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In Vitro Fertilisation (IVF)

What is IVF?

If the male's sperm parameters are normal, IVF may be the most appropriate treatment option.

IVF involves artificial fertilisation of egg and sperm in the laboratory.  This may be done with husband or donor sperm.  The egg and sperm are mixed together and allowed to fertilise naturally.  A specific quantity of sperm cell is mixed with each egg in an IVF fertilisation dish (Petridish).  The dish is placed in an incubator overnight to aid fertilisation.  Couples are notified of the number of fertilised eggs the next morning.

Conventional IVF treatment is highly recommended for couples diagnosed with unexplained infertility or cases of tubal blockage. Usually all fertilised eggs (embryos) are cultured in the incubator for possible (cleavage stage) embryo transfer on day 2, day 3 or day 5 blastocyst embryo transfer.




IVF is a licensed treatment and is regulated by The Human Fertilisation and Embryology Authority (HFEA) in the UK.


What does the treatment involve?

Click here to see the Simplified IVF Process.


We currently use two IVF/ICSI cycle types.  Click on the links to find out more:

  1. Short Antagonist protocol: uses GnRH Antagonist and Gonadotrophin injections

The team will decide which protocol best suits your individual circumstances. The protocol for each cycle is tailor-made to the individual based on various parameters, including hormone test results, previous cycle response and associated medical history. This will be discussed with you at your clinic appointment.

You will be given a 'teach' appointment in which the nurses will show you how to inject yourself at home with the appropriate medications.

Each treatment cycle lasts approximately 6-8 weeks.


Whichever protocol you are on, there are several stages that are common to both:


1. Ovarian Stimulation

Stimulation phase of the cycle with gonadotropin injections

  • You will need to have daily injections of gonadatropin.  The drug dose is decided based on Anti-mullerian Hormone (AMH - A hormone test that ascertains the ovarian reserve of eggs) blood test results.  The dose of the drug might change during treatment depending on response.
  • Injections are subcutaneous (beneath the skin) - given through the abdomen or thigh.
  • The site of the injection should be altered daily - usually from side to side (left/right).
  • We recommend you do the injections at the same time every day (between 4.00 pm-8.00 pm).
  • You may experience a feeling of heaviness or pressure inside the abdomen as the ovaries get bigger - this is normal.
  • It is important to follow all instructions on drug dosage and timing.  You should inform us immediately if there are any problems with this.
  • The injections are normally given over 10-12 days, although this may be extended if your response is suboptimal.

Trigger injection

  • An hCG injection is the last and final one before egg collection is done.
  • Timing of this injection is VERY CRUCIAL.
  • The injection must be taken at the time advised by the Unit (this is exactly 36 hours before egg collection and will therefore be based on the expected time of your egg retrieval procedure).
  • This is a late night injection (timing starts from 9.00 pm in 30 minute intervals).
  • If you miss your allocated time slot, please DO NOT inject at any other time as this can compromise your treatment.
  • Ring the Unit first thing the next morning as we might be able to provide a new time slot for you - occasionally this is not feasible and could lead to cancellation of the cycle.


2.  Support and Monitoring

You will be required to attend for scans and blood tests to monitor how the follicles are developing.

Scanning is performed 3-4 times throughout each treatment cycle.

All scans during the treatment cycle are done vaginally and in the morning along with blood tests - between 8.00 am and 10.00 am.

  • Pre-treatment scans are done within 3 months of the cycle starting to rule out problems that can affect treatment success such as polyps, fibroids, endometriosis and ovarian cysts.
  • Down-regulation scans are rarely done following Buserelin injections (long protocol). The scan will only be required if the blood tests done following the menstrual bleed do not indicate the desired effect on the lining of the womb (thin lining) and ovaries ('quiescent' - meaning there is no ongoing follicular activity in the ovaries).  2-3 scans are usually done during the treatment cycle to monitor the response to treatment - by way of growth of follicles in the ovaries.


3.  Egg Collection

  • Egg collection is a vaginal procedure performed under ultrasound guidance.  The procedure lasts 20-30 minutes.
  • You will need to starve from midnight before egg collection (this means no food, drinks, water, sweets or chewing gum).
  • The procedure can be performed under IV sedation, although on occasions general anaesthetic (GA) can be used.
  • Please be aware that not all follicles seen on scan yield eggs.
  • You may experience some pain and bleeding after the procedure.


Leaflets available:

Advice before and after egg recovery

Sedation for patients undergoing egg recovery


4.  Sperm on the day of egg collection

  • On the day of egg collection, the male partner is asked to provide a fresh sample of semen, produced on site in the Andrology Department.
  • If you have difficulty producing, it is important that you inform staff prior to start of treatment cycle.
  • Some couples may have sperm frozen previously or may be using donor sperm.
  • If sperm parameters on the day appear suboptimal, we might consider ICSI rather than IVF treatment (this will be discussed and agreed with you).  For more information about ICSI, please click here.


