Understand Pregnancy week by week

Understand Pregnancy week by week

Pregnancy is an all-natural process, which hits women after puberty. There is plenty of information about you, which can help you understand the pregnancy as a whole process. However, for some people, it takes more time to understand it.

Pregnancy is a developmental stage of life where the body is working on the creation of a new life. The baby grows inside the mother’s womb and passes a complete process, which ensures its organ development.

The typical duration of pregnancy is 40 weeks. This countdown starts from the first day of the mother’s last menstrual period till the delivery of the baby. There are many categorizations of it, which are to understand each phase at best.

Stages of Pregnancy

Usually, pregnancy has three phases. These are called trimesters. So it means 40 weeks are divided into three trimesters called first, second and third trimester. Any time before the 12th week of a healthy pregnancy is the first trimester.

The second trimester starts after the first. Typically it is the time between 13th to 27th weeks. Third and last trimester begins from 28th week and lasts till delivery. This article will explain how each of these trimester marks significant changes in mother and the growing baby.

RELATED: Earliest Signs of Pregnancy

First trimester of the Pregnancy

The first time in pregnancy is the first trimester. It is the time when conception takes place. The earliest sign of it is a missed period. Many of the women may notice it after it. There are no other most initial signs to tell the pregnancy except internal tests.

Physical changes to notice in the first trimester of pregnancy

It is the high time for hormones to take action. The visible signs, which you may feel at the first trimester, are any of the following.

  • Tiredness and fatigue
  • Swollen breast
  • Nausea
  • Food cravings
  • Extreme mood swings
  • Excessive urination
  • Fluctuating weight

All these changes are not necessary to occur at a time. You may feel any one or a few of these. Not every woman feels the same during earliest days of pregnancy. The daily routine seems to be affected the most in this phase.

You may feel like resting all day. The food intake will be increased or decreased. The cravings will be increased. You may also contact some discomfort like heartburn, dizziness, etc.

This information may not be accurate for all pregnant women. Each pregnancy is different in a way that each is different too. Not all women will feel the same way. So what you feel is more related to your personal choices, lifestyle and daily routine.

RELATED; One-Month Pregnancy- Everything You Need To Know

Development of baby in the first trimester of pregnancy

  • Four-week pregnancy

At the start of the first trimester, the baby would be of four weeks age. There are a few things, which you would like to know at this stage.

In the first trimester, the nervous system that includes brain and spinal cord start to form. Among all major organs, it is the first one, which starts developing in the first stage of pregnancy.

Next is to know that your baby is slowly growing a heart. The limbs also start to differentiate, and the baby at this stage is called an embryo. It would be only 1/25th of one inch long. Very tiny, yet developing.

  • Eight-week pregnancy

Next stop is when the baby turns eight weeks old. When at eight week age, the baby is no more an embryo instead it is called a fetus. At this stage, almost all of his vital body organs are developed.

The amazing thing is that the heart of fetus starts to beat. Limbs grow in size, even the fingers and toes are formed. The sexual organs began to develop, but they aren’t entirely developed at this stage.

By the end of week eight, the umbilical cord is visible in body scans. The overall size of fetus here is one inch. But it is even less than half ounce weight here.

  • Twelve-week pregnancy

The first trimester ends at week twelve. This time is one stage mark of the baby’s growth because he has completed one out of three phases of the development.

You will be amazed to know that by this time, you can even check the sex of your baby as the sex organs are entirely developed. The development takes a complete shift by the development of eyelids. At week twelve, the fetus becomes 3 inches long, and its weight is less than or equal to one ounce.

RELATED: Missed Period – what can be the possible reasons other than pregnancy?

Second trimester of the Pregnancy

Week 13 is when the second phase of pregnancy starts. At this stage, all the vital organs of the baby are already developed. Here the development is more rapid. By the end of the second trimester, almost half of the baby’s development is completed.

Physical changes to notice in the second trimester of pregnancy

The second trimester of pregnancy is more comfortable than the first trimester for many of the women. Most of the discomforting signs of pregnancy vanish at this stage. For example, the morning sickness or nausea is no more a thing, and you don’t feel fatigue.

Physical changes in a woman’s body are more evident at this level. The most common of them is the appearance of a baby bump. The baby bump is the expansion of abdomen, which is when womb carries the baby in it.

It is tiny at the start but grows enormously big by the end of the second trimester. The development will be so much that the movements of the baby will be felt by the mother.

The early discomfort of the pregnancy will change into a different type of physical sensations. For example, you will feel the load on back and thighs. You may feel it be painful. Due to body’s expansion, it is more likely to notice stretch marks on your body.

Nipples will become dark, and a clear line from belly button to pubes will start to show. It is called linea nigra, and it is one of the apparent signs of the pregnancy. Some women also feel dark skin patches which is a skin condition called melasma or chloasma facies.

