First trimester of pregnancy
Embryonic period of development
- 1st week During the first weekA fertilized egg moves through the uterine tube into the uterus. Already a couple of hours after the fusion with the sperm, it begins to intensively divide, the number of components in it increases every time twice - there is a process of crushing. As a result of this process, a so-called fetal egg, similar to a mulberry berry, is formed. The scientific name of the fetal egg is morula. When the morula reaches the uterus, it attaches to the wall and begins to plunge into the endometrium (mucous membrane) - implantation occurs. The tight attachment of the morula takes approximately 40 hours. It is interesting that the body is not even formed yet, and the sex of the future baby is already determined by a set of genes in the maternal and paternal cells.
- 2 nd week After attaching the fetal eggcan be considered a full embryo. At this stage of pregnancy begins the formation of the neural tube, from which the brain and spinal cord will develop in the future.
- 3rd week This stage of pregnancy is veryimportant, because right now the baby is laying the beginnings of bone, muscle, digestive, respiratory and circulatory systems. At the head end of the formed neural tube of the embryo begins to form a thickening - the future brain. And already from the 21st day a tiny heart begins to form. The embryo, until this time flat, begins to bend, on it are formed wrinkles. In addition, it is at this time that the precursor of the placenta develops, which is called the chorion. Later the villi of the chorion and the mucous membrane of the uterus together form a child's place, which will feed the child to the very birth.
- 4th week Rudiments of almost all body systemsalready formed, different organs start to form: lungs, liver, pancreas, kidneys, the heart starts beating. In addition, the development of the head of the embryo, skin and eye lenses. By the end of the 4th week, the chord ends - the future spine, on the sides in the form of "kidneys" rudiments of arms and legs are formed. The total size to 5 weeks of the embryo is about 1 mm. In this organism, the hormone of pregnancy - the chorionic gonadotropin (HG) - begins to appear in the organism of the mother. Hormonal reorganization and caused by known to all the symptoms: irritability, tearfulness, fatigue and, of course, the lack of another menstruation.
- 5th and 6th weeks During this period of pregnancythe head of the unborn child increases significantly, the brain grows and develops in it. The cerebellum, the rudiments of the eyes, nose and ears begin to form. The development of various parts of the digestive tube is actively proceeding, the liver begins to function. Trachea and bronchi develop. Formed genital rollers with primary germ cells. The thyroid gland and spleen become noticeable. The chord begins to divide into separate vertebrae, and on the limbs the rudiments of the fingers are formed.
- 7th and 8th weeks At this stage, the childthe facial features are drawn, ears and eyes are formed, which by the end of the 8th week have already been closed for centuries. Limbs are subdivided into departments, further development of the spine occurs. Up to this point, the embryo had a tail that begins to gradually disappear. All systems of a small organism continue to grow and develop. The baby's intestine is in the umbilical cord, but their connection gradually ceases to be strong. By the end of the 8th week there is already an active differentiation of the genital rollers, the formation of the floor begins. The embryo begins to react to unpleasant effects: it shudders, shrinks.
Thus, the tabulation and formation of basicfunctional systems of the body goes in the first 8 weeks, which are considered the most critical intrauterine period. Therefore, the embryo at this time is particularly susceptible to any adverse effects. 
Fertile period of development
- 9th and 10th weeks By this time the embryo had passedall the basic transformations and acquired obvious human traits. From this moment it is considered a fruit. Increasingly the child moves the handles and legs, turns his head, begins to open his mouth. The size of the fruit is too small, so mom does not feel these movements. By the 10th week, the external genitalia begin to form. But the definition of sex by ultrasound is still impossible because of their tiny size.
- 11th week The peripheral nervous system is actively developing: receptors are formed in the skin of a child. Now he can purposefully pull the handle away or squeeze it into the cam.
- 12th week Most of the time the baby sleeps,during sleep he begins to suck a finger. This is a manifestation of the unconditioned sucking reflex. The fetus starts digestion, so he opens and closes his mouth, learns to swallow. By the 12th week, an important organ, the placenta, is completing its formation. It exchanges blood between the mother and the fetus, as well as the production of hormones and structural proteins. In addition, the placenta acts as a barrier that detains unfavorable substances so that they do not enter the body of the child from the mother's blood.
