Normally, a woman carries an unborn child of 40 weeks, which is 10 obstetric months for 28 days. During this period, the embryo follows a long and complex path, developing from two parent cells into an independent organism. Among the total gestational age, experts identified the most responsible and at the same time critical periods of fetal development.
Stages of intrauterine growth
Obstetricians divide the period of gestation into two phases: embryonic and fetal. The first starts from the moment of fertilization and ends at a period of 8 weeks, totaling 2 months. In the stage of embryonic development of the fetus, the following periods are distinguished:
- Blastogenesis - lasts from the moment of the confluence of the female and male gametes to 2 weeks of pregnancy. At this time, the diploid cell moves through the fallopian tubes to the uterus, after which it is introduced into its mucous membrane.
- Embryogenesis - is a period from 2 to 8 weeks of gestation, during which the formation of the placenta and primordial organs.
After two obstetric months, a fetal period begins, which will last until childbirth. Since that time, the embryo is considered a fetus. An important feature of this time is organogenesis - the formation and development of all organs and systems of the body.
In the fetal period, the following stages are distinguished:
- early (12–28 weeks) - the organs are already formed, now their cells differentiate, that is, they change their properties;
- late (from 28 weeks to the date of birth) - organ tissue growth continues, the subcutaneous fat layer of the skin is formed.
The first trimester (up to 13 weeks) accounts for the main critical periods of fetal development.
Obstetric period 2-3 weeks
Most women are not even aware of their "interesting" position at this time, and the embryo appears the first difficulties on the way to life. A little over a week has passed since the conception, and the diploid cell moves along the fallopian tubes to the uterus. Obstacles may arise in its path: adhesions or insufficient activity of the ciliary epithelium. In this case, the embryo becomes impossible to get into the uterine cavity, which forces it to attach to the wall of the fallopian tube. A pathological tube pregnancy develops.
Even if nothing prevents the embryo from advancing, it must enter the uterus at the right time. With a slower path, an ectopic pregnancy will develop, and with an accelerated path, the egg is likely to die due to the unpreparedness for implantation.
Suppose the embryo successfully crossed the fallopian tubes and reached the uterine cavity at the right time. Now the fetal egg should attach to the organ wall. For this it is necessary that the uterus has a healthy epithelium, and the embryo itself is strong enough. At this stage, natural selection occurs: if the embryo is too weak or has developmental pathologies, the maternal organism rejects it.
What factors adversely affect embryo implantation?
Critical periods of fetal development begin almost immediately after fertilization. The newly formed embryo is very sensitive to environmental factors and the state of the mother's body. Experts identify the following reasons that affect the process of implantation of the ovum:
- individual structural features of the uterus;
- adhesions as a result of operations on the internal genital organs;
- tumors of the uterus and appendages;
- severe psychoemotional state;
- physical activity, overwork;
- alcohol and drug use, smoking;
- taking certain medications;
- endometrial diseases.
The risk factor is women who have a history of abortion, miscarriage, ectopic pregnancy.
Critical periods of fetal development of the fetus require special care from the expectant mother. If pregnancy was not planned, at this time, little can be done without knowing about your situation. Otherwise, a woman should carefully prepare for conception: to undergo an examination, cure existing diseases of the genitourinary system, not to burden herself with unnecessary work and take care of emotional stability and comfort.
Risks for a period of 4-7 weeks
The embryo successfully attached itself to the wall of the uterus and continued its development. Of the two embryonic leaves , a fetus and a placenta will form. It would seem that the most difficult stage in the life of the embryo is behind, but no. Critical periods of development of the embryo and fetus reappear at the obstetric period of 4-7 weeks. The future mother already knows about her situation.
An active development of the embryo takes place: the beginnings of organs and systems are formed. At this stage, the embryo is very sensitive to the external environment, the risk of developing pathology is high. A pregnant woman should carefully listen to the advice and warnings of doctors and take care of herself: even a mild cold can question the bearing of a child.
The critical period of 8-12 weeks
At this time, the influence of external factors on the development of the embryo is one of the main dangers. Meanwhile, changes in the maternal body, which is actively tuned to bearing the fetus, are also important. The corpus luteum formed after ovulation produces progesterone, which contributes to the development of pregnancy. By the 12th week it “transfers” its functions to the placenta. This is a very risky moment, because the amount of the hormone may not be enough for further bearing. Having registered with a gynecologist, this is easily avoided: with the help of laboratory tests, the indicators of progesterone are kept under control.
To form the placenta, it is important to lead a healthy lifestyle, eat a balanced diet. Take any medications only with the permission of the doctor and under his supervision.
