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β-hCG (human chorionic gonadotropin) is a glycoprotein that is initially secreted by trophoblast cells in the embryo shortly after it implants in the uterus. The rapid increase in serum levels of hCG following conception means it is an excellent early indicator of pregnancy. It’s also a parameter which is widely used for monitoring that a pregnancy is progressing correctly.
On a physiological level, hCG triggers the corpus luteum and thus facilitates progesterone and oestrogen synthesis. Progesterone stimulates the maturing of blood and capillary vessels that help the foetus to develop correctly.
hCG levels can be measured in blood or in urine.
Urine tests have a detection limit of 20 to 100 mUI/ml depending on the brand. If the measurement is to be taken in urine, a sample of the first urine of the day is recommended. This is particularly true during the early days of pregnancy because, if the urine is too diluted, the test can return incorrect negative results.
hCG levels in blood can be used to detect levels as low as 5 mUI/ml and the concentration levels of the hormone can therefore be calculated.
hCG levels in multiple pregnancies are 30-50 % higher than in pregnancies where there is only one foetus. However, a multiple pregnancy should be confirmed by means of an ultrasound.
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Determining the ideal day for embryo transfer has always been a controversial issue and there are, even today, still a number of doubts surrounding this issue.
Embryo culture is, basically, a selection process. Each embryo’s progress is evaluated throughout and a decision is taken on which is most likely to implant successfully. […]
It has long been known that patients who are overweight face increased reproduction and pregnancy loss issues.
Issues achieving a successful pregnancy are even greater if, as well as being obese, the patient also has illnesses such as diabetes, thyroid issues or other metabolic disorders (refer to further information on endocrinology and pregnancy).
However, little was known about the direct effect of obesity on endometrial receptivity and successful or unsuccessful embryo implantation. […]
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. […]
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. […]
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. […]
In the year 2000, human sequencing was achieved following 10 years of scientific work and now, thanks to next generation DNA sequencing, we are able to get to know a human genome in the space of just one week. It is still not possible, however, to access 100% of the genetic information contained within an embryo, the true origin of human life. But scientific progress is unstoppable and with this new technique a new range of promising options for genetics, for fertility and for life have opened up.
According to researchers, the possibilities which DNA sequencing offers are revolutionary and huge. Despite being at a very initial stage in which only the tip of the next generation sequencing iceberg has been uncovered, the number of uses is so varied that determining how to manage everything this technique implies will, in fact, be the future’s biggest challenge.
For the time being, thanks to human sequencing, nowadays “there is greater power of analysis and this facilitates many things and very significant possibilities”, explains the scientist and molecular biology and genetics investigator at Instituto Bernabeu, José Antonio Ortiz. The new technique, which can only be carried out in leading international clinics such as IB, “has revolutionised genetics. Genetic studies are now much quicker.’ […]
It has been almost 30 years since the first pregnancy from cryopreserved embryos was achieved (Trounson and Mohr, 1983). Ever since then, numbers have been steadily growing at biobanks in assisted reproduction centres, mainly due to the optimisation of reproductive treatments. Our goal is to retrieve a satisfactory amount of good quality embryos (one that is enough for a fresh transfer and also for cryopreservation) by means of an ovarian stimulation cycle. These embryos may be used for future pregnancy attempts, although couples can choose to donate them for reproductive purposes, assign them to specific research projects or dispose of them. Yet, general evidence shows that many couples, mainly those that achieve pregnancy in their first fresh attempt, choose to keep them frozen without a specific end or plan in mind for the future. […]
During the performance of assisted reproduction procedures, the best embryo is selected for transfer into the mother’s uterus. The selection is based on the “look” of the embryo shortly before transfer. As a matter of fact, waiting time normally stretches until day 5 of embryo culture in order to enhance the potential of the selected embryo and its synchronisation with the endometrium.
Sometimes the selection is favoured by performing a Comprehensive Chromosome Screening (CCS) test. Thanks to this technique, we can find out if an embryo has all the chromosomes in their exact number, in other words, if it is chromosomally normal. In this way, the selection is both morphological (external look) and chromosomal (internal look).
To be able to analyse the embryo we must first biopsy it (take a cell sample) without affecting its development and subsequent implantation. Biopsy techniques have been evolving until the process has been optimised. […]
Instituto Bernabeu strengthens is position as a European reference in matters of R&D at the Annual Congress of the British Fertility Society.
The British Fertility Society (BSF) Annual Congress, one of Europe’s leading fertility and assisted reproduction events, was held on 7th and 8th January in Newcastle (UK). Its scientific committee accepted a total of 11 pieces of research work prepared by Instituto Bernabeu (Alicante) as part of the group’s main lines of R&D. These include poor ovarian response – a pathology which is largely associated with attempts to fall pregnant later on in life – embryo implantation failure and the impact of genetics on reproduction issues. […]