Fetal Development
Human fetal development is a continuous and highly organized process that begins at fertilization and continues until birth. Early development involves rapid cell division, implantation in the uterus, and formation of the placenta and other support structures. The embryonic period establishes the basic body plan and all major organ systems. During the fetal period, the body increases in size, complexity, and functional capacity. By full term, the fetus is structurally complete and prepared for life outside the womb.
The below outlines fetal development as measured by Conception Age (CA) beginning with fertilization, also called Post-fertilization Age or Embryonic Age in embryology, rather than Last Menstrual Period (LMP). While clinicians typically use the LMP system, this framework is commonly used in embryology and developmental biology.