Baby development in the first trimester

The First Trimester | Johns Hopkins Medicine

What You Need to Know

• At your first prenatal visit, you will undergo a physical exam as well as certain tests and screenings to assess the health of you and your unborn baby.
• First trimester symptoms vary from woman to woman, with some experiencing all known symptoms and others only a few. Duration of symptoms can vary as well.
• After eight weeks, the embryo is referred to as a fetus.
• Although the fetus is only 1 to 1.5 inches long at this point, all major organs and systems have been formed.
• During the first trimester, the fetus is most susceptible to damage from substances, like alcohol, drugs and certain medicines, and illnesses, like rubella (German measles).

Your First Prenatal Visit

Your first prenatal visit is the most thorough. A complete medical history is taken, a physical exam is done, and certain tests and procedures are performed to assess the health of both you and your unborn baby. Your first prenatal visit may include:

• Personal medical history. This may include taking record of any of the following:

  • Previous and current medical conditions, like diabetes, high blood pressure (hypertension), anemia and/or allergies

  • Current medicines (prescription, over-the-counter and nutritional supplements)

  • Previous surgeries

• Maternal and paternal family medical history, including illnesses, intellectual or developmental disabilities, and genetic disorders, like sickle cell disease or Tay-Sachs disease

• Personal gynecological and obstetrical history, including past pregnancies (stillbirths, miscarriages, deliveries, terminations) and menstrual history (length and duration of menstrual periods)

• Education, including a discussion regarding the importance of proper nutrition and expected weight gain in pregnancy; regular exercise; the avoidance of alcohol, drugs and tobacco during pregnancy; and a discussion of any concerns about domestic violence

• Pelvic exam. This exam may be done for one or all of the following reasons:

  • To note the size and position of the uterus

  • To determine the age of the fetus

  • To check the pelvic bone size and structure

  • To perform a Pap test (also called Pap smear) to find the presence of abnormal cells

• Lab tests, including the following:

  • Urine tests. These are done to screen for bacteria, glucose and protein.

  • Blood tests. These are done to determine your blood type.

    • All pregnant women are tested for the Rh factor during the early weeks of pregnancy. Rh incompatibility happens when the mother’s blood is Rh-negative, the father’s blood is Rh-positive and the fetus’ blood is Rh-positive. The mother may make antibodies against the Rh-positive fetus, which may lead to anemia in the fetus. Incompatibility problems are watched and appropriate medical treatment is available to prevent the formation of Rh antibodies during pregnancy. There are also other blood antibodies that may cause problems in pregnancy that are screened for on the first visit.

• Blood screening tests. These are done to find diseases that could have an effect on the pregnancy. One example is rubella, an infectious disease that is also called German measles.

• Genetic tests. These are done to find inherited diseases, like sickle cell disease and Tay-Sachs disease.

• Other screening tests. These are performed to find infectious diseases, like sexually transmitted diseases and urinary tract infections.

The first prenatal visit is also an opportunity to ask any questions or discuss any concerns that you may have about your pregnancy.

The First Trimester: What to Expect

A healthy first trimester is crucial to the normal development of the fetus. You may not be showing much on the outside yet, but on the inside, all of the major body organs and systems of the fetus are forming.

As the embryo implants itself into the uterine wall, several developments take place, including the formation of the:

• Amniotic sac. A sac filled with amniotic fluid, called the amniotic sac, surrounds the fetus throughout the pregnancy. The amniotic fluid is liquid made by the fetus and the amnion (the membrane that covers the fetal side of the placenta) that protects the fetus from injury. It also helps to regulate the temperature of the fetus.

• Placenta. The placenta is an organ shaped like a flat cake that only grows during pregnancy. It attaches to the uterine wall with tiny projections called villi. Fetal blood vessels grow from the umbilical cord into these villi, exchanging nourishment and waste products with your blood. The fetal blood vessels are separated from your blood supply by a thin membrane.

• Umbilical cord. The umbilical cord is a ropelike cord connecting the fetus to the placenta. The umbilical cord contains two arteries and a vein, which carry oxygen and nutrients to the fetus and waste products away from the fetus.

