In vitro fertilization (IVF) is the assisted reproduction technique in which the union of egg and sperm occurs in the laboratory (hence comes the name of “in vitro”) to get embryos to be transferred to the uterus. If pregnancy happens, it will evolve naturally as any other pregnancy.

The embryo requires to be incubated in the appropriate environment to develop (temperature, darkness, osmolarity, pH and basic nutrients). In the Laboratory of Assisted Reproduction and Embryology, at Fertilab we try to make the environment as close as possible to that would occur in the fallopian tubes if fertilization had been “in vivo”. The third day, the embryo, which has not yet begun to differentiate, used to be 8 cells. Each cell has the same genetic information called pluripotent. It is from this time that embryos require other substances and growth factors and that is why, it is the best time to transfer to the uterus.

IVF is usually accompanied by a hormonal treatment to stimulate the development of more than one egg. Ideally, try to achieve growth of 8-10 follicles from both ovaries. In this way the chances of getting a viable embryo to implantation increase.

Steps to follow

1. Hormonal stimulation
2. Egg retrieval: transvaginal follicular puncture
3. ICSI IVF laboratory
4. Conventional fertilization (IVF classic)

Hormonal stimulation

Hormonal stimulation IVF usually used for higher doses than the doses required for insemination in order to achieve a higher ovarian response. However, too many eggs may damage the embryo implantation rate, since the accompanying hyperestrogenism is detrimental to endometrial receptivity. Therefore, the ideal goal is to obtain an intermediate number of eggs to ensure fertilization and subsequent embryo selection.

A proper hormonal stimulation, personalized conveniently controlled by ultrasound and plasma levels of estradiol, will be the key to the success of the technique. In Fertilab, the track always with the same gynecologist, we adapt stimulation to each woman and each cycle.

Egg retrieval: transvaginal follicular puncture

Egg retrieval or follicular puncture is an outpatient surgical procedure that is performed vaginally and guided by ultrasound. To perform transvaginal follicular puncture is coupled to the ultrasound probe guidance will pass through the needle. Puncturing each of ovarian follicles is performed, aspirating the liquid content and found swimming egg inside. During collection tubes aspiration of follicular fluid is maintained at constant temperature of 37 ° C in a heat block.

The process takes 15 to 20 minutes and is performed under anesthetic sedation, allowing maximum comfort and safety of the patient. Usually recovery is quick and the patient leaves the clinic after 2-3 hours. The complication rate is low.

The follicular puncture is performed in the surgical room because it requires sterile conditions and the use of anesthesia. A privileged and unique place with a welcoming atmosphere that our patients appreciate.

Once in the laboratory, if we have obtain the eggs, the couple will leave the sperm sample to inseminate the eggs.

ICSI IVF laboratory

Under the microscope, the embryologist checks eggs swimming inside the follicles. The eggs are the largest cells in the human body and attached to the cumulus cells are easily noticeable. Washed to remove erythrocytes and stored in culture medium.

Sperm selected by the method of gradients of different densities. Few sperm are needed but the best possible quality. So -in Fertilab we insist on this point- we recommend deliver the sample within days of sexual abstinence among 2 and 3 days (never more than 3) – because as you increase the days of abstinence, also increases the amount sperm with fragmented DNA.

There are two techniques to fertilize eggs:

Conventional fertilization (IVF classic)

The eggs are incubated at a concentration of 200,000 motile sperm / ml to be fertilised spontaneously and naturally. In cases of severe male factor or failure of fertilization in previous IVF cycle, this technique is performed and all the eggs were microinjected.

Intracytoplasmic sperm microinjection (ICSI)

A mobile sperm for each mature egg is selected and using a micropipette and micromanipulation techniques, is deposited into the oocyte cytoplasm. It is used in severe male factor when sperm concentration is very low or not present adequate mobility.

In Fertilab, whenever possible, try to fertilize the eggs with both techniques to have more possibilities for action and success.

The next day we evaluate the puncture, few properly fertilized eggs have observed the presence of pronucleus. In each pronucleus it is half the genetic information of women and men. A day later they will have been divided and we can assess embryo quality. At this point, the embryo would have 4 cells. On the third day of the puncture, the embryos should take 7-8 cells. Embryos were classified according to the number of cells, fragmentation, the rate of division, the presence of nuclei and other parameters, on a scale from 1 to 10 and one that has four categories (A, B, C and D) . Embryos with high quality grades are more likely to implantation.

Embryonic development and culture to blastocyst

Embryo transfer

Pregnancy test: The “beta expected”


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