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IVF treatment guide


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IVF helps people with fertility problems to have a baby. It works by taking an egg, fertilising it with sperm in a laboratory, and placing the embryo (fertilised egg) back inside the womb to grow. IVF is a complex process with several different stages to understand. If you have questions, please speak to a doctor or nurse caring for you.

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Starting IVF

To find out more about starting IVF, you can call our fertility service on 020 7188 2300 or email the team on You can also find out more about referrals and funding.

You treatment can start when

  • You have had your first appointment with an assisted conception unit (ACU) doctor.
  • You have signed the consent forms.
  • We have the results of virology tests for both partners. These are taken within 3 months of your expected treatment date and check for viral infections like Hepatitis B, Hepatitis C and HIV.
  • We have the result of a sperm assessment, within 1 year of your expected treatment date.
  • You have been taught by a nurse how to carry out your own injections.
  • Funding is agreed. If you are eligible for NHS funding, you will have received a letter confirming your entitlement. If you are self-funded, you will have paid for this and the required medication.

How to get your start date

The treatment start date depends on your menstrual cycle. On the first day of your period, email to say that you want to start treatment and include:

  • your name
  • your ACU number (if you know it)
  • a contact number
  • the date of the first day of your period.

We will contact you in 2 to 5 working days to arrange the next steps.


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What happens in an IVF treatment cycle

A treatment cycle is made up of 5 steps.

Step 1 - The hormone that releases your eggs is temporarily switched off. This is so we can control when your eggs are released. Then, your ovaries are stimulated to produce multiple eggs, so as many as possible can be collected.

Step 2 - Your eggs are collected from your ovaries.

Step 3 - A semen sample is collected, or if using frozen or donor sperm, the sample is prepared.

Step 4 - The eggs and sperm are placed together in a laboratory dish to be fertilised and develop into an embryo. Or, in ICSI, an egg is injected with a sperm.

Step 5 - The embryos are placed in your womb – usually on day 2, 3 or 5 after egg collection when the fertilised egg has divided. Your embryos may be frozen if they cannot be transferred straight away, or there are extra ones.


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Step 1 – medication to produce eggs

This first step is to help your ovaries to produce eggs. This is so as many as possible can be collected. There are 2 ways of doing this: the long protocol and short protocol.

There is no difference between these 2 protocols in terms of how likely they are to result in a pregnancy. At your first appointment, your doctor should let you know which one is better for you. After you’ve agreed a plan with the doctor, we will arrange an appointment with the nurse who will tell you how to use the medications and give you a written personalised schedule to follow.

The long protocol

The long protocol stops your body from producing eggs for a short time. When your ovaries are 'stimulated' to produce eggs again, the follicles (sacs containing your eggs) will grow at the same time and speed as each other. This gives a better chance of collecting more at the same time, ready for fertilisation. 

  • Medication 1 resets your cycle (down-regulation)


    You will be asked to take a medication for 2 to 3 weeks that temporarily stops your ovaries releasing any eggs. This is known as down-regulation. It is taken as a nasal spray or an injection under the skin of your stomach or thigh and will:

    • make the ovaries temporarily inactive 
    • make sure the ovaries respond better to the hormone injections 
    • stop your ovaries from releasing your eggs before we can collect them. 

    You will start the first medication on day 21 of your menstrual cycle (counted from the first day of your period). You will continue this treatment until 2 nights before your egg collection.

    Your egg collection date will depend on an internal vaginal scan about 2 to 3 weeks after you start this medication. This scan is performed by a nurse in the assisted conception unit (ACU) after 2 to 3 weeks of down-regulation. This is to check that the ovaries are inactive and contain no large follicles or cysts, and that the lining of the uterus is thin. If this is not the case, we will ask you to continue the medicine for another week. Occasionally, if there is an ovarian cyst present after down-regulation, we may drain this using a procedure similar to egg collection. 

