Production of gametes in in vitro fertilization

Just a reminder of courses the production of male and female gametes and medically assisted procreation (amp.)

The cycle of spermatogenesis is a continuous production cycle.

In the testes, are specialized cells that produce sperm continuously future. They will rise gradually during their completion to the exit. Meanwhile the seminal fluid is produced by the prostate. The sperm-liquid mixture is done only during ejaculation.

The manufacture is permanent, chromosomal errors will affect “snowball”, continue and be added throughout sperm production. Therefore we must try to younger childbearing. The manufacturing cycle takes about 90 days with 15 last used for the final maturation in the epididymis.

Sperm swimming

A contrary, the stock of oocytes is determined early in the life of the woman.

Made during oogenesis during fetal life, it evolves over the course of life and aging like the rest of the cells. Age from, the film that surrounds the egg, the zona pellucida, thickens and makes fertilization more difficult (usually after the 40 chronological age of the woman.)

But before ovulation, a cohort of oocytes is recruited and begins to evolve : most degenerate before the final maturation. One, more rarely two, three exceptionally (where the twins when fertilization), matures and will be laid during ovulation following the peak of the hormone lutéisante (LH) sent from the pituitary. The scar left on the ovary become famous “corpus luteum” producing oocytes with progesterone degenerate cycle. Between recruitment and ovulation, a cycle 90 days also passed.

Any change in food, lifestyle or taking any vitamin supplementation should take these 90 days required to mature.

An action can however be seen as early 15 days of engagement with progressive rise, gametes maturing enjoying part of this action. But sometimes, no beneficial effect will occur… Perhaps the reason for the loss she is elsewhere, or perhaps there are there several (your doctor is your best advisor !)

Courting a sperm egg : 1 one will win

The different techniques of medically assisted procreation are to intervene from gamete production to meet them.

During the use of medically assisted procreation, AMP gynecologist technician will follow day by day maturation ovocytaire and manage the timing.

It can either monitor the natural cycle or replace the natural hormones with synthetic hormones to take orders from a Stimulation ovarienne. According to long or short protocols, a rest period of the ovaries will be scheduled or not, and estrogen therapy will influence the evolution of the cohort of oocytes naturally recruited for the majority to reach maturity.

A hormone injection trigger spawning ovular 36 hours later, time the puncture oocyte will be.

At the same time, the sperm partner will be prepared for the gametes are in contact as soon as possible. In the simplest case, partner has given his sperm on the day but it is also possible that this is from a donor (from a bank of frozen semen) or that the collection has been a surgical advance (biopsy when an obstacle “mouth out”.)

The fertilization takes place over several hours. The sperm will penetrate with his head to protect the zona pellucida and the egg will grow inward toward the nucleus of the egg, and before the merger, unfold gradually : for the difference in size between the two gametes, the genetic material of sperm is “compacted” and must unfold without too much damage chromosomal (the famous “fragmentation ADN“) that links the fertilization chromosomes in male and female pairs new original. From that moment, it is more than two gametes, but an embryo, new being heir to half of the gene from both parents.

From fertilization to hatching of the blastocyst

At a artificial insemination, sperm is simply injected into the matrix of the woman and the chance to choose chair egg-sperm.

And conventional IVF, chance will still sperm from other successful fertilization : the meeting place will be in vitro, a test tube and not the woman's body.

At a ICSI, the sperm is injected into the oocyte of force by the lab technician, without having to break his head the zona pellucida.

But in a IMSI, the “sperm winner” of ICSI is selected with a digital microscope with a high magnifying power (6 times more than conventional equipment) on morphological criteria “Beauty of the head”.

The hatching or assisted hatching is to incise the membrane slightly embryo so he can crack more easily, bloom and grow out of this membrane that protects during the first divisions.

Couples carrying genetic disease such as cystic fibrosis will also follow this route to have their embryos tested by the dpi, preimplantation screening.

Depending on the number and visual quality (amp) or genetic (dpi) embryos, they will be relocated during the transfer in their natural environment, the mother's body at different times : the next (J2) or two days (J3) of fertilization, on day 5 at the blastocyst stage when the chances of implantation and pregnancy are highest for embryos that survived this stage.

The transfer can also be deferred to another cycle if the number and quality of embryos to freeze and can therefore make a frozen embryo transfer, TEC.

The next step is the verdict : the pregnancy test to J14. No need to rely on urine tests, reliability is insufficient at this stage, especially since the body does not always eliminated the hcg hormone sometimes given in support during the transfer. A blood test will indicate the rate actually present in the blood to confirm or refute the beginning of pregnancy.

A second and a third sample will verify the proper changes in the rate of embryonic development and therefore, if, before a first echo to J30 allows to count the number of embryo sacs and therefore whether the pregnancy is single or multiple.

A ce tested, pregnancy between the normal

To go further

And of course your old encyclopedia, your high school biology books, and questions to your gynecologist favorite !

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