Pregnancy and childbirth are the most amazing events in a woman’s life. And of course, every mother wants to know how her baby is developing while parents eagerly await their arrival.
The entire pregnancy period is divided into three trimesters of three months each. Each trimester has its own features in both the baby’s development and the mother’s well-being.
First trimester
During the first three months, all organs and systems of the baby’s body begin to form. This trimester is also called the embryonic period.
Month 1
The sperm and egg meet in the fallopian tube – fertilization occurs and an embryo is formed. After 6-10 days, the embryo enters the uterine cavity and attaches to its mucous membrane – this process is called implantation. During this period, the embryo begins to grow gradually. By the end of the first month, it has its own circulatory system, and the beginnings of arms and legs appear.
Month 2
At the beginning of the second month, the kidneys, liver, digestive and excretory systems begin to form. The umbilical cord appears, which connects the baby’s body to the placenta. At 6 weeks, the facial features begin to form: nose, eyes, and jaw. The genital organs also acquire a characteristic appearance, but they cannot yet be seen on an ultrasound.
By 10 weeks, the baby already has brain hemispheres and a formed face. Taste receptors appear on the tongue. External genital organs continue to develop. Antigens appear in red blood cells, which can determine blood type.
Month 3
By the end of the first trimester, the size of the fetus reaches 9 cm. The kidneys already produce urine, and white blood cells are formed in the bone marrow. The baby’s skin is covered with fine downy hair, which will disappear before birth. The genital organs are sufficiently developed, so the baby’s gender can be determined by ultrasound.
Second trimester
By the fourth month, all of the organs are already formed, and the fetus looks like a little human. During the second trimester, the baby begins to actively grow and gain weight.
4 Months
The baby’s heart is fully formed and pumps up to 600 ml of blood per day. During a check-up, the doctor can hear the baby’s heartbeat clearly. The baby can also distinguish sounds from the surrounding world as their ears and brain regions responsible for hearing are already formed.
5 Months
The baby starts to move actively. They change position, touch their face and the wall of the amniotic sac – these movements can be seen on an ultrasound. Brain cells responsible for the sense of taste and smell have already formed. Bones, joints, and muscles begin to grow actively. More calcium appears in the milk teeth buds – forming hard dental tissue.
6 Months
All organs and systems are formed. The vestibular apparatus is functioning, so the baby can determine its position in the womb and change it by moving in the amniotic fluid. Pigment begins to form in the skin, and unique fingerprints appear.
Third trimester
During this trimester, all organs and systems continue to develop and improve. By the beginning of the seventh month, the baby weighs approximately 1 kg.
7th Month
The number of folds in the baby’s brain increases. The baby can now taste and smell the amniotic fluid and reacts to sounds. By the 29th week, the baby weighs around 1150 grams. From this week on, each baby gains weight at its own pace.
8th Month
By the 34th week, the baby’s lungs are developed enough to breathe on their own. The nervous and immune systems are still developing. During this period, the subcutaneous fat layer, necessary for thermoregulation, increases.
9th Month
At 37 weeks, the baby is considered full-term. This means that it has completed its development and can be born. At this point, the baby is similar to a newborn, but has not yet learned to breathe on its own.
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