What is 1st trimester

What to Expect, Baby Development

Written by Stephanie Watson

Reviewed by Traci C. Johnson, MD on August 12, 2022

What Is the First Trimester of Pregnancy?

The first trimester is the earliest phase of pregnancy. It starts on the first day of your last period -- before you’re even actually pregnant -- and lasts until the end of the 13th week. It’s a time of great anticipation and of rapid changes for both you and your baby. Knowing what to expect will help you get ready for the months ahead.

First Trimester Changes in Your Body

Pregnancy is different for every woman. Some women glow with good health during those first 3 months; others feel absolutely miserable. Here are some of the changes you might notice, what they mean, and which signs warrant a call to your doctor.

Bleeding. About 25% of pregnant women have slight bleeding during their first trimester. Early in the pregnancy, light spotting may be a sign that the fertilized embryo has implanted in your uterus. But if you have severe bleeding, cramping, or sharp pain in your belly, call the doctor. These could be signs of a miscarriage or ectopic pregnancy (a pregnancy in which the embryo implants outside of the uterus).

Breast tenderness.Sore breasts are one of the earliest signs of pregnancy. They're triggered by hormonal changes, which are getting your milk ducts ready to feed your baby. Your breasts will probably be sore throughout the first trimester. Going up a bra size (or more) and wearing a support bra can make you feel more comfortable. You probably won’t go back to your regular bra size until after your baby is finished nursing.

Constipation. During pregnancy, high levels of the hormone progesterone slow down the muscle contractions that normally move food through your system. Add to that the extra iron you're getting from your prenatal vitamin, and the result is uncomfortable constipation and gas that can keep you feeling bloated throughout your pregnancy. Eat more fiber and drink extra fluids to keep things moving more smoothly. Physical activity can also help.

If your constipation is really bothering you, talk to your doctor about what mild laxative or stool softeners are safe to use during pregnancy.

Discharge. It's normal to see a thin, milky white discharge (called leukorrhea) early in your pregnancy. You can wear a panty liner if it makes you feel more comfortable, but don't use a tampon because it could put germs into your vagina. If the discharge smells really bad, if it’s green or yellow, or if there's a lot of clear discharge, call the doctor.

Fatigue. Your body is working hard to support a growing baby. That means you’ll get tired more easily than usual. Take naps or rest when you need to during the day. Make sure you're getting enough iron. Too little can lead to anemia, which can make you even more tired.

Food likes and dislikes. Although you may not want a bowl of mint chip ice cream topped with dill pickles, as the old stereotype goes, your tastes can change while you're pregnant. More than 60% of pregnant women have food cravings. More than half have foods they really don’t like. Giving in to cravings from time to time is OK, so long as you eat healthy, low-calorie foods most of the time. The exception is pica -- a craving for nonfoods like clay, dirt, and laundry starch, which can be dangerous for you and your baby. If you experience this kind of craving, report it to your doctor right away.

Peeing a lot. Your baby is still pretty small, but your uterus is growing and it's putting pressure on your bladder. As a result, you may feel like you have to go to the bathroom all the time. Don't stop drinking fluids -- your body needs them -- but do cut down on caffeine (which stimulates your bladder), especially before bedtime. When nature calls, answer it as soon as you can. Don't hold it in.

Heartburn. During pregnancy, your body produces more of the hormone progesterone. It relaxes smooth muscles, like the ring of muscle in your lower esophagus, the tube that connects your mouth and stomach. These muscles normally keep food and acids down in your stomach. When they loosen up, you can get acid reflux, otherwise known as heartburn. To avoid the burn:

Eat a few small meals throughout the day.
Don't lie down right after you eat.
Avoid greasy, spicy, and acidic foods (like citrus fruits).
Try raising your pillows when you sleep.

Mood swings. Increased fatigue and changing hormones can put you on an emotional roller coaster that takes you from joyous to miserable, or from hopeful to terrified in a matter of seconds. It's OK to cry, but if you feel overwhelmed, try to find an understanding ear. You can talk to your partner, a friend, a family member, or even a professional.

