The second trimester of human development is characterized by several important events and developments, particularly in fetal growth and maturation. Key events include:
-
Growth and Development of Organs: During the second trimester, major organs and systems, including the heart, brain, lungs, and gastrointestinal tract, continue to develop and mature.
-
Size Increase: The fetus experiences significant growth in size and weight. By the end of the second trimester, the fetus typically measures about 12 inches (30 cm) in length and weighs about 1 to 2 pounds (0.45 to 0.9 kg).
-
Sensory Development: The developing fetus begins to develop functioning senses. For instance, the fetus can start hearing sounds from outside the womb, such as the mother's voice and other external noises.
-
Movement: Around the 16th to 20th week, the mother may begin to feel fetal movements, often referred to as "quickening." This is a crucial milestone as it indicates that the fetus is becoming more active and developing muscle control.
-
Skin Development: By the end of the second trimester, the skin continues to develop, and a protective covering called vernix caseosa begins to form.
-
Gender Determination: By approximately 18 to 20 weeks, it is often possible to determine the sex of the fetus via ultrasound.
These developments during the second trimester are crucial for preparing the fetus for life outside the womb.
1 answer