Donor Eggs – What Does it Really Mean?

The idea of falling pregnant using oocytes (“eggs”) donated by another woman is often a hard one to process.  There are many reasons that it might be suggested as the way forward.  There is a limited window of fertility in females related to the availability of eggs in the ovary.  The ovaries are fully stocked at birth and then over the years the numbers decrease by natural attrition.  By the first menstruation egg numbers have halved in the ovaries.  Once ovulation begins in adolescent girls on average a single egg is released each month however, many eggs begin the “recruitment” phase until the one dominates.  In a lifetime therefore only a fraction of eggs actually have the potential to be fertilised and result in a baby.

The commonest reason to require egg donation is natural aging of the ovaries and depletion that is primarily programmed in an individual by the genes.  On average this will be in the 40s especially from 43 onwards.  Around the age of 38 there seems to be an accelerated loss of eggs.  Since fertility treatments such as in vitro fertilisation are based around accessing the same eggs, the same sperm and the same womb as nature it will be no surprise that the success at its very best will be a restoration to the normally expected pregnancy and delivery rates for a given age.  As you will know this rate falls naturally with age.  It is unusual for in vitro fertilisation to be successful after 43 years and certainly 45 years just as natural conception at these ages is rare.

Some women will run out of eggs at an earlier age than expected for example with premature ovarian ageing or failure.  There is no treatment for this at the present time.  Occasionally medical conditions and genetic disorders will result in the production of abnormal embryos at any age and a normal pregnancy just will not result.  There are times when it is difficult to pin down a specific reason for failure to conceive despite repeated treatments and the decision will be made to consider donated eggs.  Male same sex couples will also require donated eggs to have children through the surrogacy programme.

Often when discussing this often difficult topic it is apparent that the major concern is that the resulting baby will not be “genetically” or “chromosomally” related to the mother.  This is in part because we are conditioned to believe that this is the most important aspect in the creation of our families.  Interestingly the process of gene reading from the chromosomes is complex process that is influenced by many factors most importantly beginning in the womb.  This process is called epigenetics and it is with us for life.  Not only that but we now know DNA from the mother sourced from the womb cells is taken up and incorporated into the embryo.  This means that the baby born from donor eggs is as uniquely developed, imprinted and influenced by being carried in the womb as one from her own eggs.

No one willingly chooses to be in the position to make these difficult decisions.  It seems however that through the in vitro fertilisation process and altruism of those special people who are prepared to donate eggs something special is given back to the recipients beyond what might appear on first glance.

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