Stages of a Baby in the Womb
A single fertilized egg has ovulated. The egg begins to divide quickly into a number of cells. At this stage the baby is called a zygote. Gradually the zygote travels through the fallopian tube to the uterus where it will implant into the uterine wall.
Zygote Stage (0 – 5 days) – Baby Growth Stages the Womb
as it travels down one of her fallopian tubes ，The mother’s egg is fertilized by the father’s sperm. This fertilized egg is called a zygote. In some cases, two eggs are released in the same menstrual cycle. If both are fertilized and both develop, fraternal twins will be produced. Identical twins are produced when a single zygote is produced that divides into two identical bodies during the embryonic stage. The zygote travels the rest of the way down the fallopian tube and into the uterus, where it implants itself in the lining of the uterine wall.
Blast cyst Stage (5 – 10 days) – Baby Growth Stages the Womb
The zygote divides and replicates itself, rapidly forming a ball of several hundred cells called the blast cyst. It is only one layer of cells thick in all but one region, where it is three- to four-cells thick. The thick portion of the blast cyst will become the placenta, an organ that provides a connection to the mother and helps to mediate development. The thick section will become the embryo.
Embryonic Stage (2 – 7 weeks) – Baby Growth Stages the Womb
A part of the placenta forms a transparent, fluid filled membrane called the amniotic sac. The embryo floats in this fluid, attached to the placenta via the umbilical cord. The main parts of the body all form during the embryonic phase. The brain and spinal cord differentiate themselves from the rest of the body. The heart forms and begins to beat. Arms and legs sprout and begin to grow near the beginning of this stage. By the end of the stage, fingers and toes are formed as well. The embryo is very susceptible to damage from alcohol, drugs, radiation, and infection—as a group these are referred to as dermatogens. It is a good idea for an expectant mother to avoid dermatogens throughout the pregnancy, but, due to the rapid anatomical development of the embryo, it is especially important for her to avoid them during this stage.
Fetal Stage (8 – 37 weeks) – Baby Growth Stages the Womb
By the start of the fetal stage, all of the main body parts and organs are present. During this stage, the fetus grows greatly in size while the various body parts undergo a finishing process. In week 8, the eyelids close to cover the developing eyes of the fetus. They remain closed until week 28, when they open and begin to periodically blink open and closed. During week 13, a fine hair called lanugos begins to sprout and eventually produce a coat that covers the entire body. This will typically be shed prior to birth, but some may remain at that time, especially for premature infants.