Fertilization of an egg: how does this process occur? Conceiving a child: the process of fertilization and implantation by day

When the fertilized egg enters the uterine cavity in order for pregnancy to occur, its implantation is necessary. This process becomes possible due to the fact that immediately after fertilization of the egg, the corpus luteum in the ovary begins to produce the hormone progesterone, which prepares the lining of the uterus for pregnancy. Directly during implantation, which can take from several hours to several days, a woman may feel nagging pain in the lower abdomen or bloody discharge from the genital tract associated with damage to small vessels during the implantation of the fertilized egg into the mucous membrane. It is the moment of implantation into the uterine cavity that marks the beginning of pregnancy.

Signs of fertilization and pregnancy

Many would probably like to know from the very first days whether fertilization has occurred, but everything is not so simple. Firstly, because even if there are signs of fertilization, this does not mean that pregnancy will definitely occur in the future. Secondly, because these signs are so non-specific that only an incredibly sensitive woman can recognize them and it will most likely have a psychosomatic character in those women who have been waiting for a long time for pregnancy.

The only thing that can be noted is a persistent increase in rectal temperature of more than 37 degrees in the second phase of the cycle. This is influenced by the increased concentration of progesterone, which helps maintain pregnancy and gestation.

If fertilization has not taken place, the temperature will fluctuate slightly and will not rise clearly.

It must be emphasized that the above signs are unlikely to be suitable for diagnosing fertilization; rather, a woman can remember them “postscript” when she knows for sure about pregnancy and she feels more obvious signs. They can be noticed no earlier than 15 days after conception. These include the following:

Nausea in the morning

It is extremely rare for women to experience toxicosis even before their period is missed, which for some may seem an important criterion. Nausea may be accompanied by vomiting or may not occur. Occurs in the morning.

Drowsiness, fatigue, apathy

The cause of such symptoms is progesterone, the level of which is high. A woman often begins to sleep during the day, and in the morning she feels exhausted and sleep-deprived.

Cold

ARVI very often appears after conception, since a woman’s immunity drops sharply during this period.

Breast engorgement and pain

Thus, sensitive girls who closely monitor changes in their body can notice in the early stages, and, most likely, even feel that the conception of a child has occurred. However, the most reliable would be to perform a strip test (2 lines - pregnancy) or take a blood test to determine the level of human chorionic gonadotropin in the blood.

Birth of a child is the result of thousands of amazing processes occurring inside the female body. A caring mother wants to be aware of everything related to her baby.

It is for this reason that many future parents are interested in how fertilization occurs.

Fertilization process

Nature decided to arrange it so that a woman can become pregnant only on one day during the entire cycle, this day is called. It is on this day that it leaves the follicle and moves along the fallopian tube in the hope of being fertilized.

REFERENCE! At average speed after a few hours reach the goal, however, due to the “harsh conditions” of overcoming the path, most of the tadpoles will die and the most persistent and “worthy” will reach the goal.

2. Only one tadpole will take part in the fertilization process, the rest are destined to die. Performing intense thrusts, he breaks through the covering of the female egg. Once the tadpole is inside, fertilization occurs. From this moment on, the cell is called zygote, which soon begins its division.

Movement towards the uterus

For next days the zygote continues to divide and continues to move along the fallopian tube towards the uterus. The flickering of the cilia of the fallopian tube helps her in this. From time to time, contraction of the tube muscles is performed to accelerate the movement of the zygote, which, as a result of divisions on the 5th day, is called a blastocyst. 6-7 days after fertilization the embryo is ready for implantation.

IMPORTANT! After the blastocyst is fixed in the body of the uterus, it begins to actively interact with it, which contributes to the synthesis of a huge number of new hormones.

For successful attachment of the fertilized egg, the following conditions are necessary:



• the outer layer must have suitable thickness for the subsequent development of the embryo, and also contain the required amount of nutrients;
• in the female body the concentration of progesterone should be exceed norm, because it is this hormone that blocks the onset of menstruation, allowing pregnancy to develop.

If such conditions are not met, the egg is not able to attach to the uterine lining, which leads to menstrual bleeding. Thus it happens embryo rejection, and they begin in the ovaries.

