embryo development

Embryonic development: the embryo on day 1 (D1)

When an oocyte is in an optimum state of maturation, ovulation takes place. This is known as day 0 of development (D0) and fertilisation by a competent spermatozoon must take place during this period.

When the oocyte is fertilised, it is then known as a zygote and
we are now on D1 of development. Certain characteristics and essential
structures need […]

2019-06-20T08:31:28+02:004 de January de 2019|0 Comments

Embryo fragmentation

Embryo fragmentation is a phenomenon that takes place in most embryos and its origin is not entirely clear. Some studies would seem to suggest that the fragments come from cell remains that have no nucleus or that they are the result of the decomposition of one or more cells from the embryo itself. The oocyte plays the most important role in fragmentation. Poor oocyte quality can lead to embryos that are highly fragmented. Embryo quality is determined by several characteristics such as the number of cells, their size or if the cell interior has an abnormality of any kind such as granularity or vacuolisation. However, one of the factors that has most impact on embryo quality is the extent of fragmentation. Based on the amount, in percentage, of space that it occupies, fragmentation is categorised into 4 types or degrees. […]

2019-06-20T08:31:38+02:0021 de December de 2018|0 Comments

How many embryos should be transferred? The importance of medical advice

Following in vitro fertilisation (IVF), the embryos obtained are evaluated in the laboratory before transfer to the patient’s uterus. A key question always comes up at this point: which and how many of those embryos should be transferred? […]

2018-08-16T10:59:19+02:0017 de August de 2018|0 Comments

Physiological conditions in embryo culture: reduction of the amount of oxygen in the incubator

Improving embryo culture by mimicking the conditions generated during in vivo culture is a key contributor towards improving success rates in couples who turn to in vitro fertilisation in order to solve their sterility issue.
In vitro culture of human embryos has traditionally been carried out in incubators in a controlled atmosphere at 6% CO2 and 21% O2. However, based on studies carried out on different species of mammals, we know that these conditions do not match those found in vivo in the fallopian tubes and the uterus where oxygen tension ranges between 2 and 8%. […]

2017-12-15T10:32:55+02:0015 de December de 2017|0 Comments

Implantation failure and repeated miscarriage. Treatment options

Successfully treating implantation failure and recurrent pregnancy loss is undoubtedly a challenge for doctors and for patients.

It is an area on which we continuously focus research at Instituto Bernabeu and, whilst we are far from finding a solution to all problems, the number of couples we are able to successfully treat is forever increasing.

An approach which does not take all 3 parties into account – the female, the male and the embryo – is incomplete. When evaluation only takes the couple into account, the reason behind the issue is only determined in under 20% of all cases. […]

2018-03-28T09:17:47+02:0015 de November de 2016|0 Comments

Why does embryonic arrest sometimes happen during in vitro development?

Many factors can intervene in arrest processes during embryo development which mean cell division is detained and, therefore, it is not possible to implant the embryo in the mother’s uterus and bring about a pregnancy.
In the first instance, the conditions for development are essential.  Embryos that develop in vitro are subjected to a number of artificial conditions that do not exist in vivo and which will always be less than optimum. Embryos which were apparently viable can suffer embryonic arrest. Huge efforts have been made over the last few years to try and mimic what happens inside the mother and replicate those conditions in laboratory processes.  Most of all, the concentration of oxygen in incubators has been reduced, going from 20% down to 5%. The composition of the culture means has also been improved. This, along with exhaustive monitoring of pH and osmotic concentration, means that we can routinely carry out prolonged embryo development up to blastocyst stage in order to achieve improved embryo selection and increase pregnancy rates. […]

2018-03-26T18:18:33+02:0019 de August de 2016|2 Comments

Recurrent pregnancy loss: an issue that does have a solution

Clearly one of the most difficult situations a couple trying for children may have to face is pregnancy loss. Suffering is even greater when, prior to this, the couple has gone through fertility treatment such as in vitro fertilisation, insemination or egg donation.
Pregnancy loss is not always the result of an illness or underlying abnormality. It can be the response nature provides in order to block the development of an abnormal embryo. In fact, when the tissue from the pregnancy loss is examined, a large number of chromosomal abnormalities can be detected. […]

2016-10-13T12:23:48+02:008 de April de 2016|0 Comments

Criteria for embryo classification

Embryos develop from the moment they are fertilised up until transfer to the mother’s uterus and this development process is assessed by embryologists. The embryos that have evolved correctly and are in the best condition are selected for transfer and/or cryopreservation.

At Instituto Bernabeu, we categorise embryos in accordance the Association for the Study of Reproductive Biology (ASEBIR) […]

2019-09-06T09:50:37+02:0012 de June de 2014|1 Comment

Anembryonic gestation

The anembryonic pregnancy or “blighted ovum” is a specific type of miscarriage in which the fertilized egg implants in the uterus but the embryo does not develop. It is a relatively common problem: 10-15% of clinically detected pregnancies are lost spontaneously and one third of them are blighted ovum.
After fertilization, that is, after the union of sperm and egg, begin a series of cell divisions that lead to the formation of the gestational sac  surrounded by a “shell” or cover called trophoblast (which is the one that will lead to future placenta); inside the gestational sac the embryo will develop. In the case of anembryonic pregnancy the gestational sac is formed with the trophoblastic cover but the embryo is not displayed because it has stopped developing at a very early stage, before reaching a millimeter in size, so it cannot be detected with an ultrasound. […]

2014-05-15T10:04:18+02:0015 de May de 2014|0 Comments

First Pregnancy Scan after IVF Treatment

 Confirming pregnancy after IVF and Egg Donation . The first ultrasound in which we can see the pregnancy  is a very emotional time for the parents, especially for patients who have gone through  treatments for assisted reproduction. For these patients, after having a positive pregnancy test , their anxiety does not go away but gets stronger until the pregnancy is seen to develop normally. Therefore it is very important to know what happens during this exploration, and what to expect. […]

2017-08-17T14:36:36+02:005 de March de 2014|41 Comments
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