  • Medication 2 helps your eggs to grow

    Follicle stimulation hormone (FSH) is a hormone your body naturally produces. It helps your body to produce eggs. You will start FSH approximately 2 to 3 weeks after the start of down-regulation, if a scan confirms it's ok. These are a daily injection for 10 to 14 days. The injections are given just under the skin on the thigh or tummy. We will teach you or your partner to do this.

    These FSH injections will help or 'stimulate' eggs to develop in the ovaries. We will monitor the number and size of the follicles in the ovaries using internal scans.

    The first scan is usually done 9 to 11 days after starting the injections. In some cases a further scan is needed, usually 48 hours later. We aim to get at least 2 to 3 follicles measuring about 18 to 20 millimetres in diameter, before we book your egg collection.


The short protocol

In the short protocol, down-regulation is achieved as part of your IVF cycle, without needing to take medication for 2 to 3 weeks before starting.  

We will ask you to email on the first day of your period. It’s likely you will be asked to start contraceptive pills to time the start of your IVF. Once we have arranged your medications to be delivered and have shown you or your partner how to administer the injections, we will plan for you to stop the pills and come for a scan.  

Once you have had a scan, usually during your period, you will start taking FSH injections to stimulate your ovaries to produce eggs. You will continue FSH injections for 10 to 14 days, until the follicles in your ovaries are ready for egg collection. Side effects from FSH can include tender breasts, bloating, feeling sick, or increased emotions. 

In short protocol you also need down-regulation drug that stops eggs being released but it is added to the FSH injection from day 6 of your stimulation.

Side effects

Side effects of the first medication for down-regulation are likely to feel menopausal. These include hot flushes, night sweats, headaches, mood swings, and lack of concentration. If you do have any of these symptoms, they will improve once you start your daily injections of the second medication containing FSH. This is what your body naturally produces to stimulate your ovaries and will cause your oestrogen levels to rise again. This might cause your breasts to feel tender, bloating, nausea, or increased emotions. 

It is normal to have a period during this time. This does not mean that the medication is not working. Do not stop taking your medication until we ask you to. If you stop the medication too soon, your eggs could be released before we have had a chance to collect them. 

Having sex

You can have sex throughout your treatment and it is possible to get pregnant naturally during the down-regulation period. If this happens it is important that you tell the nurses so they can give you the correct advice.

How to get your medicine

We will send your prescription to an independent drug distributor. They will contact you directly about delivering the medicine to your home or place of work. If you are self-funded, you will pay the drug distributor directly for the prescription.

If you fund your own treatment, we cannot order your medication until full payment for the treatment cycle has been received.

You normally have FSH prescribed for 12 days. If you need more FSH injections or run out of any other medications, phone the nurses on 020 7188 2300 as soon as you realise. We will arrange to send another prescription to the drug distributor. Please note that the line is only open Monday to Friday so please let us know before the weekend.


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Step 2 - egg collection

Egg collection usually takes about 20 minutes. Our team will decide the best day for your egg collection. This decision is based on your medical history, your response to the stimulation drugs and the ultrasound findings. 

A one-off injection is given late at night 36 hours before the planned egg collection. This is called ‘trigger’. The time this injection is taken is important and will be explained clearly to you. If the trigger injection is taken at the wrong time, your eggs will not be mature, will not be released and are unlikely to fertilise. You do not need to have any more injections after the trigger injection.

Preparing for egg collection

You should not eat or drink anything for 7 hours before your egg collection. This is because you will be sedated for the procedure. Sedation is a type of anaesthetic that helps you relax and prevents pain during the procedure. It can sometimes make you feel sick so an empty stomach reduces the chances of complications if you vomit.

You should have a bath or shower on the morning of your egg collection. Please do not wear makeup, nail varnish, perfume, jewellery or contact lenses. Your partner or a responsible adult will need to go with you to hospital and take you home. 

The egg collection procedure

You may be asked to take pain-relieving medication 1 hour before the procedure. This medication is in the form of a suppository, a dissolvable medication that is inserted into your rectum (back passage). Please speak to an ACU nurse if you are concerned about this. 

