Riham Monzer
The growth of a baby from an embryo to a fetus is an amazingly complex yet exciting topic.
Pregnancy lasts about 40 weeks from the first day of the last period to the completion of pregnancy, labor, and birth. Practitioners use the weeks to help figure out where the mother is in pregnancy and how the baby is developing. These weeks are divided into three trimesters:
Dividing pregnancy into trimesters is the most efficient method to help parents, doctors, and the medical team monitor a baby’s growth, complete medical tests on time, and calculate the correct due date. What are the stages of growth month-by-month in pregnancy?
First Trimester
The first trimester spans from conception to 13 weeks, where the baby evolves from a small grouping of cells to an embryo. During this stage, the embryo begins to show some baby features. In the first month, a water-tight sac forms around the fertilized egg as it enlarges. This sac is called the amniotic fluid Sac, which protects the embryo by cushioning against blows to the mother’s abdomen. Also, the placenta develops at this stage, which acts as a food resource for the baby from the mother. Face features such as the mouth, jaw, eyes, and throat will start to form. During the second month, the baby’s facial features and extremities start shaping. The brain and spinal cord begin to form, which is also known as the process of neurulation. While the digestive tract, sensory organs, and bones begin to develop. During the doctor’s checkup at six weeks, parents could hear a heartbeat.
In the third month, the baby grows from an embryo to a fetus and all extremities have fully formed. The baby’s circulatory and urinary systems are both working at this stage, and the liver is producing bile while the reproductive organs are developing. Gender reveals through ultrasound are still not possible. At the end of the first trimester, the fetus is 10 cm long and weighs approximately 28 grams.
Second Trimester
The second trimester, is also known as the best period due to the surge of energy a mother will feel during this phase. In the fourth month, the baby’s facial features become well-defined (eyelids, eyebrows, and eyelashes). Teeth and bones become denser. The nervous system begins to function. Fetal movement in the womb includes a baby sucking his or her thumb, yawning, stretching, opening, and closing the fist. Due to the complete development of reproductive organs, the baby’s gender is now easily determined by the gynecologist.
During the fifth month, the baby develops muscles that allow the mother to feel the baby’s moves, noting that the first movement is called “quickening.” Furthermore, hair starts to grow on the baby’s head, shoulders, and back to become covered with “lanugo,” meaning soft fine hair usually falls one week post-birth. Similarly, the baby’s skin is also covered with a white-cheesy substance called “vernix caseosa,” which protects the baby from prolonged exposure to the amniotic fluid.
Throughout the sixth month, the baby’s skin is reddish, and the veins are visible. The lungs are fully developed but not fully functional yet, and now the baby has a unique set of fingerprints. The eyes begin to move underneath the closed eyelids, and the baby can experience hiccups that a mother certainly could feel. The baby responds to external sounds from its surrounding environment, especially to the mother and father’s voices. The elevation in pulse rate may also cause the baby to respond through movement.
In the seventh month of pregnancy, the baby’s hearing is fully developed, and the fetus is more likely to change his or her position and respond to external stimuli such as pain, sound, and touch). The baby is about 35.5 cm by the end of the second trimester and weighs between 0.9 and 1.8 kgs.
Third Trimester
Across the third trimester and specifically during the eighth month, the baby matures, especially the sensory organs and the brain. Simultaneously, the lungs may still be immature and not fully developed until the ninth month. The baby is quickly gaining fat and weight. The lanugo that had developed across the baby’s body begins to disappear, and actual baby hair grows.
In the final month of pregnancy, usually (not always) the baby’s head settles downwards, prepared for birth. A mother’s breathing may become easier due to the baby’s position. The baby can move less because it is in delivery position and ready to come out. At birth, the baby will be around 45 cm long and approximately 3 kgs.
In conclusion, every mother needs to be aware of her fetus’s development throughout the journey of pregnancy because, during each prenatal stage, environmental factors can affect development. The developing fetus is entirely dependent on the mother for life and growth. Thus, the mother must take good care of herself.
