How IVF Works

What is IVF?

How medicine works, even how IVF works, is fascinating to watch and understand. Everyone loves a good Lifetime movie or Grey’s Anatomy drama. However, contrary to the excitement and tension you see on television shows, medicine is often quite routine.

In a fertility clinic, so much of what we do is tedious: Rules and regulations, protocols and procedures! But sticking to these detailed protocols is what keeps our patients and their embryos 100% safe with no mistakes.

It may be tedious, but it is essential.

The process of IVF treatment is now routine in IVF labs in every country in the world. It is difficult to believe, but upwards of two million IVF treatment cycles are done every year globally. I have been a fertility doctor for more than a decade and yet many of the procedures we do every day as part of IVF treatment still amaze me. There are times when I know I have watched or participated in something incredible.

How IVF Works

IVF is a treatment that grows and collects eggs from the woman, then brings sperm and eggs together in the IVF lab. When the sperm and eggs get together, we are hoping for many of the eggs to fertilise, creating embryos.

Those embryos grow for between two to six days in sophisticated incubators in the IVF lab. The best one or two are then chosen and placed gently back inside the womb. This is called the embryo transfer procedure. If an embryo latches onto the womb lining and starts growing, then you have a pregnancy!

Some people are lucky and have surplus embryos, which are not needed for the embryo transfer. These embryos are graded and if they are of good quality, they can be frozen. Frozen embryos can be used to try for another pregnancy in the future. This is called a frozen embryo treatment cycle.

The Process of IVF Treatment requires a Team of Experts with Different Skills

There are five phases to IVF treatment. Some of these phases require medical experts, while others require scientific experts. This makes IVF treatment unique compared to most other types of medical treatment. It is essential to have this team, with its two types of specialists, working together, otherwise IVF would never work.

The five phases that make up the process of IVF treatment are:

  1. Choosing the right patient for IVF
  2. Growing and collecting the eggs
  3. Processing the sperm, then getting the sperm and eggs together for fertilisation
  4. Managing embryo growth and assessing embryo quality
  5. Embryo transfer and freezing of surplus embryos.

How IVF Works in the Lab

First, the clinical team (the medical experts) advises which patients are suitable for IVF treatment and gets the patients ready for treatment. The clinical team are then responsible for growing and collecting the eggs. We use high resolution ultrasounds along with hormone blood tests to monitor the growth of these eggs and decide on the best day and hour to collect the eggs.

It’s not as easy as you would think! Use the wrong type, combination or dose of drugs and either too few or too many eggs will grow. Choose the wrong time for the egg collection and you might waste the eggs as they are immature and will not fertilise.

The eggs are collected during an ultrasound guided procedure through the vagina. Collecting eggs from a woman’s ovaries still humbles and amazes me. During this procedure, the doctor empties each egg sac gently with a fine needle and passes the fluid to the embryologist (a scientific expert!) in the IVF lab. Eggs cannot be seen with the naked eye, so the embryologist finds the egg by looking at the fluid with a microscope. If all goes well, the doctor hears the embryologist cheerfully shout out “egg” over and over again!

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How IVF Works also Depends on that Male Factor

As each egg is found, the doctor moves around the ovaries until they have got all of the precious eggs. This egg collection procedure is done is semi-darkness, in a warm theatre, to mimic the natural environment inside the body. No-one wears perfume, hair spray or smelly body products. Why? Because these might release chemicals into the air possibly damaging the fragile eggs, embryos and sperm growing in our incubators. As the embryologist finds each egg they wash it and tuck it safely away in the incubator to stay warm.

On the day the eggs are collected, we also need the sperm. The scientific team processes the sperm and prepares it for the eggs. The scientific team then brings the sperm and eggs together. They have two choices to give the best possible chance of success at this point: IVF or ICSI (commonly called sperm injection).

If IVF is chosen, the sperm are placed around the egg in the hope that the best sperm will find their own way into the egg.

If ICSI is Chosen

If ICSI is done, the best shaped and fastest swimming sperm are chosen and injected into the egg. ICSI requires great skill! You do not want to damage the sperm or the egg as you do the injection. I try to sneak into the IVF lab if I can find time to watch the embryologists injecting eggs with sperm.

First, they gently clean the eggs, removing the cloud of cells around the shell. Next, they look at the man’s sperm sample and choose a healthy-shaped, fast, swimmer. They crush the sperm’s tail to stop it swimming, suck it up into a tiny pipette and then, using a robotic microscope, they expertly inject the tiny sperm into the egg. These are the days when I am just in awe at this fantastic job I have!

Egg Fertilisation and Transfer

The next day, the scientific team looks for signs of egg fertilisation. If a sperm fertilises an egg, the egg cell begins to divide from one into two cells. At this point it is called an embryo and is a new life. It is still a microscopic structure, only visible under a high-powered microscope.

The scientific team keeps this embryo safe for the next few days. The embryos are carefully nurtured in incubators, where special combinations of gas and temperature ensure that they get a constant and consistent supply of all the nutrients they need. After three to six days the embryologist assesses all the embryos for quality. The embryologist then chooses the embryo or embryos most likely to make a baby.

The last step is the embryo transfer procedure. This requires the embryologist to load the chosen embryo or embryos into a fine, flexible tube called a catheter. The embryologist passes the catheter to the doctor. The doctor’s job is to get the catheter to the ideal place inside the womb for a baby to grow. When the catheter is in the ideal place, the doctor holds the catheter steady while the embryologist gently ejects the embryo from the catheter.

The embryologist will now freeze any good quality surplus embryos. The clinical team will ensure the correct medications are given so the lining of the womb is as thick and sticky as possible for the embryo to find a nice place to latch on and grow. The IVF cycle finishes 10 to 12 days later with a pregnancy test.

Does IVF Always Work?

One full IVF cycle takes about three weeks. And, while IVF is the most effective form of assisted reproductive technology, there are no guarantees. IVF may not work the first time, or even the second. If it does not, there is lots of counselling and medical support on hand to help you deal with an IVF failure. Your fertility doctor will help you understand the next, best steps, including whether to opt for another IVF cycle.