Implantation: a key stage in pregnancy


Ovulation and fertilization: the key stages before implantation

It all starts around 14th day of the female cycle, namely ovulation. It is at this stage that an egg is formed, which will soon be caught by the fallopian tube where fertilization will take place. To do this, one of the 200 million sperm of the daddy reaches the ovum and manages to cross its wall. It is from this moment that the egg will form, measuring only a few tenths of a millimeter. Helped by the movements of the proboscis and his vibrating eyelashes, he then begins his migration to the uterus. It does, in a way, the reverse path of the sperm when they came to fertilize the egg. This trip lasts three to four days. Here we are 6 days after the fertilization. The egg finally arrives in the uterine cavity.

What is implantation in a woman?

We are between the 6th and 10th day after fertilization (approximately 22 days after the last period). Once in the uterus, the egg does not implant immediately. It will float for a few days in the uterine cavity.

The implantation, or embryonic implantation, will be able to begin: concretely, the egg implants in the uterus. In 99,99% of cases, implantation takes place in the uterine cavity, and more exactly in uterine lining. The egg (also called a blastocyst) sticks to the endometrium, and its envelope will divide into two tissues. The first will dig a cavity in the endometrium where the egg can nest. The second provides the cells necessary for the development of this cavity. It buries itself completely in the uterine lining.

Then, little by little, le placenta got in place, playing an essential role during implantation. Indeed, the mother-to-be secretes maternal antibodies during the implantation of the egg, believing that it is a foreign body. To protect the future embryo, the placenta neutralizes the synthesized antibodies. This prevents the mother’s body from rejecting this “natural transplant”. Namely: implantation takes place in the same way for multiple pregnancies and in the case of in vitro fertilization (IVF).

Bleeding, pain: are there signs and symptoms during implantation?

How do you know if implantation is successful? Not easy ! There is no no really significant “symptoms” at the time of implantation. Some women experience slight bleeding, such as spotting, while others claim to have felt something. Others still, are persuaded not to be pregnant and did not feel anything in particular whereas the implantation did indeed take place! Like what, it is better not to rely too much on it, to avoid unpleasant surprises and false joys.

On the other hand, the first signs of pregnancy appear as soon as the hormone HCG is secreted by the cells of the placenta. It is this famous hormone which is responsible for nausea …

Implantation: when the egg does not implant in the right place

Sometimes implantation does not proceed normally and the egg attaches itself outside the uterus. If it is implanted in the tube, then we speak of ectopic pregnancy(or GEU in the jargon). Bleeding may appear, accompanied by pain. In this case, it is advisable to consult a doctor very quickly. The egg can also implant in the ovary or in another part of the small pelvis. We then speak of abdominal pregnancy. The first ultrasound makes it possible to know where the embryo is placed and to act accordingly. Corn rest assured, in 99% of cases, the embryo develops in a completely normal way.

The implantation of the embryo, and after?

The embryo, which measures only a few microns, will now develop very quickly. At three weeks pregnant, her heart is already in place even though it has only grown by 2 millimeters! Week after week, the future baby continues to grow thanks to food intake from the placenta.

Discover, in pictures, the development of the fetus, month after month. A fabulous adventure …

In video: The clear egg is rare, but it does exist.

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