How does the woman feel?

Symptoms

After fertilization, the expectant mother is able to detect some symptoms, which manifests itself in the period from the moment of union and before the embryo is implanted into the uterine wall. During this period of time, the female body undergoes changes:

• changes slightly intensity breathing. This can be explained by the fact that the splitting zygote experiences a huge oxygen need;
• the metabolism of substances such as calcium, phosphorus and carbohydrates changes. The expectant mother can detect this by an increased appetite and specific taste preferences;
• the level increases free amino acids;

ON A NOTE! All these symptoms are not obvious; it is quite difficult to identify them and independently discover that fertilization has occurred.

Signs

After implantation of the embryo into the uterus has taken place, and missed periods has not happened yet, a woman is theoretically capable of feeling some signs of pregnancy. Namely:

The beginning of a new life is a great mystery of nature, and not all the mechanisms and nuances of this mystery have been studied by doctors and scientists. Conceiving a baby is an amazing and exciting process, which many people don’t even know about at the time of the miracle. We will talk in more detail about what actually happens at the moment of fusion of maternal and paternal germ cells. This information will help those planning a pregnancy, and will also be of interest to anyone who is already a parent or is expecting their baby.

What it is?

Conceiving a child is a very complex biological, chemical process, in which not everything can be explained only from the point of view of physiology. There is always something of the divine in conception that cannot be measured or counted. Thanks to him, conception sometimes miraculously occurs in those for whom, from a medical point of view, it should not occur.

In medicine, conception is the moment of fertilization of a female reproductive cell - an egg - by a male cell - a sperm. It is from this moment that the actual pregnancy begins; from this starting point, its embryonic gestational period begins. The obstetric period is counted from the first day of the last menstruation before pregnancy. Thus, by the time of conception, which usually becomes possible during the period of ovulation, a woman is already 2-3 obstetric weeks of pregnancy. The medical definition of the onset of pregnancy hardly reveals the full meaning of this amazing process.

In a woman’s body, changes begin from the very first tenths of a second, as soon as the fusion of germ cells occurs. The fertilization process triggers a whole cascade of changes aimed at creating the most comfortable conditions for maintaining and developing a new life.

Fertilization

A man can conceive a child any day if he is healthy. Spermatozoa - male reproductive cells - are always in “full combat readiness”. But in a woman, fertilization is possible only on certain days of the menstrual cycle. After the next menstruation ends, the stage of follicle maturation begins. Several follicles mature in a woman’s ovaries, but only one or at least two of them will become dominant. Around the middle of the cycle, the size of the dominant follicle approaches 20 mm, which means that the egg inside is mature and ready to be released. The moment the follicle ruptures is called ovulation. For women, this day occurs depending on the length of the menstrual cycle on different days. If 28 days usually pass from period to period, ovulation should be expected on the 14th day, if 30 days pass - on the 15th day.

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With an irregular menstrual cycle, it is quite difficult to determine the day of ovulation on your own, but this can be done using ultrasound - the process of maturation and growth of the follicle is clearly visible through the introduction of a vaginal ultrasound sensor.

The place of egg production is the ovaries. After the follicle ruptures, the female reproductive cell leaves the ovary and exits into the wide part of the fallopian tube. This is where fertilization must occur. The process of cell fusion itself can occur immediately after its release or a day later. The egg lives and retains the ability to fertilize for 24-36 hours.

During unprotected intercourse, sperm enter the vagina, where their journey to the location of the egg begins. The path of the sperm can be compared to natural survival, natural selection - only the strongest and strongest representatives from tens of millions of cells will survive and reach the goal. By the time sperm arrive, ovulation may not yet have occurred, but in this case, nature has endowed male reproductive cells with vitality - they can remain in the tube and retain their abilities for 3-4 days.

In this case, fertilization occurs immediately after the egg is released. If sexual intercourse took place directly on the day of ovulation, then fertilization occurs approximately 30-40 minutes after ejaculation. Thus, Favorable days for a woman to conceive are the day of ovulation, as well as 2-3 days before it and the day after it. Just 5 or 6 days during the month are ideal for intercourse in order to conceive a baby.

