Conceiving a child in stages. How many days does fertilization occur after conception? The basics of successfully conceiving a child

Nature has arranged it so that a woman’s body is ready for fertilization approximately in the middle of the menstrual cycle, when a mature egg is released from one of the ovaries—that is, ovulation occurs. An ovulated egg remains viable for only 12-36 hours: if fertilization does not occur during this time, the egg dies and is released with the next menstrual bleeding. Sometimes, extremely rarely, during ovulation not one, but two or even three eggs are ovulated - if they are fertilized, a woman can give birth to twins or triplets. A different situation arises when one egg ovulates, which, having already been fertilized, is divided into two or three equal parts - in this case, twins are born.
A few hours before ovulation, the oviduct funnel is prepared in order to “catch” the egg and thereby prevent its disappearance in the abdominal cavity. The soft villi of the funnel constantly slide over the surface of the ovary, the walls of the oviduct begin to contract rhythmically, which helps it catch the egg. The fallopian tube, where the follicle is located, is wide open due to the hormone estrogen (its concentration is higher where the follicle is) and increased blood supply. There is no follicle in the other tube, so the blood supply is less abundant, that is, the tube is physiologically closed.
The capture and movement of the egg and sperm through the fallopian tube is achieved by muscle contractions, the movement of cilia and fluid flow (Hafez, 1973). The interaction of these three mechanisms occurs at the level of two main regulatory systems: endocrine and nervous. This mechanism is facilitated by the hormone prostaglandin contained in sperm. Female orgasm can enhance the effect as it causes uterine contractions.
Simultaneously with ovulation, many “auxiliary” biochemical processes occur that promote fertilization: the secretion of mucus in the cervix changes - the mucus thins and the cervical canal, unlike normal days, becomes passable for sperm; a woman’s mood changes, libido increases, blood supply to the genitals and erogenous zones increases.
In the fallopian tube, the egg finds a comfortable environment in which its development continues, while it moves along the mucous membrane of the inner surface of the fallopian tube, moving to the ampullary section, where it should meet sperm.

During sexual intercourse, the process of ejaculation releases approximately 500 million sperm into the back of the vagina near the cervix. To carry out fertilization, sperm need to travel a path of about 20 cm (cervix - about 2 cm, uterine cavity - about 5 cm, fallopian tube - about 12 cm) to the ampullary section of the fallopian tube, where fertilization normally occurs. Most sperm travel this route within a few hours, as they encounter numerous obstacles.

The vaginal environment is detrimental to sperm. Although seminal fluid partially neutralizes the slightly acidic vaginal environment (pH about 6.0) and partially suppresses the action of the woman’s immune system against sperm, as a rule, most sperm are not able to reach the cervix and die in the vagina. According to the WHO criteria used in the postcoital test, the death of all sperm remaining in the vagina 2 hours after coitus is normal.
From the vagina, sperm move towards the cervix. The direction of movement of the sperm is determined by perceiving the acidity (pH) of the environment, in the direction of decreasing acidity. While the pH of the vagina is around 6.0, the pH of the cervix is ​​around 7.2. The cervical canal, which connects the vagina and the uterine cavity, is also an obstacle to sperm due to mucus, which is a hydrogel of glycoproteins and forms a mucus plug with a porous structure. The size of pores and the viscosity of mucus depends on hormonal levels, which in turn are determined by the phase of the menstrual cycle. By the time of ovulation, the pore size increases, the viscosity of the mucus decreases, which makes it easier for sperm to overcome this “barrier.” The flow of mucus directed outwards of the canal and more pronounced along the periphery contributes to the “filtration” of full-fledged sperm.
For subsequent successful fertilization, at least 10 million sperm must penetrate from the vagina into the uterus. After passing through the cervix, the sperm find themselves in the uterus itself, the environment of which has an activating effect on the sperm: their motility increases significantly, and “capacitation” occurs.

From the uterus, sperm are sent to the fallopian tubes, the direction to which and within which the sperm are determined by the flow of fluid. It has been shown that sperm have negative rheotaxis, that is, the desire to move against the flow. The flow of fluid in the fallopian tube is created by the cilia of the epithelium, as well as peristaltic contractions of the muscular wall of the tube. Most sperm cannot reach the end of the fallopian tube - the so-called “funnel” or “ampull”, where fertilization occurs, being unable to overcome numerous obstacles in the form of epithelial cilia. Of the several million sperm that enter the uterus, only a few thousand reach the ampullary part of the fallopian tube. In the uterus and fallopian tubes, sperm can remain viable for up to 5 days.

