Rus Articles Journal

Time to be careful
(the critical periods of pregnancy) of

The fact that future mother has to take care is perceived as common truth. But the few know that during pregnancy there are periods when the risk of various troubles with health significantly increases. Observing the increased care at “the critical moments“, the woman will be able “to make secure“ and avoid unnecessary problems in time.

Pregnancy lasts 9 calendar or 10 obstetric months * (its average duration makes 280 days of the first day of the last periods before childbirth). During this time there is the most difficult process of transformation of the impregnated ovum into the mature fruit capable to independent existence out of mother`s womb. In 9 months there is a rough cell fission, formation of bodies and fabrics of a fruit, maturing of functional systems, establishment of communication between them thanks to what the newborn will be able to adapt in external environment, to lead life, independent, separate of a maternal organism.
* consists 1 Obstetric month of 4 weeks.

it is difficult to small to Overestimate a role of any period of pre-natal life of a fruit. But during pregnancy there are several critical terms when the risk of its spontaneous interruption (an abortion or premature birth), emergence of complications of a course of pregnancy, anomalies of embryo and fetus development is highest. About these terms the speech will also go.

are Distinguished by the next periods of development of a fruit during pregnancy:

  • predymplantatsionny (from the moment of fertilization of an ovum with a spermatozoon before introduction of the impregnated ovum in mucous uterus walls);
  • implantation (an attachment of the impregnated ovum to a uterus wall);
  • organogenesis and platsentation (period of formation of all bodies and fabrics of a fruit, and also placenta);
  • fetal - the period of growth and development of the created bodies and fabrics.
the Predymplantatsionny period

Is normal of

in 12 - 14 days prior to the expected periods there is an ovulation, that is the ovum which reached the big sizes leaves an ovary, comes to a uterine tube where most often and there is a fertilization. From this point there comes pregnancy. The impregnated ovum continues the way on a uterine tube within 4 days towards a uterus cavity what is promoted:

  • of reduction of smooth muscles of a wall of a uterine tube. These reductions normal come in the unilateral direction - towards a uterus cavity from the end of a pipe turned into an abdominal cavity;
  • the movement of eyelashes of a mucous membrane which covers a uterine tube from within. The liquid which is in a pipe starts moving, and with current of this liquid the impregnated ovum gets into a uterus;
  • relaxation of a sphincter (a circular muscle) in the field of connection of a uterine tube with a uterus. This sphincter is intended for the prevention of hit of the impregnated ovum in a uterus cavity before the term before the uterus is ready for reception of the impregnated ovum.

the Movement of an ovum on a uterine tube happens under the influence of female sex hormones of estrogen and progesterone. Progesterone - pregnancy hormone which on early terms of pregnancy is produced in an ovary (on the place of the burst follicle the yellow body which produces this hormone in a large number and promotes approach and maintenance of pregnancy is formed). If progesterone is produced insufficiently, the ovum from a uterine tube will get into a uterus cavity with delay. At the raised vermicular movement of a uterine tube the impregnated ovum will get into a uterus cavity earlier, than it can take root in mucous owing to what the ovum can die. As at the same time pregnancy will not take place, the delay of the next periods will not be, pregnancy will remain not diagnosed, not distinguished.

the Period of advance of the impregnated ovum on a uterine tube is considered the first critical period of pregnancy (from 12 - 14 to 10 - 8 days prior to the beginning of the next periods). As a result of violation of difficult mechanisms of regulation of work of a uterine tube the ovum after fertilization can also take root into a pipe wall (extra-uterine pregnancy).

the Implantation period

This period also passes

to estimated periods, most often when the woman also does not suspect about the pregnancy. Getting into a uterus cavity, the germ already consists of 16 - 32 cages, however it takes root in mucous a uterus not at once, and within two days is in a free state. These two days from the moment of hit of the impregnated ovum in a uterus cavity to its attachment to a wall of a uterus make the implantation period. The place of introduction depends on a number of circumstances, however most often it is a forward or back wall of a uterus.

Food of fetal egg during this period happens due to local dissolution of a mucous wall of a uterus by means of the enzymes emitted by fetal egg. After 2 days fetal egg takes root in mucous a uterus which contains in a large number enzymes, the glycogen, fats, minerals, protective antibodies and other biologically active agents necessary for the further growth of a germ.

the Second critical period of pregnancy - implantation, that is an attachment of fetal egg to a uterus wall. If implantation does not work well, then pregnancy comes to the end behind a mask of periods (actually it is not diagnosed abortion on very small terms). As there is no delay of periods, the woman does not even assume about presence of pregnancy at it.


