How Does IVF Work: What can you expect from the IVF process?

Introduction to the IVF Process

This guide will take you through what to expect on a standard IVF process (In Vitro Fertilisation). It will assume the assessment has been made already and take it from your first appointment at the clinic. We won’t go into detail of each part; however more detailed links will be provided throughout the guide to further information on each step. For those who prefer video check out our IVF process video’s below.

Overview of the IVF process

IVF involves 5 basic steps outside of appointments and consent. These are downregulation of the cycle, ovarian and follicle stimulation, egg retrieval, fertilisation and finally embryo transfer. For those more visual see the flow chart to the left and the image below. This article will only be dealing with the process, if you are interested in the medications involved with IVF then check out our article What medications will I take & how will they impact me?

IVF Timeline

Downregulation during IVF

This will involve injecting medication (normally Buserelin in the UK) on a daily basis to reduce the thickness of your endometrial layer and stop activity in your ovaries and follicles. This is normally taken for a 2-3-week period. You will have an ultrasound to check the thickness of your layer and activity of your ovaries, once this has happened you move onto the next set of drugs.

Ovarian and Follicular stimulation during IVF treatment

During a normal cycle one follicle develops containing a single egg which comes into maturity, however during IVF treatment you will take a drug usually a gonadotrophin (usually Menopur, Follistim or Gonal F in UK) to encourage your system to increase multiple follicular development in your ovaries, create mature eggs and increase the thickness of your womb. Your clinic should give you a fact sheet or leaflet explaining how these drugs could impact you.

You will be monitored fairly carefully during this phase of treatment and often have blood tests and a transvaginal ultrasound to look at the number and size of your follicles, the specialists will use this to ascertain the right time for egg retrieval. One of the other reasons that you are monitored closely during this phase of treatment is the risk of developing OHSS (Ovarian Hyper Stimulation Syndrome) which can be potentially serious, you can learn more about this in the possible risk section below.

36 hours before the egg retrieval you will have to take your HCG trigger injection (human chorionic gonadotrophin) this is given to start the final process of egg maturation; it is vital that this is timed correctly.

Egg retrival for IVF

This is performed 34-38 hours after your HCG injection. You will be admitted to the ward and your partner if not using donor sperm will need to be present. You will be asked to confirm your name and DOB many times to ensure that that it can be 100% that the right eggs and sperm are matched for insemination and fertilisation.

The male partner will give a sample, this is usually by a normal semen method into a sterilised appropriate container. However, there are some circumstances where if a sample can’t be produced or the man has no sperm present in their semen where surgical extraction may be necessary.

The woman will be taken to a sterile room and is generally sedated and made to feel comfortable, for some this may also be done under general anaesthetic. If you are prone to nausea/vomiting be sure to mention this to them as they will give you a prophylactic antiemetic (anti sickness drug) to prevent this. They will use an ultrasound probe vaginally to guide them and then a needle is inserted into every follicle through the top and walls of the vagina and they suction out all the fluid to retrieve the eggs.

You will be allowed to go home about 4 hours after the operation and must have transport to get home and rest for 24 hours with someone around.

IVF Insemination and Fertilisation Process

At this point your work is done and the embryologist takes over. The eggs are placed into a liquid called a culture medium and then placed into an incubator.

The male sperm is analysed and prepared at this point. If good quality sperm are present and the count is good, then they select active sperm and place these with the eggs and allow fertilisation to happen naturally. However, if the sample has low numbers or very low normal forms the embryologist may use ICSI (Intracytoplasmic sperm injection) which essentially means the embryologist will select a sperm and directly inject it into the embryo.

Fertilisation is usually complete after about 18 hours you will often receive a call from the embryologist the day following retrieval to let you know how many were fertilised. 12 hours after fertilisation the embryo’s begin to divide. By day 3 they normal cellular division would be around 7-8. You should receive a call on this day to tell you the status of each embryo. It is possible if the embryologist thinks the greatest chance of success is to transfer them on day 3 you would be asked to attend for transfer on this day. This is often a double embryo implant to maximise chance of success – however in NHS clinic this is becoming a less common practice due to the additional chance of getting pregnant with multiples.  Leaving transfer to day 5 it is common practice to only implant a single embryo to reduce the additional risk associated with non-singleton pregnancies, is something that is monitored closely by the HFEA (The Human Fertilisation and Embryology Authority). However, your embryologist will advise the best time for transfer in your specific circumstance.

Embryo Transfer During IVF

The normal process is for a day 5 implant of a single embryo. Embryos are graded by a detailed allocation and a day 3 grading and day 5 grading are different. The day 5 grading usually uses the Gardner system shown to the right.

The treatment itself is performed in a sterile room, which has a microscope and imaging software to allow you to see your embryo or blastocyst. The treatment is usually painless but can be a little uncomfortable. It is often done under ultrasound guidance and tube filled with fluid and your embryo is fed through your cervix via a speculum to the top of your womb where the embryo is ejected. The tube is then thoroughly checked under the microscope by the embryologist to be 100% sure that it has been transferred as the are naturally quite sticky.

 Post Embryo Transfer Process

You will then have what is termed luteal support, this is often pessaries which is inserted vaginally but can be an injections or gels. This contains progesterone and is used to support your womb lining and encourage implantation of the embryo into the endometrial lining.

It is possible that if you had many good quality embryos that you may be offered for these to be frozen to be used in future cycles/treatments. This is a personal choice and some decisions need to be taken before.

Finally 14 days after egg retrieval(so 9-11 days after your transfer) you will have your blood test which will look at HCG levels. There are three types of result from this which could be a negative result (normally a HCG result below 5 mIU/ml), positive result (ideally a HCG result above 50 mIU/ml) or inconclusive result (between these 2). An inconclusive result can be caused by a number of things, drug interactions, high caffeine intake and other rarities such as developing anti-bodies for HCG or unfortunately a non-viable pregnancy.


What are the key Risks assosiated with IVF?

No medical procedures and treatments are risk free and IVF is no different, the key risks are: –

OHSS – Ovarian Hyper Simulation syndrome occurs in about 2-3% of IVF treatments. It can be serious and require hospital admissions to treat. Symptoms include, swelling, nausea and vomiting, shortness of breath, headaches. These symptoms should immediately be reported to the clinic or failing that attending A&E. If conception occurs these symptoms can worsen and last for much longer.

Procedural risks – As with any internal invasive procedure you can have bleeding approximately 1 in 100 will have vaginal bleeding of more than 100ml. Infections (usually urine) occur in 1 in 300 cases

Ectopic Pregnancy – Can occur in any pregnancy but has a slightly higher instance in IVF. This is where the embryo implants in the fallopian tubes or the cervix. It can cause major internal bleeding and other serious problem. This is usually picked up with the HCG blood test and an ultrasound, but not always.

Ovarian Torsion – This has an increased likelihood due to the size of the ovaries during stimulation. It causes intense pelvic pain and is a medical emergency usually treated with surgery.


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