Skip to content

Second trimester of pregnancy

Second trimester of pregnancy


The second trimester includes the 4th, 5th and 6th month of pregnancy and covers, respectively, from the 14th to the 26th obstetric week. 

What changes in body of mother in Second trimester?

The second trimester is called the golden period and even the “honeymoon” of expecting a baby. The expectant mother’s body reacts more calmly than before to its changes because its hormonal background is leveled. As a rule, now a woman has more strength and energy, her mood and well-being are better. 


This condition remains in the 1st trimester for many expectant mothers. If the morning and afternoon bouts of nausea do not leave you and even intensify, this is a reason for an urgent visit to the doctor. Toxicosis during pregnancy can be caused by an unhealthy diet, a Rhesus conflict between the mother and the child, anemia, and worsening of existing chronic illnesses.


The body retains water because, firstly, the placenta needs fluid, and secondly, it is necessary for various biochemical processes in the mother’s body and preparation for milk production.

Isolation of colostrum

Whitish-yellowish discharge from the nipples appears around the 5th month of waiting for the baby. There is no need to worry: this is colostrum, the “predecessor” of breast milk, which will begin to be produced with the birth of a child. 

Weight set: The approximate rate of weight gain in the Second trimester is 4.5–6 kg. The doctor calculates the individual rate for each expectant mother, considering her complexion, age, state of health and other parameters. 

Augmentation of the abdomen and breasts

The tummy of the expectant mother becomes noticeable starting from the 14-16th week. And the breasts continue to grow, although in some pregnant women, the bust does not change size throughout the entire waiting time for the baby (this is the norm or not, the doctor should establish). The abdomen and chest volume increase leads to stretch marks – pinkish or reddish stripes on the skin.

Frequent urination

The growing uterus puts pressure on the bladder, which provokes an increased urge to empty it. So, by the end of the second trimester, at 26–27 weeks, the size of the uterus is 25–28 cm. It affects the bladder of a pregnant woman. It changes her body’s hormonal background: an increase in the level of progesterone in the blood makes muscles and ligaments more elastic and relaxes them, including the muscles of the bladder’s walls, thereby increasing the excretion of urine. 


The contractions of the legs, arms, and neck muscles that cause discomfort are usually provoked by a deficiency of calcium, magnesium, and potassium in the woman’s body: the child actively consumes these trace elements, taking them from the mother. There may be other causes of seizures, such as varicose veins, so you need to find out the “culprit” of an unpleasant symptom with the doctor. 

Changes in the cardiovascular system

The volume of blood circulating in the expectant mother’s body increases by 20-30% so that the child receives oxygen, nutrients, vitamins and minerals promptly. A pregnant woman’s heart slightly changes its position due to the rise of the abdominal cavity and slightly increases in size as its load increases. 

Vaginal discharge

They have a milky white color and a slight smell, painless. Caused by hormonal changes. Safe for mom and baby, but you should consult a doctor to rule out thrush and other infectious diseases.  

Change in the state of the veins

The veins become more visible, and in the legs, there is a feeling of heaviness and burning. This condition is caused by increased blood volume and hormone progesterone levels, which weakens the venous valves and leads to the buildup of blood in the lower body. You will most likely need to consult a phlebologist: this specialist will recommend how to avoid varicose veins or stop its symptoms.

Feeling baby moving

In the second trimester, a long-awaited event happens: you begin to feel your child’s movements. In first-time mothers, the onset of labor typically happens around the 20th week of pregnancy. In contrast, labor usually begins around the 16th week or slightly later in mothers who have already given birth.

Baby at second trimester Ultrasound at second trimester
Baby at second trimester Ultrasound at second trimester

How baby develops during Second trimester?

By the beginning of the second trimester, the puffer looks like a little man, not only outwardly: its organs and systems are already almost formed, and the stage of its active growth and development begins.

4th month: The formation of the internal organs of the crumbs is completed. The baby has 20 milk teeth, and their kidneys, adrenal glands, nervous system, and endocrine system are all functioning.

The baby pees every 45-60 minutes, with the urine becoming part of the amniotic fluid. The placenta is fully formed and supplies the baby with vital resources, such as oxygen, nutrients, vitamins, and minerals. It also removes waste products and protects the baby from toxins and hazardous substances.

