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Just Look At Spermatozoid Critically

September 21, 2001

In vitro fertilisation is one of the methods for overcoming infertility. This procedure is rather complicated and expensive. That is why the patients want to be sure about the successful result in advance. The investigations carried out at the Ott Research Institute of Obstetrics and Gynaecology, Russian Academy of Medical Sciences, and St. Petersburg State Medical University named after Pavlov enable the doctors to increase the efficiency of the method. The doctors evaluate the external appearance of spermatozoids and offer the optimal variant of fertilisation based on the results observed.
      
In a simplified form, the procedure of getting in vitro babies consists of two stages. At first, simultaneous maturation of several egg-cells (oocytes) is triggerred in the woman with special medicaments. Then oocytes are extracted and placed in the suspension of spermatozoids (one hundred thousand mobile cells in a milliliter). The probability of becoming pregnant depends on how many oocytes were impregnated. The only obtained embryo does not guarantee the success because it may not survive in the uterus. The researchers from St. Petersburg analyzed the results of fertilisation in 304 infertile patients who applied to the International Center of Reproductive Medicine of the Ott Research Institute. Then they screened under manyfold magnification tens of thousands fixed stained spermatozoid samples and made a conclusion that the effectiveness of impregnation depended on the external appearance of these cells.
      
The scientists know exactly how a normal spermatozoid has to look. However, the ejaculate can contain only one tenth of the normal cells. All the other spermatozoids have some pathology of the tail (broken, twisted, short, doubled), too large or too small head or some defects inside the head. If the ejaculate contains more than 14 per cent of normal spermatozoids the frequency of impregnation is very high. If this percentage is less it is better to study the sperm more carefully.
      
The scientists created a formula which accounted different characteristics of sperm. In such a way they obtain a number that indicates the success of fertilisation. This number is a constant characteristic of sperm. It is very important because a man can test his sperm for impregnating ability now. But what should he do if this ability is low?
      
In this case the investigators offer two solutions of the problem. Firstly, it is possible to inject a spermatozoid right into the cytoplasm of the oocyte under the microscope. Such aimed impregnation is obviously much more effective. However, this operation is more complicated and there is no point in using this method always. The other possibility is to make the suspension of spermatozoids, in which the egg-cells are placed, very thick. If the concentration of mobile cells is more than forty million per a milliliter, the success of impregnation does not depend on how many normal spermatozoids the ejaculate contains.

Informnauka (Informscience) Agency