Breakdown of Each Trimester: Click to expand
1.First Trimester (Weeks 1–12)
Key Events :
- Weeks 1–4 : Conception occurs, and the fertilized egg implants in the uterus. Early cell division happens, forming the blastocyst.
- Weeks 5–6: The embryo’s heart starts beating, and the beginnings of the brain, spinal cord, and other organs start to form.
- Weeks 7–8 : Limb buds (arms and legs) appear, and facial features begin to take shape.
- Weeks 9–12: The fetus looks human-like. Major organs are formed, and fingers and toes are distinct.
The fetus begins to move, although it's too small to feel.
2. Second Trimester (Weeks 13–26)
Key Events :
- Weeks 13–16: The fetus develops more distinct features, and bones begin to harden. The sex of the
baby can often be determined through ultrasound.
- Weeks 17–20: By now, the mother can feel fetal movement. Hair (lanugo) starts to grow on the baby’s
head and body.
- Weeks 21–24 : The baby’s lungs develop and become more functional. The baby can hear sounds from
the outside world and might respond to music or voices.
- Weeks 25–26 : The baby’s skin becomes less translucent, and the baby begins to practice breathing
movements in the womb, although the lungs are not fully mature yet.
3. Third Trimester (Weeks 27–40)
Key Events:
- Weeks 27–30: The baby’s brain and lungs continue developing, and bones are fully formed, though still
soft. The baby is gaining fat to regulate body temperature.
- Weeks 31–34: The baby’s brain continues maturing, and the baby’s eyes can open and close. The baby is
gaining weight quickly during this time.
- Weeks 35–37: The baby’s organs are almost fully developed, and the body is preparing for birth. The
baby is in a head-down position for most births.
- Weeks 38–40: The baby is considered full-term. The lungs are fully developed, and the baby is ready to
be born.
Important Milestones:
- First Trimester: Major organ formation, and the fetus begins to take on a more recognizable human form.
- Second Trimester: Growth and development of external features and organs, baby’s movements become more noticeable.
- Third Trimester: Final maturation and preparation for birth, with the baby gaining weight and developing skills for life outside the womb.
This breakdown helps to highlight how the baby’s development accelerates in the second and third trimesters, with significant growth and preparation for birth in the final stages.