In the world of pregnancy, the term trimester is certainly no stranger to mothers. In simple terms, trimester refers to the period or stages of fetal development during pregnancy. From the moment mom is declared pregnant, the fetus in the womb will grow and develop for approximately 40 weeks. So that mom understands better and is ready to face every stage of the trimester in pregnancy, let's see the full explanation in the article below.

Distribution of Pregnancy Trimesters 

Generally, gestational age lasts for 40 weeks divided into three trimesters. Each trimester has different phases, namely the first trimester, second trimester, and third trimester.

• In the first trimester, the age of the fetus ranges from 1-13 weeks.
• In the second trimester, the fetal age ranges from 14-27 weeks.
• In the third trimester, the fetal age ranges from 28-40 weeks.

First Trimester

In this phase, generally pregnant women will experience morning sickness or recurrent nausea which is a common symptom. Don't worry if you don't realize you are pregnant, because in the early stages of pregnancy many women experience something similar. If you don't experience menstruation for a week after having sexual intercourse, you can do a pregnancy test or consult with your obstetrician to confirm your condition.

Second Trimester

The second trimester of pregnancy, which lasts from 14 to 27 weeks, marks an important stage in fetal development. Vital organs such as the heart, lungs, kidneys and brain have started to form properly. At this time, the fetus is also getting bigger and starting to move with small movements. In addition, small hairs begin to grow. As for pregnant women, the symptoms that appear in the first trimester begin to decrease in the second trimester, providing a little comfort for the mother.

Third Trimester

Changes in pregnant women in the third trimester feel tired and uncomfortable considering the growing size of the stomach. In this trimester, the fetus is also considered mature enough. Mental changes are also experienced by pregnant women because it is getting closer to the time of delivery.

The development of the baby in this phase is quite perfect. The bones have completely formed. At 36 weeks, the baby's head should be facing down in preparation for labor. If at a sufficient gestational age, the head position does not move, the doctor will perform a cesarean delivery.

How to Calculate Pregnancy Trimester

There are three ways that can be used to calculate the trimester of pregnancy, namely by referring to the First Day of Last Menstruation (LMP), knowing the date of ovulation, or through an ultrasound examination (USG).

• First Day of Last Menstruation (HPHT)
  To easily calculate the trimester of pregnancy, one way that can be done is to use the HPHT calculation method. This method is very effective for pregnant women who have regular menstrual cycles. The method is quite simple, namely by knowing the date of your first and last menstruation, then calculating the gestational age from those dates.
  
  Fertilization usually occurs about 11 to 21 days after the first day of the last menstrual period. By knowing the date of the HPHT, you can also estimate the expected day of birth (HPL) by adding 40 weeks from the date of the HPHT.
  
  
• Ovulation Date
  Knowing when ovulation occurs can help calculate gestational age more accurately. Ovulation itself occurs when an egg is released from the ovary and into the fallopian tube during the menstrual cycle. Usually, ovulation occurs on the 12th to 14th day before the next scheduled menstruation and can be marked by increased cervical mucus discharge. However, not all women can easily recognize the signs of ovulation.
  
  
• Ultrasound examination (USG)
  Estimating gestational age is important for pregnant women to know the development of the fetus. One accurate way to find out the trimester of pregnancy is through an ultrasound examination. This examination is generally carried out between the 8th and 18th week of pregnancy. Even so, many pregnant women do ultrasound examinations from the age of their womb reaching 5-6 weeks.
  
  In the first trimester, an ultrasound examination will focus on measuring the baby's length from head to toe. Meanwhile, in the third trimester, an ultrasound examination will focus on measuring certain body parts to monitor fetal growth.

Knowing the stages of the trimesters of pregnancy is very important to ensure the success of the pregnancy process until delivery. Therefore, don't forget to fulfill this obligation so that everything goes smoothly, mom!

References:

https://usgmajalengka.com/artikel/usg/kehamilan/trimester-adalah/

https://bocahindonesia.com/trimester-kehamilan/