When you arrive in the ACU you will be taken to the procedure and recovery area by the nurses and asked to change into a hospital gown. Once you are in the egg collection room you will be introduced to the team involved in the procedure. This will include a gynaecologist, nurse, embryologist, an anaesthetist and their assistant. 

A small cannula (plastic tube) is put in a vein in your arm or hand and used to give you medication to keep you sedated during the procedure. Sedation is given by an anaesthetist (specialist doctor). It keeps you asleep and pain free during the procedure. We will give you oxygen to breathe and monitor your pulse, blood pressure and breathing throughout the egg collection. You can read more about sedation on the Royal College of Anaesthetists (RCOA) website.

An ultrasound probe is placed inside the vagina and a fine needle is attached to the side. The needle is gently passed through the vaginal wall into the ovary. It collects fluid from the follicle and is moved from one follicle to the next until we have emptied all the follicles in the ovary. The needle is then removed and the procedure is repeated in the other ovary. 

Not every follicle will contain an egg and on rare occasions no eggs will be found. Sometimes despite draining a good number of follicles we may get a low number of eggs. We will tell you after the procedure how many eggs were collected.

Recovering after the egg collection

After the procedure you will rest on a bed in the recovery area for 1 or 2 hours. A responsible adult should take you home by car or taxi. We do not recommend public transport. This is particularly important if your partner has had a procedure for sperm retrieval on the same day, as they will have also had sedation. Sedation can affect your reasoning, reflexes, judgement, coordination and skill. 

Read more about the side effects and instructions after sedation on 

You may feel some lower tummy or pelvic pain after the procedure. It is safe to take paracetamol for this. You might have some blood-stained vaginal discharge which should become darker and stop after a few days. This blood is coming from where the needle has passed through the vaginal wall. 

You will be prescribed the hormone progesterone to take for 17 days after the egg collection. This helps the lining of your womb prepare for pregnancy. We will tell you how to take progesterone before you go home on the day of egg collection.

If your egg collection is cancelled

About 5% of cycles have to be cancelled before egg collection. This is usually because the medication to prepare your body has not worked as we hoped. 

It may be that not enough follicles have developed in the ovaries or you may have produced too many follicles. If you have too many follicles, you are at risk of ovarian hyperstimulation syndrome (OHSS) and this will be made worse if you become pregnant. If a large number of eggs are released at once, there's a risk of triplets or higher number of pregnancies. The more babies you are carrying, the greater the chance of miscarriage or other problems. You should use a condom to prevent pregnancy in the days that follow. 

If your cycle has to be cancelled, we will ask you to stop taking all of the medications. We will arrange a follow up appointment with a senior doctor as soon as we can. At this appointment we will reassess your treatment and plan another attempt, if appropriate. 

We realise that it is very disappointing to have a cycle cancelled, and will offer you the opportunity to speak with one of our fertility counsellors for support. Remember, having your cycle cancelled does not mean you will never respond appropriately. Every cycle is different and we may be able to adjust your treatment to achieve a better response and give you an improved chance of becoming pregnant in a future treatment cycle.

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Step 3 - sperm collection

If you are having treatment with someone who is providing semen, they will be asked to produce a sample in private room in ACU. This will happen on the same day as your egg collection. If either of you feel anxious about giving a sample in the unit, please let us know in advance. 

Your partner or donor should not have sex or masturbate for 2 to 3 days before the egg collection (but also not longer than a week before) in order to try and get the best semen sample. The sample will be assessed in the laboratory. If the sample is not of sufficient quality to do IVF, then the laboratory may recommend ICSI to improve the chances of fertilisation.

If you have treatment with frozen sperm, the sample will be thawed and prepared only once we have collected your eggs. 

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Step 4 – fertilisation

Our checking and witnessing guidelines make sure that the eggs, sperm and embryos used in your treatment belong to you. An electronic tagging system adds to the security. You will find that you are often asked to give your name and date of birth as this help ensure accuracy.

What happens in the laboratory?

