Most critical stages of pregnancy: complete guide

stages of pregnancy

Pregnancy is an intricate and charming period filled with changes and transformations for both the expecting mother and the growing fetus. Fetal development starts even when the mother-to-be doesn’t know about her pregnancy. However, early pregnancy symptoms and body transformation that a woman may experience will “drop a hint” on pregnancy. The first 20 weeks mark the most significant stages in fetus development. In this article, we will delve into the stages of pregnancy, explaining the symptoms experienced by mothers-to-be and the fetus development stages.

Stages of pregnancy: conception to 12 weeks

Pregnant women experience changes in their bodies: from symptoms expected to ones that are completely out of the blue, every woman will have a different pregnancy experience. Tips on how your body will change during different stages of pregnancy will make your pregnancy more enjoyable. Knowing how pregnancy may affect emotions and feelings is also very helpful.

Body changes that may indicate pregnancy

Often, women realize that they are pregnant when they miss their period. In such a case, we recommend taking a pregnancy test or talking to the healthcare provider. Additionally, early pregnancy symptoms may include:

  • morning sickness
  • nausea or vomiting (doesn’t just happen in the morning)
  • tiredness
  • cravings for food
  • back pain
  • a need to urinate more often
  • leg cramps
  • skin changes and itching
  • vaginal thrush
  • dizziness
  • shortness of breath
  • larger, tender breasts

When you find it difficult to manage one of these symptoms, contact your healthcare provider.

1-3 weeks of pregnancy

The first week of pregnancy begins with conception when a sperm successfully fertilizes an egg. During this period, women may not experience any symptoms. However, mild spotting or fatigue can be noticed.

In weeks 1-4, the fertilized egg undergoes rapid cell division, forming a blastocyst.

Week 4 of pregnancy

In the first 4 weeks of pregnancy, you probably will not notice any symptoms. During this time, you may notice that your period hasn’t arrived, or you may experience such symptoms as breast tenderness or tiredness.

Week 5 of pregnancy

At this stage, the embryo is around 2mm long. During week 5 of pregnancy, the baby’s nervous system is already developing. All the foundations for its major organs are in place. Additionally, the baby’s heart is forming, and it has a like-tube structure. Blood begins to circulate, and the fetus has its own blood vessels at this stages of pregnancy.

By the fifth week of pregnancy, some women may begin to experience early signs such as:

Breast Changes

Women may notice transformations in their breasts. They may become tender, swollen, or sore as hormonal changes prepare the body for breastfeeding.


During pregnancy, increases the levels of the hormone progesterone. It can cause fatigue, making women feel more tired than usual.

Frequent Urination

The growing uterus can put pressure on the bladder, leading to more frequent trips to the bathroom.

Morning Sickness

Some women may start to experience nausea and vomiting, commonly referred to as morning sickness. It can occur at any time of the day.

It is advisable to start taking folic acid to prevent spina bifida. Do it as soon as you find out you’re pregnant.

week 5 of pregnancy

Weeks 6-10 of pregnancy

During these stages of pregnancy, the baby undergoes remarkable growth and development. Finally, it goes from the embryotic to the fetal stage. At week 6 of pregnancy, the baby’s facial features, including eyes, ears, and mouth, start forming. It continues limb development. Baby’s heart starts beating faster during this period. Week 7 of pregnancy is characterized by the development of the arms and legs. The brain is also growing during this week. Baby’s toes and fingers become more distinct during 8 weeks of pregnancy. Also, this week is remarkable because the baby starts moving, although it’s too tiny for the mother to feel yet.

Week 9 of pregnancy

At week 9 of pregnancy, your baby is not an “embryo” anymore, it becomes a “fetus”. Its facial features become more human-like. Week 10 of pregnancy is characterized by the rapid development of vital organs such as the heart, kidneys, liver, and intestines. The fetus starts making spontaneous movements.