It is during this first trimester that the fetus is most susceptible to damage from substances, like alcohol, drugs and certain medicines, and illnesses, like rubella (German measles).

During the first trimester, your body and your baby’s body are changing rapidly.

Johns Hopkins Hospital Designated as Baby-Friendly

The Baby-Friendly Hospital Initiative, a global program launched by the World Health Organization and the United Nations Children’s Fund, has designated The Johns Hopkins Hospital as Baby-Friendly. This designation is given to hospitals and birthing centers that offer an optimal level of care for infant feeding and mother-baby bonding.

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The First Trimester: Changes to Your Body

During pregnancy, many changes will happen to your body to help nourish and protect your baby. Women experience these changes differently. Some symptoms of pregnancy continue for several weeks or months. Others are only experienced for a short time. Some women experience many symptoms, and other women experience only a few or none at all. The following is a list of changes and symptoms that may happen during the first trimester:

• The mammary glands enlarge, causing the breasts to swell and become tender in preparation for breast-feeding. This is due to an increased amount of the hormones estrogen and progesterone. A supportive bra should be worn.

• Your areolas (the pigmented areas around each breast’s nipple) will enlarge and darken. They may become covered with small, white bumps called Montgomery’s tubercles (enlarged sweat glands).

• Veins become more noticeable on the surface of your breasts.

• The uterus is growing and begins to press on your bladder. This causes you to need to urinate more often.

• Partly due to surges in hormones, you may experience mood swings similar to premenstrual syndrome, a condition experienced by some women that is characterized by mood swings, irritability and other physical symptoms that happen shortly before each menstrual period.

• Increased levels of hormones to sustain the pregnancy may cause “morning sickness,” which causes nausea and sometimes vomiting. However, morning sickness does not necessarily happen just in the morning and rarely interferes with proper nutrition for the mother and her fetus.

• Constipation may happen as the growing uterus presses on the rectum and intestines.

• The muscular contractions in the intestines, which help to move food through the digestive tract, are slowed due to high levels of progesterone. This may, in turn, cause heartburn, indigestion, constipation and gas.

• Clothes may feel tighter around the breasts and waist, as the size of the stomach begins to increase to accommodate the growing fetus.

• You may experience extreme tiredness due to the physical and emotional demands of pregnancy.

• Cardiac volume increases by about 40 to 50 percent from the beginning to the end of the pregnancy. This causes an increased cardiac output. An increased cardiac output may cause an increased pulse rate during pregnancy. The increase in blood volume is needed for extra blood flow to the uterus.  

The First Trimester: Fetal Development

The most dramatic changes and development happen during the first trimester. During the first eight weeks, a fetus is called an embryo. The embryo develops rapidly and by the end of the first trimester, it becomes a fetus that is fully formed, weighing approximately 0.5 to 1 ounce and measuring, on average, 3 to 4 inches in length.

First Trimester Fetal Growth and Development Benchmarks

The chart below provides benchmarks for most normal pregnancies. However, each fetus develops differently.

The fetus is most vulnerable during the first 12 weeks. During this period of time, all of the major organs and body systems are forming and can be damaged if the fetus is exposed to drugs, infectious agents, radiation, certain medications, tobacco and toxic substances.

Even though the organs and body systems are fully formed by the end of 12 weeks, the fetus cannot survive independently.

Stages of Fetal Development - First Trimester

Stages of Fetal Development - First Trimester

One - 13 Weeks

Pregnancy management, 1st trimester - basic studies.

It is necessary to register for pregnancy, as this allows timely diagnosis of:

1. Pathologies of fetal development;
2. Maternal chronic conditions that may affect the course and outcome of pregnancy;
3. Acute pathologies in the mother during pregnancy, affecting the growth and development of the fetus and the health of the mother.

Pregnancy is a complex restructuring of the body, diseases in the mother are not always known if the examination before conception is not passed. nine0003

What happens to the body during the 1st trimester of pregnancy

1st trimester is counted from conception to 12 weeks of pregnancy.