Morning sickness.Nausea is one of the most common pregnancy symptoms. Up to 85% of pregnant women have it. It results from hormone changes in your body and it can last through the entire first trimester. For some pregnant women, nausea is mild. Others can't start their day without vomiting. Nausea is usually worse in the morning (hence the name, "morning sickness"). To calm your nausea, try eating small, bland, or high-protein snacks (crackers, meat, or cheese) and sipping water, clear fruit juice (apple juice), or ginger ale. You may want to even do this before you get out of bed. Avoid any foods that make you sick to your stomach. Nausea itself isn't anything to worry about, but if it’s severe or just won’t go away, it can affect the amount of nutrition your baby gets. Call your doctor if you can't stop throwing up or can't keep down any food.

Weight gain. Pregnancy is one of the few times in a woman's life when weight gain is considered a good thing, but don't overdo it. During the first trimester, you should gain about 3-6 pounds (your doctor may suggest you adjust your weight gain up or down if you started your pregnancy underweight or overweight). Although you're carrying an extra person, you really aren’t eating for two. You only need about an extra 150 calories a day during the first trimester. Get those calories the healthy way, by adding extra fruits and vegetables, milk, whole-grain bread, and lean meat to your diet.

Baby’s Growth in the First Trimester

During the first 13 weeks, your baby changes from a fertilized egg into a fully-formed fetus. All the major organs and systems are taking shape. That means your baby could be harmed if you use street drugs, have an illness, or get exposed to radiation. Here’s what’s happening:

The fertilized egg becomes a cluster of rapidly dividing cells that implants in your uterus. The placenta, umbilical cord and amniotic sac all start to grow.
Your baby’s nervous system changes from an open neural tube to a brain and spinal cord. Nerves and muscles start working together. Your baby can move on its own, but it’s too soon for you to feel it.
The heart takes shape and begins to beat. You can hear it on ultrasound as early as week 6. It beats 120 to 160 times per minute. Red blood cells are forming.
Your baby develops a digestive system, including intestines and kidneys.
They have lungs and other major organs, but they’re not fully developed.
A soft skeleton is starting to grow.
Your baby starts to look like a baby, with arms, legs, fingers, and toes. Their face gets eyes, ears, a nose, and mouth. A tongue and tooth buds grow. Eyelids cover your baby’s eyes, and by the end of the trimester, they even have fingernails.
Genitals start to grow, but it’s too early to tell by ultrasound whether you’re having a girl or a boy.

By the end of the first trimester, your baby will be about 2 ½-3 inches long.

First Trimester To-Dos

Having a baby is one of the most joyous times in many women's lives. From thinking about the day you'll bring your little one home, to picking a name and nursery colors, the excitement is intense. But you also need to take some practical steps during the first trimester, including:

Choose a doctor. Do you want an obstetrician or a midwife? Get referrals and find out what your health insurance covers.
Schedule a prenatal visit as soon as you know you’re pregnant. You’ll cover a lot of ground in the first appointment. The doctor will take a full medical history and talk to you about your lifestyle and health habits. They’ll figure out your due date. You’ll also have blood and urine tests and possibly a pelvic exam.
Continue with prenatal visits every 4 weeks. The doctor will check your weight and blood pressure, test your urine and listen to your baby’s heartbeat.
Learn what other tests and screenings you may need, such as tests to look for genetic problems with your baby.
Start taking a prenatal vitamin with at least 400 micrograms of folic acid to help your baby’s brain and spinal cord grow properly.
Ask your doctor what prescription and over-the-counter medicines you can still safely take.
Take a look at your diet and make any changes you need to make sure you and your baby get the right nutrition. Drink plenty of water.
Break bad habits like smoking and illegal drug use. Cut out alcohol and cut down on caffeine.
Keep up your workout routine, but listen to your body. You may need to change what kind of exercise you do, or ease up a little.
Research what it costs to have a baby and start making changes. Will you have to pay for child care? Will you cut back on work? Draw up a new budget that reflects the new addition.
Decide when and how you’ll share your news. You may want to wait until you’ve heard the baby’s heartbeat, or made it safely past the first trimester. It’s also smart to find out your company’s policies on maternity leave and learn your rights before you tell your boss.