The baby’s skin is very thin, translucent and wrinkled due to the lack of subcutaneous fat. It is covered in a protective fluff called lanugo which helps retain fatty lubrication. This fluff will disappear when the baby is born or in the first weeks of life outside of the mother’s body.

The baby is moving gradually, bending their legs and arms, clenching their fists, squinting, and demonstrating grasping and sucking reflexes – though not all pregnant women, usually those who have been pregnant before, can feel these movements early. By the end of the month, the child reaches 16–20 cm in length and weighs 140–200 g. 

5th month: The baby’s fingers and toes with a unique pattern of prints are fully formed, hair, eyebrows, and cilia appear, while colorless and full-fledged nails appear. There are already the rudiments of permanent teeth (they are located above the milk teeth), the lungs develop, the intestines work (and the original feces appear – meconium), the pancreas secretes insulin, and the endocrine system prepares for the independent synthesis of hormones. 

The baby’s immune system gradually strengthens, producing its own interferon and immunoglobulin. The vestibular apparatus is formed. The ability to hear sounds and distinguish them from now on is also given to the baby by nature. The facial expressions and movements of the child become more complex and conscious, although his eyes are not yet able to see because of the protective film. 

The doctor can listen to the baby’s heartbeat with an obstetric stethoscope. A baby’s normal pulse is 120-160 beats per minute, and the expectant mother should feel at least 6 movements per hour, unless the baby is sleeping. At the end of the month, the child’s height is 20–25 cm (while the head remains large relative to body proportions), and the weight is 250–350 g.

6th month: For the baby, the time of active weight gain begins. 

The baby’s sleep and wakefulness pattern often does not match the mother’s, making it difficult for her to get enough sleep due to the baby’s nightly movements. The baby’s taste buds also appear, allowing him to distinguish between sweet, sour, salty and bitter. His bone marrow also begins to function, producing erythrocytes (red blood cells that carry hemoglobin to the baby’s organs and tissues) and leukocytes (white blood cells that protect the body from harmful microorganisms and toxins).

The baby begins to practice breathing movements and produces a surfactant in the lungs to prevent them from collapsing. The baby also starts making its own growth hormone, and the internal genital organs continue to develop. In girls, the ovaries move near the uterus, and the formation of the vagina begins, while in boys, the testicles move from the abdominal cavity to the scrotum. By the end of the month, the child is about 600–900 grams in weight and 30–34 centimeters in length. 

Second trimester with twins

Carrying multiple pregnancies is an increased burden on a woman’s body. 

  • A mother expecting twins typically feels the baby’s movements around the 15th or 16th week of pregnancy, although this may not happen until 18 or 20 weeks for a first-time mother.
  • When carrying twins, symptoms such as frequent urination, weight gain, constipation, anemia, shortness of breath, heartburn, pain in the back and joints, and swelling of the face, arms, and legs are more pronounced.
  • By the end of the second trimester, both babies reach about 35 cm in length and weigh about 800 g – 1 kg each.
  • In multiple pregnancies, premature birth is the norm. At 28 weeks, the twins are so viable that the babies can go out in the event of premature birth.

Medical examination Procedures for second trimester

  • An electrocardiogram may be performed in the second trimester if there are indications, to detect any heart disorders due to the increased load on the mother’s heart.
  • An ultrasound performed between 18-21 weeks of pregnancy can be used to evaluate the placenta, amniotic fluid, and baby’s development and determine its gender.
  • Screening, known as the triple test, is done between 18-21 weeks of pregnancy. It includes an ultrasound, a blood test for hCG, a blood test for alpha-fetoprotein (AFP), and a blood test for the content of the steroid hormone, free estriol. This screening test helps to detect the presence or absence of genetic abnormalities in the child.

What is analyzed during second trimester

  • A complete blood count (CBC) is taken regularly, with the most important indicators being the hemoglobin level, the number of leukocytes, platelets, and the erythrocyte sedimentation rate (ESR).
  • A biochemical blood test is taken regularly throughout pregnancy, with the most important indicators being sugar levels, bilirubin, creatinine and urea. At the 26th week, this test is mandatory to exclude or diagnose gestational diabetes in pregnant women.
  • A correlogram (taken every three months, with the most important indicator being the speed of blood clotting) is required.
  • An examination of amniotic fluid taken between the 14th and 20th weeks of pregnancy is conducted to detect any potential genetic abnormalities in the baby.
  • A general urinalysis is regularly performed, with the most important indicators being transparency, density, acidity, protein content, and the presence or absence of bacteria and yeast fungi.
  • A vaginal swab is regularly given three times during pregnancy to test for the presence or absence of infections, including sexually transmitted infections.

