2023 Author: Anita Thornton | [email protected]. Last modified: 2023-05-22 03:30
In vitro fertilization is the most effective treatment for infertility. However, it remains mysterious for those who have to consider it! Marie Charbonniaud describes all the steps!
Appointment for in vitro fertilization
In vitro fertilization consists of bringing the egg and the sperm together outside the woman's body and then, a few days later, placing the young embryo in her uterus so that it can develop there. But between the theory and its unfolding in the laboratory, there is a whole world! Here's how it really goes.
First step: stimulation of ovulation
Exceptionally, IVF can be performed “in a natural cycle”, not stimulated. But generally, whether you ovulate regularly or not, stimulation of ovulation is essential. This makes it possible to obtain several follicles and eggs, and thus increase the chances of obtaining several embryos. To do this, you must first take hormones to temporarily “deactivate” the natural cycle and its ovulation, for two weeks. The sole purpose of this stage is to prevent the brain's control over the ovaries and to control the day of ovulation, to prevent the brain from causing it.triggers itself. It is sometimes said that the ovaries are put “to rest”. The doctor will use GnRH “agonist” drugs, injected subcutaneously (just under the skin).
Then to stimulate the ovaries, it lasts another two weeks. Taking the first drugs is continued until ovulation is triggered (because they prevent premature ovulation), but are added daily injections of one or more drugs to “wake up” the ovaries. The goal? Cause “superovulation”, i.e. the growth of several follicles (future eggs) instead of just one. The drugs most often prescribed are Gonal-F, Repronex, Bravelle or Follistim. They are made up of the hormone FSH, similar to that produced by the pituitary gland in the brain. They come in white powder, packaged in glass ampoules, to be mixed in saline water and then injected.
From there, the doctor will closely monitor the response of the ovaries to treatment. It will be based almost exclusively on ultrasounds (carried out two or three times during the cycle). They will allow him to visualize the follicles inside each ovary and determine their size; but also to measure the uterine lining, which must be thick enough for the embryo to implant. Statistically, nearly 90% of visible good-sized follicles produce an egg.
Second step: Triggering ovulation
One time out of ten, the treatment will have to beinterrupted before the onset of ovulation. Either because there is a risk of overstimulation, or because the response is too weak to hope to obtain fertilizable eggs. But nine times out of ten, everything goes well, and as soon as the three largest follicles reach 18 mm or more in diameter, the triggering of ovulation is decided.
The same evening, an ampoule of hCG – a hormone that has the property of mimicking the signal normally given to the ovary by the brain – is given intramuscularly and causes ovulation 38 to 40 hours later. But beware, the goal is to collect the follicles just before ovulation! That is to say, a few moments before they expel their egg. The puncture will therefore take place between 35 and 36 hours after the injection of hCG. For example: if the injection takes place at 10 p.m., the puncture will take place two days later at 9 a.m.
Third step: Collection of sperm and eggs
Semen collection is done by masturbation, the same day as the puncture so that the sperm are as "fresh" as possible. Most of the time, a small private room will be allocated to the spouse and magazines or films will always be available to help him (note that he can always be accompanied by his spouse). If he suffers from erectile dysfunction, solutions can be found: such as Viagra, which clinics always have. And exceptionally, doctors will use frozen sperm. For example, if the spouse cannot be present on the day ofIVF, if he has serious reluctance to masturbate, or if his sperm has been stored for medical reasons.
In women, egg retrieval is done vaginally, just before ovulation, under local anesthesia of the vagina. No scar will be visible. A vaginal probe is inserted then, once the follicles have been identified on the ultrasound, the content of each follicle (about 5 cm of liquid) is aspirated using a needle guided by the probe. The sample is taken from each of the ovaries and lasts between 5 and 15 minutes, depending on the number of follicles to be aspirated. On average, between 5 and 12 eggs will be retrieved, sometimes less (four or five), sometimes more (15 to 30). Not all of them will be able to be fertilized: some will be immature, empty or a little damaged. But about 70% of collected eggs are usually mature.
Fourth step: meeting and transfer
Each egg is brought together with 100,000 motile sperm in a small plastic tube, filled with one milliliter of culture medium (s alts and nutrients). Then, the next day, the embryos will be examined under a magnifying glass. If the embryo contains two nuclei inside (pronuclei), this is a sign of fertilization. One represents the genetic contribution of the mother, the other, that of the father. Then, following a fusion of the nuclei and then a division, about half of the inseminated eggs will become embryos.
All you have to do is transfer these embryos to the cozy nest that awaits them!
This will be done atlaboratory, between 2 and 6 days after egg collection. No anesthesia is necessary. But relaxation is desirable, because stress can cause uterine contractions that would reject the embryo. The woman is placed in a gynecological position, the bust elongated, the legs slightly raised and ajar. The two most beautiful embryos will be checked one last time under the microscope, then placed in a catheter (thin flexible plastic tube connected to a syringe), and presto! They will be placed 1 or 2 cm from the uterine fundus. The operation is completely painless.
Fifth step: the pregnancy test
It is thanks to the hCG hormone in the blood, produced by the placenta of the developing fetus, that early pregnancy can be detected. It can be detected as early as the eighth day after ovulation; but we can only be certain of this between the 12th and 14th day. The result is announced in person, if possible by opening the laboratory envelope in front of the patients, so that the team does not find out before them.
If the value is positive (greater than 5), it's a very good sign! However, as long as the number remains between 5 and 20, you should not claim victory. The blood test will therefore be repeated every two days to ensure that the hCG level doubles with each dosage. Then, a vaginal ultrasound is performed at the 6th week of pregnancy, two weeks after the positive pregnancy test. At this time, most of the time, the heartbeat of the fetus will be audible. Victory!
If, byOn the other hand, the result is negative, it means that no embryo has implanted and the rules will occur in the following days. Sometimes menstruation comes just before the test. And, even if the news is painful, it still needs to be confirmed with a test.