What is ‘Cytoplasmic transfer?

The technique ofcytoplasmic transfer, or cytoplasmic donation is among the most modern and advanced of all assisted reproduction protocols. Here, using the ICSI technique, both the sperm of the husband and about 5% of the cytoplasm (the ‘yolk’) of an egg donated from another patient are injected into the wifes’ eggs. The advantage of this is that the couple seeking children can have babies with their own eggs, even if the untreated egg quality normally does not permit this. This is especially important in cases where the wife is over 37 years old, because her eggs will start to deteriorate in quality, lowering the chances that she can get pregnant. Even young women sometimes suffer from poor quality eggs, hence infertility. In these cases, cytoplasmic transfer can increase the egg quality to the point in which implantation and hence pregnancy is a real prospect.

What is egg ‘cytoplasm’?

‘Cytoplasm’ consists of the inner part of the egg that does not include the nucleus i.e. the nutritive portion of the egg. This part contains several features that help the egg grow such as mitochondria (the energy factory of the cell), the endoplasmic reticulum (makes proteins) and the soluble part of the egg (i.e. all components that are dissolved in water or fats). Obviously, this part gives the egg its’ potential to make a baby, and any defects here compromise the whole baby-forming process.

Advantages of Cytoplasmic Transfer

1) Cytoplasmic transfer (or donation) is NOT egg donation. This means the genetic material and hence inherited traits remain that of the mother and father. This is obviously far more acceptable than full egg donation. The advantage of this is that the couple seeking children can have babies with their own eggs, even if the untreated egg quality normally does not permit this.

2) Cytoplasmic transfer can help couples where the wife is over 37 years old, because her eggs will start to deteriorate in quality, lowering the chances that she can get pregnant.

3) Cytoplasmic transfer can help even young women in cases where their egg quality is poor and several attempts to conceive have been tried without success.

Disadvantages of Cytoplasmic Transfer

1) The pregnancy rate is not as high as that of full egg donation, this because cytoplasmic transfer does not completely substitute the oocyte cytoplasmic component. Therefore, full rejuvenation of the oocyte is not possible. However, a patient can expect up to a five-fold increase in probability to conceive.

2) Theoretical constraints on the introduction of foreign cell parts (i.e. mitochondria) has led to the technique being severely restricted in many parts of the world (i.e. USA itself, UK, Italy). However, it must be stated that these theories are yet to be proven by data. However, more recently the UK health authorities are said to be revising their opinion.