During swimming, the characteristics of sperm gradually change - the influence of substances on the cervix, uterus and fallopian tubes is affected. Spermatozoa acquire the ability to fertilize. If there is still no egg in the fallopian tube, then the sperm “bathe” in a wide part of the oviduct and are able to wait for an egg for up to 3-5 days.
Sperm are most mobile at a body temperature of 37 degrees - the female body “helps” them with this: after ovulation, under the influence of progesterone secreted by the corpus luteum formed at the site of the ovulated follicle, the woman’s body temperature is slightly increased. Estrogen, also produced by the corpus luteum, prepares the uterine mucosa for the attachment of a fertilized egg and stimulates the development of the muscular layer of the uterus and mammary glands.

Fertilization

In the ampullary (widest) part of the fallopian tube, the egg is surrounded by sperm, one of which must perform the final task - fertilize the egg. A new obstacle stands in his way: a rather dense protective membrane of the egg.

The head of the sperm contains an acrosome - a specific organelle that contains special enzymes that promote the dissolution of the egg shell and the penetration of the genetic material of the sperm inside.
So that one of the sperm (the winner) can penetrate the cytoplasm. 400-500 sperm will literally “lay down their heads” so that the winner - the 501st in a row, who will be at the right time and at the weakest point of the egg membrane, can overcome it.
Thus, during natural conception, the number of living sperm in close proximity to the egg plays an important role. The statement that one sperm is enough to conceive a child is not entirely accurate. In natural conditions, the “statistical factor” is the main one! Millions of actively motile sperm are needed, without which conception is impossible, but only one of them fertilizes the egg.

Once the first sperm manages to break through the membrane and invade the cytoplasm of the egg, the chemistry of the membranes immediately changes to thus exclude the entry of other sperm, even if they have almost penetrated the egg - more than one set of chromosomes will have disastrous consequences for the egg. The sperm that remain outside the egg, where their entrance has been so strictly cut off, swarm around the egg for several more days and then eventually die. It is believed that these sperm create the necessary chemical environment that helps the fertilized cell on its way through the fallopian tube. Thus, it is not the most active sperm that wins: the winner is only that random member of the “first cohort” who turns out to be next after hundreds of faster and more active ones who (literally) laid down their heads to clear his path.

Immediately after conception

After the head of the winning sperm penetrates the egg, the nuclei of the egg and sperm merge into one, with 46 parts of a set of chromosomes - a completely new combination of the ancestral heritage, which contains the blueprint for the new person. The fertilized egg is called a “zygote” (from the Greek “to combine, join together.”
Approximately 24-30 hours after fertilization, the zygote begins, and after 48 hours, completes its first division. The resulting two equal cells are called blastomeres (from the Greek blastos - sprout and meros - part). The blastomeres do not grow and with each subsequent division (up to the formation of the blastula) they are reduced by half, while the size of the zygote remains the same.
The doubling of zygote cells occurs every 12-16 hours. The fragmentation of blastomeres apparently occurs asynchronously and unevenly: some of them turn out to be somewhat lighter and larger than others, which are darker. This difference persists in subsequent divisions.

3rd day after fertilization.The embryo consists of 6-8 blastomeres, each of which is totipotent, i.e. each of them can give rise to an entire organism. Until the stage of 8 blastomeres, the cells of the embryo form a loose, unformed group. Damage to the embryo that occurs at the 8 blastomere stage is easily compensated; at the same time, it is possible to divide the embryo into 2 or more parts, giving rise to identical twins.

At the end of the second - beginning of the third day of development, the embryo’s own genome is “turned on” for the first time (i.e., the genome formed by the fusion of the sperm nucleus and the egg nucleus), whereas until this moment the embryo developed as if “by inertia”, exclusively on maternal “reserves” "accumulated in the egg during its growth and development in the ovary. The further development of the embryo directly depends on which genome was formed during fertilization and on how successfully and timely this switch occurs. It is at the stage of 4-8 blastomeres that many embryos stop developing (the so-called “in vitro development block”) - their genome contains significant errors inherited from parental gametes or arising during their fusion.

4th day after fertilization.On the 4th day of development, the human embryo usually consists of 10-16 cells, intercellular contacts gradually become denser and the surface of the embryo is smoothed out (compactization process) - the morula stage begins (from the Latin morulae - mulberry). It is at this stage that the embryo moves from the fallopian tube into the uterine cavity. By the end of 4 days of development, a cavity gradually forms inside the morula - the process of cavitation begins.
The movement of the zygote along the fallopian tube occurs unevenly. Sometimes quickly - in a few hours, sometimes slowly - within 2.5-3 days. Slow progress of the fertilized egg or its retention in the fallopian tube can cause an ectopic pregnancy.

The morula continues its journey along the fallopian tube, repeating the path of the sperm, but in the opposite direction. In this state, it enters the uterine cavity.