A woman can guess that ovulation is approaching by some characteristic signs. Usually her libido increases - this mechanism is provided by nature so that the fair sex does not accidentally miss the most favorable moment. The discharge becomes viscous, profuse, reminiscent of the consistency of raw egg white. The sensitivity of the nipples of the mammary glands increases, and the breasts themselves may increase slightly in size.

Many women are even able to feel the moment of ovulation. They feel the rupture of the follicle as a slight nagging pain in the left or right lower abdomen - the location of the pain depends on whether ovulation occurred in the right or left ovary.

Some women do not feel this moment, and this is also a variant of the norm: it all depends on the individual characteristics of the female body.

The egg is covered with a three-layer membrane. After a fairly large number of sperm reaches it, a massive “attack” of the membranes begins. Special structures in the head of the sperm secrete substances that can dissolve the membranes of the egg. However, only one sperm is destined to fertilize it. After the most stubborn, persistent and strong person penetrates the membrane of the female cell, the body immediately receives a signal that fertilization has occurred. The membranes of the egg sharply change permeability, and no more sperm will be able to penetrate inside.

The male reproductive cells left empty-handed swarm around the egg for a few more days and then die. If fertilization does not occur, the egg itself dies a day after ovulation and begins its journey into the uterine cavity. Two weeks after this, menstruation begins - with menstrual blood, the woman’s body is cleansed of biomaterial that has become unnecessary. If conception has occurred, a new stage of development begins.

The egg must also travel to the uterine cavity, but for a different purpose - to attach and create a cozy “house” for the embryo. In the very first minutes after the fusion of germ cells, the future baby’s own genetic makeup is formed. He takes exactly 23 pairs of chromosomes from mom and dad.

From the very first minutes, everything is determined - the gender of the child, the color of his eyes and hair, skin color, physique, hereditary diseases and even talents and abilities. All this information is contained in the genetic code. A fertilized egg is called a zygote, it is constantly fragmented and modified, processes proceed at cosmic speed.

Changes in the body after fertilization

Immediately after the egg is fertilized, a large-scale operation unfolds in the body to create new conditions that are most optimal for the development of a new life. The hormone progesterone begins to be produced in large quantities. Its task is to make the walls of the uterus looser so that the embryo can easily attach to one of them and “grow” into the tissue. This place will then become the basis for the placenta.

Under the influence of progesterone, from the first minutes after conception, metabolic processes begin to proceed somewhat faster. Of course, a woman will not be able to feel these changes, at least in the first couple of weeks after fertilization.

Progesterone provides everything for the development of the baby - it suppresses the mother's immunity so that he does not “mistakenly” mistake the embryo for something foreign and destroy it. Under the influence of this hormone, the uterine muscles relax, reducing its tone, which ensures pregnancy.

The cervix also reacts to innovations from the first minutes after conception and begins to fulfill its role. The cervical canal inside it, which is slightly open on the day of ovulation and ensures the transfer of sperm from the vagina, immediately closes, filling with thick mucus.

This mucus plug will protect the uterine cavity from viruses, pathogenic bacteria and other unwanted penetrations throughout pregnancy. Only before childbirth will the mucous plug leave its place. Its departure belongs to the category of harbingers of an imminent birth.

A lot of interesting things happen at the cellular level. The zygote, which is the egg that unites with the sperm, begins to form nuclei within the first 30 hours after conception. It is constantly fragmented, which means that the number of cells increases, but the size of the cell does not, it’s just that the new cells are smaller. The crushing period lasts about three days. All this time, after sexual intercourse and fertilization, the zygote is in constant motion - it strives to reach the uterine cavity.

On day 4, the embryo consists of approximately 16 cells. The blastomeres begin to divide into inner and outer layers. On the 5th day after conception, the zygote changes its status and becomes a blastocyst. It has about 30 cells at the very beginning and already about 200 cells by the end of the stage. The blastocyst has a round, spherical shape. This is what the former egg looks like at the time of embryo implantation.

