The concept of egg quality of a woman is derived from the belief that the embryo implantation probability is powerfully related to the age and ovarian reserve of the woman. Thus, it is regarded that the quality of the egg is almost synonymous with the chances of embryo implantation. Its quality cannot be assessed merely by looking at the egg or measuring its ability to receive the fertilization by sperm or simply observing the initial embryo division.
There are a few important factors that contribute to the success or failure of the embryo implantation and some of them are:
Therefore, it is important to have the eggs tested to find out any sort of chromosomal abnormality. In case the mother is deficient of producing high-quality eggs, the best option is to have donor eggs.
Mitochondrial replacement (MRT, sometimes called mitochondrial donation) is a special form of in vitro fertilization in which the future baby's mitochondrial DNA comes from a third party. This technique is used in cases when mothers carry genes for mitochondrial diseases. The two most common techniques in the mitochondrial donation are pronuclear transfer and maternal spindle transfer.
Cells are the tiniest part of an organism including the human body but has various parts within, which have specific functions. The mitochondria, for instance, are the batteries of the cells and produce energy for all functions, including cellular movement and adequate cellular function.
The egg, being a single cell, also is highly dependent on the mitochondria for its optimal function. For an egg to be healthy, it should have optimal energy, and that comes only when the mitochondria is functioning at its best. This determines the overall quality of the egg too. Poor eggs, it is well established, is one of the major cause of infertility, as it cannot implant itself and sustain the entire term of pregnancy.
Studies have confirmed that eggs have more mitochondria than normal cells, as their energy requirements are higher.
The ovaries have cells called precursor cells, which eventually can become eggs and get fertilized. Studies have shown that when mitochondria from these precursor cells are infused into the fertilized egg, the overall quality of the egg improves and therefore improves chances of fertilization.
The mitochondrial transfer is the new technique which is being developed and has resulted in a baby but involves third-party IVF and hence is in an ethical debate.