From what week does the second trimester of pregnancy begin? 13 weeks pregnant - what's going on
From what week does the second trimester of pregnancy begin? 13 weeks pregnant - what's going on

Video: From what week does the second trimester of pregnancy begin? 13 weeks pregnant - what's going on

Video: From what week does the second trimester of pregnancy begin? 13 weeks pregnant - what's going on
Video: Prunes Juice & Prunes Puree for Baby and Toddler Constipation - YouTube 2023, September

Pregnancy for every woman is like a long-awaited holiday that is about to happen. What could be better than pressing your own child to your chest, feeling its warmth with your whole body?! At the same time, the second trimester is considered the safest period of all trimesters. Most of the internal organs have already formed and during the remaining time they go through the development path, being enriched with useful trace elements that come with maternal blood. But what week does the second trimester of pregnancy begin? Many parents ask a similar question.

What week does the second trimester of pregnancy begin?
What week does the second trimester of pregnancy begin?

It should be noted that there is an obstetric period, where the term is counted a little differently, and therefore there are certain discrepancies. But bothall in order.

Obstetrical period

To begin with, it is worth clarifying what the obstetric week of pregnancy means. This will allow you to understand when the second trimester begins. Often, expectant mothers notice some disagreements: doctors at an appointment at a antenatal clinic mention one time frame, while an ultrasound scan shows completely different ones. This can confuse women and confuse them. Understanding this confusion is not difficult, the main thing is to understand a number of nuances.

First of all, it is worth considering that gynecologists operate with their own data, for example, the 13th obstetric week of pregnancy. And this period is usually two weeks earlier than the real period.

That is, as such, the actual pregnancy has not yet occurred. The fact is that, according to special gynecological ideas, the beginning of the obstetric period falls on the first day of the last menstruation before pregnancy. The entire period lasts until the expected date of birth (EDD).

Thus, the entire obstetric period is equal to 280 days, 40 weeks or 10 months (with 28 days in 1 month). That is, these weeks covers the process of maturation of the egg and its release on a long journey through the fallopian tube.

Embryonic period

Now we should move on to the consideration of this period. This is already the life span of a child, only at first in the status of an embryo, and then as a fetus. The entire period spans from 265 to 266 days, 38 weeks, 9 regular months.

From what week does the second trimester of pregnancy begin? With the help of ultrasound, the estimated period is determined depending on the size of the fetus. The data obtained are then compared withdevelopmental standards for embryonic (up to 12 weeks) and obstetric (after 12 weeks) terms.

Since a very tiny organism has individual characteristics (just like adults), the size of a child can be very different. That is, not only small children are born, but also real heroes! In other words, ultrasound does not allow you to determine the exact gestational age.

Ultrasound in the second trimester of pregnancy
Ultrasound in the second trimester of pregnancy

However, this does not mean that there is no point in conducting an ultrasound examination at all - it can be used to identify significant deviations from the norm. This usually indicates the development of various pathologies. In this regard, it is certainly not worth neglecting such a study!

The importance of the obstetric period

What exactly is the meaning of the obstetric week definition? Here it is worth turning to history: this period began to be calculated quite a few years ago, and then experts still did not have the slightest idea about such a phenomenon as ovulation, including the features of the course of pregnancy. It is now that even some mothers, due to their curiosity, can get the necessary information from available sources regarding the 13th obstetric week of pregnancy. Fortunately, nowadays there are no special problems with this.

At that distant time, every woman guessed her special status by the absence of menstruation, which should occur. It is for this reason that the period began to be counted from the moment of the last menstruation. There are a few more convincing arguments:

  • Not only that,that people did not have the slightest idea about ovulation, so ultrasonic scanners did not exist in nature. Therefore, the main factor is the absence of bleeding, which should be.
  • The body of each woman is purely individual, and therefore the range of the duration of the menstrual cycle varies between 21-35 days. This imposes certain difficulties with determining the day of release of the egg. Therefore, it is much easier to calculate based on the date of the last period.
  • Male sex cells can stay in the reproductive organ for 5 days. In this regard, even if a woman remembers the day of intimacy with a man, it is not a fact that it was then that conception occurred. Ovulation itself and fertilization could happen later.
  • As medical practice shows, the importance of obstetric weeks is undeniable! A lot of knowledge has been accumulated regarding the condition of the mother and her child. In the future, this allows you to identify any problems in a timely manner (for example, at 12-13 weeks of pregnancy) and, if necessary, take appropriate measures.

In addition, no doctor is able to accurately determine the day when ovulation occurred, and therefore, the conception was successful. Moreover, this is not given to women themselves! Of course, they can guess the day of a possible conception, but no one has complete certainty.