The fertilization of the egg occurs directly in the abdominal cavity. After fertilization, the egg is in the abdominal cavity and is actively split into smaller cells and becomes like a raspberry or mulberry, such an embryo is called a morula. Then it is captured by the villi of the fallopian tubes and moves into the uterine cavity. On the 7th day, the embryo is attached to the wall of the uterus. The fetal egg begins to form, consisting of amniotic fluid and the yolk sac, from which the embryo will form. At 7-8 weeks, the fetal bladder and placenta form from the fetal egg. From 8 to 12 weeks, the placenta is finally formed (in the future it only develops), it becomes visible on ultrasound. At 12 weeks, the fetus looks like a full-fledged baby about 9 in size.cm, he has formed limbs, head and main internal organs.

Mother's changes. Ideally, a woman does not feel pregnancy in any way. The only sign is an increase in the mammary glands, due to the development of glandular tissue under the action of hormones. The stomach practically does not increase.

During pregnancy, many women experience so-called "toxicosis" - nausea and/or vomiting. This is due to an increase in the level of estrogen (in particular progesterone) and hCG (chronic gonadotropin). Moreover, these symptoms can complicate the life of a pregnant woman, not only in the morning, but at any time of the day. Sometimes nausea or vomiting may persist throughout pregnancy. nine0003

There is such a formidable complication as excessive (uncontrolled) vomiting of pregnant women, which leads to maternal dehydration, electrolyte imbalance, liver and kidney dysfunction and encephalopathy, requiring hospitalization and treatment in a hospital.

It is best to eat according to your appetite. Food should not cause negative reactions, eat in small portions, pay attention to what kind of food provokes nausea and try not to eat it for a while, listen to your body, usually a woman herself feels what she would like to eat. Do not forget that food should not only be desirable and tasty, but also healthy. It would be ideal to eat according to the Harvard Healthy Eating Plate method, when ½ of the volume of the plate is occupied by vegetables, ¼ proteins (including plant origin), ¼ complex carbohydrates (grains, potatoes, cereals, etc.). nine0003

Your body will also begin to change. And the first thing you will feel will be engorgement and an increase in the sensitivity of the mammary glands, the nipples will swell a little and increase in size. It is important to wear comfortable, comfortable underwear and clothing to minimize discomfort. Sometimes there is pain in the nipples, your gynecologist may recommend ointments for this case.

We all remember that a pregnant woman becomes more vulnerable, whiny and sometimes even capricious. It is also associated with rising estrogen levels and requires patience and understanding on the part of family and partner. A calm atmosphere at home and, if possible, at work is important. You can connect such relaxation methods as walking, listening to your favorite music, aromatherapy in the absence of reactions to smells. Think about what could bring back your balance and calmness? nine0003

The main pregnancy hormone, progesterone, causes fluid retention in the body. In parallel with this, the growing uterus squeezes the bladder and there are frequent urges to urinate. This is normal, it is important to plan your day so that you always have the opportunity to visit the toilet.

Progesterone also reduces the tone of blood vessels, which can lead to dizziness. You can minimize these discomforts by changing the position of the body smoothly, do not get up and do not sit down abruptly. Another reason for frequent dizziness can be a decrease in the level of magnesium in the blood, your doctor will help you figure it out. nine0003

Pregnant women often have an increased need for sleep, which is explained by the same action of hormones, as well as the need for additional rest for the body, because there is a lot of work to bear, give birth and then feed the baby.

Under the action of progesterone, the smooth muscles of the whole body (uterus, intestines, blood vessels, bile ducts and pancreatic ducts, etc.) relax, the work of internal organs slows down, which in turn leads to constipation and heartburn. In addition to medication correction (prescribed by a doctor), fractional meals in small portions, foods rich in fiber (our favorite vegetables), sufficient fluid intake, feasible physical activity (exercise therapy, walking, swimming, yoga, Pilates, etc.) help

Unfortunately, sometimes pregnancy is overshadowed by pathology, let's talk about the most common problems of the first trimester of pregnancy.