First Trimester Risk Factors
The main critical periods of intrauterine development of the fetus by months are in the first trimester. At the initial stage, both the embryo and the woman in the role of mother are weak. Any external influence calls into question the life of the embryo. In order not to put the pregnancy at risk again, doctors recommend to beware:
- Taking medications - the contents of the first-aid kit will have to be carefully reviewed. For example, only paracetamol is allowed to be used as an antipyretic and analgesic, and acetylsalicylic acid should be forgotten, as well as preparations based on it (analgin, aspirin). As an antispasmodic, use no-shpa (drotaverine). Among antibiotics, only penicillin rows are allowed.
- Medicinal herbs and traditional medicine - most medicinal fees, teas are prohibited for use during pregnancy and lactation. Before using such funds, it is better to consult a doctor.
- Stress, psycho-emotional disorders - the state of the mother directly affects the baby, which is most dangerous in the first months of pregnancy.
- Physical activity - do not exhaust yourself at work or carry heavy loads. The expectant mother needs rest and reasonable motor activity;
- alcohol, drugs, smoking - the toxic effects of poisons cause serious pathologies in the development of the embryo.
- Infectious diseases - any virus can seriously harm the fetus.
Critical periods of development of the embryo and fetus require special care from the mother. If you do not neglect the recommendations of the doctor and take care of yourself, reasonably limiting everything harmful and dangerous, then the most difficult first months of pregnancy will be successful both for the mother and the baby.
Duration 18–22 weeks
What critical periods of fetal development await after the first trimester? The fifth to sixth month of pregnancy (18–22 weeks of gestation) is considered an equally responsible period. During this period, the uterus is actively growing, accelerating the pace by about 2 times. Diseases of the mother are no longer so dangerous for the child, but still undesirable. The worst thing in this period is to catch an infectious STD (herpes, toxoplasmosis, chlamydia, ureaplasmosis). However, this happens quite rarely, especially if a woman has only one regular sexual partner.
The period is also risky for women with isthmic-cervical insufficiency (ICI). This is a condition in which the cervix and isthmus cannot cope with the increasing load on them. As a result, premature disclosure occurs, which often leads to spontaneous miscarriages. However, if a woman is under the supervision of a doctor, then the pathology is diagnosed in time. A mini operation is performed: a suture is placed on the cervix under local anesthesia. This allows you to convey the baby to the full gestation period.
Critical periods of fetal development between 18-22 weeks of gestation require careful medical monitoring. A woman should still protect herself from infections, physical exertion and stress. But this time is not so dangerous for the baby, and if the expectant mother is responsible for visits to the gynecologist, then it is easy to survive without consequences for the health of the fetus.
Risks in the eighth month of pregnancy
At a period of 28–32 weeks, the next critical periods of fetal development occur. Obstetrics notes that this time is no less important for the health of the child. The danger is a premature birth process or a fading pregnancy, which usually occurs due to hormonal disorders in the mother's body. Complications such as placental abruption, late toxicosis, and placental insufficiency are also possible . All this can lead to the death of the fetus before childbirth or a halt in its development.
If a woman has a history of miscarriage, monitoring the preservation of pregnancy should be carried out especially carefully. There is not much time left, so you need to make every effort to inform the child at least up to 38 weeks. Hospitalization in an obstetric hospital is often recommended.
Individual critical dates
The main critical periods of fetal development by weeks of gestation were considered above. It is during these periods that the most common situations arise that threaten the life and health of the embryo. But each organism is individual, therefore, doctors identify other dangerous periods of pregnancy. These include weeks during which:
- a miscarriage or abortion has occurred;
- there was a risk of miscarriage in a woman's previous pregnancy;
- excessive physical or psycho-emotional stress has occurred;
- the woman had menstruation after conception.
This also includes the period after the expectant mother suffered a disease.
What you need to know about the "dangerous" pregnancy?
If the doctor has identified a woman at risk, during critical periods you should adhere to bed rest and sexual rest, or even spend them in an obstetric hospital under the supervision of specialists around the clock. If at least one of the alarming symptoms occurs, you should immediately consult a doctor:
- pain in the sacrum, lower abdomen;
- vaginal discharge (spotting, bloody, brown);
- suspected disappearance of signs of pregnancy;
- lack of movement or activity of the fetus in the last trimester;
- amniotic fluid release.
How to successfully survive critical deadlines?
Critical periods of fetal development and their characteristics warn the expectant mother about the possible risks and factors of their occurrence. After learning about pregnancy and deciding to keep it, you should responsibly approach the pace of your life. Avoiding trouble is much easier if a woman regularly visits a doctor, fully eats and rests. All the hard work will have to be entrusted to other family members, unloading your day to the maximum. It will also be necessary to protect yourself from harmful factors (sources of infections, useless and dangerous products, toxic substances).
Critical periods of fetal development are the most dangerous times during which the embryo is most susceptible to environmental influences. At these times, malfunctions in the maternal body also occur, which often lead to miscarriage or miscarriage. Do not dismiss “dangerous” periods. Fulfilling all the prescriptions of doctors and protecting herself in these difficult weeks, the woman will not only successfully survive them, but also significantly increase the chances of having a strong and healthy baby on time.