Why do some women need to extract more eggs than others when freezing their eggs?
More and more women are turning to egg freezing as a way of preserving their fertility. With the average age in the UK for first-time property purchase and the cost of living increasing, more women are deciding to have children later in life. Yet later conception puts women at risk of infertility, or a child born with Down’s syndrome. Therefore, in a bid to reduce fertility risk, egg freezing is a viable option.
Egg freezing involves artificially stimulating egg release using artificial versions of the hormones Oestrogen, Luteinising hormone (LH) and Follicle Stimulating Hormone (FSH). This is to ensure that the maximum number of eggs are harvested from the follicle and womb. The more eggs that are harvested, the better the chance of survival of the eggs when frozen under liquid nitrogen and thawed later for use in IVF. Ideally at least 15 eggs must be retrieved. This number is often hard to achieve and may involve several rounds of egg extraction and artificial hormone injections.
The number of eggs that need to be extracted depends on the age of the female, her ovarian egg reserve count (determined after scanning with ultrasound and blood analysis of anti-mullein hormone (AMH) to test ovarian egg reserves), her weight and general health and the skill of the physician extracting the egg. As you age your egg cell count decreases, and therefore often more rounds of egg extraction are required. Those with a genetic history of early menopause will also require more that one round of egg extraction. As will women with naturally unbalanced hormones due to being under or overweight (too high or low body cholesterol affects hormone synthesis), having polycystic ovarian syndrome (PCOS), or those on medications such as antidepressants SSRIs such as Florexetine which impact Cholesterol synthesis. Cholesterol is the biological basis of most hormones and so those with PCOS or type two diabetes and on Metformin, an Insulin sensitiser drug which helps control insulin resistance but also lowers LDL Cholesterol, may also require more than one cycle of egg extraction.
Why does stress impact egg freezing?
Stress hormone Cortisol is made of cholesterol. When stressed our bodies prioritise the production of Cortisol over other hormones, such as Oestrogen and Testosterone and LH and FSH production. This Cortisol “steals” the cholesterol from the synthesis of sex hormones, reducing their production. Therefore, stress impacts fertility and those with stressful lives, may need more artificial hormone support, or more than one round of freezing treatment.
Do artificial hormone injections hurt?
Artificial hormones for use in egg freezing, are given for 10–14 days both via medication and injection route in a bid to stimulate the production of multiple eggs. This is because different hormones have different biological absorption mechanisms. The drugs are usually injected at the top of the thigh and contain artificial FSH or LH such as follitropin alfa or beta (Follistim AQ, Gonal-f) or menotropins (Menopur). The eggs are then collected, usually under sedation.
The ovaries may swell after artificial stimulation, and this may cause ovarian hyperstimulation syndrome (OHSS) which may make your ovaries painful and swollen and cause bloating and diarrhoea. The best solution in these circumstances is to take pain killers and rest and try to avoid foods and drinks which will exacerbate the bloating symptoms.
Is there a maximum number of eggs I can freeze?
Usually only approximately 50–75% of eggs that are frozen survive the freezing and thawing process, but this varies hugely from person to person and egg to egg. Only one viable egg is needed for a successful pregnancy, however the more you freeze the better your chance of successful conception, especially if you may wish to have more than one child later in life. The Human Fertilisation and Embryology Association (HFEA) permits no limit to the number of eggs you can freeze, and the length of time permitted for freezing is being changed in the UK from 10 to 65 years. What limits most women’s ability to freeze their eggs is money, health and time.
What is the financial cost of egg freezing?
The financial cost of egg freezing varies from fertility clinic place to place and patient person to person but is usually around £5000 privately plus the costs of medications and egg storage. As egg storage technology improves, the process will become cheaper and more accessible. At present it is only offered to those with Ovarian cancer or premature menopause on the NHS. The best time to freeze your eggs is before the age of 35, but the average age for this process is 37 in the UK. After the age of 35 the quality of your egg declines. Some women may require more than one egg extraction process or require more hormone treatment than others or wish to store their eggs for longer. This can increase the financial costs of egg freezing. On average it is advised to budget around £8000 for egg freezing.
