In Vitro Fertilisation: Making a baby... the scientific method
Question: What is involved when a woman goes for IVF (In Vitro Fertilisation)?
Answer: When a woman has IVF treatment her ovaries are stimulated using fertility drugs to produce more eggs than the usual one per month.
When the eggs are mature they are removed from the body by a fertility doctor using a fine needle under ultrasound guidance.
At this stage, they can be fertilised with sperm in the laboratory or frozen and stored. In the case of the frozen procedure, when the woman is ready to use her eggs they are thawed and fertilised.
If successful, fertilised eggs, known as embryos, are transferred back in to the patient and a pregnancy test is taken two weeks later.
Question: So, how are the eggs frozen?
Answer: The eggs are frozen by a rapid freezing method called vitrification.
Question: What are the risks when the eggs are frozen?
Answer: There is a risk that the eggs may not survive the freeze/thaw process.
Question: How long can the eggs be stored once they have been frozen?
Answer: Currently, eggs can be stored for up to 10 years although this can be extended in certain circumstances.
Question: What is the difference between freezing an egg and an embryo?
Answer: The same process, vitrification, is used to freeze both. However, you need sperm to create an embryo, therefore a woman can choose to freeze her eggs without having a partner involved or having to use donor sperm to create an embryo.
Question: Who would want to freeze eggs?
Answer: Egg freezing is suitable for several different groups of women:
- Cancer patients who have not yet begun chemotherapy or radiotherapy, which is toxic to eggs, or who need surgery which will compromise fertility;
- Those who need to delay conception while receiving medical treatments;
- Women at risk of premature ovarian failure or early menopause;
- Single women who wish to preserve their fertility until they meet the right partner;
- Those who wish to delay having a family for personal reasons;
- As an alternative to embryo freezing.