In future a new method could help some couples who are childless against their will. The microscopic procedure significantly improves the success rate of 'ICSI' (intracytoplasmic sperm injection).
{IMAGE}This was discovered by scientists at the University of Bonn together with colleagues from China and industrial partners in a study of 124 women. Up to now, the desire to have a child is only fulfilled for every third couple that decides to have ICSI. In a study the artificial insemination method was twice as successful. The scientists have now published their data in the journal 'Reproductive BioMedicine'.
For many couples ICSI is the last resort in their attempt to have a child. 'The method is recommended if the man produces too few sperm cells,' the Bonn reproductive biologist Dr. Markus Montag explains. Doctors can in most cases still extract individual functioning sperm cells from testicular tissue, which they then inject into the ovum. The partner must take hormone preparations before an ICSI. They result in several ova maturing in the ovaries, normally it is only one ovum per month.
'We inject a sperm into every one of these cells,' Markus Montag explains. 'Then it takes more than 26 hours until the plasmosomes of the ovum and sperm cell fuse and an embryo forms. In this time frame we have to decide which of the fertilised ova to insert into the uterus.’ The reason for this is that the German law for the protection of embryos lays down that only a maximum of three fertilised ova are allowed to be implanted per attempt. 'We even restrict ourselves to only two, in order to exclude the possibility of births of triplets,' Markus Montag explains. With pregnancies involving multiple births there is an increased risk of miscarriages and malformations.
Choosing the 'best' ova
Which of the fertilised ova are finally implanted has usually been left up to chance. But today it is known that not all ova have the same quality. Using a special procedure the Bonn scientists can select the two most suitable candidates. 'For this we observe the ovule integument under a DIC microscope,' Dr. Montag explains. 'There it appears as a luminescent orange-red ring. The brighter this ring is and the more uniformly it shines, the greater the chance that it becomes a child.' The reason for this is that the ovule integument always seems to have a particularly uniform structure if the cell has matured under good conditions.