The importance of proper embryo transfer technique for successful IVF cannot be overstated.
No matter how good the IVF laboratory culture environment is, the physician can ruin everything with a carelessly performed embryo transfer.
Here are the crucial steps to take when performing an embryo transfer.
The entire IVF cycle depends on delicate placement of the embryos at the proper location near the middle of the endometrial cavity - with as little trauma and manipulation as possible.
In order to get sufficient eggs for IVF, the woman is first stimulated with injectable medications 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 (now called embryos) are cultured in the laboratory for 1-5 more days and then an appropriate number are selected for transfer to the woman's uterus.
We usually transfer 1 or 2 embryos - see below for more details.
Ultrasound guided embryo transfer technique The embryo transfer procedure seems very similar to a Pap smear for the woman.
There should be no pain involved and no sedation or other drugs are required.
We use a moderately full bladder for embryo transfer.
This helps in 2 important ways.
It allows good ultrasound visualization of the catheter which helps with smooth and proper transfer of the embryos to the best location, and it also unfolds the (anteverted, "tipped up") uterus to a more accommodating angle,making 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" (squirted out of the catheter) to the lining of the uterine cavity (endometrial lining) 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 (uncommon) the transfer procedure is repeated immediately and the catheter is checked again for a retained embryo.
Proper location for placement of the embryos Research has been done to determine the optimal location to place the embryos in the uterine cavity.
Basically, the middle of the endometrial cavity - half way from the internal os 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.
Activity restrictions and bedrest after IVF transfer Typically, the woman lies on her back for 1 hour after embryo transfer before going home and it is requested that she also limit physical activity for the remainder of that day.
This means bedrest after the IVF transfer for the rest of the day and that night.
It does not necessarily mean total "bed rest" but can be hanging out on the couch or in the Lazy-boy recliner - watching videos, reading, bossing hubby around, etc.
"Normal activity" is allowed, such as working, walking around, etc.
beginning 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 probably not a good idea until after the pregnancy test.
Once pregnant, we should be OK to start all that fun stuff again.
IVF embryo transfer and travel For our couples that travel here from out of town for IVF and embryo transfer, it is recommended that they do not fly out on the day of the transfer, but wait until the next day.
For patients that are diving back home - it is acceptable to drive home (regardless of the length of the drive) after one hour of bedrest in our office following the transfer procedure.
When does the embryo implant following IVF transfer? A healthy human embryo will hatch from its shell on day 5-7 after fertilization and implant within hours after hatching out.
So actual invasion of the embryo with attachment to the uterine wall occurs about 2-5 days after a day 3 transfer and within 1-3 days after a day 5 transfer.
How soon to do a pregnancy test after IVF? About 9-11 days after the transfer (9 days for day 5 transfer and 11 days for day 3 transfer), a blood test is administered to find out if she is pregnant.
If embryo implantation has occurred, HCG hormone will be detectable in the mother's blood at that time.
How soon can I do a pregnancy test after IVF? A urine pregnancy test (HPT) after IVF is not recommended.
The reason is that there are a lot of falsely negative results.
A blood test is needed because it is much more sensitive and reliable.
How many embryos can be implanted in IVF? The number of embryos to be transferred is decided by the couple after a discussion with the physician regarding their embryo quality and how it impacts on the risks for multiple pregnancy versus the risk of failing to conceive at all.
As female age increases, the implantation rate of the embryos tends to decline.
This means that the chance that an embryo will implant drops gradually (and progressively) as the female partner ages beyond about 32 years old.
On the baby side of things, a singleton pregnancy is safest.
So, in general, it is preferred that only one fetus actually implants and continues development.
However, because couples fear failing IVF more than they fear the risks of twins, the large majority at our center decide to replace back 2 embryos when the female partner is under 38, 2 or 3 embryos when she is 38-41, and 3 or 4 (if they have that many) if she is over 41 years old.
Transferring this number of embryos seems to result in a "reasonable" balance of high overall pregnancy success rates, and low high-order multiple (triplets or more) rates.