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What is in vitro maturation (IVM) and how does it work?

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Petrie dishes during in vitro maturation

What is IVM?

In the IVM process, eggs are removed from your ovaries when they are still immature. They are then matured in the laboratory before being fertilised..

The difference between IVM and conventional in vitro fertilisation (IVF) is that the eggs are immature when they are collected. This means that the woman does not need to take as many drugs before the eggs can be collected as she might if using conventional IVF, when mature eggs are collected.

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Is IVM for me?

Your clinic may recommend IVM:

  • if you are susceptible to developing OHSS (ovarian hyper-stimulation syndrome - a potentially dangerous over-reaction to fertility drugs), for example, if you have PCOS (polycystic ovarian syndrome)
  • where the cause of a couple’s infertility has been identified as being male factor only.

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How does IVM work?

The procedure for IVM is as follows:

Step 1. As in conventional IVF, eggs are collected, but at an earlier stage, when they are immature. This means that you do not need to take as many ovary-stimulating hormones before your eggs are collected.

Step 2. The eggs are matured in a dish placed in an incubator in the laboratory for one to two days.

Step 3. When the eggs are mature, they are fertilised with your partner’s, or donor’s sperm. Embryos are cultured then transferred to your womb, just as they would be with conventional IVF treatment.

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What is my chance of having a baby with IVM?

The chances of a successful pregnancy with IVM are similar to those with conventional IVF, with the following additional risks:

  • because the eggs are immature when they are collected, it is likely that fewer eggs will be collected than in a conventional IVF cycle
  • there is also a risk that not all the eggs will mature sufficiently to be fertilised with your partner’s or a donor’s sperm.

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What are the risks of IVM?

As IVM is a new technique, there is not enough evidence to be absolutely certain of its safety as the number of children born is very few - about 400 worldwide - and those that have been born are still very young.

The known risks of IVM are:

  • fewer eggs are collected than in conventional IVF
  •  the usual risks involved in having a general aesthetic.

A clinic should suggest IVM because they consider that your susceptibility to OHSS is higher than average. If your clinic offers this technique, they should let you know why they think it is beneficial to you.

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Where do I start?

If you are having problems getting pregnant, your first call should be to your GP. They will look at your medical history, give you a physical examination and may recommend some tests or lifestyle changes.

Your GP can also refer you to see a specialist at your local hospital or fertility clinic.  

What to expect at the fertility clinic

When at the fertility clinic, your full fertility history will be taken and an examination carried out.

It may be that there are simple treatments that can be offered before IVF or IVM needs to be considered.

If IVM is indicated, your specialist will be able to refer you to an appropriate Assisted Conception Unit. 

What to expect at the assisted conception unit

Be prepared to answer questions on your medical and social history. This allows the clinic to assess the impact of a potential birth on the baby and on any other children you may have. 

Once you are accepted for treatment blood tests will be taken from both you, and your partner, if you have one. These include tests for HIV and Hepatitis B & C.

You will be screened to ensure that you are immune to Rubella (German Measles). Your hormone profile will be assessed. This is done via a blood sample taken early in the menstrual cycle to see if there could be difficulty in obtaining eggs and to detect any hormone imbalance. 

Your clinician will then discuss your treatment plan with you in full.

You will also need to sign forms that consent to the use and/or storage of your sperm, eggs or embryos and consent to the disclosure of identifying information.

Clinics should offer you the opportunity to have counselling- it can be particularly helpful while going through this process.

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Other options

If you’re concerned about the risks of OHSS (ovarian hyper-stimulation syndrome) you may want to discuss with your clinician the possibility of receiving natural or mild in vitro fertilisation treatment:

Page last updated: 07 January 2015

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