Difficulties during second trimester

The second trimester is generally a quieter time for the expectant mother in terms of concern for her well-being and the child’s health. But there are risk factors that you should be aware of and inform the doctor of the slightest alarming symptoms to cope with the situation.

Miscarriage: The second trimester accounts for 25% of spontaneous pregnancy termination cases (for comparison, in the 1st trimester, this figure is even more significant: 80%). Such miscarriages are referred to as late-term miscarriages, and their causes can include the following:

  • An unfavorable environment for the mother’s body (e.g., poor air quality, stress, trauma, bad habits, an infectious disease, etc.).
  • Unviability of the baby.
  • Premature opening of the cervix.

This issue is usually solved through surgery.

Non-developing pregnancy

According to statistics, only 1 out of 176-180 pregnancies ends in the second trimester with the cessation of the child’s development. The risk factors, in this case, are the mother’s bad habits, her physical and psycho-emotional overload, infectious diseases, hormonal or genetic failure, previous missed pregnancies, and age 35+. You can determine the pathology during an ultrasound scan. Its main symptoms are pulling pains in the lower abdomen, fever, weakness up to fainting, discharge of blood clots and the absence of baby movements if they were there before but stopped. 

Ectopic pregnancy

When implanting a fetal egg, not in the uterine tube but on its neck, pregnancy can continue until the 20th week. It is subject to termination, like other types of ectopic pregnancy, because it cannot be carried and poses a threat to the health and life of a woman, in particular, leading to infertility or removal of the uterus. It is detected using ultrasound and a blood test for the level of chorionic gonadotropin, the content of which is lower than during normal pregnancy. The symptoms are similar to those of an undeveloped pregnancy. 

Increased tone of the uterus

Hypertonicity of the uterus is tension and involuntary contractions of its muscular walls. This condition is dangerous because uterine contractions lead to miscarriage. It is possible to detect an increased uterus tone on ultrasound and when examined by a gynecologist. Pathology is provoked by stress and overload, infectious diseases and inflammatory processes carried by the mother, as well as her bad habits and unbalanced nutrition. It is treated with medication. 


Excess or deficiency of amniotic fluid can be detrimental to the baby, leading to possible miscarriage, difficulties in intrauterine development, and complicated childbirth. The causes of oligohydramnios are the pathology of the development of the child’s kidneys, high blood pressure, bacterial infections, metabolic disorders in the expectant mother, and a deficiency of amniotic fluid is inherent in multiple pregnancies. 

Genetic abnormalities

Genetic abnormalities can trigger Polyhydramnios, anemia of the baby, infection or exfoliation of the placenta, bad habits, cardiovascular, endocrine (including diabetes), urinary diseases of the expectant mother, a conflict of Rh factors between mother and child, multiple pregnancies. It is diagnosed on ultrasound and when examined by a gynecologist. Under the supervision of doctors with these pathologies, the chances of enduring and giving birth to a healthy baby are high. 

Premature birth

They can occur from the 22nd week to the 37th week, while the births that occur at the 22–28th week have an extremely unfavorable prognosis. Early labor symptoms are the same as ordinary ones: painful contractions, spotting, and stool disorder. Unbalanced nutrition and bad habits of a woman, infections of her urinary tract, the experience of previous premature births or abortions, multiple pregnancies, anemia, severe stress, anomalies in the structure of the uterus and other reasons can provoke premature birth. 

Do’s and don’ts of Second trimester of pregnancy

Do’s of Second trimester 

  • To refuse bad habits.
  • Get enough sleep (norm – 8-9 hours sleep).
  • Switch to regular but light fitness training: jogging, Nordic walking and regular walking, yoga for pregnant women, swimming and water aerobics.
  • Wear a bandage from the 24th week to reduce the load on the spine, avoid the appearance of stretch marks and reduce the pressure on the abdominal organs from the growing uterus.
  • Observe the “rule of clean hands” to prevent infectious diseases.
  • Avoid overwork and stress.
  • Take multivitamins and supplements only as directed by your doctor.
  • Eat regularly and properly.
  • Return to sexual activity if the doctor sees no contraindications for this (it is important to choose positions safe for a growing tummy).
  • Fly again if there are no contraindications.
  • Take a course in massage, discussing this decision with your doctor in advance. 

