In Vitro Fertilization: Embryo Culture

In the assisted reproductive technology method of In Vitro Fertilization (IVF), embryo culture is an important process. Although all the steps of IVF have to be performed very accurately to get a positive outcome, the embryo culture stage is more crucial in determining the success rate of IVF.

What Is an Embryo Culture?

When a fertilized egg (zygote) grows, it is referred to as an embryo, and thus embryo culture refers to the formation of zygote and its development to embryo. In IVF, eggs (oocytes) are retrieved from the woman; immediately after this retrieval, In Vitro Fertilization is performed. In other words, the sperms from the male partner are combined with the eggs for the formation of zygote. This zygote is allowed to grow into an embryo, and this embryo culture process may take 2 to 5 days for completion.

Zygote Formation

During the IVF process, your follicular fluid is aspirated and taken to a sterile laboratory environment. Then eggs in this fluid are examined under a microscope. Toxins and impurities present (if any) are removed by washing each egg and its surrounding cells with a special medium. Washed eggs are separated and placed in separate dishes. These egg-containing dishes are then transferred to a special incubating setup having carbon dioxide. Thus, eggs are preserved until they mature for fertilization (usually 2 to 6 hours).

The dish containing mature egg is supplemented with a culture medium having antibiotics, protein and salt. Then, washed sperms from the male partner are combined with each of the eggs and placed back into the incubator.

Controlled Monitoring

The success rate of IVF depends on selecting good quality embryos for transferring. Hence, after the fertilization process, embryos are carefully monitored in a controlled environment. Within 18 hours of development, there should be two clear bubbles seen in an embryo, which confirms the pronuclei stage. Generally, embryos without the pronuclei are discarded. After a day, the cell division of the embryo is monitored, and good embryos have divided into 2 or 4 cells at this stage.

Duration of Embryo Culture

Duration of embryo culture is decided based on your reproductive history. Embryo culture is done for 2 days if you have poorly developing embryos or a low number of viable embryos. It is done for 3 days when increased monitoring of the embryos is required. If you have a history of repeated IVF failures or miscarriages, embryo culture is done for 5 days.

Control Environment

An embryo can grow properly when the control factors are monitored strictly. The control medium in which the embryos grow is really important for the proper growth of the embryos in IVF procedure. Another important factor is the temperature maintained in the incubator. Fallopian tubes have a temperature of 37 degrees Celsius inside, and hence, this temperature has to be maintained in the incubator. Controlling these factors will ensure the survival of the embryos during this process.

Success of IVF treatments are governed by many factors apart from the quality of embryo. Hence, it is important to have realistic expectations while undergoing IVF treatment instead of believing that you will surely become pregnant.

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