Risks of IVF

IVF treatment

All types of medical treatments and procedures have risks. A doctor in the assisted conception unit (ACU) talks to you about the risks of IVF.

Multiple pregnancy

Multiple pregnancies have a much higher risk of complications, including:

  • late miscarriage
  • high blood pressure
  • diabetes
  • premature birth

Premature babies have a higher risk of complications, such as:

  • a weakened immune system
  • physical and mental disability
  • feeding and breathing problems

The risks at all stages of a triplet pregnancy are even higher. At the end of treatment, the chance of having even one healthy baby is lower than with a single pregnancy or twins. 

According to the current guidelines from the Human Fertilisation and Embryology Authority (HFEA), we can transfer up to 2 embryos to your womb. If you are aged over 40, we can consider transferring up to 3 embryos.

Ovarian hyperstimulation syndrome (OHSS)

Some people have a high number of eggs and may over respond to fertility medicine. This makes the ovaries get bigger and the level of the hormone oestrogen in the blood rises. When these things happen, it is called ovarian hyperstimulation syndrome (OHSS). 

OHSS is more common if you are younger or have polycystic ovary syndrome (a condition that affects how the ovaries work).

It is not always possible to predict or avoid OHSS. However, in most cases, we can find if you are at risk before you start your daily hormone injections. To prevent OHSS, we can:

OHSS can develop only after your egg collection or embryo transfer. You might find that things improve, but get worse again nearer to the time of your pregnancy test. 

In OHSS, the ovaries can grow up to 3 times their normal size. This can cause problems producing pee (urine), mineral imbalances in your blood and clotting problems. Symptoms include:

  • tummy pain and swelling (which gets worse after egg collection)
  • passing small amounts of concentrated (dark in colour) urine
  • thirst
  • feeling and being sick (nausea and vomiting)
  • diarrhoea
  • feeling dizzy
  • shortness of breath

If you have any of these symptoms, please contact us so that we can give you advice.

Most cases of OHSS are mild. They can be resolved by drinking 3 litres of fluid a day and taking mild pain medicine, such as paracetamol. 

If we are concerned that you are at risk of getting moderate or severe OHSS, we keep you under regular review. If your symptoms get worse, you might have to come into hospital for monitoring and treatment. Very rarely, OHSS can be life-threatening. Please tell us if you have been to another hospital for advice or treatment. 

Having OHSS does not affect your chances of getting pregnant. About 1 in 100 people get mild to moderate OHSS. Severe cases happen to less than 1 in 1,000 people.

Pelvic infection

Very occasionally, you might get a pelvic (lower tummy) infection after your egg collection. Rarely, an abscess might develop. This is a painful, swollen area that contains pus (a thick, yellow liquid) caused by a bacterial infection.

We try to make sure that this does not happen by giving antibiotics to people who are at higher risk of infection. Less than 1 in 100 people get a pelvic infection after their egg collection. However, we cannot prevent all infections because there are always bacteria in the vagina.

Symptoms of an infection include: 

  • pain
  • bright red bleeding from the vagina
  • smelly vaginal discharge (fluid from the vagina)
  • diarrhoea
  • a high temperature (fever)
  • generally feeling unwell

If you have these symptoms, we admit you to St Thomas’ Hospital for antibiotic treatment. In severe cases, you might need surgery. 

Other complications

There is a very small risk that the needle used for egg collection may puncture the bowel or blood vessels. The needle that we use is fine and it is unusual to have any complications.

We can stop most cases of bleeding from the vagina at the end of the procedure. To do this, we put pressure on the area of the puncture (the puncture site). 

Please contact us if you have any of these symptoms: 

  • pain in your tummy
  • shortness of breath
  • swelling or a bloated (full and uncomfortable) feeling in your tummy 
  • a high temperature, or feeling shivery or generally unwell
  • feeling or being sick (nausea or vomiting)
  • heavy or irregular bleeding from the vagina
  • diarrhoea
  • feeling dizzy
  • you are passing a small amount of urine (pee) or your urine seems dark in colour and concentrated

Resource number: 2687/VER4
Last reviewed: July 2023
Next review: July 2026

Trusted Information Creator. Patient Information Forum

Contact us

If you have any questions about IVF, please contact our assisted conception unit (ACU).

Phone: 020 7188 2300

Email: [email protected]

Do you have any comments or concerns about your care?

Contact our Patient Advice and Liaison Service (PALS)

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