Meiosis

What is meiosis?

Meiosis is the process by which the number of chromosomes of the germ cells, both masculine and feminine, is reduced from 46 to 23 chromosomes. In this way when the chromosomes of the sperm and of the eggs are joined after fertilisation, the number of 46 chromosomes is again established in the embryo.

How is meiosis studied?

To study meiosis, the structure of the so-called bivalents that are observed in the germ cells and more specifically, in the primary sperm, are analysed. Depending of whether these structures enter in intimate contact, so that the genetic recombination takes place, or if they separate prematurely, we can speak of a normal or pathological meiosis.

Is it difficult to conduct a testicular biopsy?

The testicular biopsy is a minimally invasive technique that can be carried out in 15 minutes with minimal discomfort to the patient.

How can abnormal meiosis affect my fertility?

Abnormal meiosis can affect the separation of the chromosomes both during the formation of the sperm and during the embryonic development and, therefore, can interfere with a normal embryonic development. It can decreases the probability to pregnancy and increases the risk of miscarriage.

When should a meiosis study be conducted?

Meiosis should be studied in couples with a long history of infertility, when a full-term pregnancy has not occurred after several cycles of IVF, when the semen of the husband is of low quality and when there is recurring miscarriage.

Can abnormal meiosis be corrected?

No. The only thing that we can do is select those embryos that have been fertilised by sperm derived from germ cells with normal meiosis.

Why can meiosis be bad?

There are many causes. Some are congenital and others are acquired. Among the acquired, the use of chemotherapy and radiotherapy can be highlighted, and among the congenital causes, the exposure of the foetus to endocrine disrupters during the pregnancy.

Does abnormal meiosis mean that we cannot use the semen of the male?

No. It means that the possibilities of transferring a normal embryo are much lower than in males with normal semen and that, therefore, one must turn to the selection of chromosomally normal embryos by means of Preimplantational Genetic Diagnosis.