Welcome to this lesson today on fetal development. Today you will be learning about fetal development in pregnancy specifically during:
The second trimester of pregnancy starts at the fourth month and lasts until the end of the sixth month. During this time of fetal development, organ and organ systems are maturing, and also at this point fetal movement can be felt.
During the second and third trimesters, the child that's developing in the mother's uterus is referred to as a fetus and is no longer considered an embryo.
The third trimester is marked as the seventh month until birth; which on average is within the ninth month. During this time, organ and organ systems are continuing to mature, and the fetus is preparing for birth. Babies who are born before the third trimester will generally have a low survival rate because their organ systems are too underdeveloped. The time within the mother is very important for organ and organ systems to properly develop. Essentially, if the baby is born before the ninth month the baby's organ systems aren't well enough developed to allow for survival outside of the uterus.
The circulatory system of a fetus is composed of temporary vessels and lungs that do not function while inside the uterus. While the fetus is within the uterus gas exchange is not occurring like it normally would. The lungs at that point are not functioning because the placenta is playing the role of delivering oxygen and removing carbon dioxide; the fetus is not actually breathing. Once the baby is born, the circulatory system becomes independent and the lungs will begin gas exchange when the first breath is taken. While the fetus is within the mother, the circulatory system depends on the mother's circulation to undergo gas exchange vs. breathing air.
This lesson has been an overview on fetal development during the second and third trimesters of pregnancy.
Keep up the learning and have a great day!
Source: THIS WORK IS ADAPTED FROM SOPHIA AUTHOR AMANDA SODERLIND
Marks the start of the 4th month until the end of the 6th month of pregnancy in which the fetus continues to develop as organs and organ systems mature.
Marks the 7th month of pregnancy until birth, and is characterized by the continued development of the fetus as it prepares for birth.