Emergency Symptoms During the First Trimester

Any of these symptoms could be a sign that something is seriously wrong with your pregnancy. Don't wait for your prenatal visit to talk about it. Call your doctor right away if you experience:

Severe abdominal pain
Heavy bleeding
Severe dizziness
Rapid weight gain or too little weight gain

Health & Pregnancy Guide

Getting Pregnant
First Trimester
Second Trimester
Third Trimester
Labor and Delivery
Pregnancy Complications
All Guide Topics

What to Expect, Baby Development

Written by Stephanie Watson

Reviewed by Traci C. Johnson, MD on August 12, 2022

What Is the First Trimester of Pregnancy?

First Trimester Changes in Your Body

If your constipation is really bothering you, talk to your doctor about what mild laxative or stool softeners are safe to use during pregnancy.

Eat a few small meals throughout the day.
Don't lie down right after you eat.
Avoid greasy, spicy, and acidic foods (like citrus fruits).
Try raising your pillows when you sleep.

Baby’s Growth in the First Trimester

The fertilized egg becomes a cluster of rapidly dividing cells that implants in your uterus. The placenta, umbilical cord and amniotic sac all start to grow.
Your baby’s nervous system changes from an open neural tube to a brain and spinal cord. Nerves and muscles start working together. Your baby can move on its own, but it’s too soon for you to feel it.
The heart takes shape and begins to beat. You can hear it on ultrasound as early as week 6. It beats 120 to 160 times per minute. Red blood cells are forming.
Your baby develops a digestive system, including intestines and kidneys.
They have lungs and other major organs, but they’re not fully developed.
A soft skeleton is starting to grow.
Your baby starts to look like a baby, with arms, legs, fingers, and toes. Their face gets eyes, ears, a nose, and mouth. A tongue and tooth buds grow. Eyelids cover your baby’s eyes, and by the end of the trimester, they even have fingernails.
Genitals start to grow, but it’s too early to tell by ultrasound whether you’re having a girl or a boy.

By the end of the first trimester, your baby will be about 2 ½-3 inches long.

First Trimester To-Dos

Choose a doctor. Do you want an obstetrician or a midwife? Get referrals and find out what your health insurance covers.
Schedule a prenatal visit as soon as you know you’re pregnant. You’ll cover a lot of ground in the first appointment. The doctor will take a full medical history and talk to you about your lifestyle and health habits. They’ll figure out your due date. You’ll also have blood and urine tests and possibly a pelvic exam.
Continue with prenatal visits every 4 weeks. The doctor will check your weight and blood pressure, test your urine and listen to your baby’s heartbeat.
Learn what other tests and screenings you may need, such as tests to look for genetic problems with your baby.
Start taking a prenatal vitamin with at least 400 micrograms of folic acid to help your baby’s brain and spinal cord grow properly.
Ask your doctor what prescription and over-the-counter medicines you can still safely take.
Take a look at your diet and make any changes you need to make sure you and your baby get the right nutrition. Drink plenty of water.
Break bad habits like smoking and illegal drug use. Cut out alcohol and cut down on caffeine.
Keep up your workout routine, but listen to your body. You may need to change what kind of exercise you do, or ease up a little.
Research what it costs to have a baby and start making changes. Will you have to pay for child care? Will you cut back on work? Draw up a new budget that reflects the new addition.
Decide when and how you’ll share your news. You may want to wait until you’ve heard the baby’s heartbeat, or made it safely past the first trimester. It’s also smart to find out your company’s policies on maternity leave and learn your rights before you tell your boss.