The most common problems in the 1st trimester of pregnancy

Bleeding : due to lack of progesterone, there is a spasm and relaxation of the muscles of the uterus and, accordingly, detachment of the ovum and bleeding (in severe cases - miscarriage). Also, with hypothyroidism, there is a violation of the implantation of the fetal egg, which also leads to bleeding. nine0003

Thrombosis . During pregnancy, blood clotting increases (this is normal - the body is preparing for blood loss). To prevent thrombosis of the veins of the lower extremities, it is necessary to stop taking oral contraceptives 6 months before the start of pregnancy planning, and during the onset of pregnancy, maintain sufficient physical activity (long walks, swimming) and be observed by a doctor. If you experience pain, swelling, "cyanosis" in the lower extremities, you should immediately consult a doctor. nine0003

Developmental anomalies and genetic pathologies . In the 1st trimester, abnormalities in the development of the fetus most often develop and manifest, which can occur as a result of ionizing radiation, infectious diseases suffered during pregnancy (rubella, influenza, etc.), taking drugs prohibited during pregnancy (fluoroquinolones, macrolides, tetracyclines, tranquilizers , etc.), genetic pathologies and hereditary diseases.

Anemia . More often it happens due to iron deficiency, tk. the fetus consumes a huge amount of it, taking away iron stores from the mother, less often due to bleeding. B12 and folic deficiency anemias also occur, also associated with increased consumption and insufficient intake by the mother. Anemia is a dangerous chronic lack of oxygen, causing fetal growth retardation syndrome. In severe cases, it can lead to fetal death. nine0003

During pregnancy chronic diseases may worsen . This is due to the fact that the fertilized egg already carries a part of DNA alien to the mother. To prevent egg rejection, the mother's body suppresses its immunity throughout pregnancy, which affects the body as a whole. Therefore, all diseases not identified at the stage of preparation for pregnancy should be detected and cured. This applies mainly to infectious diseases. For example, exacerbation of chronic pyelonephritis, or herpes virus infection. nine0003

Also during pregnancy there is a sharp restructuring of the hormonal background , which, in turn, affects somatic (non-infectious) diseases. For example, due to thickening of bile and compression of the gallbladder by the uterus, chronic cholecystitis may be exacerbated. As the fetus develops, the islets of Langerhans (cells that produce insulin in the pancreas) sometimes don't develop fast enough and the baby begins to consume the mother's insulin. If the mother has diabetes or impaired glucose tolerance (including hidden ones), both the child and the mother lack insulin, which leads to tissue damage to both the child and the mother (early aging of the placenta, fetal growth retardation, premature birth, polyhydramnios, increased blood pressure in a pregnant woman, the formation of a large fetus, the risk of injury to a woman and a child during childbirth, and the most formidable complication is intrauterine fetal death). nine0003

In addition, the fetal liver does not yet function as a detoxifying organ, and all the decay products produced by the child must be processed by the mother's liver. 2% of pregnant women develop benign cholestatic hepatosis of pregnant women - violation of the formation and outflow of bile, which causes: effects on cells and bile ducts

1st trimester tests

Compulsory tests

Urinalysis . Needed to assess kidney function and determine the risk of eclampsia, a dangerous condition that develops during pregnancy, as well as to exclude asymptomatic bacteriuria.

Complete blood count . It aims to detect anemia, the risk of thrombosis, and inflammatory reactions.

Blood biochemistry - assessment of liver and kidney function, detection of diabetes mellitus and impaired tolerance (immunity) to glucose.

Coagulogram - detection of pathology of blood coagulation - risk of thrombosis or bleeding.

Therapist – to exclude the pathology of the internal organs, which may prevent or complicate the normal course of pregnancy and the upcoming birth. Most often, diseases such as pyelonephritis, anemia, cholecystitis, gastritis, vegetative dystonia, arterial hypertension are determined. nine0003

ECG in the direction of the therapist - detection of pathology of the cardiovascular system. Indirect signs of pericarditis, enlargement of the left ventricle, blockade of the conduction system of the heart.

Examination by an ophthalmologist - to determine the pathology of the organs of vision, incl. assessment of the risk of retinal detachment during childbirth.

ENT - the presence of chronic foci of infection (chronic tonsillitis, pharyngitis, sinusitis) increases the risk of miscarriage in the 1st trimester of pregnancy and the development of rheumatic complications. nine0003

At the period of 11-14 weeks, the first ultrasound screening is carried out to detect abnormalities in the fetus.