Expecting mothers may experience a mix of symptoms during these stages of pregnancy. They include:

Morning Sickness

The most common symptoms during these weeks are nausea and vomiting. They can intensify during these weeks and vary from woman to woman. Some may experience severe morning sickness, while others may have none.

Breast Changes

Breast tenderness and enlargement continue, and the areolas (the darker area around the nipples) may darken.

  • Fatigue: Feelings of exhaustion can persist due to the increased demands on the body.
  • Frequent Urination: This symptom often continues as the uterus expands and places more pressure on the bladder.
  • Food Aversions and Cravings: Women might develop aversions to certain foods and strong cravings for others.
  • Mood Swings: Hormonal changes can lead to mood swings, heightened emotions, and irritability.

Stages of pregnancy: weeks 11-15

During weeks 11 to 15, both the fetus and mother-to-be are going through significant changes. As an expectant mother enters the second trimester, she may feel relief from morning sickness. Read our article with tips for dealing morning sickness. However, some women may still experience mild nausea. What’s more, some women may feel increased energy levels. Breasts may continue to grow and become more tender as they prepare for breastfeeding.

When can you hear heartbeat on doppler?

Starting from week 12 of pregnancy, expecting parents may start using fetal heartbeat doppler. With the help of this device, you can monitor your baby’s heartbeat from the comfort of your home.

at home fetal doppler

At-home fetal doppler brings joy and calmness to expectant parents. When you do not know how to use fetal doppler, read our step-by-step guide.

During these stages of pregnancy, the expecting mother may experience hormonal changes and fluctuations, leading to mood swings. Also, his period is characterized by frequent urination as a growing baby puts pressure on the bladder.

Weeks 16-20 of pregnancy

These stages of pregnancy are full of changes for both the expecting mother and the developing fetus. For women, this period is characterized by such symptoms:

  • Weight gain: expecting mothers continue to gain weight steadily during these stages of pregnancy.
  • Appetite changes: because of appetite fluctuations, some women may experience increased hunger.
  • Skin changes: such a problem as a mask of pregnancy” (melasma) can occur, resulting in the darkening of skin on the face.
  • Growth of abdomen: The abdomen tends to grow noticeably.
  • Breast Growth: as breasts prepare for breastfeeding, they continue to grow.

week 15 of pregnancy

Fetal Development

During these stages of pregnancy, the fetus goes through essential changes. By week 20, the fetus measures about 6.5 inches in length and weighs approximately 10-11 ounces. During these pregnancy stages, expecting mothers may experience the first baby’s movements, called quickening. To find out more about quickening, read our article on top 3 facts about quickening in pregnancy. The fetus’s lungs continue to develop and produce surfactant. Also, taste buds form at this stage, allowing for the differentiation of flavors. What’s more, baby’s inner ears can hear sounds from the outside world, including the mother’s heartbeat and voice.

Gender confirmation

At these stages of pregnancy, gender can be confirmed through ultrasound at this stage, though it may still be challenging depending on the baby’s position.

Word from Sonohealth

There are three stages of pregnancy called trimesters: first (1-12 weeks ) trimester, second (13-28 weeks) trimester and third (29-40 weeks). The first 20 weeks of pregnancy are filled with profound changes and milestones for both the expectant mother and her developing baby. Each week brings new developments, making this period a remarkable and transformative journey. As pregnancy progresses, mothers-to-be should continue to receive regular prenatal care, ensuring the health and well-being of both themselves and their growing babies. This is just the beginning of an incredible adventure that will ultimately lead to the birth of a beautiful, healthy newborn.


1. How many stages of pregnancy are there?

There are three stages of pregnancy, known as trimesters, of about three months each. First trimester – conception to 12 weeks. Second trimester – 13 to 27 weeks. Third trimester – 28 to 40 weeks.

2. How long is the first trimester?

The first trimester begins on the first day of your last period and lasts until the end of week 12.

3. How do you count pregnancy weeks?

There is a belief that pregnancy does not start at conception. The pregnancy stages start on the first day of your last menstrual period.
 This means that pregnancy actually ends up being 40 weeks or ten months long!

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