The Embryo Transfer Procedure

With in vitro fertilization, conception occurs in a laboratory through collected sperm and collected eggs. The fertilized eggs are allowed to grow into the embryo stage. Once they've developed sufficiently, the embryos are placed directly into the woman's uterus. This happens between five to seven days after fertilization.

Embryo Selection

Only the healthiest embryos are chosen to be transferred. They are carefully examined by a specialized doctor called an embryologist. The embryologist examines each egg based on the number of cells, the degree of fragmentation and the evenness of growth. Often more than one embryo is transferred to increase the chances of implantation.

Many countries have laws limiting the number of embryos that many be transferred. According to the UK Human Fertilization and Embryology Authority (HFEA) regulations, women over 40 may have a maximum amount of three embryos transferred. In the United States, younger women can have numerous embryos transferred depending on individual clinics guidelines regarding implantation numbers.

Careful transfer of the embryo is crucial and requires a lot of skill. For best chances, the embryo needs to be placed in the middle of the endometrial cavity. The doctor completing the transfer needs to be experienced in handling embryos to reduce the amount of trauma to it during the transfer.

The Transfer

The embryo transfer procedure shouldn't be painful and no sedation is required. The entire procedure is comparable to a Pap smear as far as comfort levels are concerned. The woman will be asked to have a moderately full bladder before the transfer. A full bladder puts pressure on the uterus and moves it slightly making it easier to see what going on and making it easier to properly position the embryo. Overall, embryo transfer completed with a full bladder is less traumatic for both the embryo and the uterine lining.

The doctor will fill the embryo transfer catheter with the selected embryos. The catheter is placed through the cervical opening while an abdominal ultrasound is used simultaneously to help position the catheter tip. When the catheter tip reaches the ideal location, the embryos are carefully squirted out of the catheter towards the endometrial lining. The catheter is carefully removed and then the doctor will check it under a microscope to make sure there are no retained embryos. Any retained embryos are immediately transferred and the catheter is checked again.

After the Transfer

After the embryo transfer is completed, the woman will be asked to remain on her back for about one hour. She is then free to go home but should limit physical activity for the rest of the day. Most clinics allow normal activity the morning after the embryo transfer, although any activity that could cause heavy bouncing of the uterus is discouraged until pregnancy is confirmed with a pregnancy test. This includes jogging, skiing, dancing and highly active sex.