Egg freezing: age, numbers and realistic expectations

The largest group is women between 30 and 38 who are not planning pregnancy in the next few years: without a partner, in the middle of a career, or simply not ready. This is called elective or social freezing. The second group is women facing medical treatment that threatens the ovarian reserve, such as chemotherapy, radiotherapy or planned ovarian surgery, particularly for an endometrioma; here it is medical freezing and the process is usually arranged urgently, within days.

In our practice a distinct group is diaspora women living in Germany, Switzerland or elsewhere who want the procedure during a longer stay in Kosovo. For them there are extra practical questions: how long they need to stay, how the monitoring scans are arranged, where the eggs will be stored and how they could be transported later if they want to use them somewhere else. These questions should be settled before stimulation starts, not afterwards.

The process is almost identical to the first part of an IVF cycle. After an assessment with AMH and ultrasound, ovarian stimulation begins with daily injections for about 10 to 12 days, with three or four monitoring scans to see how the follicles are growing. When the follicles reach the right size the final trigger injection is given, and about 36 hours later the eggs are collected, a procedure guided by transvaginal ultrasound that takes 15 to 20 minutes under a short anaesthetic. The same day the embryologist identifies the mature eggs and vitrifies them.

Vitrification is an ultra-rapid freeze that prevents ice crystals forming; it is the reason today’s results are far better than with the older methods. Recovery after collection is quick: most women are back to normal activity within a day or two, with bloating and a feeling of heaviness that pass. Two cycles are often needed to reach the target number of eggs, particularly when the reserve is low or the woman is over 35; this is discussed from the outset.

Two factors determine the outcome: your age when the eggs are frozen and the number of mature eggs stored. Age determines quality, that is how many of those eggs carry a normal number of chromosomes; number determines how many chances you have. As a general guide, roughly 15 to 20 mature eggs frozen before the age of 35 give a woman a high chance of at least one live birth later. After 38, the same number of eggs gives a noticeably smaller chance, because fewer of them are chromosomally normal.

After thawing, about 80 to 90 per cent of eggs survive with vitrification. They are then fertilised with ICSI, some develop into embryos and a proportion reach the blastocyst stage. The number falls at every step, which is why the starting number matters so much. This is also why egg freezing should be understood as an insurance policy rather than a guarantee: it buys chances, not certainty. And a fact that is rarely stated: most women who freeze eggs never use them, because they conceive naturally or their plans change, and that does not make the decision wrong.

If you have a settled partner and you both agree, embryo freezing is usually more efficient, because fertilisation happens straight away and you know how many embryos you actually have rather than how many eggs. But embryos belong to both partners and need the consent of both to be used later; eggs remain yours alone. That is an important difference and deserves an open conversation before you decide, not after.

The practical questions matter as much as the medical ones. How long storage lasts and how it is renewed, what it costs and what is included, and what happens if you move country are details that differ from place to place. The legal framework for storing and using gametes is different in Kosovo, in Albania and in European Union countries, including storage limits and the conditions for transport. Ask the clinic directly, in writing, about the rules that apply to you before you start.