Additional tests

When registering, all pregnant women determine the blood type and Rh factor. If the Rh factor is negative, antibodies to the Rh factor in the mother and the blood type, the Rh factor of the father of the child, are determined. Sometimes there is incompatibility in blood types, this can happen if a woman has group I, and a man has any other. Analyzes are carried out once a month, starting from the 8th week of pregnancy. All this is done in order to take the necessary measures in time to prevent hemolytic disease of the newborn. nine0003

Anemia is initially diagnosed using a complete blood count and determination of hemoglobin (Hb), mean red cell volume (MCV), and mean red cell hemoglobin (MCH). If there is a decrease or increase in these indicators, the level of ferritin, transferrin, iron, folic acid, B12 is additionally examined.

Sometimes a consultation with a gastroenterologist is necessary to correct gastrointestinal disorders . He will select dietary nutrition, as well as identify pathologies that lead to malabsorption of nutrients, iron and vitamins. nine0003

2nd trimester of pregnancy.

Child development by week | Regional Perinatal Center

Expectant mothers are always curious about how the fetus develops at a time when it is awaited with such impatience. Let's talk and look at the photos and pictures of how the fetus grows and develops week by week.

What does the puffer do for 9 whole months in mom's tummy? What does he feel, see and hear?

Let's start the story about the development of the fetus by weeks from the very beginning - from the moment of fertilization. A fetus up to 8 weeks old is called embryo , this occurs before the formation of all organ systems.

Embryo development: 1st week

The egg is fertilized and begins to actively split. The ovum travels to the uterus, getting rid of the membrane along the way.

On the 6th-8th days, implantation of eggs is carried out - introduction into the uterus. The egg settles on the surface of the uterine mucosa and, using the chorionic villi, attaches to the uterine mucosa.

Embryo development: 2-3 weeks

Picture of embryo development at 3 weeks.

The embryo is actively developing, starting to separate from the membranes. At this stage, the beginnings of the muscular, skeletal and nervous systems are formed. Therefore, this period of pregnancy is considered important.

Embryo development: 4-7 weeks

Fetal development by week in pictures: week 4

Fetal development by week photo: week 4

Photo of an embryo before the 6th week of pregnancy.

The heart, head, arms, legs and tail are formed in the embryo :) . Gill slit is defined. The length of the embryo at the fifth week reaches 6 mm.

Fetal development by weeks photo: week 5

At the 7th week, the rudiments of the eyes, stomach and chest are determined, and fingers appear on the handles. The baby already has a sense organ - the vestibular apparatus. The length of the embryo is up to 12 mm. nine0003

Fetal development: 8th week

Fetal development by weeks photo: weeks 7-8

The face of the fetus can be identified, the mouth, nose, and auricles can be distinguished. The head of the embryo is large and its length corresponds to the length of the body; the fetal body is formed. All significant, but not yet fully formed, elements of the baby's body already exist. The nervous system, muscles, skeleton continue to improve.

Fetal development in the photo already sensitive arms and legs: week 8

The fetus developed skin sensitivity in the area of ​​the mouth (preparation for the sucking reflex), and later in the area of ​​the face and palms.

At this stage of pregnancy, the genitals are already visible. Gill slits die. The fruit reaches 20 mm in length.

Fetal development: 9–10 weeks

Fetal development by week photo: week 9

Fingers and toes already with nails. The fetus begins to move in the pregnant woman's stomach, but the mother does not feel it yet. With a special stethoscope, you can hear the baby's heartbeat. Muscles continue to develop. nine0003

Fetal development by week photo: week 10

The entire surface of the fetal body is sensitive and the baby develops tactile sensations with pleasure, touching his own body, the walls of the amniotic sac and the umbilical cord. It is very curious to observe this on ultrasound. By the way, the baby first moves away from the ultrasound sensor (of course, because it is cold and unusual!), And then puts his hands and heels trying to touch the sensor.