Start of second term

With the end of the first trimester, a woman can relax a little, because a calm period begins for her. Toxicosis, accompanied by her at the beginning of pregnancy, ended. The doctor who will lead the entireprocess to the end, already selected, also left behind the first medical examination. A woman can only enjoy the changes in her body.

Second trimester of pregnancy
Second trimester of pregnancy

The question of which week the second trimester of pregnancy begins is asked by almost every young girl who is preparing to become a mother for the first time. This period includes three calendar months or 14 obstetric weeks (we now know what it is). That is, this is the period from 4 to 6 months of the onset of pregnancy or from 14 to 26 weeks according to the gynecological period.

At the same time, many women begin to argue about when exactly you can feel the baby's movements. Only by listening to her friends, each mother should take into account that here everything is again individual and many factors influence this indicator.

For example, girls who are naturally overweight may feel fetal movements later, while thinner mothers feel the baby's presence earlier. Those women who are already expecting a second child, or even a third, fourth, feel the first movements of the fetus also earlier. As statistics show, this period comes with the onset of the interval from 16 to 20 weeks.

Women approaching the middle of the second term of pregnancy should purchase a birth bandage. His role is important:

  • Prevent stretch marks.
  • Save the pregnancy.

At the same time, the fetus itself at this time feels like a fish in the uterine cavity - nothing prevents it from swimming freely and giving pleasantfeeling to your mom.

Features of the II trimester

With the beginning of the second trimester of pregnancy, the emotional background of a woman stabilizes, unlike the initial period. Hormonal fluctuations are already in the past and the level of biological substances has leveled off. The impact of various external stimuli is no longer as strong as before.

Also, the second trimester is associated with other serious physiological changes occurring in the female body. The mother's abdomen is already largely rounded, the breasts are still full and enlarged, the uterus is preparing for the future delivery.

Fortunately, while the size of the abdomen in the second trimester of pregnancy does not interfere with household chores, but it is already clearly visible. This is a good reason to visit the store in order to choose maternity clothes.

pregnant at work
pregnant at work

Other changes worth noting:

  • Training bouts. At the end of the 20th week, the reproductive organ periodically comes into tone, and the woman may feel weak muscle contractions. This is called training contractions and thus the uterus prepares for the birth of the child in advance.
  • Iron deficiency anemia. This condition occurs due to the active development of the fetus and the increasing need of the body for micronutrients. Sometimes medication is prescribed. Only expectant mothers should not be "amateur": moderate anemia is a natural phenomenon. Losses of iron are replenished by foods that are rich in this element. Can be used during pregnancyunlimited.
  • Constipation. This is caused by the pressure the uterus puts on the intestines. The problem is solved by eating foods with a lot of fiber - vegetables, fruits, cereals.
  • Heartburn, that's another thing that happens at 13 weeks pregnant quite often. Moreover, having appeared, it can last until the very delivery.
  • Selections. Their number can be increased, but you should not worry ahead of time. If they have a whitish tint, and there is no itching, burning, or other unpleasant signs, then there is no cause for concern. Otherwise, seek immediate medical attention.
  • Puffiness. Usually, such a phenomenon appears in the third trimester, so the presence of such symptoms in the second term should already be alarming.
  • Skin pigmentation. It is also a common occurrence among pregnant women, which affects certain areas - usually the abdomen, face. You should not worry about this, because after the birth of the child everything will return to normal.

In addition, in order to provide the developing child with everything necessary, the mother's body begins to function intensively. This puts a strain on all systems.

Weight gain

What happens at 13 weeks pregnant or a little later in addition to the above? During the second trimester, expectant mothers are still actively gaining weight, as at the beginning of the term. Nutrition of a woman has a close relationship with the weight of the fetus. All this is due to quite obvious reasons - there is an increase in blood, which is necessary to provide nutrition to the baby. ATon average, many women put on 2-5 kg.

Weight gain during pregnancy
Weight gain during pregnancy

It is with the onset of the second term of pregnancy that the child requires an intensive diet due to its active growth and development. Previously, there was no such load. Therefore, it is clearly not worth limiting yourself to a future mother! Especially when it comes to not only tasty, but also he althy food.

You need to eat a balanced and varied diet, because the development of the child largely depends on this. However, here too the measure should be observed, but if the allowable weight limit is exceeded by 2-3 kg, it is worth arranging a fasting day for yourself.

Compliance with proper nutrition allows you to avoid intrauterine growth retardation, since the physical parameters of the fetus (height, weight, development of its internal organs and systems) are completely dependent on what exactly its mother consumes.

How to sleep during pregnancy in the second trimester?

Perhaps for those women or girls who are expecting a baby for the first time, it will be a surprise to learn that the usual posture during a night's rest will already become uncomfortable. If earlier it was possible to take any position, now you will have to change habits, having acquired a new one. The best option is lying on your side.

