How can the best spermatozoon for fertilising an egg be selected?

Selection of the spermatozoon capable of fertilising an egg and generating a viable embryo is a subject that has been covered in a great number of studies aiming to provide this question with an answer.
Although assisted reproduction techniques have been used for dealing with fertility issues for many years, there is still room for improvement in terms of the results obtained. First of all, we need to fully determine the role of the spermatozoon because it tends to be thought of simply as the transporter of the father’s genetic material with no impact on later development. This idea has already been turned on its head and sperm does not only play a role in the fertilisation process. An abnormal spermatozoon can give rise to abnormal embryos and can even influence implantation failure. […]

2017-09-01T14:27:10+00:001 de September de 2017|0 Comments

What is a spermatid?

Spermatozoa production takes place in the testicular seminiferous tubules and the process is known as spermatogenesis.  At the end of this process, a germ cell generates 4 mature spermatozoa which will survive in the human body for between 62 and 75 days.  The final stage in spermatogenesis, known as spermiogenesis, is a cell differentiation and maturation process consisting of the change from spermatids to spermatozoa.  As can be seen in the picture, the spermatids develop from secondary spermatocites and have already undergone Meiosis I and II division. They have a normal set of chromosomes (haploid) which means that fertilisation of a mature egg can take place. Therefore, and despite the fact that they are immature cells, they can be used in assisted reproduction techniques using ICSI when there are no mature sperm in samples taken from the ejaculate or testicles. […]

2017-01-13T14:38:30+00:0013 de January de 2017|0 Comments

Asthenozoospermia: What is it? How can it be detected? What course of treatment can be used in order to get pregnant?

Asthenozoospermia is a decrease in the percentage of motile sperm in a sperm sample and it is identified by means of a seminogram or semen analysis.
Nowadays, seminograms are a basic tool which provide us with information in order to evaluate a man’s fertility and they are very useful when determining personalised treatment for the couple concerned. The analysis can be used to evaluate numerous factors such as the concentration, motility and morphology of sperm present in the ejaculate, amongst others.
According to the criteria included in the 5th edition of the World Health Organisation (WHO) (2010) manual, a man has asthenozoospermia when less than 32% of sperm in the ejaculate have progressive motility (sperm which move around) or when there it less than 40% total motile sperm (motile sperm which do and do not move around). […]

2016-12-30T09:49:27+00:0030 de December de 2016|0 Comments

Teratozoospermia and male infertility

Teratozoospermia is an increase in the percentage of abnormal sperm in a sperm sample and it is identified by means of a seminogram or semen analysis.
According to the criteria in the 5th edition of the World Health Organisation (WHO), 2010 manual, a man has teratozoospermia when the percentage of normal spermatozoa in the ejaculate is below 4%.
Defects in sperm […]

2016-11-25T14:28:40+00:0025 de November de 2016|0 Comments

Oligozoospermia: What is it? How can it be detected? What course of treatment can be used in order to get pregnant? What about criptozoospermia?

Oligozoospermia is the presence of an abnormally low number of sperm in a semen sample.
According to the criteria in the 5th edition of the World Health Organisation (WHO) manual, normal sperm content in a sample of semen should be equal to or above 15 million per millimetre. If a sperm count gives a result below this figure, this is known as oligozoospermia and it may be associated with fertility issues. More than one sample will need to be evaluated in order to confirm this.
The diagnosis method consists of a spermogram which, amongst other things, gives a sperm count per millimetre of semen. […]

2016-11-03T13:48:55+00:004 de November de 2016|0 Comments

The endometrial receptivity array (ERA) test

Embryo implantation is the least well known phase of reproduction within the field of reproductive medicine. This fact is of special relevance if we also take into account that the human embryo is not very efficient when compared to other closely-related species in the evolution timeline.
We currently know that pregnancy is based upon three basic pillars: the embryo, the endometrium and the tolerance of the mother’s immune system. Not only is it essential that all three function correctly, but there needs to be optimum interaction between them. We have already covered the role of the embryo and the immune system in detail. Therefore, we will now concentrate on the endometrium and, more specifically, on studying endometrial receptivity. […]

2017-10-02T14:50:28+00:009 de September de 2016|0 Comments

What does embryo biopsy involve?

Preimplantation Genetic Diagnosis (PGD) is a tool designed to “get to know” the embryos genetically before they are transferred into the mother’s uterus. Thanks to this technique, we can study their chromosome count and find out if they are carriers of a hereditary disease. This information helps us to select the embryos that will produce healthy babies. Yet, how can we find that information?
Today, the only way to find genetic information about embryos is by performing an embryo biopsy. What does embryo biopsy involve?
To explain the biopsy procedure we should keep in mind that our point of departure is EMBRYOS. Embryos are retrieved after performing an assisted reproduction cycle, preferably by Intracytoplasmic Sperm Injection (ICSI), and their development is assessed during the culture period until day 3 or day 5. […]

2016-08-04T13:16:47+00:004 de March de 2016|0 Comments

Why does Comprehensive Chromosome Screening (CCS) by array-CGH reduce miscarriage rates?

Miscarriage rates in the general population with no fertility problems range around 15-20%. In other words, one out of every five couples who achieve pregnancy suffers a spontaneous miscarriage, and 5% of these couples suffer it more than once. Even when pregnancy is achieved with the help of assisted reproduction techniques, miscarriage rates do not vary. For this reason, it is important when couples come to our clinic seeking reproductive counselling to perform comprehensive testing and design an adequate protocol for their case to secure the best result, which is a healthy baby at home, minimising the chances of miscarriage. In order to do that, one should know that miscarriages and pregnancy losses are caused by different reasons (uterine problems, immunological problems, and so on), and yet in half the cases there are chromosomal abnormalities in the embryo that prevent pregnancies to progress, hence causing miscarriages. Normal embryos have two copies of each chromosome, one inherited from the father and the other from the mother, and the chromosomal anomalies they may suffer involve a change in the number of copies, producing an imbalance in their genetic load which might block embryo development. […]

2016-08-04T13:18:08+00:0012 de February de 2016|0 Comments

Choosing a fertilisation technique when oocyte counts are poor. IVF or ICSI?

A low ovarian response is an increasingly common situation for clinicians. It is mainly associated with delayed motherhood and, accordingly, with lower ovarian reserves. In this type of patients, the number of oocytes retrieved after puncture is normally limited. In this situation, choosing the most adequate fertilisation technique, conventional IVF or Intracytoplasmic Sperm Injection (ICSI), may stir a little controversy (of course, provided that the sperm quality and the medical history lead us to consider conventional IVF as a reasonable option). […]

2016-08-12T13:40:38+00:0029 de January de 2016|0 Comments

The male factor in infertility

In contrast with the old-fashioned belief that reproduction issues are a female thing, current figures are clear: 47% of infertility cases in a couple are down to an issue with the man. Therefore, when a couple has infertility issues and they seek the help of a clinic specialising in assisted reproduction, the tests and analyses are carried out on both members of the couple. This practice of looking into both the female factor and the male factor is now common and carried out by all experts in the field, but there is still a lack of understanding of the fertility issues which men can have. What are they? What solutions do leading assisted reproduction clinics offer nowadays?
The most common issues amongst men are “changes in the sperm count with no apparent cause”, explains Instituto Bernabeu in Alicante. That is, a low number of sperm, poor sperm mobility or abnormal morphology. Additionally, there may be more concrete and identifiable reasons for changes in sperm such as obstruction issues, infection, diseases or genetic reasons which impede egg fertilisation or which affect embryo quality. […]

2016-08-04T13:30:33+00:003 de December de 2015|0 Comments
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