Don’ts of Second trimester 

  • Take any medications without the doctor’s approval.
  • Give yourself intense exercise.
  • Lack of sleep.
  • Be constantly under stress.
  • Ignore your diet.
  • Lift weights over 3 kg.
  • Wear uncomfortable, tight clothing, underwear and shoes, as these things impair blood circulation.
  • Undergo x-rays.
  • Visit the Finnish sauna (since the air is dry).

Nutrition during second trimester

In the second trimester, compared with the 1st, the daily calorie intake of the expectant mother increases by no more than 500 kcal and averages 2,800 kcal. During this period, doctors recommend switching to 5-6 meals a day, even if you adhered to 3 meals a day before pregnancy and in the 1st trimester. 

In general, the principles of nutrition remain the same as in the 1–13th week of pregnancy:

  • Fruits, berries, nuts except for peanuts, vegetables and herbs, dairy products, eggs, lean meat, fish and poultry, cereals, whole grains, butter and vegetable oil – the basis of the diet.
  • Fruits and whole grains are good for breakfast, animal and vegetable protein (fish, meat, poultry, legumes) is better to eat for lunch, and leave fermented milk products and vegetables for dinner.
  • Recommended volume of 1 serving – 200 ml.
  • Any changes in diet, allergic reactions, heartburn, constipation, diarrhea and bloating should be discussed with a doctor.
  • Fast and junk food is banned (products with dyes, preservatives, high sugar content, trans fats, etc.), an abundance of pastries, carbonated drinks, sweetened juices, strong tea and coffee, mushrooms, sausages, curd cheese, mayonnaise, ketchup, fatty, fried, smoked, spicy (including spices), marinated.

What vitamins are needed in second trimester

Nutrition experts call the 2nd trimester of pregnancy the time of minerals since the expectant mother and her baby especially need these microelements during this period. However, you can’t do without vitamins either. 

Iodine: important for the normal functioning of the mother’s thyroid gland, metabolism and prevention of immune disorders in the baby, and the full mental and physical development of the unborn child.

Calcium: indispensable for the formation of the skeleton, the nervous, genitourinary and endocrine systems, the prevention of rickets in a child, replenishment of calcium losses in the body of a future mother.

Iron: Iron is essential for producing red blood cells, preventing iron deficiency anemia, and increasing uterine blood flow in pregnant women to improve placental perfusion and protect the baby from hypoxia.

Zinc helps to avoid malformations in the baby, is underweight in newborns, and positively affects the immune system and the condition of the expectant mother’s skin, hair and nails. 

Folic acid (vitamin B9): reduces the risk of congenital malformations of the nervous and cardiovascular systems of the child, as well as the risk of miscarriage, and improves iron absorption.

Vitamin D: necessary for the formation of bone tissue and the prevention of rickets in a child.

Vitamin C: strengthens the immune system and the walls of the expectant mother’s blood vessels and improves iron absorption.

Remember to consult with your doctor when choosing a multivitamin complex. 

Fitness in second trimester

The second trimester is considered an ideal period for the physical activity of expectant mothers, as their health, as a rule, improves compared to the 1st trimester. In addition, moderate physical activity in this trimester prevents varicose veins, uterine hypertonicity, back pain, the expectant mother’s cardiovascular problems and the baby’s hypoxia. And it is also a guarantee of an excellent mood for you and the baby. We remind you that you must practice smoothly, without shortness of breath, with a pulse of no more than 120 beats per minute. And be sure to coordinate your type and training regimen with your doctor. Stop exercising (change to another load) if they worsen your well-being. 

Common diseases of expectant mothers 

The 2nd trimester is when a woman’s body has adapted to its new state. But, unfortunately, not all difficulties are left behind: new ones are added to the diseases that could disturb the 1st trimester. If something in your well-being does not suit you, do not postpone a visit to the doctor!

The most common diseases of expectant mothers in the second trimester of pregnancy are as follows:

  • Hypertension. An alarming symptom is considered to be blood pressure in pregnant women exceeding 130/80 mm Hg. Art. Increased pressure worsens the future mother’s well-being and leads to complications in bearing a child, as the blood supply to the placenta suffers. In the 2nd trimester, elevated blood pressure can provoke preterm labor. The causes of hypertension in pregnant women are varied. Among the main ones are changes in hormonal levels, an increase in circulating blood volume, and chronic hypertension (when the mother has the disease even before the conception of the child).