- The 13th and 14th weeks The digestive organs of the fetus are alreadyare formed, although they will not really start functioning until after birth. The intestine begins to be filled with meconium - the primary feces, the basis of which is bile. By 14 weeks, the urinary system begins to function, the baby begins to "walk in a small way" into the amniotic fluid. The first trimester of pregnancy ends, which is the most important for the bookmarking and formation of all organs and systems of a small organism.
Second trimester of pregnancy
- 15th week. Now there is active development of the brain. Gyruses and furrows stand out. "Turn on" the endocrine system, adrenal glands and thymus begin to function (thymus gland).
- 16th week The child already has the firstemotions, he smiles when he is comfortable. The hair covering grows: the first pushkovye hairs, eyebrows and eyelashes. The external genitalia are already sufficiently formed to determine the sex by ultrasound.
- The 17th and 18th weeks of the work of the adrenal glands andThe thymus is joined by the thyroid, pancreas and pituitary gland. Sebaceous glands on the skin begin to produce a lubricant that protects the baby's skin from constant contact with amniotic fluid. The baby becomes more active, begins to move from one wall of the uterus to the other. Just at this age you can feel the first stirring.
- 19th week At this time of pregnancythe nervous system continues to develop, the vestibular apparatus develops. The baby begins to express more emotions. Now he not only smiles, but frowns, if something hinders him.
- 20th and 21st weeksnails, ears get the right shape. Under the skin begins to be deposited fat. This fat is somewhat different from the usual for us and because of its color is called "brown fat", in adults it is almost absent. Since this period, the fetal heartbeat can be caught not only with the help of special equipment, but also with the help of an ordinary listening tube.
- 22nd and 23rd weeks The baby's lungs beginpreparation for breathing, although until the birth of oxygen to the fetus comes with blood through the umbilical cord. The baby reacts to external stimuli: a loud sound; too bright light, falling on the belly of my mother; pressure and vibration. In response to stimuli, he begins to toss and turn, move the handles and legs.
- 24th and 25th weeks Most of the timethe child is still sleeping, swimming in the amniotic fluid, and periodically pushes the mother from inside and turns. The digestive system of the fetus has fully developed.
- 26th week A sense of taste develops. The diet of the mother affects the taste qualities of the amniotic fluid, the baby frowns if they become bitter. Approximately from this period the mother can feel the hiccup of the fetus. The second trimester of pregnancy is coming to an end, the kid's organs and systems are already formed, now they have only to grow and develop.
Third trimester of pregnancy
- The 27th and 28th weeks The wrinkles on the face and body begin to smooth out. The sense organs have already developed significantly, the child feels, feels the taste and hears, and begins to recognize the voice of the mother.
- 29th week. Active development of muscles, the child learns new movements: scratching, touching his face, sticking out his tongue.
- 30th week The subcutaneous layer increasesfat, the child is "rounded". The immune system begins its work, immunoglobulins are sent from the mother via the placenta - antibodies, which will protect against diseases for the first time after birth.
- 31st and 32nd weeks The fruit is already large enough,for him in the uterus is not so much space, so he is always in the "embryo pose". The amount of amniotic fluid, compared with the mass of the child, decreases, all of its movements become noticeable.
- Week 33 The sense organs of the baby are already enoughformed, he opens his eyes, listens to the sounds of the voice, mom's heartbeat and rumbling in her belly. He grabs himself by the legs, touches his body.
- The 34th and 35th weeks The baby's lungs are already quite developed; if premature birth occurs, the baby will be able to breathe on his own.
- 36th week Pushkin hair on the body of the fetus begins to disappear, there is an active preparation for childbirth. In the liver, there is an accumulation of iron, necessary for hematopoiesis.
- 37th week The weight of a child is almost equal to the weight at birth. Now the baby picks up about 15 grams of fat every day. The brain and skull are the most active.
- The 38th week The fetus takes the finalposition before childbirth, the part that comes to the exit (most children have a head) is lowered, it is ready for birth. At this time, you can feel that the baby began to behave more quietly, the stomach sank lower, it became easier to breathe. All these are true signs that the baby will soon be born.
- 39th - 41st week During this time the baby should be born, it is fully formed, its organs are ready to work independently
- 42nd week If the period has approached the 42-th week of pregnancy, most likely, it is calculated incorrectly. But all the same it is necessary to discuss with your doctor the possibility of artificial stimulation of labor.
If you were eating well for a pregnancy, andtook vitamins, avoided stress, then the development of your baby at all stages, most likely, passed without special features and serious problems with the baby's health will not.
