Mar 13, 2020

Pregnancy Trimesters: All You Need to Know

The typical pregnancy has three trimesters and lasts around 40 weeks from the first day of a woman’s last menstrual period. In each pregnancy trimester, the fetus will meet specific developmental milestones. Infants delivered before the end of week 37 are considered premature and may have certain complications in the long term with their growth and development, as well as difficulties in breathing and digesting.


First trimester (1 to 12 Weeks)

The first trimester in pregnancy is the most crucial to the baby’s development. During this period, the baby’s body structure and organ systems develop. Most miscarriages and birth defects also occur during this period. Therefore, it is advised to be extra cautious during the first trimester in pregnancy.

Fetal Development

Considered to be the most dramatic phase during pregnancy, the first trimester in pregnancy onsets fetal changes. During the first eight weeks, the fetus, called an embryo, develops constantly and by the end of the first trimester, it is a fully developed fetus. The embryo by the end of the first trimester may measure up to 3 to 4 inches in length.

Physical Changes

During the first trimester of pregnancy, women’s body undergoes major changes and these changes often cause a variety of symptoms. Some of the first trimester symptoms are as follows:

  • Tender and swollen breasts
  • Nausea with or without vomiting
  • Fatigue
  • Frequent urination
  • Food cravings or aversions

Psychological Changes

The first trimester in pregnancy may often cause unexplainable mood swings. A pregnant woman may feel delighted, anxious and exhausted, all at once. However, if the emotional fluctuation disturbs the day-to-day functioning, one may consult the general physician or a gynecologist.

Second trimester (13 to 27 Weeks)

The second trimester in pregnancy is typically considered the most comfortable period of time for the majority of pregnant women.

Fetal Development

In the second trimester of pregnancy, the fetus will multiply more than seven times. The fetal development in the second trimester will include the following:

  • The fetus will start kicking, moving, and will start turning from side to side.
  • The fetus will start hearing the mother’s voice.
  • It will develop reflexes, like swallowing and sucking.
  • The fetus can respond to certain stimuli.
  • The placenta will be fully developed.
  • The fingerprints and toeprints will be formed.
  • The fetus will go through cycles of sleep and wakefulness.

The second trimester in pregnancy is when most women can feel their baby move for the first time, usually by 20 weeks.

Physical Changes

During the second trimester, the women experiences decreased nausea, better sleep patterns, and an increased energy level. However, a whole new set of second-trimester symptoms, such as back pain, abdominal pain, leg cramps, constipation, and heartburn may appear.

Psychological Changes

 Expectant mothers may expect some relief in the symptoms of the second trimester. The mood swings aren’t that frequent, but fetal movements may make pregnant women feel overwhelmed. Emotional dependency on the partner may also increase. Some women may even experience an increased libido in their second semester.

Third trimester (28 to 40 Weeks)

The third trimester in pregnancy is the final stage of pregnancy.Pregnancy trimester

Fetal Development

Most of the organs and bodily systems fully formed during the third trimester of pregnancy. However, the fetus continues to grow and mature. Fetus may also suck its thumb and cry. By the time of delivery, the head may turn downward, but that may vary from case to case. The lungs at the beginning of the trimesters are not fully developed, but by the time of delivery, the lungs are developed.

Physical Development

Some of the physical symptoms during this period include shortness of breath, hemorrhoids, urinary incontinence, varicose veins, and sleeping problems. Many of these third-trimester symptoms arise from the increase in the size of the uterus.

Psychological Changes

The onset of the third trimester in pregnancy may often mark with mild forgetfulness. As the due date approaches, anxiety may increase about the childbirth and the arrival of the baby. In the third trimester, some women may feel enthusiastic and positive about childbirth while others may feel irritable which is a common symptom in the third trimester. Feelings of fatigue and uncomfortable is common amongst many women.

During different trimesters of pregnancy, the changes, symptoms may vary in each woman. It is important that expecting mothers are regularly consulting gynecologists.

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