A verdade sobre o congelamento de óvulos

Why freeze?

Egg freezing has become a hot topic. In January 2018, the Sociedade Britânica de Fertilidade released new guidelines on fertility preservation for doctors and patients. And research published in 2018 in the journal, Molecular Human Reproduction, demonstrates that it is possible to mature eggs outside of the body, which could help young people who are pre-pubescent and undergoing medical treatment that threatens their fertility.

Preserving female fertility through the freezing of eggs and ovarian tissue is becoming more common for cancer patients, women with other medical conditions which cause infertility or when treatment risks infertility, and the transgender community, as well as women wanting to delay starting a family until they are older.

A 2014 HFEA Report found that the most common reason for egg freezing was not having found a suitable partner and this remains the key motivating factor when seeking treatment.

Egg collection for fertility preservation is the same procedure as that which women undergo during IVF treatment. The patient takes hormonal medication that stimulates the ovaries to produce mature eggs, which are then harvested during a short and minimally invasive surgical procedure.

These will then be frozen using vitrification technology, a fast-freezing process that ensures the cells remain structurally intact and are not damaged by the formation of ice crystals. It is usually recommended that you freeze eggs before you reach the age of 35.

Success rates

UK statistics on egg freezing are not reliable at present because they include the previous slow-freezing method (which had a low success rate). However, figures provided by other countries that just include the new fast-freezing process are promising.

Professor Geeta Nargund, fertility expert and medical director of Create Fertility which runs fertility clinics across the UK, says: "With the new fast-freezing method, more than 90% of eggs can survive," she says. "And more than 70% can fertilise. There's almost a 50% chance of a woman having a baby if she freezes at least 12 eggs (usually with one cycle of egg retrieval) when she's under the age of 35. For example, the average woman wanting to get pregnant at 42 would have about a 5-10% chance using IVF treatment with her fresh eggs, but using eggs she had frozen at say 32, her chances would rise to nearly 50% because it is the age of the egg that is so important."

Quality and quantity

A woman's egg count is determined at birth and eggs decline in quantity and quality over time. One common misconception is that taking the pílula anticoncepcional stops eggs being released and therefore prevents the decline in egg count.

"Taking the pill long-term doesn't mean you're storing up your egg reserve," says Nargund. "On average, all women lose around 1,000 eggs per month and by the age of 30 have lost 90% of their egg supply."

It is also crucial to find out the age at which your mother went through menopausa as this will be a likely indicator of when you will experience it. Don't just assume it will happen around 51, which is the national average.

"If your mother had an early menopause it is likely you will do so also," says Nargund. "Other factors such as low thyroid function, smoking, endometriose and high levels of stress can also affect egg reserve and the age of menopause. It is possible to get a fertility check at a private clinic that will tell you where you are in terms of your egg count and onset of menopause. This can empower you to make crucial decisions about preserving your fertility, and egg freezing if appropriate."

Barriers to access

Health risks

There are health risks involved in egg collection, although complications are rare and new 'mild stimulation protocols' have significantly lowered the risk of ovarian hyperstimulation syndrome (a potentially serious complication of fertility treatment, which can cause abdominal swelling and vomiting because of enlarged ovaries).

Legal limits

By law, eggs can be kept for a maximum of 10 years, though in exceptional medical circumstances this period can be reviewed in conjunction with regulatory body, the HFEA.

How much it costs

Cost is still prohibitive for many women.

Dr Melanie Davies from University College London Hospital (UCLH), spokesperson for the British Fertility Society, explains: "Freezing eggs for social reasons is becoming increasingly in demand but the NHS does not fund this at all. It is also rare that the NHS funds fertility preservation for transgender people who have ovaries and are undergoing medical transition. In areas where the NHS does not provide funding, it can be quite expensive - up to around £5,000 for the egg collection, and ongoing storage costs of around £200-£300 per year."

Nargund believes that society also discourages younger women from investing in egg freezing: "It upsets me that women are being perceived as selfish just because they want to delay having children. The term 'social' is used to degrade the decision to freeze eggs to the level of wish rather than a need. It is not social, it is medical or preventative. I call it AGE banking - Anticipated Gamete Exhaustion."

The way forward

As egg freezing technology continues to advance, Dr Nargund is keen to see a similar evolution in society's attitude to the concept: "I strongly believe that egg freezing is the next stage of female emancipation after the contraceptive pill, and a key milestone on the road to gender equality; it provides women with the freedom to choose when they have their children and is a reproductive right that all women should have access to."

As a minimum, Dr Nargund believes women should be allowed to have a fertility MOT on the NHS regardless of whether they are currently trying for a family. "This could be done at the time of their exames de rastreamento cervical; then women would have an insight into where they are at with their fertility and what steps they might want to take. As a society, we need to make the shift from treating infertility to preventing infertility, and egg freezing has an important role to play."