Understanding your friend's IVF Cycle | Stage by Stage

4:26 pm


During an IVF cycle when you start to tell friends and family what's happening on the timeline, is probably exactly when you realise that the knowledge you have about eggs, sperm, egg collection, fertilisation, embryos, blastocysts, embryos transfer, implantation and chemical pregnancies is not known by everyone.  In fact, it seems to be its own little language that people do not understand.

For an easy way to understand the IVF process, lets go over the basic timeline of how eggs start in the female to becoming a pregnancy.  The entire process is normally around 30 days and your friend will be grateful that you understand the complexity of what happens.

The misunderstanding that eggs are taken out, fertilised and out back in is all too common.  This can be frustrating for someone going through IVF as they need to deal with the hormones they are taking,  the various critical moments during the process and they also have to deal with the reality that this may not work.  Also, it may not be the first time they have done this and after several attempts it becomes a very difficult struggle where support is greatly appreciated.

So what are the various processes that occur during IVF, read on.

Stage 1 - Collecting Eggs (10 - 18 days)

One does not simply pop to the clinic and they take your eggs out.  Normally, only one egg is released from a lead follicle on one of your ovaries each month during ovulation around day 14 of a cycle and many more than that are required to have a chance of getting pregnant.

Before anything can begin a scan is performed internally on day 2-5 of a cycle bleed to ascertain if the lining is thin enough and the ovaries are quiet enough to begin.  If all is well, the injections that are the better known part of IVF commence.

Stimulation medication in an injection is taken to make the ovaries produces multiple follicles of a size big enough to hold mature eggs.  Each follicle that develops has one egg and these follicles must measure above 14mm to have a chance of holding mature eggs.  Yes, not all eggs can be fertilised, only mature ones.  You see, already the odds are dropping and the eggs are not even out yet.  Welcome to IVF.

What stops the body from naturally releasing the eggs you ask?  Every day alongside the stimulation injection, a second daily injection of a down regulation medication tis administered that tells the body not to do anything such as ovulate.

When the follicles are deemed big enough, a procedure known as egg retrieval is performed.  This removes the fluid in each follicle and the egg inside.  It is performed vaginally, with an internal ultrasound wand whilst the female is sedated.  Not all follicles contain eggs so knowing how many is a lottery.

Eggs are counted after egg retrieval and the amount is advised.  Clinics need to let eggs rest before being able to know how many are mature.  Some ladies may be lucky and all eggs may be mature and for some, only half the amount collected may be mature.  For some ladies, no eggs may be mature and the cycle is cancelled.

Once eggs are assessed and some are confirmed to be mature, the next stage is started that same day.

Stage 2 - Fertilisation (1 day)

A few hours after eggs have rested, they are fertilised and by the morning following this procedure, a telephone call will be made by the embryologist who checks the incubator.  They will advised of the eggs collected how many were mature and could be fertilised and how many successfully fertilised.

This is when numbers can really drop for some people.  Some are very lucky and all eggs are mature all fertilise normally.  For others the mature numbers are lower and the fertilised number is lower still.  Someone could start with 13 eggs, only have 9 mature and only have 4 fertilise.  Suddenly that huge number of 13 is now only 4 and there are 5 more days to go yet.

Sometimes none of the eggs fertilise and the cycle is cancelled.

Stage 3 - Monitoring Cleavage of embryos (1-5 days)

And I do not mean gracing the what was 3rd page of The Sun with your eyes.  This is when the embryologist monitors the embryo development.  Those fertilised eggs are no longer eggs, they are embryos.  The cleavage process is when the embryo splits to 2 cells, then those both split to 4, then to 8, and so on.  It's a simultaneous process normally of a properly developing embryo.

Embryos are generally dated from the days after they were collected.  So if egg collection and fertilisation happened on a Monday, on Tuesday it would be deemed as day 1 and the embryo should be 4 cells.  By day 3, they would be expected to be 8 cells.  At 3 day, the Embryologist calls again to advise on the progress of the embryo development and typically states the number of embryos at each stage.  For example of those 4 that fertilised, only 2 may be at cell stage 8, 1 at 6 cells and 1 at 5 cells.  This means they are all developing but at different rates.  The embryologist will indicate the ones at 8 cell are currently looking like the strongest.

If the development is slow or the numbers are reducing this fast, the Clinic may call in the female for an early 3 day transfer.

If there are enough embryos developing well that the embryologist is unable to specify the strongest embryo yet, they will wait until day 5 to review and transfer.  Waiting to day 5 means the embryo goes from being an 8 cell embryo to a blastocyst which has various parts to it, including the inner cell mass (which becomes the baby) and it contains well over 100 cells by this stage.  Because this stage is more advanced, it is easier for Embryologists to determine which are further advanced and ready for transfer.

During the cleavage process sometimes no embryos develop properly and the cycle is cancelled.

Stage 4 - Transfer (1 day) 

Once it is advised that embryos are suitable for either the 3 or 5 day transfer, the number of how many can be transferred is discussed.  Depending how many previous transfers the female has had may determine the number transferred.  Also the quality and growth rate will help the Embryologist decide on the advice.  Also, the age of the female and what country the transfer occurs determines the number that can be transferred.  In the UK, first transfers are single embryos unless the quality is very low and then 2 may be will be transferred.  Normally only someone over 40 will have 3 transferred.

Sometimes a hatching blastocyst embyo or an early blastocyst that needs to finish expanding and hatch is transferred.  The difference in the stage will ultimately add time to how soon a positive test can be seen.  Only a hatched embryo that escapes the shell can implant the uterus lining.

Stage 5 - The 2 week wait and pregnancy testing (13-15 days)


This time is known as PUPO - Pregnant until proven otherwise.


This is also a very difficult stage whilst waiting for the embryos to implant and start producing HCG. It is the HCG released that is in the urine that is detected which displays that all wanted second line that denotes a positive pregnancy test after transfer.

Some get the line as early as 3 days past 5 day transfer (known as 3dp5dt in the IVF community) and for others it does not appear until 8dp5dt or as late as 13dp5dt.  Whether tests are performed early or not is up to the female undergoing IVF.  Some wait patiently until 13dp5dt for a definite clear answer and others test daily from 3dp5dt to see progression of the test line as it darkens with the HCG increasing.  If by 13dp5dt a line is visible, many then have an HCG beta test to find out the HCG levels in their blood and repeat this 2/3 days later to check the result is doubling as it should at that stage.  This would indicate a correctly progressing pregnancy.

A faint line at any stage means pregnant, however, as many ladies find out, this can also remain faint and indicate a chemical pregnancy.  A chemical pregnancy means it has not progressed and a loss occurs.  If lines are faint around official test date, blood beta HCG tests are recommended to monitor the progression.

Read more about faint lines, testing early and chemical pregnancy loss here.


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