5-7th day after fertilization.From the moment the cavity inside the morula reaches 50% of its volume, the embryo is called a blastocyst. Normally, the formation of a blastocyst is allowed from the end of the 4th to the middle of the 6th day of development, more often this occurs on the 5th day. The blastocyst consists of two populations of cells - the trophoblast (single-layer epithelium surrounding the cavity) and the inner cell mass (a dense clump of cells). The trophoblast is responsible for implantation - the introduction of the embryo into the uterine epithelium (endometrium). Trophoblast cells will subsequently give rise to all the extraembryonic membranes of the developing fetus, and from the inner cell mass all the tissues and organs of the unborn child will be formed. The larger the blastocyst cavity and the better developed the internal cell mass and trophoblast, the greater the potential for implantation the embryo has.
Having reached the uterine cavity on days 4-6 after ovulation and conception (according to the “mathematics” of doctors, this is the third week of pregnancy 1 ), the blastocyst remains in it for one to two days in a “suspended state,” that is, not yet attached to the wall of the uterus. At this time, the fertilized egg, being foreign to the mother’s body, secretes special substances that suppress the defenses of her body. The temporary endocrine gland - the corpus luteum, which formed at the site of the former follicle in the ovary from which the egg was ovulated, produces, the maximum level of which is observed on days 5-7 after ovulation. Progesterone, in addition to influencing the uterine mucosa, preparing it for implantation of the fertilized egg, also suppresses the contractility of the uterine muscles, that is, it calms its reaction to a foreign body, relaxes the uterus, increasing the chance of implantation of the fertilized egg. While the fertilized egg is not attached to the uterus, its source of nutrition is the intrauterine fluid secreted by endometrial cells under the influence of high levels of progesterone.
The introduction of the blastocyst into the uterine mucosa begins on the 6th day after ovulation (5-6 days after fertilization); 4 at this point the blastocyst has 100–120 cells. Implantation usually occurs near a large spiral artery. Most often, these are the upper parts of the uterus and its posterior wall, which, during the growth of the uterus and the enlargement of its cavity, stretches much less than the anterior wall. In addition, the posterior wall of the uterus is naturally thicker, saturated with a large number of vessels and is located deep in the pelvis, which means the developing embryo is more protected.

When a fertilized egg comes into contact with its wall, at the point of contact the underlying section of the falling membrane melts and the egg sinks deep into the latter - implantation (nidation) of the egg into the uterus occurs. The products released when the falling shell melts - protein substances and glycogen - are used to nourish the developing embryo. When the decidua melts, the integrity of the capillaries located in it is disrupted. The blood they contain flows around the growing epithelium of the villi.

The tissue defect formed at the site of egg implantation is closed by a fibrinous plug. This process of egg encapsulation ends with the restoration of the shed membrane over the site of egg insertion. The edges of the shell adjacent to the egg embedded in its thickness grow, rise above it and, heading towards each other, merge into a continuous layer covering the egg in the form of a capsule. Thus, the egg appears to be walled up on all sides in a lush compact layer of the falling shell.
Implantation (nidation) - the introduction of the embryo into the wall of the uterus - lasts about 40 hours. During implantation, the fertilized egg is completely immersed in the tissue of the uterine mucosa. There are two stages of implantation: adhesion (sticking) and invasion (penetration). In the first stage, the trophoblast attaches to the uterine mucosa; in the second, it destroys a section of the uterine mucosa. In this case, the forming trophoblast villi (chorion), penetrating into the uterus, successively destroy its epithelium, then the underlying connective tissue and vessel walls, and the trophoblast comes into direct contact with the blood of the maternal vessels. An implantation fossa is formed, in which areas of hemorrhage appear around the embryo. It is at this time that a woman can feel the very first symptom of conception - implantation bleeding.
From the mother's blood, the fetus receives not only all the nutrients, but also the oxygen necessary for breathing. At the same time, in the mucous membrane of the uterus, the formation of connective tissue from cells increases and after the embryo is completely immersed in the implantation fossa, the hole, the defect in the mucous membrane is covered with regenerating epithelium.
The formation of outgrowths (villi) is noted on the trophoblast, which during this period are called the primary chorion and which begin to release the “pregnancy hormone” - choreonic gonadotropin - into the mother’s bloodstream.
entering the woman’s bloodstream, it supports the function of the corpus luteum in one of the ovaries for the constant production of progesterone until the placenta takes on such a role. There is a close direct relationship between these two hormones: if implantation goes poorly (most often due to a defective fertilized egg), then the amount of hCG will be insufficient and the function of the corpus luteum will begin to fade, which will lead to a lack of progesterone to support pregnancy.
HCG is also an immunosuppressive substance, that is, one that suppresses the mother's defenses, preventing her from rejecting the attached fertilized egg.
The operation of all pregnancy tests, including Early Pregnance Test, is based on this principle. However, the MediSmart of Switzerland early pregnancy test, due to its high specificity specifically for hCG and the low threshold level for determining this hormone, allows you to determine the onset of pregnancy not 13-14 days after ovulation, as most conventional tests do, but at 7-8 day, that is, 7 days before the expected menstruation.
Thus, in the first 2 weeks of pregnancy the following events occur:
fertilization of the egg and the formation of a single stem cell - the zygote;
division of the zygote into blastomeres and its movement through the fallopian tube into the uterus;
transformation of the zygote into a morula and search for a place of attachment to the uterine mucosa (pre-implantation development);
blastocyst implantation (first critical period of pregnancy) and decidual transformation of the endometrium;
placentation (formation of primary and secondary chorionic villi) and blastogenesis (differentiation of germ layers) is the second critical period of pregnancy.
The developing placenta lacks protective functions, and therefore exposure to unfavorable factors and hormonal disorders most often cause one reaction - cessation of development of the fertilized egg and spontaneous miscarriage.

