Embryo transfer is an assisted reproductive technique that sends an embryo back into the mother’s body to develop into a fetus. This is considered a very important step to decide the success or failure of the whole process of artificial insemination. Usually, this technique is performed 48 hours after the egg and sperm are fertilized.
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What is embryo transfer?
Embryo transfer is the next step used in an in vitro fertilization (IVF) procedure that involves inserting an embryo into a woman’s uterus. These are embryos that have been cultured up to day 3 or 5 and used embryos can be either fresh or frozen (stored) embryos created in a previous cycle.
The time to perform embryo transfer is about the 18th to 20th day of the menstrual cycle, when the mother’s uterine lining has reached the standard thickness (9-10mm) with the mother’s health ready. for pregnancy.
The process of transferring embryos
Today, thanks to the advancement of science, technology and technology, the devices used in embryo transfer have minimized pain and maximum impact on the uterus of the woman. Normally, the embryo transfer process will go through 3 processes as follows:
1. Pre-transfer of embryos
1.1. Estrogen use
- Estrogen will be administered on day 2 of the menstrual cycle and the time before embryo transfer is 2 to 3 weeks.
- At this time, the doctor will prescribe oral medicine, in many cases it is prescribed for injection, vaginal or skin paste.
- Estrogen stimulates the growth of the uterine lining and inhibits natural ovulation.
- After about 6-7 days of use, you will be scheduled to have an ultrasound checkup.
- Around this time, mothers need to monitor the development of the quadrant mucosa 3 – 5 days.
1.2. Use Progesterone
- If the endometrium has reached the correct thickness, you will be given Progesterone to create the hormone suitable for embryo implantation.
- Progesterone is recommended to be inserted into the vagina to move directly to the uterus. But can still be used orally, injected or vaginally.
- Progesterone is used before embryo transfer at about 2 to 5 days depending on the stage of embryo storage.
1.3. Prepare for transfer of embryos
After taking Estrogen and Progesterone, you will be examined to determine if the uterine lining is healthy enough for embryo transfer or pregnancy. If you can transfer embryos during this cycle, doctors will advise the date of transfer along with the quality and quantity of embryos to ensure the highest success rate and minimize the risk of multiple pregnancies.
- In case of transferring fresh embryos: Eggs and sperm are successfully fertilized to form embryos and are raised up to day 3 or 5 depending on the quality of embryos. The embryo is then transported to prepare for transfer.
- In case of transferring stored embryos: The embryo, after being previously agreed by the doctor and mother, will be transferred by an embryo specialist working in the laboratory to perform thawing technique.
2. Transfer of embryos
Before transferring the embryo you must hold urine and lie on the transfer table in obstetric position. Nurses will wear sterile gloves to clean the woman’s uterus by placing a speculum, wiping the cervix with a cotton swab and IVF culture medium.
The doctor will do an ultrasound of the abdomen to easily see the lining of the uterus, cervix, uterine position, angle of the cervix and uterus. Through an image on an ultrasound machine, the embryo transfer doctor will insert an external catheter with a metal barrel into the uterine cavity and locate the embryo.
Once the external catheter has entered the uterus, your doctor will fix the external catheter and remove the metal barrel to prepare the inner catheter containing the embryo to be inserted into the uterus.
Right in the embryo culture room, the embryo specialist will insert the clear catheter by rinsing the 1ml syringe with IVF medium, then suction 0.7 ml of the IVF medium to attach the catheter to the syringe and pump out the medium to rinse the catheter. .
The embryo is then aspirated into the catheter in the order of IVF medium – air column – IVF medium containing µl – air – IVF medium 2 µl outside. The embryo catheter will then be referred to the referral doctor.
At this point, the embryo transfer doctor will gently pass the inner catheter containing the embryo through the external catheter to the uterine cavity and slowly pump the embryo into the uterine chamber away from the bottom of the uterus.
The inner catheter is then removed and checked for the catheter’s purity (with mucus, blood or missing embryos) by the embryo practitioner. As a final step, the embryo transfer doctor removes the external catheter, removes the speculum, and completes the embryo transfer procedure.
3. Post-transfer
After the embryo transfer, you will have to lie down for 1-2 hours to monitor, if everything is stable then you can go home.
The doctor will prescribe oral or order medications for 14 days after embryo transfer. You must follow the dosing rules instructed by the nurse, such as taking it on time, at the correct dose, and by mouth. Absolutely not arbitrarily use any medicine without the prescription of a doctor, including supplements, herbal remedies, …
Regularly move gently, limit up and down stairs, exercise vigorously or exercise. But also do not lie motionless because it may increase the risk of venous thrombosis.
