IVF Time Table

The approximate timetable post insemination(mixing of egg and sperm) In IVF

Day 0:
Egg retrieval
Sperm collection and preparation

Day 1
Check eggs for fertilization, usually should happen by 17-18 hours post insemination
Day 2
Embryos  divide and reach 2- 4-cell or more stage of development Embryos can be transferred  into uterus to achieve pregnancy.

Day 3
Embryos at the 8-cell or more stage of development, embryo can show uneven blastomeres or signs of fragmentation. Usually this is the stage where embryos are replaced back into the uterus.

Day 4
The Morula Stage
Embryos at the compacted morula  stage, the number of cells vary between 16-32 cells. The embryo continues to divide and the distinction between the cells becomes difficult to see.

Day 5
The blastocyst stage
Embryos  continues developing and starts to cavity and cells starts forming two parts ,one which will eventually develops into fetus and other which will form the placenta. As it grows further, theembryohatches out of the Zonal or the outer shell, ready to implant.

Numeric grading systems for multicell embryos usually have 4 levels:.
Grade 1: even cell division, no fragmentation
Grade 2: even cell division, small fragmentation
Grade 3: uneven cell division, moderate fragmentation
Grade 4: uneven cell division, excessive fragmentation
Blastocysts are graded differently with a number and two letters.

The number refers to the degree of expansion of the blastocyst (1 is the least expanded, 6 is the most expanded).

The first letter (A,B, or C) refers to the quality of the inner cell mass (the part of the blastocyst that is going to be the baby)

The second letter (A, B, or C) refers to the quality of the trophectoderm (the part of the blastocyst that is going to be the placenta).


The fertilized eggs on day 5-7 divides and contain approximately 60-100cells. The embryo now starts forming cavity and the cells are now divided into two area, inner cell mass, which will develop into the fetus and outer layer, which will develop into placenta. In natural pregnancy the embryo leaves fallopian tubes at this to enter the uterus.

In blastocyst culture, the embryos are cultured to day 5 and if they survive and develop are transferred to uterine cavity. The blastocyst culturing requires a fully equipped lab, and embryologist trained in blastocyst culturing assome or all embryos may not survive and  a embryologist would be able to identify and if required advise for day3 transfer or freezing.

The advantage:

The implantation potential of blastocyst is better, as in a natural cycle this the time the blastocyst enters the uterine cavity.
The chance of multiple pregnancies is decreased, as few embryos are transferred.
The blastocyst stage embryo does not survive the freezing, so the option of cryopreservation is not available to these patients.
Who should be advised to go for blastocyst culture?

Multiple failed IVF

Patients with good quality embryos
Patients with more embryos ,There is a 50% chance of survival
To avoid multiple pregnancy