Conception is a set of processes as a result of which pregnancy begins to develop in a woman’s body.

Conception includes not only direct sexual intercourse, but consists of a number of complex processes that in most cases proceed unnoticed by the man and woman.

Main stages

1. Ovulation;
2. Fertilization;
3. Advancement of the fertilized egg into the uterine cavity;
4. Attachment of the embryo to the wall of the uterus.

Ovulation

From the first day of the menstrual cycle, a woman’s body begins to prepare for the possible onset of pregnancy. Under the influence of high levels of follicle stimulating hormone (FSH), the ovaries begin to develop (on average, about 10 in each ovary).

One of the follicles outstrips the others in growth and becomes dominant. At the same time, increased production of luteinizing hormone begins. After 12-36 hours, the main follicle ruptures and the egg is released.

information Ovulation in most cases occurs 14 days before the start of menstruation: for example, with a 28-day cycle, follicle rupture occurs on the 14th day, with a 25-day cycle - on the 11th day. However, in women with irregular menstrual cycles, the ovaries do not function regularly, and as a result, ovulation can occur at any time.

The egg exists for 12-24 hours. If fertilization does not occur during this time, then it dies and is excreted along with menstrual blood. Sperm are more persistent: they are able to exist in a woman’s genital tract for about 48-72 hours or more (according to some sources, up to 7 days). For conception to occur, sperm must already be in the fallopian tubes at the time of ovulation or must arrive there within a short time, so it is important that the woman knows the date of release of the egg in advance.

The following methods are used to determine ovulation:

1. . The method is quite effective and does not require material costs, but strict compliance with all measurement conditions is necessary;
2. Ovulation tests. The tests are easy to use and easily help determine the onset of ovulation, but this method is expensive: at least two tests are required per day;
3. Ultrasound control. The method is the most effective and is based on determining ultrasound signs of ovulation. At the approximate time of ovulation, a woman must visit a medical facility every day, which is not always possible.

Fertilization

Fertilization- This is the fusion of the genetic material of a sperm and an egg. During sexual intercourse, about 2-3 ml of ejaculate enters the vagina, which contains up to 500 million sperm, but only some of them can overcome the cervical mucus and enter the cervical canal.

The journey to the egg through the uterine cavity and fallopian tubes takes about 2-2.5 hours. In order for fertilization to occur, sperm must destroy the corona radiata surrounding the female reproductive cell. At the same time, the egg is attacked by millions of sperm, but only one of them is able to penetrate inside, after which a dense shell is formed that prevents other sperm from entering.

Within 12 hours after the sperm penetrates the egg, their nuclei come together and the genetic material combines, resulting in the formation of a zygote (one-cell embryo).

Advancement of a fertilized egg into the uterine cavity

After about a day, the zygote begins to divide and over the next 24 hours it already consists of two cells - blastomeres. Cell division continues in geometric progression, with their number constantly increasing and their size decreasing, so the size of the zygote initially does not change.

Simultaneously with division, the zygote moves through the fallopian tubes into the uterine cavity. The zygote is not capable of moving independently, so its movement is carried out due to contractions of the fallopian tubes, which is controlled by the level of progesterone and estrogen in the body. Gradually, the level of progesterone increases and the utero-tubal junction relaxes, as a result of which the zygote freely penetrates into the uterus.

The movement of the zygote is uneven and can take varying periods of time, on average 3-4 days. Prolongation that takes too long is dangerous, because... can lead to tubal forms of ectopic pregnancy.

Attachment of the embryo to the wall of the uterus

After entering the uterine cavity, the embryo begins to produce special substances that will help dissolve the endometrial area and attach to the wall. This process is called implantation and occurs approximately 7 days after conception and lasts about 40 hours.

additionally At this time, slight spotting may appear, which lasts no more than 1 day.