Embryo implantation

Implantation is the process of implantation of a blastocyst into the tissue of the uterine wall. The embryo is usually attached a week after conception, often exactly 7-8 days after fertilization. From this moment, the woman’s body begins to produce chorionic gonadotropic hormone, which is also called the pregnancy hormone and the determination of the concentration of which underlies all currently existing pregnancy tests.

In order for the contact with the endometrium to be more dense and the “docking” to be successful, the blastocyst gets rid of the zona pellucida immediately after the fertilized egg descends into the uterus. Attachment of the fertilized egg is a signal for the start of active work of the corpus luteum of the ovary. Now progesterone is produced even more, because the main task of the entire female body is to maintain pregnancy.

A necessary condition for implantation is the level of progesterone in the blood that supports pregnancy, as well as the viability of the embryo itself. If a baby is conceived with genetic errors, then with a high degree of probability the implantation will be unsuccessful and the fertilized egg will be rejected.

The sensations during implantation are also highly individual. Some women are not even aware of what important processes are happening in their body, others may notice that about a week after ovulation they begin to get tired faster, and their mood changes like the weather in a seaside town. On the day of implantation, a small amount of spotting discharge may appear due to a violation of the integrity of the endometrium. Implantation bleeding does not last long - no more than a day. This is the first obvious sign of pregnancy before delay.

Not everyone can feel implantation; implantation bleeding may not occur. In any case, a week after implantation in the blood and urine of pregnancy, the concentration of human chorionic gonadotropin reaches a sufficient level so that the fact of a new life can be determined by a laboratory blood test for hCG or a test strip, which can be easily purchased at any pharmacy or even in a supermarket.

On women's forums you can find descriptions of the sensations after conception. Usually they are left by women who dream of becoming pregnant and have been trying to conceive a baby for quite some time. Such women often describe that their breasts began to hurt almost the next day after intercourse, or that their lower abdomen hurts after the alleged conception. Doctors tend to call such sensations psychogenic, since there are no objective reasons for such pain and symptoms.

There is still not enough progesterone, even if conception is successful, for the breasts to hurt and grow at a rapid pace, and nagging pain in the lower abdomen is unlikely to be associated with cellular processes that so far occur only in the fallopian tube.

Violations

In theory, everything sounds quite optimistic, but in practice, conception and subsequent transportation of the fertilized egg into the uterine cavity can occur with disturbances. In most cases, these disorders lead to termination of pregnancy in the earliest stages. Some women may even remain unaware that they were pregnant. It’s just that the next period comes with a delay of two or three days, and women, as a rule, do not pay much attention to the fact that they are a little more abundant than usual.

Difficulties may arise at the very initial stage - low quality of the egg or impaired sperm properties can prevent conception, even if sexual intercourse was carried out immediately at the time of ovulation.

The female body can be affected by chronic gynecological diseases, sexually transmitted infections, ovarian dysfunction, addiction to alcohol or nicotine. Also, any woman has anovulatory cycles - months in which ovulation does not occur at all.

On the part of men, the causes of infertility can be hormonal disorders, exposure to radiation, harmful substances, alcohol and drugs, prostatitis, varicocele, sexually transmitted infections, sexually transmitted diseases. Even with a common cold, which one of the partners suffers at the time of intercourse, the likelihood of conception decreases.

Problems can arise at the stage of fertilization itself. If more than one sperm penetrates the egg, a triploid embryo is formed, which is not capable of development and growth, since its genetic set will differ from the normal set of 46 chromosomes. Genetic pathologies can also develop if fertilization is performed by a sperm with altered morphology - a deformed or forked head, with a damaged acrosome, with mutations and deformities of the tail.

Such an embryo will develop as much as the specific genomic abnormality allows. Most often, such a pregnancy ends in miscarriage, spontaneous abortion in the very early stages, less often - during the first trimester of pregnancy.

Unforeseen difficulties may also arise at the stage of transporting the zygote. The movement of the egg into the uterine cavity is ensured by special villi inside the tube; the egg itself is the largest and most immobile cell in the human body.