5.  Egg Insemination

If the sperm parameters are normal then the egg will be inseminated using IVF, whereby the embryologist will prepare the eggs and sperm and mix them together in a container (Petridish) and allow them to fertilise naturally.

If there are any concerns about the sperm, the ICSI method will be used.  This involves taking up a single sperm in a fine glass needle and then injecting it directly into an egg.


6.  Embryo Development and Progress

During IVF, the embryos are cultured for up to six days and they are graded when necessary.

Grading is necessary in order to evaluate your embryos to decide which ones(s) should be selected and replaced into your uterus and which ones, if any, to store.

There are a number of ways in which embryos can be graded.  At Saint Mary's we assess embryos by carefully evaluating and scoring some aspects based on their morphological appearance. For example, you can have 2 to 4 cells after 48 hours, and 7-10 cells after 72 hours. The cells in an embryo are referred to as the 'blastomeres'. It is generally considered best if all these blastomeres are even and similar in size or close.

When portions of the embryo's cell are broken and are separate from the nucleated cells, these portions are referred to as fragmentation.  Ideally, there should be very little or no fragmentation present.  However, the occurrence of fragmentation is quite common and several beautiful babies have resulted from fragmented embryos.

The blastocysts are graded based on the expansion state (early, expanding, expanded, and hatching) as well as the quality of the other cell type in the blastocyst. The blastocyst consists of the inner cell mass - which eventually forms the fetal tissues, and the trophectoderm - which forms the placenta.

The pictures below show the development of a hatching blastocyst from an egg to two cells, four cells, eight cells, blastocyst and a hatching blastocyst.

We carefully assess the morphology of all the embryos and select the best embryo(s) to replace for our patients considering every individual patient's case.


Embryonic stages


Embryo Grading


The table below shows an example of the outcome from an IVF cycle.  These may vary significantly, and there are not always embryos available to freeze.

Egg Collection Chart



This is a revolutionary new technique involving time lapse imaging technology.  At Saint Mary's we use this equipment to record images of your embryos every 15 minutes.  Embryonic cells are normally programmed to divide at set time intervals and the timing of these divisions is known to be of high clinical value to optimise IVF outcomes. Time lapse videos of your embryos enable our embryologists to enhance embryo selection for transfer by studying these timelines of cell division. This novel and unique application has shown to have a vast improvement in pregnancy rates, as patterns of embryo development can be monitored to select the most viable embryo(s) from a cohort.  Recent reports emerging about the use of this technology is very promising and can also be used to reduce the number of embryos to transfer in order to minimise the risks of multiple pregnancy.

7.  Embryo Transfer Process

  • Embryos are normally transferred back into the uterus either 2, 3 or 5 days after egg collection.
  • The procedure involves introducing a speculum into the vagina, as in a smear test.
  • A fine tube is passed into the womb under ultrasound guidance and the embryo(s) is replaced into the cavity of the womb.
  • The procedure does not require an anaesthetic or fasting.
  • No hospital admission is required.
  • We recommend that after the procedure you carry on as normal.

Available leaflet:

How to help yourselves getting through the days of waiting following embryo transfer.


Day of embryo transfer: Day 2, Day 3 or Day 5?

Our aim is to select the best one or two embryos for transfer to maximise your chance of pregnancy, but minimise the risk of twin pregnancy.

  • You must agree to be available for embryo transfer potentially on day 2, day 3 or day 5.
  • If there are 1 or 2 embryos, transfer is usually on day 2 - this applies to around 1 in 4 patients.
  • Around two thirds (2 out of 3) of patients will have transfer on day 3, when we can select the best quality one or two embryos.
  • Only patients with at least 4 top quality embryos on day 3 will be selected for extended culture (approximately 1 in 12 couples).


Blastocyst culture to day 5 is a method of embryo selection, not suitable for all couples/cycles, and involves some degree of extra risk over culture of embryos to day 2 or day 3.

The blastocyst programme does carry the following additional risks, although these risks are considered very small:

  • There may be no blastocysts available for transfer.
  • The risk to offspring of extended culture are slightly greater than the risks with day 2/3 culture.
  • Vitrification* used to cryostore spare embryos is a new procedure in our unit, and it will take time to assess thaw or defrosting outcomes.
  • There is an increased risk of identical twins.

*Vitrification is a new method of embryo freezing and appears to be most suitable for blastocysts, but success is not guaranteed.  Some increased risk is involved because of higher concentrations of chemicals required.


8.  Pregnancy

  • A pregnancy test is performed 14 days after embryo transfer.
  • If positive - an ultrasound scan is booked 2-3 weeks later to confirm the pregnancy.


It is imperative that you inform the unit of the outcome of the treatment cycle - as it is compulsory for the unit to notify the HFEA of all outcomes.


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