The sperm sample is prepared by separating the normal and moving sperm from the ejaculated fluid and placing it in an electronically tagged test tube. In an IVF cycle, the prepared sperm and egg(s) are placed together in a carefully labelled and electronically tagged dish. In an ICSI cycle, a single sperm is injected into each egg and this is put into a dish labelled and tagged with your name and unique number. These dishes are left in the incubator overnight, to allow fertilisation to take place. 

The difference between IVF and ICSI

ICSI (intracytoplasmic sperm injection) is part of IVF. Your treatment will be exactly the same. The difference is how the eggs are fertilised. In IVF, eggs are placed together with sperm in a laboratory dish to allow the sperm to naturally fertilise the eggs. In ICSI, each egg is individually injected with a sperm.

This may be recommended if you have a low sperm count or poor mobility (the sperm don't move normally). This is to give the best chance of fertilisation, as it helps the sperm inside the egg. Your doctor will let you know if this is the right treatment for you. 

Fertilisation and embryo development

The next morning the embryologist carefully examines each egg to see if they are fertilised. We will call you the day after your egg collection to tell you how many eggs have fertilised and when to come in for embryo transfer.

Rarely, in about 5% of cycles, none of the eggs fertilise and there are no embryos for transfer. This is obviously very disappointing. We will offer you the earliest available appointment to see a senior doctor to discuss the cycle and your future treatment options. You will also be offered an appointment to see one of our counsellors. 

Eggs that have fertilised are called embryos. As embryos develop, their cells divide. By day 2, an embryo should have 2 to 4 cells after 2 days. By day 3, anembryo should have 6 to 8 cells. By day 5, an embryo has more than 100 cells. Embryos with good potential to implant should reach a stage known as 'blastocyst'. We transfer embryos to the womb 2, 3 or 5 days after fertilisation.

Freezing spare embryos

It is possible to freeze embryos from an IVF or ICSI cycle for later use. However, this only happens in 40% of cycles. We will freeze good quality blastocysts on day 5 or 6 of development. 

If you have 1 or 2 good quality embryos to transfer and spare embryos that are suitable for freezing, you have an above average chance of conception.

Embryos are frozen at an extremely low temperature to make sure they do not deteriorate over the number of years they are stored. Even if your first IVF cycle results in a live birth, if you have frozen embryos you might wish to use them to expand your family at a later date. 

However, most people do not have any spare embryos to freeze. So, if you have NHS funding that states that you can have 1 initial cycle and 1-2 cycles using your frozen embryos but your initial cycle did not result in spare embryos to freeze, this means there won’t be any NHS funding available for further cycles as there are no frozen embryos to transfer. 

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Step 5 - transferring embryos to your womb 

During embryo transfer we place the best 1 or 2 embryos into your womb. This is a much simpler procedure than egg collection and there is no need for sedation. During the procedure, we use an ultrasound scan probe on your tummy to help us to place the embryos where they have the highest chance of implantation. 

Preparing for embryo transfer

You will need to have a full bladder for this procedure so that we can see the uterus clearly on the ultrasound scan. A full bladder also makes the procedure technically easier in most people, by making it easier to insert a soft catheter (small plastic tube), containing the embryos. An ACU nurse will give you instructions on how to prepare for this.

Transferring the embryo - what will happen

As part of our identity checks, you and your partner or donor (if you attend together) will be asked to state your names and dates of birth before the transfer. The doctor and embryologist will check that the dishes containing your embryos are labelled with your name and unique identity number. 

The embryologist will have selected the best embryo(s) for transfer. The doctor and the embryologist will discuss this decision with you. 

A speculum, which is the small device used for a smear test, is placed in the vagina to help us clearly see the cervix (neck of the uterus). The outside of the cervix is cleaned, and any mucus from inside the cervical canal is removed. This mucus might prevent the embryos getting to where we want them to be in the uterus. 

The soft catheter, which holds the embryos, is inserted into your uterus. We usually try with an empty catheter first to see the best position and path. Once we are happy that the catheter can be easily inserted, the embryo(s) is placed in the catheter and gently injected into the uterus. The catheter is then removed and checked to make sure all of the embryo(s) have been transferred. 