Prevention: a balanced diet, regular moderate physical activity, and taking vasoconstrictor drugs as prescribed by a doctor.

  • Gestational diabetes mellitus . Violation of carbohydrate metabolism is diagnosed in 4% of pregnant women. The disease develops due to a decrease in the sensitivity of the expectant mother’s body to her insulin, provoked by hormonal changes. In addition, the increased insulin production by the mother’s body is due to the child’s needs and the placenta for glucose. A woman’s diabetes, in the absence of corrective therapy, negatively affects the development of her baby: he gains excess weight, the development of defects in the respiratory, cardiovascular and nervous systems is possible, and miscarriage is likely at an earlier date. Under the supervision of doctors, the risk to the health of the mother and baby is minimal.

Prevention: daily control of blood sugar levels (up to 5.1 mmol / l on an empty stomach); body weight control; a balanced diet with a minimum of easily digestible carbohydrates; compliance with the drinking regime; moderate physical activity.

Checklist second trimester

  1. Complete scheduled examinations and tests.
  2. Read literature for mothers.
  3. Enroll in the school of future parents, inviting the baby’s dad to keep you company.
  4. Visit the dentist (tell us which week of pregnancy you are in).
  5. Make large purchases for the child: choose a car seat, stroller, crib, baby chest of drawers or changing table, bathtub, or sling.
  6. Buy a few things (tunics, dresses, trousers, etc.) in the clothing departments for expectant mothers in which your body will be comfortable until the very end of pregnancy.
  7. Try sleeping on your left side to improve blood flow to the placenta. It is generally safe for pregnant women to sleep on their stomach until 10-12 weeks of pregnancy and on their back until 16 weeks.
  8. Use a moisturizer or special cream daily to protect the skin of the chest and abdomen from stretch marks or minimize their severity
  9. Create a playlist for your little one to listen to while doing household chores or to relax. 
  10. Switch to natural home cleaning products (vinegar, soda, citric acid, mustard powder, etc.) or gentle household chemicals.
  11. Visit your hairdresser and consider dyeing your hair, though many mothers prefer to wait until after the baby is born to use hair dye.
  12. If it is safe to do so, take a short trip with your doctor’s approval: for instance, enjoy a relaxing stay at a maternity resort, visit family members, or explore the nearby area on a weekend getaway.

3 tips for pregnant mothers in second trimester

Buy a maternity bra: Look for a maternity bra that is specifically designed for expectant mothers, as it can help keep the shape of your breasts and prevent stretch marks. Purchase nursing pads with a sufficient supply, as they will be beneficial during the period of waiting for the baby to consume colostrum and while breastfeeding to protect clothing from milk leakage.

Start preventing varicose veins: To help the veins cope with the increased load caused by an increase in the body weight and blood volume of the expectant mother, you can use compression underwear (stockings, tights, stockings that improve blood circulation), the habit of resting lying down with a pillow placed under your feet (this causes the outflow of “excess” blood from the lower part of the body), walking daily walks and avoiding tight clothes and shoes. 

Take a massage course: If your doctor has no objections, make an appointment with a massage therapist. The skillful hands of a specialist will help relieve pain and tension in the body, and improve skin condition, emotional background and sleep. 

3 tips for a dad to be in second trimester

Attend parents-to-be’s school together: Courses for expectant mothers are also useful for dads. Here they talk about preparing for childbirth, the rules for caring for a baby, the sexual life of a couple during pregnancy and after it, the features of nutrition and the daily routine of a pregnant and lactating mother, and much more. Not only will you learn many important things and valuable skills, but you will most likely make new friends among couples who, like you, are expecting a baby.

Talk to the baby: At around the 16th week of pregnancy, the baby in the mother’s stomach can start to hear. By the 26th-27th week, it can start to react to what it hears, such as calming down or moving more actively. Neonatologists and psychologists agree that a baby who has heard their father’s voice before they are born will recognize and trust him more than anyone else. 

Arrange a holiday for the expectant mother: In the 2nd trimester, at the 20th week, the middle of pregnancy falls. Congratulate to your beloved on passing the halfway mark to meeting your baby! Why not throw her a celebratory event – a romantic dinner for two or a fun gathering with family and friends? By the way, there is nothing shameful in suggesting to guests what kind of things for a child will be very useful as gifts.