How many eggs should I freeze and what are the success rates?

Dear Professor Winston
I’m a 37 year old female who has recently undergone egg freezing for social reasons. 12 eggs have been frozen.
I would like to ask :
1 – Do you have any statistics of successful pregnancies from egg freezing?
2 – I don’t think 12 are enough, what is your opinion ?
3 – Would you like me to be part of any research? Happy to do so.
I look forward to hearing from you , J

Dear J,

The most recent figures I obtained from the Department of Health and from the Human Fertilisation and Embryology Authority (just 2 months ago) report on all the pregnancies obtained following egg freezing from all IVF clinics in the United Kingdom.

Where women have frozen their eggs for their own use later (usually like you to delay pregnancy), in the last six years a total of 3145 eggs have been thawed in attempts to achieve a pregnancy. There have been 45 live births and a number of miscarriages (probably over 25 but the records for miscarriages are incomplete which I believe is disgraceful). 45 pregnancies from 3145 eggs is a live birth rate of around 1.5%. The best success rate was in 2012 and was 2.9%. The success rates were a bit lower in 2013 and 2014.

I should add that claims have been made that the technique of slow freezing which was the original method widely used up to a few years ago has been replaced by the process called vitrification. Although many clinics often claim that the ‘new technique’ of vitrification is much more successful, it is worth remembering that the first birth after vitrification was published by Alan Trounson in Australia 16 years ago – so it is hardly new. Regrettably I have to say that a number of clinics have not been properly transparent with the data they present to prospective patients.

Best wishes
Robert Winston