You will be able to empty your bladder immediately after the transfer without any risk of losing the embryos. 

How many embryos will be transferred

If you are under 35 years and in your first cycle, you will usually have 1 embryo transferred, especially there are extra embryos for freezing. This gives a high chance of pregnancy (over 50%) and a low chance of twins. If you are older, or if the embryo quality is not as good, you may have 2 embryos trransferred. If you are aged 40 or over, we will talk to you about whether we think you should have 3 embryos transferred. If the remaining embryos are suitable, they will be frozen for future use. 

Transferring blastocysts

By day 5 after egg collection, the cells of embryos have divided and multiplied to become ’blastocysts’. Blastocyst transfer will have the greatest benefit for people who have a good chance of becoming pregnant, but also have a risk of having a twin pregnancy if 2 embryos are transferred. If we transfer a single embryo, we hope to reduce the incidence of twin pregnancies, without reducing the overall chance of pregnancy. 

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After embryo transfer 

You will know if the treatment has been successful 16 days after egg collection when you take the pregnancy test that we give you. We appreciate that this wait can be difficult. Please do not be tempted to take the pregnancy test earlier than the date on the information sheet given to you at embryo transfer. The trigger injection that you had before your egg collection can stay in your blood stream for 8 to 10 days and this can make the test positive, even if you are not pregnant. 

You should take a pregnancy test 16 days after the egg collection, even if you bleed before this time. Doing the test, even if you bleed, is essential. This is because some people who have bleeding after a cycle could have an ectopic pregnancy - an uncommon but serious complication.

We will give you a pregnancy test kit and explain how to use this. It is important that you to email or telephone the unit to give us the result.

There is no evidence that anything you do at this stage will increase the chances of you becoming pregnant. We encourage you to return to work but you may prefer to have a few days off around the time of embryo transfer. Having baths or sex is not known to affect the chances of pregnancy. 

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A positive pregnancy test

A positive result means that one or more embryos have implanted but we will not be able to see this on a scan until you are about 6 weeks pregnant (4 weeks after embryo transfer). We will usually arrange for you to have a scan at around 7 weeks of pregnancy to check baby’s heartbeat. 

Sadly, we sometimes diagnose miscarriages (10 to 20% of people, depending on age) and ectopic pregnancies (about 1 to 3% of people) at this stage. Our dedicated fertility counsellors will be able to provide emotional support.

If we confirm that you have an ongoing pregnancy, we will discharge you back to your GP to arrange your antenatal care at your local hospital. You must continue to take the progesterone pessaries (suppositories) if you have a positive pregnancy test until you are 8 weeks pregnant. Unfortunately, a small number of pregnancies can still miscarry even if these early scans are encouraging. 

If you develop one of the following symptoms after you have confirmed positive pregnancy test and before your pregnancy first scan at ACU, please let us know and we will arrange for you to be reviewed by our medical team:

  • heavy bleeding
  • brown spotting (discharge)
  • sharp abdominal pain, particularly if on one side 
  • shoulder pain
  • faintness.

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A negative pregnancy test

A negative result sadly means that the treatment has not been successful. You might already have started bleeding but, if not, your period will come in the next few days. This might be heavier than normal due to the medications you have taken, which have made the lining of the uterus thicker than usual.

We know this can be a very disappointing time and it is important that you ring or email in with your result and speak to one of the nurses. We will offer you an appointment within 4 to 6 weeks to come in and see a senior doctor to discuss the cycle and possible treatment options for the future. You might also find it helpful to see one of our dedicated fertility counsellors. 

Please stop taking progesterone if you have a negative pregnancy test.

Why do cycles fail?

It is impossible to see what exactly happens to the embryos once they have been transferred, and it is often difficult to give a specific reason why a cycle has failed. 

