About Fertility Preservation
The Sims IVF Fertility Preservation Programme gives women the opportunity to conceive a child in the future, when due to personal choice or circumstance they must put the idea of having a baby on hold.
What is Egg Freezing?
Egg freezing is the process of extracting, freezing and storing a woman’s eggs so that they may be used to conceive a child at a later date. There are no absolute guarantees but egg freezing does give a woman the opportunity to try for a baby in the future.
What does Egg Freezing involve?
There are three general steps involved in an egg freezing cycle:
· Stimulation of the ovaries to encourage development and maturation of the eggs.
· Retrieval of the eggs
· Cryopreservation (freezing) of the eggs
These steps are described more fully below:
Stimulation of the ovaries to encourage development and maturation of the eggs
Under the care of a consultant gynaecologist, the woman is given fertility medications to stimulate her ovaries to produce many follicles. Follicles are the small fluid filled structures which develop on the ovaries, each of which will hopefully contain an egg. The number and size of the developing follicles is measured by trans-vaginal ultrasound scans. The exact number of follicles which develop varies between patients, but the average is about 10.
The final preparation for egg retrieval involves a hormone injection which mimics the natural trigger for ovulation. Egg retrieval takes place 36-38 hours after this injection.
Retrieval of the Eggs
Egg retrieval is a minor theatre procedure which is carried out on an outpatient basis under local anaesthesia. The trans-vaginal ultrasound probe is used to visualise the ovaries and a needle attached to the probe is passed through the vaginal wall into the follicles. The fluid within each follicle is aspirated and then examined in the IVF laboratory for the presence of an egg. After identification, the eggs are washed and transferred into special culture medium in Petri dishes in an incubator.
Freezing of the eggs
The eggs are frozen in the laboratory using a method known as vitrification. The eggs can then be stored until the woman is prepared to conceive a child, then the eggs are thawed and used for IVF.
What is Vitrification
Egg freezing is a relatively new procedure, because of the complications involved in preserving eggs. The fact that the egg is the largest cell in the body and high in water content makes it difficult to freeze safely. Traditional cryopreservation technology caused crystals which resulted in damage to a high proportion of eggs, making freezing unviable.
A new cryopreservation technology called Vitrification – a flash freezing process where a patient’s unfertilized eggs are placed in a special freezing solution – helps eggs to survive freezing and thawing so that they are intact and viable.
Current pregnancy rates following the use of thawed, vitrified eggs have begun to rival those achieved when fresh, unfrozen eggs are used. Thousands of babies have been born worldwide to those who have recovered from cancer and other serious illness, following egg vitrification.
How Fertility Preservation Evolved
Fertility Preservation was originally developed to assist cancer patients, impacted by strong drugs, to freeze their eggs prior to treatment and conceive a baby at a later stage. However, there is an increasing trend among women to defer having a baby for financial, career and relationship reasons. Age related infertility is an increasing problem in the Western World, where according to the World Health Organisation (WHO) one in six people experience fertility challenges.
The reason for this is that female fertility reaches a peak in the early 20s and begins to decline significantly from age 30 onwards.
§ Women are most fertile between the ages of 20 and 24
§ At 35, you’re half as fertile as you were at 25
§ At 40 you’re half as fertile as you were at 35.
A woman’s ovaries age in the same way that normal aging affects all of her organs and tissues. Most women have about 300,000 eggs in their ovaries at puberty. For each egg that matures and is released or ovulated during the menstrual cycle, at least 500 eggs do not mature and are absorbed by the body.
As a woman ages, the remaining eggs in her ovaries also age, making them less capable of fertilisation and their embryos less capable of implanting.
Fertilisation is also associated with a higher risk of genetic abnormalities such as chromosomal abnormalities. The risk of a chromosomal abnormality in a woman aged 20 years is one in 500 while the risk in a woman age 45 is one in 20.
Where a woman decides to freeze her eggs for non-medical reasons, we prefer that she be under the age of 35 at the time of egg freezing, for these reasons.
Is Embryo Freezing an Option?
Sperm freezing has been around since the 1950s, meaning that men can also preserve their fertility. Up to now, the only option open to women was to undergo an IVF cycle and to freeze the embryos that resulted from fertilising the egg with sperm. This meant that a young woman must have a male partner, which many, especially younger women may not have and that the couple would remain together in the future. If the couple split up, the male, whose sperm was used to fertilise the eggs, could withdraw his consent to use of the embryos.
An altogether more desirable route is to freeze the woman’s eggs, giving her autonomy over her pregnancy options. The Sims IVF Fertility Preservation programme allows women to freeze their eggs now and to conceive a child with a partner of her choice at a later date.
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