In this case, it is better to go to the left side, because, in this way, the possibility of clamping the inferior vena cava is excluded. This important vessel is located to the right of the spine and provides blood supply to the lower half of the body. That is, when positioned on the left side, the nutrition of the fetus will not be disturbed.


Before approximately 21 weeks of gestation, the size of the child hardly exceeds the dimensions of the average apple. However, with each subsequent week, he gains weight, and his height increases. The child begins to learn new skills and along with this, additional functions develop.

During the first trimester, the laying of internal organs and systems took place. That is, now in the fetus in the second trimester of pregnancy, they are already beginning to function independently. The urinary system begins to work. The baby takes the first breath and exhale, and surfactant begins to be produced in the lungs - a liquid medium for lubricating the inner surface of the respiratory organs.

Gastrointestinal tract is gradually preparing for food intake from the outside - for this, the baby swallows a liquid in which he actually swims in order to assimilate its necessary components. All this is processed in the intestines with the formation of meconium, which is stored until the birth of the child.

fetus in the second trimester of pregnancy
fetus in the second trimester of pregnancy

The small heart is one of the first to form (for obvious reasons). It experiences very frequent contractions (2 times faster), pumping up to 22 liters of blood. In addition, the brain is formed with the formation of convolutions. The pituitary gland is also connected, and the bladder, kidneys, and other organs continue to develop.

Significant changes affect not only the height of the child, but also his weight. In the second trimester of pregnancy (more precisely, towards its completion), the length of the fetus is about 250 mm, and the weight is from 850 to 1000 grams. For comparison: for period Itrimester, his weight was about 20 grams (he was still in the embryonic stage). As for growth, it did not exceed 70 mm in length.

Important changes in the baby

At a period of 4 months, this is almost a full-fledged person who is still at the stage of development. Inside the crumbs, all processes proceed rapidly! Key changes that occur in the second term of pregnancy:

  • The skeleton is strengthened, the bone structure is growing.
  • Development of the abdominal organs.
  • Renal excretion of urine.
  • The stomach, gallbladder, intestines begin to function.
  • Formation of the cerebral cortex.
  • The first production of hormones in the adrenal glands.
  • Completion of the formation of milk teeth.
  • Change body proportions.
  • Development of the gonads.
  • Growth of fingernails.
  • Inside the girl's body at 12-13 weeks of pregnancy, the laying of the uterus occurs, and the genitals are formed in future men.
  • Completion of the formation of facial muscles.

With the onset of 16 or 18 weeks of pregnancy, the formation of the auditory ossicles has already been completed, so that he can hear his mother. In addition, during this period, he leads a rather active lifestyle - often moves, changes position. Therefore, at this time, women can feel the movements of the child. By week 20, the fetus often opens its mouth, blinks, or even squints.

By the end of the second trimester, the mental abilities of the child are formed, and the entire cerebral cortex is already fully developed. The placenta has also completed its formation and now supplies the fetus with all the necessary “building materials”, including vital oxygen. But besides this, it provides him with protection from the harmful effects of various factors.

Pregnant diet

Now we already know what week the second trimester of pregnancy begins. The importance of proper nutrition is also clear to us - this is the key role of the entire period of bearing a child. In the second trimester, toxicosis goes away, and the appetite returns to the woman. This usually happens between the 14th and 16th week. So, it's time to learn how to make the right menu.

Diet of a pregnant woman
Diet of a pregnant woman

The body is already fully adapted to the new life inside it. Many pregnant women, rejoicing in new pleasant changes (in particular, the return of appetite), begin to eat "for two." However, this approach is fundamentally wrong, since everything needs a measure (this was also mentioned above).

The “golden mean” should be observed, that is, there is no need to impose strong restrictions, at the same time there is no need to lean on food. Neither overeating nor undereating leads to anything good. In addition, this has a detrimental effect not only on the female body, the baby also risks the possibility of intrauterine growth retardation.

The menu for the second trimester should include foods rich in beneficial micronutrients:

  • beef;
  • fish;
  • beef liver;
  • dairy and sour-milk products;
  • eggs;
  • porridge (buckwheat,rice, oatmeal, millet, barley);
  • vegetables;
  • fruit;
  • tomato juice.

When cooking, products must be subjected to heat treatment. An exception may be those that can be consumed raw. But in addition to proper nutrition, women should take care of supplying their bodies with additional trace elements in the form of multivitamin complexes. This will avoid the lack of "building materials" so necessary for the full development of the child.

But what vitamins in the second trimester of pregnancy should expectant mothers take? Such decisions can only be made by a doctor, taking into account the situation of the pregnant woman, and no one else in order to avoid serious complications. At the same time, drugs should be taken with a certain regularity.