In most cases, the cause is likely to be that the embryos have stopped dividing and don’t reach the right stage of development to be able to attach to the uterus. Embryos are less likely to attach if they are not of the best quality. 

If you have fibroids in your womb, or the fallopian tubes are swollen and contain fluid we may recommend surgery to remove these before your next IVF or ICSI cycle. If there have been problems with the thickening of the womb lining, we might add in extra medications to try and improve this in any future attempt. 

There are several treatments you may read about in the press or on the internet that claim they can improve your chances. Many of these treatments have not been proven to work and may actually be harmful. We have a policy not to use treatments that have not yet been shown to be effective. Please talk to our doctors if you have any questions about other treatments you heard about somewhere else.

When can we try again?

We recommend that you wait at least 2 months before you have another attempt so you can have a break from treatment and allow yourself time to recover from such a big disappointment. Your body also needs a chance to recover from the medication. If you have frozen embryos we usually recommend using these before trying another fresh embryo transfer. 

How many attempts can we have?

We do not have a set limit for the number of attempts you may have. After each unsuccessful cycle you will be offered an appointment with a senior member of the team to discuss the reasons why your cycle may have failed and how we may be able to improve your chances of success. 

You are assessed individually and advice is given about the likely success of further cycles. If we feel your chances of being successful are very low, we will be honest with you and may advise you to stop treatment. 

Some Clinical Commissioning Groups (CCG) will only pay for 1 cycle of treatment and you might have to self-fund further attempts. Most people need more than 1 embryo transfer to achieve a live birth.

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Frozen embryo transfer

In a frozen embryo transfer cycle (FET) we thaw some of your frozen embryos and transfer 1, 2 or 3 of them into the uterus. The number of embryos to be thawed in any one attempt will be discussed with you in advance by an ACU doctor or embryologist. We are selective about the embryos we freeze in order to give you the best chance of pregnancy after thawing and transfer. Currently about 85% of our blastocysts, and our early stage embryos survive being frozen and thawed. Our current successful pregnancy (live birth) rate for frozen embryo transfer is 27%. The average national rate is 26%. An advantage of a FET is that we do not need to use hormone injections to stimulate the ovaries and you do not have a surgical egg collection procedure. 

For more information about a FET, please speak to a member of our team. Before starting frozen cycles we would need to sign a consent form with both you and your partner physically present at ACU.

If you have frozen embryos, it is essential that you keep in touch with us to let us know what you wish to do with them and tell us of any changes of address. 

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Risks of IVF

All types of medical treatments and procedures have risks. An ACU doctor will talk you through the risks involved. Below are some of the possible risks associated with IVF. 

Multiple pregnancy

One of the common complications is multiple pregnancy. Multiple pregnancies have a much higher risk of complications including late miscarriage, pre-eclampsia (high blood pressure), diabetes and premature birth. Premature babies have a higher risk of complications, such as a weakened immune system, physical and mental disability, feeding and breathing difficulties. The risks at all stages of a triplet pregnancy are higher still and so the chance of having even one healthy baby at the end of treatment is lower than with either a single pregnancy or twins. 

The Human Fertilisation and Embryology Authority (HFEA) current guidelines allow us to transfer up to 2 embryos (or to consider a maximum of 3 if the woman is over 40). 

In 2009, when the multiple pregnancy rate across the UK was well above 25% for all IVF pregnancies, HFEA requested all clinics aim to have multiple pregnancy rate under 15% by 2012. Our team has achieved a persistently safe rate of multiple pregnancy rate under 10% without compromising overall live birth rate.

Ovarian hyperstimulation syndrome (OHSS)

Some people have a very high number of eggs and may over respond to fertility drugs. This causes the ovaries to enlarge and blood oestrogen levels to rise. This is more common if you are younger or have polycystic ovarian syndrome. OHSS is not always predictable or avoidable but in the majority of cases we would be able to identify if you are at risk before stimulation. We would prevent OHSS by:

  • reduced dose of FSH injection
  • short stimulation protocol
  • extra monitoring by checking blood hormone level and scans during stimulation
  • alternative trigger drug. 