If the mobility of the villi is impaired due to inflammatory diseases of the female reproductive system, if the patency of the lumen of the fallopian tube is impaired, the zygote can remain in the fallopian tube and become fixed in it for lack of an alternative for 7-8 days after conception. Then an ectopic pregnancy develops. After its discovery, the embryo is removed surgically, since it poses a serious danger to the life of the mother - rupture of the fallopian tube leads to severe internal bleeding, which quite often leads to the death of the woman even before the ambulance arrives.

It happens that, without sufficient full contact after descent into the uterus with the endometrium, the fertilized egg can migrate to the isthmus or cervix. Such an ectopic pregnancy has a more dangerous prognosis; in most cases of cervical pregnancy, the situation can only be corrected by removing the entire uterus, which leads to subsequent post-traumatic infertility.

However, such a frightening scenario for the development of the situation is quite rare. Most often, if implantation processes are disrupted, the egg simply dies before attachment and is released along with menstrual blood after some delay.

Sometimes the fertilized egg dies after implantation. The cause may also be chromosomal abnormalities, non-viability of the embryo, as well as hormonal deficiency. With a low amount of progesterone and hCG, the fertilized egg can be rejected by the woman’s own immunity. The endometrium of the uterus will not thicken and cover the fertilized egg from all sides with progesterone deficiency.

Harmful effects - contact with varnishes, paints, chemicals, pesticides and toxins, drinking alcohol and drugs, smoking, viral diseases of a woman at this stage can also cause early rejection of the fertilized egg from the uterine wall and its death.

If death occurs even before the missed period, they often talk about biochemical pregnancy. With it, there will be a delay, tests will show a second weak line, identifying traces of human chorionic gonadotropin in the urine, but menstruation will still occur after several days of delay.

After a biochemical pregnancy, there are no contraindications to planning a pregnancy. However, it is still advisable to take a spermogram and donate blood for hormones in order to exclude the causes of biochemical pregnancy, which may happen again.

How to increase the likelihood of conception?

Those planning a pregnancy are always interested in knowing whether they themselves can do at least something that can affect the likelihood of successful conception. The answer to this question is generally positive; yes, a lot depends on the spouses themselves and their attitude towards their health, including reproductive health.

To maximize your chances of conceiving, it is advisable to first visit a doctor and undergo at least basic tests - for sexually transmitted infections, sexually transmitted diseases, and a spermogram. Men don't like to admit this fact, but About 40% of unsuccessful attempts to get pregnant are associated with male factor infertility.

Planning a pregnancy is not only a decision to have children together, it is also targeted actions. 3 months before conception, a man should start taking vitamins A, C, E, D, preparations containing zinc and selenium, and folic acid. Such substances are contained both in special men's vitamin complexes and in dietary supplements, for example Selenzinc, Spermaktiv and others. Three months is the period required to complete one cycle of spermatogenesis, during which time the composition of the seminal fluid is completely renewed.

It is advisable for a woman to take vitamins and folic acid at least two months before the expected conception. Folic acid accumulates in the body and has a beneficial effect on the formation of the fetal neural tube, its future brain and spinal cord. With a large number of anovulatory cycles during the year, a woman can undergo stimulation of ovulation and subsequent conception.

Hormonal therapy after menstruation will help the follicle to mature, and as soon as its diameter is determined to be sufficient according to ultrasound results, stimulating hormones are used to provoke its rupture and the release of the egg. Stimulation should be carried out exclusively under the supervision of an experienced doctor, because errors in choosing a drug and determining the dosage can lead to premature depletion of the ovaries and their complete dysfunction.

In preparation for conception, men and women should avoid drinking alcohol and nicotine, since these substances have a destructive effect on the reproductive cells, both male and female. As a result, not only can conception itself become a difficult task, but the likelihood of conceiving a baby with chromosomal abnormalities also increases.

Also, those planning to conceive a baby should not eat fast food, canned food, pickled foods, and factory-made sweets, since they contain a large amount of preservatives and dyes that cause mutations of germ cells. Only a complete healthy diet, balanced and enriched with vitamins, will help a couple prepare for conception correctly.

Don't forget about weight. It is much more difficult for overweight women to get pregnant, and for women suffering from thinness or anorexia, conception is sometimes not possible at all.

