preembryonic
Preembryonic refers to the earliest stage of prenatal development, from fertilization through the formation of the germ layers, before the embryo begins to generate distinct tissues and organs. In humans, this period roughly spans the first 14 days after fertilization and ends with the onset of gastrulation, when the three germ layers begin to form.
Key events during the preembryonic period include fertilization to form a zygote, followed by cleavage that
Understanding the preembryonic period is important for fields such as reproductive biology and obstetrics, as well