On implantation process the great influence is exerted by hormonal factors: concentration of such hormones as progesterone, estrogen, Prolactinum (hypophysis hormone - gland located in a brain), glucocorticoids (hormones of adrenal glands) etc.

Huge value has also readiness of a mucous membrane of a uterus to implantation, readiness to take its fetal egg. After abortions, vyskablivaniye, long carrying an intrauterine spiral, infections, inflammatory processes the receptor (perceiving) device an endometriya can be broken, that is cages, sensitive to hormones, located in a mucous membrane of a uterus incorrectly react to hormones, from - for what mucous a uterus is insufficiently prepared for the forthcoming pregnancy. If fetal egg insufficiently active, in due time does not allocate the necessary amount of the enzymes destroying mucous a uterus, then it can take root into a uterus wall in the lower segment or in a neck to a uterus therefore there is a cervical pregnancy or an abnormal platsentation (the placenta blocks an exit from a uterus partially or completely).

Existence of unions (sinekhiya) in a uterus cavity after inflammatory processes, vyskablivaniye, and also uterus myomas can interfere with normal implantation too.

the Period of an organogenesis and platsentation

This period proceeds from the moment of introduction of fetal egg in a mucous membrane of a uterus till 10 - 12 weeks of pregnancy when all bodies and fabrics of a fruit are completely created, and also a placenta (an afterbirth - a link between a fruit and a maternal organism by means of which there are processes of food, a metabolism and breath of a fruit in mother`s womb). It is very responsible period of pre-natal life since at this time there is laying of all bodies and fabrics of a fruit. Already on 7 - y day after fertilization of an ovum the organism of mother receives a signal of pregnancy thanks to hormone - the horionichesky gonadotrophin (HG) which is allocated with fetal egg. HG, in turn, keeps development of a yellow body in an ovary. The yellow body excretes progesterone and estrogen in the quantity sufficient for pregnancy maintenance. At the initial stage of pregnancy, before formation of a placenta, the yellow body undertakes function of hormonal support of pregnancy and if for one reason or another the yellow body works defectively, then there can be a threat of an abortion, an abortion or not developing pregnancy.

the Entire period of an organogenesis and platsentation is also the critical period of pre-natal life of a fruit since the fruit is highly sensitive to the damaging influence of environment, especially in the first 3 - 6 weeks of an organogenesis. This critical period of development of pregnancy is especially important since under the influence of adverse factors of environment the embryo can die or it can have anomalies of development.


During these periods is especially dangerous influence on a germ of factors of environment among which:

  • of physical (ionizing radiation, mechanical influences); it can be action of the ionizing radiation, for example in the conditions of technogenic accident on nuclear objects, mechanical influences in the form of vibration and so forth on the corresponding productions or at the time of sports trainings;
  • chemical: phenols, a nitrogen oxide, pesticides, heavy metals etc. - these substances can also get to the pregnant woman`s organism if it works at the corresponding productions or when carrying out repair indoors where long there is a woman. The nicotine, alcohol, some medicines for example used for treatment of oncological diseases, etc. belong to chemicals;
  • biological (for example, herpes virus, cytomegalovirus, rubella virus, etc.) .

needs to emphasize


that during the critical periods harmful effects lead to the most serious consequences - death of a germ or to formation of rough malformations.

according to the French researchers if the pregnant woman for the first time in life faced a cytomegalovirus - the activator causing a disease which at adults can proceed as banal ORZ (acute respiratory disease) during pregnancy (that is visible on a blood test on immunoglobulins to TsMV), especially on early terms then in 1/3 cases fruit malformations can arise. If before pregnancy she was already infected, the organism turns on protective mechanisms of fight against a virus in time) this probability decreases to 1%. The same can be told also about a virus of simple herpes.

Special danger is constituted by a rubella virus at infection with it on early terms of pregnancy. Recommend to the woman in such cases artificial interruption of pregnancy since the risk of the birth of the child such malformations as a mikroftalmiya - a malformation of eyes, a mikrotsefaliya - a serious malformation head a brain is high; deafness, congenital heart diseases etc.