After attachment, the embryo continues to develop intensively and produce human chorionic gonadotropin. This hormone is an immune suppressive substance: by suppressing the protective properties of the mother’s body, it does not allow it to perceive the embryo as a foreign body and reject it.

Factors for successful conception

Conception– a fairly long process and at any stage under the influence of various factors it can be disrupted, as a result of which pregnancy will not occur.

Factors contributing to successful conception:

• A sufficient number of morphologically normal motile spermatozoa. If the spermogram is abnormal, reproductive ability sharply decreases, which leads to the impossibility of natural conception;
• Egg maturation and ovulation. Of course, in the absence of ovulation, pregnancy will never occur;
• General health of the woman, promoting a rational process of conception. Severe chronic diseases and infectious processes can lead to the absence of conception or its interruption at any stage;
• Patency of the cervix for sperm. Violation of the properties of the mucus in the cervical canal can prevent the passage of sperm into the uterine cavity. Formations located in the cervix can also prevent conception: for example, large polyps;
• Violation of the patency of the fallopian tubes. This pathology interferes with both the movement of sperm and the fertilized egg;
• Implantation disorder. Tumors of the uterus, abnormalities of its structure, immature endometrium disrupt the implantation process, which leads to the death of the zygote;
• Hormonal imbalances.

Probably the greatest mystery on earth is the birth of a new life, namely the conception of a child. From time immemorial, man has been trying to unravel the mystery of creating a new life, but still many mysteries remain unsolved.
Today we will talk about the process of conceiving a child - it is truly fantastic!

Fertilization

A female reproductive cell, capable of conception, looks like this when awaiting sperm.

Female egg

For the fertilization process to occur, about 60-100 million male cells (sperm) must enter the woman's body. This is the required amount for conception (otherwise the probability is reduced). The sperm nucleus may contain 2 types of sex chromosomes: Y - carries male information and X - with a female set. So the sex of the child is determined by which sex chromosome was in the last pair; if X, then the future parents will have a girl, if Y - a boy.
The “meeting” of the sperm with the egg occurs in the fallopian tube, where the egg moves after ovulation.

Sperm penetration

Within three days after the fusion of the parents' germ cells, intensive division of the embryo occurs. At the same time, it moves into the uterine cavity. There it will develop for 9 months.

Fertilized egg

Nothing happens in the next 32 hours after fertilization.
And then the first division of the fertilized egg is observed - two are formed from one cell.

Fetal development by week

First week of pregnancy

The rate of egg division is 1 division per day. Over the course of 7 days, the rate of division increases.
During division, either an even or an odd number of cells are formed.

Human embryo on days 1-8

The first 8 days of the embryo’s life are extremely important, since if any disturbances occur in its development now, the woman will have normal menstruation, as the pregnancy will end. During these 8 days, the embryo is not connected to the mother; it is nourished by the substances that have accumulated in the egg.

Blastocyst

Implantation - implantation of an embryo in the uterus.
An ectopic pregnancy can occur due to inflammation of the female genital organs, abortion, abnormal development of the uterus, etc. This occurs if, on the way from the fallopian tubes to the uterus, the fertilized egg encounters slow peristalsis of the fallopian tubes.

If a woman has hormonal disorders, then peristalsis of the fallopian tubes may accelerate. Then the fertilized egg enters the uterus earlier, which is also dangerous - further pregnancy does not develop, or pregnancy occurs, but a serious complication occurs - placenta previa.

Implantation process

From the moment the fertilized egg implants in the uterine cavity, a new stage begins - the development of the fetus week by week. On the seventh day of pregnancy, the outer layer of the embryo (trophoblast) begins to produce the hormone chorionic gonadotropin (CG). Thanks to this hormone, the woman will receive news of pregnancy. At the same time, the pregnant woman’s body will begin to rebuild.

It is important to note that the hormones produced in the second phase of the menstrual cycle are essential for the full development of the fetus week by week. Their insufficient quantity can lead to the death of the embryo. In this case, the woman does not even know that she was pregnant. So 50% of women lose pregnancy at this stage.

Embryo at 4 weeks of development

Embryo at 8 weeks of development

The first weeks of pregnancy are truly very important for the baby. Moreover, when you don’t even know that you are already pregnant, the unborn baby’s heart is already beating, he is actively developing and growing. That is why, as soon as you realize the possibility of conceiving a child, immediately give up bad habits, do not go to work, and eat right.

We wish you and your child good health!

The birth of a new life is a touching, amazing, almost fantastic process. Expectant mothers have always been interested in the question of how a child is conceived. Two small autonomous cells, uniting, create a new person. And if the period when the fetus begins to move is more or less noticeable for the expectant mother, then the first days and even weeks of pregnancy remain “behind the scenes.”

