Embryo transfer is perhaps the second most anticipated part of the IVF process (next to the pregnancy test). It is the culmination of an intensive IVF treatment cycle.
The embryo(s) to be used for the transfer procedure may be considered ‘fresh’ or ‘frozen’. A ‘fresh’ embryo was created a few days ago when the embryology lab fertilized the egg with the sperm. A ‘frozen’ embryo will have been created in a prior fresh IVF cycle and frozen for later use. Either way, a couple or patient will be hoping that embryo transfer will ultimately lead to a successful pregnancy.
The following steps are quite typical on the day of your embryo transfer:
Commonly ultrasound scanning will be used to help place the embryo(s) in the correct part of the uterus. If this is how your clinic performs embryo transfer, you will be instructed to have a fairly full bladder prior to the procedure. This allows for the abdominal ultrasound to have a clear image of your uterus (since ultrasound waves travel better thru water). A full bladder also helps straighten a uterus that may be curved, allowing for a smoother procedure.
The fertility physician and/or the embryologist will go over the status of your embryo(s). This will typically include information on the visual grading of the embryos. Fertility centers may use different grading systems that describe how the embryos look under a microscopic view.
You may also have a discussion on how many embryos you wish to transfer (if this has not already been predetermined by you and your doctor). This is a discussion that is often based in part on your age, diagnosis, prior history, and embryo number/quality.
Increasingly nowadays, many clinics may recommend that only one embryo is transferred. This is to reduce the risk of a multiple pregnancy (for example twins) which would carry additional risks to both the mother and the babies themselves. In other situations, your clinical team may recommend that more than one embryo is transferred, particularly in situations where the biological intended mother is older, or where previous attempts at IVF with single embryo transfer have been unsuccessful. Read more about IVF treatment with donor sperm here.
The embryo transfer procedure is performed by a physician or nurse who may have the assistance of an ultrasonographer. An embryologist will also be involved. An ultrasound image of the uterus allows the physician or nurse to properly insert an embryo transfer catheter. The embryologist is there to have the microscopic embryo loaded in the catheter once the physician is ready.
The transfer procedure starts with the physician or nurse inserting a speculum into the vagina. The cervix is then gently cleaned. The physician or nurse may perform a trial or practice embryo transfer by gently inserting an empty catheter into the uterus (often under ultrasound guidance). The catheter is soft, made of plastic material, and about the thickness of a strand of spaghetti. The catheter insertion is a delicate process and most of the time, you will not feel the catheter insertion. This trial transfer allows the physician to make sure the actual transfer procedure will go smoothly.
Once the physician or nurse is ready, the embryologist will be instructed to load your embryo(s) into a new catheter. Until that time, your embryo(s) continue to be safely stored in an incubator.
Remember that the embryo(s) are microscopic and cannot be seen with the naked eye. The embryologist uses a high-power microscope to load the embryo(s) into the tip of the transfer catheter. A thin syringe is attached to the other end of the catheter.
The syringe and loaded catheter are promptly handed to the physician or nurse. The loaded catheter is gently inserted into the uterus with or without ultrasound guidance.
Once the tip of the catheter is about 1-2 cm from the upper part of the uterine cavity, the physician or nurse gently presses the plunger of the syringe.
This allows the embryo(s) at the catheter tip to enter the uterine cavity. You will typically not feel this happen.
The catheter is gently removed and handed back to the embryologist. The embryologist looks at the catheter tip under a microscope to confirm the embryo(s) no longer remains in the catheter.
The physician or nurse subsequently removes the speculum, and the procedure is completed. There is no benefit in continuing to lay still or flat.
You are free to get dressed and use the restroom on your way out. Congratulations on successful completion of the embryo transfer, and best wishes on the upcoming pregnancy test!