It's amazing when a mother puts her hand to her stomach, the baby tries to master the world and tries to touch with his pen "from the back". nine0253

fetal development: 11–14 weeks

The development of the fetus in the photo of the legs: weeks 11 9000

In the baby's arms, legs and eyelids, and the genitals become distinguishable (you can find out the floor child). The fetus begins to swallow, and if something is not to its taste, for example, if something bitter gets into the amniotic fluid (mother ate something), then the baby will begin to frown and stick out his tongue, making less swallowing movements. nine0003

Fruit skin appears translucent.

Fruit development: Week 12

Photo of the fetus 12 weeks on 3D Ultrasound

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Development urine. Blood forms inside the bones. And hairs begin to grow on the head. Moves more coordinated.

Fetal development: 15-18 weeks

Fetal development by weeks photo: week 15

The skin turns pink, the ears and other parts of the body, including the face, are already visible. Imagine, a child can already open his mouth and blink, as well as make grasping movements. The fetus begins to actively push in the mother's tummy. The sex of the fetus can be determined by ultrasound.

Fetal development: 19-23 weeks

Fetal development by week photo: week 19

Baby sucks his thumb, becomes more energetic. Pseudo-feces are formed in the intestines of the fetus - meconium , kidneys begin to work. During this period, the brain develops very actively.

Fetal development by week photo: week 20

The auditory ossicles become stiff and now they are able to conduct sounds, the baby hears his mother - heartbeat, breathing, voice. The fetus intensively gains weight, fat deposits are formed. The weight of the fetus reaches 650 g, and the length is 300 mm.

The lungs at this stage of fetal development are so developed that the baby can survive in the artificial conditions of the intensive care unit. nine0003

Fetal development: 24-27 weeks

Lungs continue to develop. Now the baby is already falling asleep and waking up. Downy hairs appear on the skin, the skin becomes wrinkled and covered with grease. The cartilage of the ears and nose is still soft.

Fetal development by week photo: week 27

Lips and mouth become more sensitive. The eyes develop, open slightly and can perceive light and squint from direct sunlight. In girls, the labia majora do not yet cover the small ones, and in boys, the testicles have not yet descended into the scrotum. Fetal weight reaches 900–1200 g, and the length is 350 mm.

9 out of 10 children born at this term survive.

Fetal development: 28-32 weeks

The lungs are now adapted to breathe normal air. Breathing is rhythmic and body temperature is controlled by the CNS. The baby can cry and responds to external sounds.

Child opens eyes while awake and closes during sleep.

The skin becomes thicker, smoother and pinkish. Starting from this period, the fetus will actively gain weight and grow rapidly. Almost all babies born prematurely at this time are viable. The weight of the fetus reaches 2500 g, and the length is 450 mm. nine0003

Fetal development: 33–37 weeks

Fetal development by week photo: week 36

The fetus reacts to a light source. Muscle tone increases and the baby can turn and raise his head. On which, the hairs become silky. The child develops a grasping reflex. The lungs are fully developed.

Fetal development: 38-42 weeks

The fetus is quite developed, prepared for birth and considered mature. The baby has mastered over 70 different reflex movements. Due to the subcutaneous fatty tissue, the baby's skin is pale pink. The head is covered with hairs up to 3 cm.

Fetal development by weeks photo: week 40

The baby perfectly mastered the movements of his mother , knows when she is calm, excited, upset and reacts to this with her movements. During the intrauterine period, the fetus gets used to moving in space, which is why babies love it so much when they are carried in their arms or rolled in a stroller. For a baby, this is a completely natural state, so he will calm down and fall asleep when he is shaken.

The nails protrude beyond the tips of the fingers, the cartilages of the ears and nose are elastic. In boys, the testicles have descended into the scrotum, and in girls, the large labia cover the small ones. The weight of the fetus reaches 3200-3600 g, and the length is 480-520 mm. nine0003

After the birth, the baby longs for touching his body, because at first he cannot feel himself - the arms and legs do not obey the child as confidently as it was in the amniotic fluid. Therefore, so that your baby does not feel lonely, it is advisable to carry him in your arms, press him to you while stroking his body.

And one more thing, the baby remembers the rhythm and sound of your heart very well .

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