Especially important during this period of pregnancy is the intake of vitamins A, C, E, D, including trace elements: calcium and magnesium. Folic acid is involved in the formation of the nervous system of the fetus, and also helps reduce the risk of developing hypertension.

What to avoid

As you can see, nutrition during the second trimester is the same as during the I or III period. And along with the permitted products of each expectant mother, it is necessary to remember what should be minimized, and what should be completely abandoned. We have already familiarized ourselves with what is possible in the second trimester of pregnancy and now it is worth touching on what should be abandoned.

First of all, it concerns spicy food, which is contraindicated during pregnancy. That is, various spices,including fried foods and foods with dyes, carcinogens are also banned.

Is it possible for pregnant women to have sweets
Is it possible for pregnant women to have sweets

The use of sweet and flour products should be minimized, and it is better to also exclude from the diet. The same applies to ketchups, mayonnaises, smoked meats and other similar delicacies. These products contribute to fluid retention in the body, and also provoke a sharp increase in blood sugar levels, which is undesirable for pregnant women. In addition, this is the main reason for gaining excess weight.

Research for the period of the second trimester

With the advent of the second trimester, the expectant mother will have to visit the antenatal clinic often. This is due to the need to control the development of the fetus, since various problems are identified precisely in the period from 15 to 25 weeks. The doctor conducts a visual examination, measures the volume of the abdomen and the height of the uterine fundus.

Planned ultrasound in the second trimester of pregnancy is carried out at 20-24 weeks, depending on the indications. The procedure is done traditionally - on a full bladder. In this case, the assessment of the condition of the child, including amniotic fluid, will be better. And if the problem is detected in a timely manner, the risk of complications is markedly reduced.

In order to monitor the condition of the mother and her child, the doctor usually prescribes a number of additional tests:

  • Complete urinalysis (OAM) - allows you to evaluate the functionality of the kidneys.
  • Complete blood count (CBC) - to determine the level of hemoglobin.
  • Gynecological or bacteriological smear - to assess the flora of the vagina.
  • Researchfor TORCH infections - carried out if necessary.

In addition, a “triple test” can be prescribed - hCG, estriol, alpha-fetoprotein. This comprehensive study allows you to identify the presence of malformations in the development of the child, chromosomal abnormalities, and also determine whether the brain is formed correctly by the back. As a rule, a triple test is prescribed for those women who have been diagnosed with a miscarriage in the past. The optimal time for such studies is from 16 to 18 weeks.

But what is dangerous in the second trimester of pregnancy? See the video below for possible complications.



The appearance of dizziness a pregnant woman should not be disturbed, as the phenomenon is normal, even in the second trimester. For obvious reasons, the body of a pregnant woman reacts with some delay, for which there are reasons:

  • Woman stays motionless for a long time.
  • In case of oxygen starvation of the brain due to impaired blood supply.
  • Attempts to rise sharply or change position.
  • Lower pressure.

This condition is usually classified as mild, so no special treatment is required.

Dizziness in the second trimester of pregnancy
Dizziness in the second trimester of pregnancy

But in some cases, when the head is spinning in the second trimester of pregnancy, contacting one of the specialists will help to cope with the problem. In this case, it all depends on the testimony:

  • hematologist - if the level of iron in the blood is verylow;
  • neurologist - in case of problems with blood vessels;
  • to an endocrinologist - if a malfunction of the thyroid gland is suspected;
  • oncologist - when tumors are detected.

And if the fact of pathology is detected, then the decision on the necessary course of treatment is made by a narrow-profile specialist with the support of the attending gynecologist. Here it is important to assess all possible risks, comparing the threat from taking medication to the fetus in relation to the severity of the condition of his mother.


The appearance of pain is often associated with an increase in the uterus, as well as its upward displacement. Usually in the second trimester of pregnancy, back pain, lower back or pain is localized in the pelvic area. This shouldn't be a cause for concern either.

But if pain is observed in the abdomen, accompanied by bloody discharge, in combination with lumbar discomfort, this is a possible sign of miscarriage. In this case, seek medical attention immediately.

Heartburn can also contribute to this, as the uterus puts pressure on the stomach. Drawing up a correct and balanced menu allows you to avoid its occurrence.


In conclusion, it remains to wish every expectant mother to carefully listen to herself and, at the slightest fear, seek medical help. Let it turn out to be a “false alarm” in the end, rather than overlook serious circumstances. The acquisition of a special status by a woman imposes certain obligations that must be strictlyobserve.

Quiet period for the expectant mother
Quiet period for the expectant mother

The result of such a difficult test will be a he althy and happy baby. Holding him close, mom already forgets about all the problems of the past - new successes and achievements are ahead!