In Vitro Fertilisation treatment consists of different phases, after the patient ovarian stimulation and the removal of her oocytes, the obtained eggs are fertilised by partner sperm or an anonymous donor. After these three phases, the achieved embryos are transferred into the uterus, but how many embryos should be transferred? Which are the necessary requirements to increase the embryo development?
How many embryos should be transferred and of which quality?
Eva Clinics doctors talk about this topic counting on their experience. Nowadays the Spanish law on assisted reproduction allows transferring up to a maximum of three embryos. This requirement is different in other countries like United States where is possible transferring up to four or five embryos, an exaggerated option according to Eva Clinics doctors.
This doesn’t happen in Spain for a logical reason and for prevention. Transferring more embryos means more options of implantation and the result would be multiple pregnancies of two, three, four babies. This happened when assisted reproduction treatment were introduced, an example is the famous case of septuplets in Huelva.
This kind of pregnancy (3 o 4 babies) could be previously seem as a good idea but actually it would cause an high risk for the mother and the babies. For example when a woman gets pregnant with triplets the labour can be induced obtaining 20, 22, o 23 weeks of gestation and these babies would have many problems, like breathing problems.
For this reason in Eva Clinics we always try avoiding multiple pregnancies, starting from triplets, because with twins the risk is considerably lower. The final decision is up to the patient after assessing the options provided by the doctor that will depend on how embryos are placed the transfer day.
In conclusion and as a general rule, how many embryos should be transferred?
- As a general rule two embryos should be transferred.
- Three embryos could be transferred, if required but is unusual.
- Just one embryo can be transferred if the patient clearly claims that doesn’t want to have twins. Despite transferring just one embryo can have twins as well if the embryo is divided into two parts but is a strange situation.
How choosing the best embryo?
Embryo is transferred the third or fourth day when it is in four or eight cells. In Eva Clinics we choose the best embryos depending on the cells number, their size number and degree of fragmentation. With all this information a score from 1 to 10 is established.
The second day embryo is the best when it has four cells and when on the third day it has eight cells.