Oocyte Retrieval Day (Day 0)

On this day, the embryologist has the important task of preparing the couple's eggs and sperm so that fertilisation can take place. Insemination is carried out by either placing each egg into a droplet of washed sperm suspension (IVF) or by injecting each egg with a single sperm (ICSI). After this, the eggs and sperm are left undisturbed in the incubator which is set at body temperature (37oC), a gas environment of 5% CO2 and 100% humidity, which are the exact conditions found in the fallopian tubes and womb of women.

Day 1

Fertilisation is being determined 16 to 20 hours after insemination.  The fertilised eggs are carefully separated and transferred to new droplets of culture medium. They are then returned to the incubator where they are kept until the next morning.

Day 2 to Day 6

The couple's embryos are taken out of the incubator and graded as good, fair or poor, using a microscope once every morning. Grading of the embryos is carried out very quickly and they are then returned to the incubator. The embryo culture medium is also changed according to the developmental stage of the embryos. This is again carried out very quickly but yet accurately and gently. A lot of respect and dignity is paid to the embryos by the embryologist.

The following is the developmental stage of the embryos on different days after fertilization:

Day 2    4-cell stage

Day 3    either 8-cell stage or compacting stage

Day 4    compacted stage (16 to 32 cells)

Day 5    either cavitating or early blastocyst stage (> 50 cells)

Day 6    either expanding or fully expanded blastocyst stage (>160 cells)

At the time of the replacement, Assisted Hatching may be done. This is to increase the chance of pregnancy in some patients; your doctor will discuss this with you.

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Copyright © 2007 O & G Partners. All rights reserved. Last update: 11/02/2008