Fertilization

Fertilization (conception) is the moment when the sperm penetrates the egg and fuses with it. From this moment begins cell division: Any division of the number of cells doubled in the fertilized egg. About two days after fertilization, the fertilized egg travels to the rest of the way down the oviduct into the uterus, where it takes root.

So that there can ever come to fertilization, some prerequisites are necessary to perform all together to meet that sperm and egg can.


Prerequisite for fertilization
As the sperm reach the egg?
The actual fertilization
Multiple pregnancies
Natural family planning (NFP)



Prerequisite for fertilization: a fertilized egg cell

Any woman mature in the first half of the cycle in the ovary follicles (follicles) approach. One, sometimes several follicles develop until about the middle of the cycle to jump prepare dominant follicle. In the middle of the cycle - average 15 days after the first day of last menstrual period - is the egg (ovulation) production: a dominant follicle emerges from the egg into the fallopian tubes and out. Over the next twelve to 24 hours after ovulation the egg travels the fallopian tube towards the uterus. During this "tour" they can be fertilized by a sperm cell.

As the sperm reach the fertilizable egg?

The sperm or sperm cells are produced in the testes of the male. During orgasm, these sperm mix with secretions from the prostate. This mixture is called ejaculate. Depending on the state are to an average of 150 million sperm. The ejaculate during orgasm during intercourse, the man from the penis into the vagina of the woman. "Float" from where the sperm into the uterus and fallopian tubes.
The "race" to the sperm for fertilization

The milieu of the uterus and uterine lining ensure that the sperm remain in the body of the woman moved and survive as long as possible. In the period around ovulation is around the otherwise consistent with closed cervical mucus so that sperm can pass through it.

After crossing the sperm reach the cervix into the uterus and the fallopian tubes. There is up to 24 hours after ovulation the egg. In the oviduct, the sperm move by cilia through to the egg.

The arduous journey to the egg can not survive all the sperm. Many are already applied before. Those who have come to try the egg, to drill through the shell.

The actual fertilization

Those sperm that could be drilled through the shell, are now in a space that is filled with liquid. It creates a sperm to penetrate into the cytoplasm of the cell nucleus, the fertilization takes place: both egg and sperm have saved all the genetic information that are necessary for the formation of a human. Both merge together at fertilization. Key characteristics of the resulting human (gender, hair color, blood type, etc.) are therefore from that date already set.
After the fertilization the hike in the womb

Egg and sperm fuse together altered the chemical composition of the egg immediately to prevent the penetration of other spermatozoa. All sperm that did not make it die soon from it. Inside the egg is - after the merger with sperm - now back to a cell which splits after some time every few hours.

The fertilized egg is while still in the fallopian tube. Only a few days later, she continues her journey into the uterus. The last section is the most dangerous because he is particularly close. Not all fertilized eggs make it through here: Some hang on the walls and it is developing an ectopic pregnancy.
In the womb

If the fertilized egg through the fallopian tube on the hike were harmless, it is in the womb (uterus) to. Here are some cells divide in the shell off again. From these cells produced the placenta (placenta), which combines with the body of the woman and the embryo is supplied with all essential nutrients.

The remaining cells are escaping from the egg case and dock in the upper part of the uterus in the mucosa. When this phase of implantation, the implantation completed, hormones are emitted that cause the physical changes necessary to allow the embryo can develop in the womb of the woman. If the hormone hCG (human chorionic gonadotropin) detected in the blood of women, there is certainly a pregnancy.

Multiple pregnancies

It occasionally happens that two eggs mature simultaneously in the ovaries. These two eggs "jump" and at the same time: After ovulation, thus two fertilizable egg cells migrate to the ovaries. Both are fertilized, there is a multiple pregnancy with twins. Basically, it is held in parallel with each fertilization of an ovum and a sperm cell, which are similar to normal siblings or dizygotic twins as not similar.

The egg divides after fertilization in two nuclei, resulting from identical twins. These are - depending on the timing of cell division - the same, or to have their own placenta (placenta) associated with the mother. Identical twins look almost identical and have always the same sex.

Multiple pregnancies with three or more embryos are usually a combination of identical and fraternal twins, or of three individual eggs, each fertilized by separate sperm. Especially after artificial fertilization there are often multiple pregnancies.

Natural family planning (NFP)

Although strictly speaking, only the egg can be fertilized for about a day after ovulation, so it does not mean that it is sufficient to prevent, refrain from sexual intercourse during this time. Sperm are in the favorable climate of the cervix and uterus viable up to five days, possibly longer. Sexual intercourse before ovulation week can therefore still lead to pregnancy.

Conversely, the knowledge is beneficial to the time of ovulation, when fertility is. It is recommended then the sexual intercourse in the days before and immediately after ovulation.