Mother Nature is a wonderful and wise creator. Everything related to procreation is thought out to the smallest detail. Approximately in the middle of the menstrual cycle, a “girl of marriageable age” appears from the ovary - an egg ready for fertilization. It will remain in a state of readiness from 12 to 36 hours. If during this time conception does not occur after sexual intercourse, the egg dies and is excreted from the body along with menstrual bleeding. Thus, conception by days after ovulation can occur within a period of one to three days. In some cases, during the period of ovulation, not one, but several eggs are formed. In this case, there is a high probability of multiple pregnancy.

It is no secret how egg fertilization occurs. A female cell alone is not enough to generate a new life. The immediate process of conception begins when potential “suitors” - sperm - quickly burst into the female body. Like heroes from fairy tales and epics, they face a long and dangerous path to their cherished goal. The road ahead is not close - from the cervix to the fallopian tube - about 20 cm. Considering the tiny size of the sperm, this is a very decent distance.

First test

First of all, the “tadpoles” end up in the vagina. This happens in the first seconds after the act of intimacy. Here the first danger awaits them. Due to the acidic environment of the vagina, weak sperm (and these are the majority) die within 2 hours, never reaching the cervix. Thus, out of 500 million sperm that enter the vagina after sex, only a third reaches the cervix. This is how natural selection works.

Second test

For successful conception, there must be at least 10 million sperm in the uterus. Not everyone will be able to achieve the goal, because the second barrier - the cervix - is no less difficult and dangerous. There is also a high acidity environment here; in addition, there is a mucus plug in the cervix that interferes with further movement. True, during ovulation the amount of mucus decreases somewhat. The mucus usually moves towards the sperm, as if “washing away” the weak and indecisive on its way. The remaining specimens have sufficient strength to move “against the flow.”

Third test

Having passed the cervix, the sperm end up in the uterus. The reproductive organ helps the “tadpoles” in every possible way, increasing the speed of their movement. Gradually they make their way to the last point - the fallopian tube. The catch with this test is that the tube is covered with epithelial cilia. Vibrating, they block the path to the final goal for most applicants. So, from the multi-million army of sperm that find themselves in the uterus, by the end of the fallopian tube only a few thousand fighters remain in the row.

During their movement through the uterus and tubes, sperm change qualitatively, becoming capable of fertilization. Gentlemen are more patient: if the egg is “late,” they will wait for it, and fertilization can take up to 3-5 days.

What happens after conception

Let's look at the fertilization of an egg by day. We will consider the first day of the life of an intrauterine baby not the day of sexual intercourse, but the great moment when the sperm meets the egg.

Day one: fertilization

And now the coveted egg appears in the field of view of the applicants. They surround her in an attempt to complete the task at hand.

But a reliable barrier stands in their way - the protective membrane of the egg. To break through it, sperm will have to try very hard. But nature again came to the aid of the “tadpoles” by placing an acrosome in their heads. This is a special substance that helps the sperm dissolve the shell of the egg and penetrate inside.

Trying to break through the barrier, most of the “fighters” die, having exhausted their vitality. But the protective layer is weakened in some places by the action of the acrosome. At this moment, that very single sperm detects a “crack” in the membrane armor of the egg. He overcomes it and finds himself directly inside the egg.

Thus, the number of sperm entering the vagina plays a primary role in conception. The statement that only one sperm is needed for fertilization is not entirely true. Millions of “tadpoles”, having gone through a difficult thorny path, thus pave the way for one, the most successful.

It is not always possible to accurately predict how long it will take for pregnancy to occur after ejaculation. This largely depends on the presence of ovulation, sperm motility and the state of the woman’s gynecological health. The answer to the question of when conception occurs after intercourse is ambiguous. On average, up to 3 days can pass from the time sperm enter the female body to the direct meeting with the egg. However, sometimes the partner’s sperm are so tenacious that they are ready to wait for an egg for a whole week.

Days two to four: division

The sperm and egg become one, forming a zygote. About 36 hours will pass after fertilization and the zygote will begin to divide. Still in the fallopian tube, the zygote is now an entire cellular complex. Modern medicine can accurately indicate on what day the division of the zygote will end. After the fourth day after fertilization, the division process is considered complete. The zygote is represented by two cells - blastomeres. It remains the same in size, although the number of blastomeres will gradually increase. A future person needs space for growth and development. The pipe becomes cramped and uncomfortable.

On the third day, the zygote already has about 8 blastomeres, but still remains motionless. Only a day later, on the fourth day, the zygote of 16 blastomeres begins to move towards the uterus. At the same time, the blastocyst (embryo) itself remains tiny for all four days, practically unchanged in size. This is necessary for convenient passage through the fallopian tube. Full growth from this moment will begin directly in the uterus.