When we collect very high number of eggs, we may recommend not going ahead with a fresh embryo transfer and instead freeze all embryos. This allows time for hormone levels to settle, and prevents or reduces the symptoms of OHSS. A frozen embryo transfer cycle will not cause OHSS as the ovaries are not stimulated.

Symptoms of OHSS occur only after the time of egg collection or about 10 days after embryo transfer. You may find that things improve only to get worse again nearer to the time of your pregnancy test. 

In OHSS, the ovaries can enlarge up to 3 times their normal size. Your blood protein level drops which causes fluid to leak out into the abdominal cavity or around the lungs. This can result in problems producing urine, mineral imbalances in your blood and clotting problems. Symptoms include:

  • tummy pain and swelling (progressively increasing after egg collection)
  • passing small amounts of concentrated urine 
  • thirst
  • nausea and vomiting 
  • diarrhoea
  • dizziness
  • shortness of breath. 

If you have any of these symptoms please contact us so we can give you the necessary advice. Most cases of OHSS are mild and resolved by drinking 3 litres of fluid a day and using mild pain-relieving medicine, such as paracetamol. 

If we are concerned that you are at risk of developing moderate or severe OHSS we will keep you under regular review. If your symptoms worsen we might have to admit you to St Thomas’ hospital for monitoring and treatment. Very rarely OHSS can be life threatening. Please also contact us if you have been to another hospital for advice or treatment. 

Having OHSS will not jeopardise your chances of becoming pregnant. The incidence of mild to moderate OHSS is around 1 in 100 people, while severe cases are less than 1 in 1,000 people.

Pelvic infection

Pelvic infection can very occasionally follow an egg collection and, rarely, an abscess might develop. We try to make sure this does not happen by giving antibiotics to people who are at higher risk of infection. The incidence of pelvic infection is less than 1 in 100 people. 

However, since it is not possible to sterilise the vagina where there are always some bacteria present, it is not possible to prevent all infections, despite precautionary measures. Symptoms of an infection include: 

  • pain
  • bright red vaginal bleeding
  • smelly vaginal discharge
  • diarrhoea
  • fever
  • generally feeling unwell. 

In these cases, we will admit you to St Thomas’ hospital for antibiotic treatment. In severe cases, an operation might be necessary. 

Other complications

There is a very small risk that the needle used for egg collection can puncture the bowel or blood vessels. The needle used is very fine and it is unusual to have any complications. Most cases of vaginal bleeding can be stopped at the end of the procedure by applying pressure to the puncture site. If there is a concern that a tiny hole has been made in the bowel, antibiotics will be given. 

Please contact us if you feel any of the following symptoms: 

  • pain in your tummy
  • shortness of breath
  • swelling/bloated feeling in your tummy 
  • feeling feverish, shivery or generally unwell
  • nausea and vomiting – especially fluids
  • heavy or irregular vaginal bleeding
  • diarrhoea
  • dizziness
  • you are passing a small amount of urine or if your urine seems concentrated.

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Success rates for IVF

It is important to be realistic about the likelihood of a successful treatment cycle. IVF success depends mainly on maternal age. Your chances increase as you progress successfully through each step of the treatment process. Your chances of a clinical pregnancy are:

  • 1 in 3, when you start a cycle
  • 1 in 2 if you are under 35 years old young and have a blastocyst embryo transfer. 

Our live birth rates per cycle for women of all ages for IVF and ICSI is consistent with the national average of 27% (HFEA, 2012-2015). 

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Useful resources

More detailed up to date information on our success rates can be found on HFEA website. Visit 

During this period, you may find it useful to speak to other people in a similar situation to you through the HealthUnlocked IVF community.

Contact us

For more information about IVF, please speak to a member of our team. You can phone us on 020 7188 2300 or email

Find more about our fertility services at


Ref number: 2687/VER3

Date published: June 2019 | Review date: June 2022

© 2020 Guy’s and St Thomas’ NHS Foundation Trust

A list of sources is available on request

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