What is Embryo Transfer and How Does it Work in Thailand?


Embryo transfer is the final element of the in vitro fertilisation (IVF) process. A professional clinic or specialist hospital will use fertility medication at the start of the IVF process to stimulate increased egg production in the female. The eggs are then removed from the female’s ovaries during a minor surgical procedure and fertilised in a laboratory. After fertilisation, the now embryos are returned to the woman’s uterus, and the normal pregnancy process will begin whereby the embryo must become attached to the female’s womb where it will develop.

When is Embryo Transfer Needed?

Embryo or IVF treatment in Bangkok can be required in a range of different circumstances. It usually is when couples are experiencing problems with natural fertilisation. The reasons for this could include:

  • Damage to the fallopian tubes
  • Various ovulation problems
  • Irregular release of eggs
  • Male fertility problems
  • Genetic disorders

Couples who are experiencing any of these problems are potentially suitable for IVF and embryo transfer treatment in Thailand.


The experienced medical professionals at the IVF clinic in Bangkok will carefully select the healthiest eggs for embryo transfer around two or three days before the embryo transfer treatment. If there are a large number of high-quality embryos, some can be frozen if the process is unsuccessful the first time.

The Actual Embryo Transfer Process

The actual procedure is straightforward, although the female must understand that it will involve some invasive procedures. It is similar to a pap smear test, and the medical professional will keep the woman’s vagina open by inserting a speculum inside. It may cause mild discomfort but nothing too severe.

The doctor and accompanying team will use ultrasound for accuracy when trying to place the embryo into the womb. The embryo will pass through a catheter and is a short process usually lasting in the region of ten minutes. If the patient so desires, they can request sedatives, although this is not typically required.

Follow-up Appointments

The clinic will request that the female returns for a follow-up appointment approximately two weeks after the embryo transfer took place. The purpose is to establish if the embryo has become implanted in the womb. If it has, the transfer was a success. It is common for the patient to experience mild vaginal discharge, cramping and bloating after this follow-up appointment.

Different Types of Embryo Transfer

Unlike the extraction of eggs process, which takes place at the beginning of the IVF treatment, after fertilisation, there are several different options that the doctor may choose for the embryo transfer. These include:

  • Fresh embryo transfer: After the eggs have fertilised, they will be allowed to develop for around two days. At this point, your doctor will select the best embryos, which will then be transferred back to the female.
  • Frozen Embryo Transfer: If some of the embryos are not used for the initial transfer or if the eggs are being stored for future use, they can be frozen. Once the patient is ready, the eggs can be thawed and placed back in the uterus.
  • A Blastocyst Transfer: This process is often used when many healthy embryos develop. Doctors will wait to see which develop further into blastocysts. This form of the procedure has a higher than average rate of success in terms of the embryo becoming embedded, although further research is required.
  • Assisted Hatching (AH): The method involves deliberately weaken the outer layer of the embryo before it being transferred to the uterus. Research suggests that this process does little to improve implantation and pregnancy rates.

How Many Embryos are Typically Transferred?

The number of embryos that are transferred back to the female’s uterus is often dependent on the female. In some cases, only one fertilised egg can be transferred, although in many cases, doctors prefer to transfer two or maybe more embryos to increase the chances of becoming pregnant. There is plenty of debate where this is actually necessary.

Current guidelines outlined by the International Journal of Gynaecology and Obstetrics suggest that the female’s age and outlook should be the main determining factors with regards to how many eggs are transferred. Women over the age of 35 typically have two or more fertilised eggs implanted with females under 35 usually only one embryo is transferred. The chances of birth defects are also higher in women over the age of 38.

Success Rates

According to a study published in the International Journal of Reproductive Medicine rates with frozen embryos are around 18 per cent with this figure vary from the mean average with age. According to other studies, it appears that the success rates experienced with fresh and frozen embryos are very similar with both forms of IVF producing very similar results. As techniques improve, success rates will naturally increase, bringing joy to more couples.

Several other factors may also play a more significant effect on success rates. The reason for the problems conceiving naturally is a big factor as too is age, ethnic backgrounds and genetic disorders. Unfortunately, the quality of the clinic or hospital can have a significant impact, especially in countries where regulations aren’t as strict. It is advisable to do your own research before deciding which clinic you will use.

Potential Risks and Sensible Precautions

The process of embryo transfer carries very few risks; however, it is impossible to remove the risk entirely. The most common risks are related to the hormone stimulation, which has been linked to increased risk of blood clotting, potentially causing embolisms or thrombosis.

Other potential side effects include vaginal discharge, bleeding, infections such as urinary tract infections, and complications that may arise when anaesthetics are used. The risk of miscarriage is the same as those experienced with embryos that are formed via natural conception.

Multiple pregnancies, something that can be quite common, present itself as the most significant risk. Multiple pregnancies can increase the potential for stillbirth or congenital disabilities. Statistical evidence points to this being more prevalent in pregnancies from IVF.

Of course, all couples should be made aware that there are no guarantees of success. Both parents should be prepared both physically and emotionally for something that will naturally be very stressful.