Egg Freezing Facts- From The Expert
‘‘Women need to know that their fertility will inevitably decline with time. They also need to know that they have options to manage this. It is therefore our duty to offer these fertility facts earlier on in life so young women can make informed decisions about their reproductive future at the right time.’’
Embryologist and Lab Director - Christiana Antoniadou
Egg freezing means that cancer patients and those with premature ovarian failure are now able to preserve their fertility. It has rendered fertility management for the LGBTQ population as a very viable and successful option. But the importance of egg freezing can go beyond these extremely important groups of patients: it can also form a type of preventative medicine.
We are born with all the potential eggs we will ever have, a staggering 1-2 million of them. By puberty we will end up with about half of these and with each menstrual cycle thereafter, we will lose up to 1000 eggs, with just one egg potentially maturing and being ovulated. However, not every ovulated egg will lead to a pregnancy or ultimately a baby, no matter how young or healthy a woman is.
A popular misconception is that we have a 100% chance of achieving a pregnancy each month. In fact, according to the American Society of Reproductive Medicine, a healthy young woman (under 30) only has about a 25% chance of achieving a pregnancy each month, a woman over 30 will have around a 20% chance, while a 40-year old’s chance would be just 5%. Our reproductive life starts with our first menstrual cycle and lasts until our last menstrual cycle approximately 40 years later (menopause), but we are not fertile for the duration of this timespan. As we go through life and are exposed to all the inevitable nasties of modern-day life - such as toxins, free radicals, infections and a countless number of other everyday forces - the DNA inside our eggs is being inadvertently and irrevocably damaged. Older eggs thus become more prone to accumulating genetic errors during cell division (a process known as meiosis) which ultimately leads to eggs with incorrect genetic make-up.
Despite this fertility decline being a gradual process over time, it tends to intensify from our mid-thirties onwards. Even though our fertility does not “drop off a hill” the day after our 35th birthday, it has been shown that the rate of fertility decline starts to accelerate around this age, so that by the time we reach our forties our ovarian reserve (the number of potential eggs we have left) is much lower and the quality of these eggs is much poorer. At this point it is more likely that we will have some genetically abnormal eggs, which may lead to difficulties in achieving a pregnancy, miscarriage or in some cases babies born with genetic disorders. So, as a woman grows older, her egg count, as well as her egg quality, gradually and inevitably decline. This is where egg freezing comes into the picture. It allows us to freeze our eggs whilst we are still young and healthy and, in this way, preserve our fertility and potentially bypass this fertility decline. In effect a woman can now be her own egg donor in the future. Yet, this will only work if eggs are frozen at a young enough age.
In most countries internationally women are now able to freeze their eggs at any point during their reproductive life. Egg freezing represents a highly lucrative business and thus most clinics would allow a patient of any age to proceed with the process (often disregarding the outcome in the event of the patient actually needing to use these eggs). Hence, the numbers published in the HFEA’s report on Trends & Figures in Fertility Treatment from 2014 – 2016 should not come as a surprise. The report showed that the highest birth rates (19%) were seen in cycles which used eggs frozen by patients aged below 35, with the birth rates reducing to 5% for cycles which used eggs frozen by patients aged between 40 and 42. The numbers published are based on calculated birth rates per thaw cycle and not per egg (which would render the statistics even poorer than those published). This corresponds with all the evidence-based science currently available.
Nevertheless, we should be very cautious about drawing conclusions due to the very small number of thaw cycles taking place (just 1.5% of total cycle numbers in the UK). The main reason for this is that a very small proportion of the women who freeze their eggs go back to use them. Another point worthy of mention is that these birth rates are just two percentage points lower than the overall IVF birth rate per embryo transfer in 2016 in the UK (which was just 21%). So, these egg thaw cycle results are not nearly as bad as they seem. Clinics choose how to represent their success rates, so the general public has a very distorted perception of the real success rates of IVF.
The take home message is that egg freezing success rates are directly linked to the age at which a woman froze those eggs (as well as her overall health at the time of freezing). Women need to know that their fertility will inevitably decline with time. They also need to know that they have options to manage this. It is therefore our duty to offer these fertility facts earlier on in life so young women can make informed decisions about their reproductive future at the right time. The proactive management of one’s fertility via egg freezing has the potential to become the future of IVF, provided it takes place at the right time and with revised storage limits (#extendthelimit).