Days five to seven: embryo in the uterus

For the first few days, the woman does not suspect that such amazing events are happening in her body. Meanwhile, the embryo is already moving freely across the expanses of the uterus, in search of its place of residence. Having chosen a place convenient for itself, the future baby is attached to the wall of the uterus. The long and exciting journey is over. In this place he will live and develop for the next 9 months.

Days seven to twelve: implantation

The egg has implanted into the endometrium.

The zygote appears in the uterus 5-7 days after fertilization. After a few days (9-10 days following the fusion), the embryo will be completely immersed in the wall of the uterus. This process is called implantation. It lasts about 40 hours. It is reliably known how many days later implantation is completed - on the 12th day. From this moment on, the woman is considered pregnant.

After implantation, around day 20 of the cycle, a woman may experience certain symptoms indicating that a new life has arisen in her body. These include:

• Implantation bleeding. It is often confused with menstruation. However, it is less abundant and ends, as a rule, on the same day it began. But if spotting brown discharge continues for up to 10-14 days, the woman should immediately consult a doctor.
• The production of hCG - a special “pregnancy hormone”. It begins to be produced 5-6 days after conception. It is because of it that a woman feels morning sickness, weakness or drowsiness.
• Sensitivity and swelling of the mammary glands;
• Increased ;
• Aversion to certain odors;
• You may feel a tingling sensation in the uterus or a feeling of heaviness in the lower abdomen.

All the events described occur in the body before a woman starts to miss her period or the main symptoms of pregnancy appear.

If it is the first pregnancy, a woman often writes off such symptoms as a normal malaise. Ladies who have been pregnant before are usually more sensitive to such manifestations and quickly realize that they are pregnant.

Days thirteen to twenty: delay

The most important sign by which a woman finds out about her pregnancy is a delay in menstruation. If it does not start on a certain day of the cycle, pregnancy can be suspected. Sometimes the delay can be caused by menstrual irregularities. One way or another, a woman should do a test to make sure her guesses are correct.

This period corresponds to approximately 5 weeks of pregnancy. At this stage, the fetus is still very small - its size does not exceed 7 mm, and its weight is 4 g. But the doctor will already be able to see it on an ultrasound. The future person himself at this time resembles the shape of the letter C. Despite its tiny size, upon careful examination on the monitor you can see processes - future arms and legs. Sometimes you can even distinguish small tubercles in the area of ​​the top of the processes - future fingers.

Facial contours also begin to appear during this period: dimples of the eyes and cheeks, nasal and oral slits. The tiny embryo floats freely in the amniotic fluid, which begins to be produced at around 5 weeks.

It is during this period that the rudiments of the internal organs of the future person begin to form. At the initial stage of formation are the respiratory, circulatory and nervous systems. The cells of the small organism continue to actively divide. Very soon the heart of the unborn baby will begin its work.

How to keep your baby safe

It often happens that a woman finds out about her pregnancy even before the test results and consultation with the doctor. Women's intuition tells the expectant mother that a new life is growing inside her. But this does not always happen, and many women are not aware of their situation.

The first days and weeks are considered the most dangerous period for the unborn baby. After all, a potential pregnancy can end at any early stage. That is why a woman should worry about her health and do her best to help her body accept a tiny creature.

To do this, you should follow some recommendations:

• It is worth preparing for conception in advance. In a few months (ideally, six months), potential parents should give up smoking, drinking alcohol and other bad habits.
• The expectant mother needs to be thoroughly examined to study her women's health. The presence of inflammation or adhesions in the uterus or tubes can lead to dire consequences. A fertilized egg, without passing through the adhesive barrier, can begin to develop in the fallopian tube and subsequently lead to its rupture (ectopic pregnancy).
• A woman is advised to drink. Preparations containing folic acid and vitamin E are especially recommended for expectant mothers. They significantly increase fertility (the ability to conceive).
• Proper nutrition should become a woman’s companion for the entire period of pregnancy. Harmful foods should be excluded from the diet, but water, on the contrary, should not be neglected.
• Serious physical activity is strictly not recommended for a potential mother. You should also avoid lifting weights. You can practice leading a calm lifestyle even before conception - the movements of the expectant mother should be smooth, unhurried and soft.

Pregnancy is a complex and simple process at the same time. It is complex due to the fact that the baby goes through a long journey from the fusion of two cells to birth. And at the same time, nature has simplified and thought through everything - the process of conceiving a child and its further development is thought out almost day by day. All that is required from the expectant mother is a little effort and unconditional love for the being within herself to make bearing a child as simple and enjoyable as possible.

Fantastic video

An incredibly exciting and realistic video about the conception and subsequent development of a child. Everything about the intrauterine life of a future person. A touching and at the same time very educational fantastic video.

The birth of a child is the result of thousands of incredible processes occurring inside a woman. A loving mother wants to know everything she can about her baby. For this reason, many future parents are interested in how fertilization occurs.

