From what week does the trimester of pregnancy begin?

Often, in future mothers, when calculating the period of pregnancy there is confusion, especially when it comes to trimester. Under this time interval it is customary to understand 3 calendar months. However, most often the duration of gestation is considered in the so-called obstetric months. The last of the calendar is different in that it lasts exactly 4 weeks. Let's take a closer look at the features of calculating the term and give an answer to the question as to which week begins the trimester of pregnancy, which precedes the birth.

How long does the gestation period last?

Before you name the time when the 3 trimester of pregnancy begins, consider the entire gestation process for weeks.

So, according to the obstetric term, the entire pregnancy normally lasts 280 days. In this case, the starting point for the beginning of the count of this time interval is the last day of the last menstruation. For more convenience and accuracy of counting, midwives usually divide the entire pregnancy into trimesters.

The first trimester, or as it is also called early fetal, begins directly from conception and lasts until the 13th week of pregnancy. At this time, the implantation of the fetal egg in the endometrium occurs, which, in fact, indicates the onset of pregnancy. The period itself is characterized, first of all, by the formation of axial organs and systems of the future baby.

The second trimester starts from the 14th week and ends at 27. It is characterized by the maturation and growth of the organs already formed.

If we talk about how many weeks begins 3 trimester, then this is 28 weeks of gestation. This time period is characterized by a significant increase in the already formed child. He ends with childbirth, which is normally observed at the 40th week of the gestational process.

What changes are observed in the 3 trimester of pregnancy in mother and baby?

Having dealt with when, or rather, in how many weeks begins the 3rd trimester of pregnancy, we will give a brief description of this time period.

Every day the child grows, which leads to an increase in the height of the standing of the bottom of the uterus. So, for example, this parameter is 29-30 cm at week 28, and 37 cm at 36 weeks. That's why the expectant mother often becomes difficult to breathe, develops dyspnea, which increases after exercise, for example - after climbing the stairs.

Also, we can not say about training battles, which are now marked more often (can be fixed up to 10 times a day). At the same time, a woman should know exactly how to properly distinguish them from generic ones. there is always the possibility of premature birth.

As for the baby himself, at that time all systems and organs are formed, and are actively functioning. An exception, perhaps, is only the respiratory system, which begins to work with the appearance of the baby in the light.

Lungs are not in a straightened state before birth. For this to happen, starting from week 20, a substance such as a surfactant begins to be synthesized, which prevents the alveolus from falling off. It is worth noting that this system matures only by the 36th week of gestation. Therefore, the appearance of a baby in the light earlier than this period may be accompanied by a malfunction of the respiratory system.

Thus, as can be seen from the article, the 3 trimester of pregnancy is no less responsible than the previous two. At this time, the expectant mother must actively prepare for the forthcoming generic process and strictly follow the doctor's instructions. If a woman noticed something strange, there was pain in the lower abdomen, - it is necessary to inform the doctor about this.