Numbness, itching, and swelling of limbs are common here. However, if you feel something is consistently hitting you, you must talk to your doctor about it.

RELATED: Can you Workout During Pregnancy?

Development of baby in the second trimester of pregnancy

The physical changes in pregnant woman’s body are an indication that the baby is going through a rapid development. From the appearance of a small baby bump to feel the baby’s movement, each week shows one level of this growth.

  • Sixteen-week pregnancy

At this level, the baby starts to develop muscles and skeleton. The skin predominantly forms and completes by the end of it. The intestines of the baby grow meconium, which completes its digestive system.

By the end of 16th week, the baby begins to do the sucking movement. Its size is 4-6 inches long and the weight ranges to 3-4 ounces.

  • Twenty-week pregnancy

at the 20th week of the second trimester, the growth of the baby is in bloom. He is active and shows his response, i.e., kicking or changing side. The eyelashes, eyebrows, and nails like tiny body parts also start to form which complete by the end of this week.

At this stage, the baby can hear you. It’s a midway during pregnancy and the baby is now 6-7 inches long and up to 9-ounce weight.

  • Twenty-four-week pregnancy

At the 24th week, the changes are even more obvious in baby’s development. The body’s bone marrow starts generating blood cells. Minute things like fingerprints, taste buds develop. The baby grows his hair at this stage.

The sleep cycle of the baby is adjusted at this developmental level. The sexual organs are completed and the baby starts growing mass. The average length at week 24th is 12 inches and weight is nearly 1.5 to 2 pounds.

Third trimester of the Pregnancy

The third trimester is the last stage of the baby’s development during pregnancy. The baby’s growth takes the final turn at this level. It continues till the delivery. The healthy pregnancy takes 40 weeks of development but sometimes it is one week early or late.

Physical changes to notice in the third trimester of pregnancy

Here comes the final level of pregnancy when the baby gains size and weight. It becomes sometimes difficult for the mother to tolerate it as the growing baby puts so much pressure on the internal organs of the mother.

Finding difficulty in breathing, walking or move is common in the third trimester. The urge to urinate is even more frequent. However, all of these go away with time, and eventually, they end when you deliver the baby.

Some common changes a pregnant woman feels is swelling on her face, ankles, fingers, hands, etc. She may suffer from hemorrhoids, which are not common, but they do occur. The belly button of the mother become protrudes and her breasts grow tenderer.

The breasts may sometimes excrete watery liquid, which is a pre-milk. It is called colostrum and it is common to have it. The movements of the baby are faster. Contractions may also start hitting you.

As you get closer to your delivery due date, the body goes through some profound changes. The cervix of the mother becomes soft and thin which helps her for giving birth. When the due date is as close as 2-4 weeks, the doctor will suggest a regular checkup every few days.

RELATED; Early Age Pregnancy- Complications And How To Avoid Them

Development of baby in the third trimester of pregnancy

  • Thirty-two-week pregnancy

The development of the baby at 32nd week is at peak. The bones are entirely formed and the movements are rapid. The baby is even able to move, open and close his eyes.The breathing occurs but as the lungs are not entirely formed, it is just an exercise of breathing. The body of the baby starts producing vital nutrients. The baby gains weight and becomes 4-4.5 pound at this level. The size is 15-17 inches long at week 32.

  • Thirty-six-week pregnancy

It is the high time when the due date is near. The protective coating of the baby thickens, body fat and weight also increase. The size increases, so the baby’s movements are restricted as there is less space to move. By the end of the 32nd week, the baby becomes 6-6.5 pound of weight and 16-20 inches long.

  • Thirty-seven to forty week pregnancy

It is the last stage of the baby’s development. Consider this time as the final time before delivery. All organs start functioning at this stage. As the due date approaches, the baby changes its position, suitable for the delivery.

RELATED: Hair fall in Pregnancy

It is common to have the final weight of the baby between 6 to 9 pounds. The average length of the baby is between 19-21 inches. However, it may be slightly variable. As the contractions start taking rapid action and the water breaks, it is the indication that it is the time of delivery.

Your doctor will explain you to make preparations for the delivery. You may need to pack a bag for the necessary things so that you can rush to the hospital as soon as possible. If you prefer a natural birth at home, make sure that you have complete information, guideline and someone to assist you.



  • https://www.pregnancy.com/
  • https://www.webmd.com/baby/default.htm
  • www.parents.com/pregnancy/stages/
  • https://www.womenshealth.gov/pregnancy/youre-pregnant-now…/stages-pregnancy
  • https://my.clevelandclinic.org/health/articles/fetal-development-stages-of-growth

The author is a Medical Microbiologist and healthcare writer. She is a post-graduate of Medical Microbiology and Immunology. She covers all content on health and wellness including weight loss, nutrition, and general health. Twitter @Areeba94789300

Leave a Reply
Your email address will not be published. *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

error: Content is protected !!