Weight should be brought into order, as this contributes to changes in hormonal levels. Reducing body weight by just 5% already increases the likelihood of conception by 30%.

A woman needs to know well the features of her menstrual cycle so as not to be mistaken in determining ovulation and the period most favorable for conceiving a baby. Sex should be unprotected. The couple can choose any position, as long as it ensures deeper penetration of seminal fluid into the vagina. Ejaculating close to the cervix shortens the distance sperm need to travel and increases the likelihood of conception.

Intimate gels and lubricants, douching before and after sex can disrupt sperm motility and cause their mass death - the chances of fertilization will decrease tenfold. After sex, a woman should not get up immediately, it is advisable to lie down for about half an hour (we remember that this is the time it takes for sperm to reach the wide part of the fallopian tube where the egg is located. You can make their task easier by raising your legs. Such a half-hour rest after sex increases the likelihood of successful conception rate by 20 percent.

If one of the partners has recently suffered from a viral infection or the flu, it is worth postponing the important moment to a later date. In the same way, you should take a break if a man or woman, shortly before the time planned for conception, took antibiotics, hormonal drugs, anticonvulsants or psychotropic substances.

A woman who dreams of motherhood will benefit from yoga, swimming, and daily walks in the fresh air. Excessive psychological fixation on conception as the ultimate goal usually causes the opposite effect - pregnancy does not occur even with good test results and the absence of objective reasons for infertility.

The fact is that stress hormones, released in considerable quantities, if a woman cannot think about anything other than conception, suppress the production of sex hormones, and pregnancy becomes almost impossible at the biochemical level.

The intensity of sexual intercourse in the month determined for conception should be slightly reduced. Too frequent sexual intercourse makes sperm more scarce in volume, and the concentration of sperm in the ejaculate volume decreases. Doctors recommend the frequency of sexual intercourse - once every 2 days, while after menstruation you should refrain from active sexual activity for 4-5 days.

Women have known for a long time other ways to increase the likelihood of conception - uterine massage, folk remedies, special Kegel exercises. Massage of the uterus is carried out through the vagina and abdominal wall. Its goal is to improve blood circulation in the pelvic organs. Internal manual massage is not performed at home; it should only be performed in a medical facility with the participation of an experienced obstetrician-gynecologist.

Massage does not cause pain to a woman if it is performed correctly. Several such sessions can solve problems with menstrual irregularities, adhesions, and minor inflammatory processes, increasing the chances of conception.

Among folk remedies, a decoction of boron uterus, which is taken in small portions throughout the entire menstrual cycle preceding the month of planning, is especially popular among women. The grass with the interesting name “red brush” has also proven itself well. A water decoction is prepared from it and drunk in courses. Sage works real miracles for female reproductive health.

Kegel exercises are a very popular set of exercises for the pelvic muscles. At the pregnancy planning stage, it will help a woman get more pleasure from sex, and will also bring many pleasant moments to her partner. Then such exercises will help strengthen the pelvic muscles and prepare them for labor. After childbirth, the Kegel complex will promote a speedy recovery.

Conception - in facts and figures

The probability of conception in each menstrual cycle, which is accompanied by full ovulation, in young men and women is 11%. As partners age, the quality of their reproductive cells and genetic material deteriorate. So, the chances of conceiving a baby in one menstrual cycle for a 30-year-old woman are 7%, for a 35-36-year-old woman - only 4%, for a woman 40 years old - no more than 2%.

If you cannot conceive a baby within one or two cycles, you should not despair. According to statistics, approximately 60% of married couples of reproductive age become pregnant after having regular unprotected sex for six months. Another 30% of families manage to conceive a child within a year of planning. If, after 12 months of trying, pregnancy does not occur, you should definitely consult a doctor and undergo an examination.

If a woman who dreams of motherhood is over 35 years old, then the likelihood of conceiving not just one child, but twins or triplets, increases by 25%. Unfortunately, after 35 years of age, the likelihood of conceiving and giving birth to a child with chromosomal abnormalities increases; this is due to the natural aging of eggs.