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Fertilization of the egg

Nature has decreed that a woman can usually become pregnant in the middle of the cycle, when the well-known ovulation occurs. Unlike sperm, an egg can survive in a woman’s natural environment for 12 to 36 hours. If she does not meet the male seed, she dies and leaves the female body through menstrual bleeding.

Hidden here is the answer to the question of how long after ovulation the egg is fertilized. If ovulation has just passed, the egg has escaped from its “nest”, and sperm are already waiting or on the way, fertilization can take place in a matter of hours.

What you've been waiting for for so long

It also happens that during one ovulation, not one egg matures, but two or even three. How does fertilization of the egg occur in this case? Everything happens as usual, only as a result two or three babies are born at once.

Let's look at how fertilization of an egg occurs point by point.

1. After ejaculation, sperm travel a long, winding path towards the egg. If we take the average speed of a male seed, it takes about 3-6 hours to reach its goal. Only one sperm will participate in the fertilization process, and the rest are destined to die.
2. Pushing hard, the sperm breaks through the coating of the female egg. At this moment, the entire body is informed that fertilization occurred a moment earlier. This very signal contributes to some restructuring of the female body, designed to preserve any valuable pregnancy.
3. Now that we have figured out how fertilization of an egg occurs in a person, we can see what happens next. Each of the two parent cells contains one half of the set of chromosomes. As a result, the parent cells unite and form a new, perfect cell, with all the genetic data, known as a zygote. The genetic code of the neoplasm is completely unique.
4. Over the course of seven days, the zygote develops inside the fallopian tube, and then begins its journey to the uterus, “looking for a cozy place” where it will develop over the next nine months.
5. Further, moving away from the place where fertilization occurs, the egg takes with it the corpus luteum as food. For this reason, in the first week, lifestyle does not affect the development process in any way.
6. Having found a cozy place, the embryo “buries itself” in the wall of the uterus. This period of development, which lasts no more than 40 hours, is called implantation.
7. The outer cells begin to divide and join with the lining of the uterus. At the site of the branches, microscopic vessels are formed, which later form the placenta - the environment within which the baby grows, feeding and developing, until birth.
8. The body of the future baby is formed from the embryonic nodule. But the above-mentioned placenta, amniotic sac and umbilical cord are formed from the surface cells necessary to ensure development and safe existence. To better understand how egg fertilization occurs, you can watch the video.

Basal temperature

Measuring basal temperature is perhaps the classic method of determining the day of ovulation. Charts of this temperature are usually made by women planning to give birth to a child. But how does basal temperature change after ovulation if long-awaited fertilization has occurred?

If a woman is pregnant, her basal temperature rises to 37 degrees. This allows you to identify the possible situation even before your period is missed. Of course, it is much more effective to get tested, but since hCG is produced only after implantation of an already fertilized egg, it must be done at least a week after sexual intercourse. Well, when you don’t want to wait, measuring your basal temperature will help.

After fertilization occurs, and the body has received a signal about the beginning of the process of fetal maturation, active production of progesterone begins. It is the beneficial effect of this hormone on the development of the embryo that increases the basal temperature to 37.0-37.1 degrees.

The long-awaited result

It should be noted that the remaining normal temperature after fertilization occurs in the female body indicates a lack of progesterone, and this problem, in turn, is a threat of miscarriage or spontaneous abortion. In this case, you need to consult a doctor for help.

Conceiving a child by day

First, let's figure out where a child is conceived.

1. When the ovulation process has taken place and the egg is released from the ovary, it ends up in the fallopian tube. If sexual intercourse has taken place, the sperm will wait for the egg ready for conception inside the fallopian tube.
2. Within a few days after fertilization, the embryo that is created moves down the fallopian tube to the uterus. If development does not proceed correctly or the movement of the embryo is too slow, the embryo can penetrate the lining of the tubes, and this can lead to an ectopic pregnancy.
3. After about 7 days, the embryo reaches the uterus and looks for a warm place where it plans to settle and continue its development.

It is no less interesting to find out how the long-awaited fertilization of an egg occurs day by day in a person.

Important process

We also invite you to watch a video about how human egg fertilization occurs day by day.

How quickly does the process happen?

Many people are interested in how long it takes for fertilization to occur after unprotected love.

There are several possible answers to this question. Firstly, conception of a child can occur exclusively during ovulation or within 12-36 hours after, no more. If during this time the egg does not meet the sperm, it dies and then leaves the female body.

Not really

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The information published on the website is for informational purposes only and is intended for informational purposes only. Site visitors should not use them as medical advice! The site editors do not recommend self-medication. Determining the diagnosis and choosing a treatment method remains the exclusive prerogative of your attending physician! Remember that only complete diagnosis and therapy under the supervision of a doctor will help you completely get rid of the disease!