Emergency Symptoms During the First Trimester

Any of these symptoms could be a sign that something is seriously wrong with your pregnancy. Don't wait for your prenatal visit to talk about it. Call your doctor right away if you experience:

Severe abdominal pain
Heavy bleeding
Severe dizziness
Rapid weight gain or too little weight gain

Health & Pregnancy Guide

Getting Pregnant
First Trimester
Second Trimester
Third Trimester
Labor and Delivery
Pregnancy Complications
All Guide Topics

1st trimester of pregnancy: what happens to the fetus

1st trimester of pregnancy: what happens to the fetus - Private maternity hospital Ekaterininskaya Clinics

1st trimester: 1st-12th weeks

The gestational age is calculated from the first day of the last menstruation, since it is difficult to determine the exact day of conception. Since conception usually occurs in the middle of the menstrual cycle, you are not actually pregnant during the first two weeks, but this period is counted as the beginning of pregnancy.

As soon as the fertilization of the egg takes place around the 3rd week, the hormones begin to produce changes in your body little by little. As a result, you may experience some of the following symptoms:

Morning sickness. As a result of rising levels of hormones characteristic of pregnancy, up to 80% of women in the 1st trimester experience morning sickness with symptoms such as nausea and vomiting. The idea that such malaise is observed only in the morning is a common misconception. In fact, symptoms can appear at any time of the day or night. Up to 1 in 5 women experience morning sickness in the 2nd trimester of pregnancy and can sometimes persist throughout pregnancy.
If you experience morning sickness, avoid foods that make you sick, eat little and often, avoid fatty and spicy foods, drink more water. If you experience severe symptoms or symptoms that bother you, see your doctor.
Breast changes. The mammary glands will begin to increase in size, soreness may appear. The nipples will increase in size, become darker and more protruding.
Fatigue. High levels of the hormone progesterone can make you feel tired and sleepy. Rest as often as possible in a horizontal position with your legs up and eat as well as possible, which is not easy if you are experiencing morning sickness!
Increased emotionality. A higher level of emotionality, manifested as a result of an increase in hormone levels, is normal. Understanding and patience on the part of your partner and loved ones is very important here.
Food likes and dislikes. You may find yourself intolerant of one food and addicted to another. This is usually not a problem, unless you feel like eating weird foods like chalk. If you are concerned about the situation, contact your doctor.
Frequent urination. As your fluid levels increase and your uterus puts pressure on your bladder, you will become more likely to visit the toilet. Go to the toilet as soon as you feel the need - this minimizes the pressure on the bladder.
Feeling of dizziness. Sometimes you may feel a little dizzy (this is due to hormonal changes). Try not to stay on your feet for a long time and slowly rise from a sitting or lying position. If you experience severe dizziness, contact your doctor immediately.
Heartburn and constipation. Your digestive system will slow down to give you more time to digest your food. This can lead to heartburn and constipation. To help manage heartburn, try to eat small meals at regular intervals and avoid fried or spicy foods and carbonated drinks. Constipation is helped by eating a diet rich in fiber, maintaining physical activity and drinking plenty of water.

1st trimester milestones

Approximately 7 days after fertilization, the embryo implants in the uterine wall. The placenta, umbilical cord and amniotic sac will begin to form to provide nourishment and protection to the embryo.
By the end of the first 12 weeks of pregnancy, the uterus is palpable through the wall of the abdomen, the abdomen will begin to grow.

Child development in the 1st trimester of pregnancy

By the end of the 1st trimester:

All the main organs of the baby are formed, the circulatory system works.
The development of the sexual organs has begun.
Fingers are formed on the hands and feet, nails have appeared.
Facial features have formed.
The length of the baby's body is about 6 cm from the head to the lower part of the body, he is already recognizable. The baby moves in the amniotic sac, but you don't feel it move yet.

Clinic mobile app

You can make an appointment with a doctor, get tests
and much more...

Fill out the form to make an appointment or order a call back

I agree with personal data processing policy and user agreement I also give my consent to the processing of personal data.

By continuing to use rd.clinic23.ru, you agree to the use of cookies. How to ban the use of certain cookies can be found in Politics

Pregnancy management, 1st trimester - basic studies.

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

Pathologies of fetal development;
Chronic medical conditions in the mother that may affect the course and outcome of pregnancy;
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.

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.

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.).

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?

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.

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 organism (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 of 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.

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.

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.

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.

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).

In addition, the fetal liver does not yet function as a detoxification 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 pregnancy - 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.

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.

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.

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 .