From of chemical compounds especially adversely affect a condition of a germ lead, mercury, benzene, nicotine, oxides of carbons and other substances which can cause malformations.

Some medicines are especially contraindicated to

during pregnancy (for example, antineoplastic antibiotics); if they were accepted, then interruption of pregnancy on early terms is recommended. At reception of some medicines consultation of the geneticist, careful supervision are necessary during pregnancy behind a condition of a germ and a fruit (ultrasonography, a blood test on a horionichesky gonadotrophin, an alpha - fetoprotein, estriol which allow to suspect existence of malformations of a fruit - the analysis is carried out to 16 - 20 weeks of pregnancy).

of Women, working at a chemical factory , during pregnancy it is necessary to transfer to other, less dangerous shops. As for influence of radiation, if it influences the woman before implantation of a germ (during the predymplantatsionny period), in 2/3 cases the embryo perishes. In the period of an organogenesis and a platsentation often there are malformations or there occurs the pre-natal death of a germ or fruit.

In 7 - 8 weeks of pregnancy the return development of a yellow body in an ovary usually begins

: figuratively speaking ovaries transfer to a horion (future placenta) function of hormonal support of pregnancy and if horion it is insufficiently developed, is not active, then there is a pregnancy interruption threat.

of 7 - 8 weeks is also critical period for pregnancy development. Very often the abortion, not developing pregnancy or threat of an abortion (bloody allocations from a genital tract, pains in the bottom of a stomach and a waist) appear on this term. If it occurred, hospitalization is necessary for the woman. In a hospital use various medicines which will help to keep pregnancy if it is possible.

So as we were convinced, the first trimester of pregnancy almost completely consists of the critical periods therefore at this time it is especially important:

  • whenever possible to exclude negative impact of harmful production;
  • to change
  • a complex of physical exercises at active trainings during the period before pregnancy, to postpone occupations by extreme sports for the postnatal period;
  • to carry out by
  • enough time in the fresh air;
  • enough time (8 - 10 hours) to give to a dream;
  • not to take active part under repair of rooms;
  • to refuse addictions, especially such as alcohol intake, drugs, smoking.

the Foetal period


With 12 weeks of pregnancy the fetal period of pre-natal life of a fruit which lasts till 40 weeks. At this time the fruit is already completely created, however physically did not ripen.

Terms of pregnancy of 13, 20 - 24 and 28 weeks are critical for patients with a giperandrogeniya - the increased content of male sex hormones - from - for the beginnings of production of hormones of a fruit. In these terms it is necessary to check the level of hormones and to correct a dose of preparations which are appointed for decrease in amount of male sex hormones (deksametlzon, metip - red etc.) . At the same time the doctor watches a condition of a neck of a uterus as increase of amount of male sex hormones can lead to its premature disclosure.

In 13 weeks of pregnancy the male fruit begins to produce own testosterone - male sex hormone, in 20 - 24 weeks development of cortisol and male sex hormones begins bark of adrenal glands of a fruit therefore the woman with a giperandrogeniya can have the next raising of male sex hormones that will lead to pregnancy interruption.

In 28 weeks the hypophysis of a fruit begins to synthesize the hormone stimulating work of adrenal glands - adrenokortikotropny hormone therefore production of male sex hormones amplifies that can also lead to pregnancy interruption. If necessary on this term the doctor will correct a dose of medicines.

So, action of adverse factors during the critical periods of pregnancy can lead to the most adverse effects. Therefore to the woman throughout all waiting time of the child, and especially during the critical periods, it is necessary to avoid action of adverse factors and at any “malfunctions“ to see a doctor. There is a wish to advise future mothers to keep itself especially as pregnancy lasts only 9 months, and health and life of your kid depend on its current.

What has to become a reason for alarm?

If action of adverse factors in critical terms led

to threat of interruption of pregnancy, women complain of pains in the bottom of a stomach, in a waist - pulling or skhvatkoobrazny. Pains can be followed by bloody allocations from a genital tract. It is impossible to leave such symptoms indifferently since after them there can be massive bleeding from - for incomplete a spontaneous abortion at which pregnancy cannot be rescued.

it is Very important to address at the first symptoms of the menacing abortion the gynecologist at once, to pass necessary researches, including survey on a chair, ultrasonography, hormonal blood tests on female sex hormones, male sex hormones, hormones of a thyroid gland.

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