If you encounter any unusual signs: Vaginal bleeding, fever, abdominal pain, constipation, urinary retention, … need to quickly see a doctor for advice and appropriate and timely treatment. .
When is the best embryo transfer?
Eggs and sperm after being fertilized to form embryos will be cultured in an embryo culture cabinet. After 3 days, the embryo will split up to about 8-10 embryos and can transfer into the mother’s womb.
Day 5 embryo transfer has a 1.35-fold higher chance of conceiving than a day 2 or 3 transfer with a 70% success rate. This is an advanced technique that reduces the risk of miscarriage due to a more carefully selected embryo. At the same time, the 5th day embryo transfer will also limit the possibility of multiple pregnancies, because each time embryo transfer, the doctor will only transfer from 1-2 embryos.
Furthermore, pre-implantation genetic screening helps to eliminate the risk of the fetus having a genetic birth defect and is best done with day 5 embryos. Because, to conduct screening it is necessary to biopsy takes a few cells from the embryo, so those on 3 days have only 7-8 cells and screening will be able to affect the embryo.
However, not all cases are allowed to cultivate embryos until day 5 because the culture of embryos is longer than that of day 2 and 3 and can reduce the number of qualified embryos or even no longer qualified embryos for embryo transfer. Because, only embryos that are very strong can develop for a long time.
According to statistics, the average doctor has about 10 eggs per woman. These eggs will be sent for in vitro fertilization with about 5-6 embryos on day 2, cultured on day 3, there are about 4-5 embryos and by day 5, only 2-3 embryos remain. For women with poor embryo quality, there will be no more embryos left over time.
Although the 5th day embryo culture will be highly effective, it is only suitable for young women with many good 2nd and 3rd day embryos or in cases where there have been many failed embryo transfers or the need to perform pre-transfer screening. . For older women, there will be fewer good embryos on days 2 and 3, so transferring embryos on days 2 and 3 will have a better chance of conception.
How long after transferring embryos?
In many cases, the signs of success will be evident on the mother’s body. After the 1st, 2nd, 3rd, 4th day embryo transfer, … you will start to appear signs such as headache, nausea, urinating many times.
The most important time after embryo transfer is day 5, because this is when the embryo has found a place to nest. At this time, mothers need to pay attention to gentle movement and movement to avoid affecting uterine contractions along with adding essential nutrients to daily meals.
Usually, the successful embryo transfer is encountered such as:
- Chest tightness, difficulty breathing, headache.
- Pain and heaviness in the lower abdomen.
- Back pain, side pain.
- Pregnancy report bleeding.
Should transfer fresh embryos or stored embryos?
According to many medical studies have demonstrated, the success rate between fresh embryo and stored embryo is the same or in other words that the nesting capacity of fresh embryos and stored embryos are equal.
At present, the embryo and thawing technologies will ensure that the embryo quality is not affected. Theoretically, once embryos have been frozen they should be able to be stored indefinitely.
Therefore, transfer of fresh or stored embryos must also depend on the pathological status, health, thickness of the uterine lining and the quality of the embryo of the woman at the time of embryo transfer preparation.
If all the factors are good, the mother can transfer fresh embryos immediately. However, if you are in poor health or have not yet scheduled the implementation time, you can transfer frozen embryos to the next cycle or in a few cycles.
Why is transfer of stored embryos more indicated than transfer of fresh embryos?
Whether transferring stored (frozen) or transferring fresh embryos has about the same success rates. However, the tendency to transfer frozen embryos is increasingly being used by the following advantages:
- Frozen embryo transfer enables doctors to choose a time when a woman’s hormones are stable and appropriate to transfer the embryo and increases the chances of conception after ovarian stimulation. If the hormones in the body are raised many times higher, it is not good for the embryo to implant.
- The woman will have time to fully replenish and prepare well for the upcoming pregnancy instead of immediately using the fresh embryo to conceive.
- Reduces multiple pregnancies. This is a very dangerous condition, which directly affects the health of the mother as well as the fetus. Transferring multiple embryos at a time increases the chances of conceiving, but is also extremely unpredictable. Therefore, using frozen embryos will help reduce this situation.
- Frozen embryo transfer is indicated in cases of uterine fluid or ovarian hyperstimulation failure to transfer fresh embryos.
It can be said that embryo transfer is a fertility support method and helps to bring hope to become parents of infertile couples. Besides performing embryo transfer, you should also eat, rest and exercise under the guidance of your doctor to help the rate of embryo transfer be successful from the first time.
