Following fertilisation, embryos are cultured under the appropriate conditions in the laboratory, until they are ready to be transferred back to the patient’s uterus. Embryos are cultured in special mini incubators with the use of special culture media. Of course, there is always a possibility that some embryos will not develop.
Embryo transfer is performed on the 2nd, the 3rd or the 5th day following ovulation. On the 2nd day, embryos consist of 4 cells, on the 3rd day of 8 cells, while embryos cultured until the 5th day have reached by then the “blastocyst” stage (see below). We must stress that regardless of the embryo transfer day, satisfactory pregnancy achievement rates are expected.
On the embryo transfer day, the best embryos are selected and placed in the uterine cavity with a special thin catheter. Embryo transfer is performed without sedation and is completely painless. The entire procedure is performed under ultrasound guidance and resembles a simple abdominal ultrasound or Pap test.
Following embryo transfer and for the next 2-3 days, the patient must avoid intense activity. The pregnancy test is carried out 14 days following oocyte retrieval.
The number of embryos transferred depends on embryo quality, as well as on the patient’s age and medical history. When 3 or more embryos are transferred, there is a risk of multiple pregnancy (triplets). At “gennima” we try to avoid multiple pregnancy, which is risky for the pregnant woman, as well as for the embryos. Due to the optimal operation of the embryology laboratory, we have been transferring 2 embryos in patients under 35, with exceptional pregnancy achievement rates (the law allows transfer of up to 3 embryos). In patients over 40, we transfer up to 3 embryos (the law allows transfer of up to 4 embryos). Thus, we avoid unpleasant therapeutic options, such as selective embryo reduction, during which one or more embryos are being selectively removed.
In Greece, the legislation in force (L.3089/2002 and L.3305/2005) states that up to 3 embryos can be transferred in patients under 40, while up to 4 embryos can be transferred in patients over 40 (the older a woman gets, the fewer her chances of becoming pregnant are). In other European countries, legislation is different, e.g. in the UK, no more than 2 embryos are allowed to be transferred in all cases, while in some clinics in Scandinavian countries only one (1) embryo is transferred. This is possible because the optimal operation of the embryology laboratory allows the development of higher quality embryos, i.e. embryos with better chances of implantation. However, doctors as well as couples have accepted the fact that pregnancy achievement rates are reduced when only one embryo is transferred, which is compensated though with reduced chances of multiple pregnancy.
In any case, the couple is fully informed and has a detailed discussion with the doctor about the number of embryos to be transferred.
Mr. Evripidis Mantoudis believes that embryo transfer is “the easiest, yet the most difficult step in IVF”; easy from a technical point of view, but difficult to be properly performed:
• The doctor must be careful so as to avoid injuring the patient’s uterus. For that reason, at “gennima”, we use special catheters that do not injure the cervix or the uterus.
• The patient’s uterus often has a forward or backward inclination (due to anatomy or to a past surgery). In that case, it is more difficult to perform embryo transfer, because the catheter must follow the inclination of the uterus.
• Embryos are particulary sensitive and adversely affected by fluctuations in temperature, pH and oxygen levels. If embryo transfer delays for some reason, embryos are aggravated. Painful and time-consuming embryo transfers have a negative impact on the odds of the cycle in question to succeed.
• If the catheter comes into contact with cervical mucus (which is usually abundant at the time of embryo transfer), embryos may “stick” there; this means that embryo transfer isn’t actually performed, as embryos are not aptly deposited in the uterus.
• Based on numerous clinical studies, embryo transfer must be performed with the help of an ultrasonogram (catheter guidance); the doctor’s clinical assessment alone cannot ensure the optimal result.
For all the above reasons, Mr. Evripidis Mantoudis performs a mock embryo transfer (using the special catheter, without transferring any embryos) in the beginning of every cycle. In this way, the doctor is prepared for possible difficulties and surprises are avoided (the right catheter, the ideal conditions etc. are selected). Mock embryo transfer benefits the patient too, as she knows what to expect and doesn’t feel stressed about this procedure.
On the embryo transfer day, the patient’s bladder must be full, so as to facilitate the ultrasound imaging (1-2 glasses of water are enough). Of course, if pressure from the bladder makes the patient feel uncomfortable, in agreement with the doctors and midwives, she can empty some urine to feel better. During embryo transfer, the patient doesn’t need to hold still, e.g. if she has a cramp, she may move without negative impact on the final result (pregnancy). However, if the patient feels really stressed, taking a mild sedative 2 hours earlier is recommended.
At “gennima”, we encourage the husband to be present at the time of embryo transfer. In this way, the couple has the opportunity to see together, before embryo transfer, the embryos to be transferred, on the special screen connected to the microscope camera in the laboratory. Then the couple receives a written report on the progress of the entire IVF cycle, as well as pictures of the embryos.
Mr. Mantoudis summarises the factors for the “perfect” embryo transfer:
• Experience and technical skills of the gynaecologist who performs the embryo transfer.
• Use of catheters that do not injure the uterus and cervix.
• Patience and no hurry during the embryo transfer procedure.
• Doctor’s qualification to overcome possible difficulties.
• Embryos “charged” on the catheter only when the doctor is sure that everything is fine and that he can proceed without any problem.
• Embryo transfer performed under ultrasound guidance.
Embryo transfer is the most important moment during the attempt of achieving pregnancy with the aid of IVF. Even if everything has been perfect so far (satisfactory response to ovarian stimulation, production of sufficient good quality oocytes, development of good quality embryos), if embryo transfer is not properly performed, the entire cycle is condemned not to have the expected good result.