Medical Subject Headings (MeSH): Embryonic and Fetal Development

Embryonic and fetal development refer to the stages of development that occur during pregnancy, from the moment of fertilization until birth. During this time, a fertilized egg (also known as a zygote) grows and develops into a baby through a series of stages, including the embryonic stage and the fetal stage.

During the embryonic stage, which occurs from fertilization to about 8 weeks after fertilization, the fertilized egg divides and grows into a ball of cells called a blastocyst. The blastocyst implants into the lining of the uterus and begins to differentiate into the various cell types that will make up the baby’s body. This includes the formation of the embryo, which will eventually develop into the baby’s body, and the placenta, which will provide nourishment and oxygen to the growing baby.

During the fetal stage, which occurs from about 8 weeks after fertilization until birth, the embryo continues to grow and develop. The baby’s organs and systems begin to form and function, and the baby begins to move and respond to stimuli. The baby also continues to grow and gain weight, and the placenta continues to provide nourishment and oxygen.

Understanding embryonic and fetal development is important for healthcare providers, as it helps them monitor the health and development of a pregnancy and identify any potential issues that may need to be addressed. It is also important for expectant parents, as it can help them understand what to expect during pregnancy and prepare for the arrival of their baby.