs develop in structures in the ovaries called follicles. Each follicle contains one egg and can be seen on ultrasound. When the follicles are mature, the egg aspiration procedure is performed to remove the eggs from the ovary. Sperm is mixed with the eggs about 4 hours after the egg aspiration, and the following morning we check the eggs for evidence of fertilization. The fertilized eggs are cultured in the laboratory for 1-5 more days and then an appropriate number are selected for transfer to the woman's uterus. Usually 1 or 2 embryos are transferred.
The procedure is very similar to a Pap smear and no pain is involved. A moderately full bladder is for embryo transfer as it helps in proper visualization in Ultrasound with a smooth and proper transfer of the embryos to the best location, and it also unfolds the uterus to a more accommodating angle which makes the process easier and less traumatic for both the endometrial lining and the embryos.
The embryo transfer catheter is loaded with the embryos and the physician passes it through the cervical opening up to the middle of the uterine cavity. Abdominal ultrasound is used simultaneously to watch the catheter tip advance to the proper location. It is sometimes difficult to keep the tip of the catheter in the exact plane of the ultrasound beam at all times - but it is very important to control the proper placement of the embryos. When the catheter tip reaches the ideal location, the embryos are then transferred to the lining of the uterine cavity by the infertility specialist physician. After the embryos are transferred, the catheter is slowly withdrawn and checked under a microscope for any retained embryos. If any embryo is retained in the catheter the transfer procedure is repeated immediately and the catheter is checked again for a retained embryo.
Basically, the middle of the endometrial cavity - half way from the internal of the cervix to the uterine fundus (top of cavity) - is the best place. Care should be taken to keep the catheter between the top and bottom layers of the endometrium and not to allow it to dissect under the endometrial surface. This is called subendometrial embryo transfer. Pregnancies will occur with subendometrial placement of the embryos, but success rates are lower.After care
The patient is made to lie on her back for 1 hour after embryo transfer before getting discharged. Physical activity should be limited for the remainder of that day. Normal activity such as working, walking around, etc can start the morning after the embryo transfer. Heavy bouncing of the uterus is restricted until after the pregnancy test. Therefore, water skiing, jogging, uterus bouncing sex, and other high impact activities are best avoided until after the pregnancy test.