What is the difference between how pregnant you are and how old your fetus is?

Fetal Development and Movements

The development of a new human form during the pregnancy term is marvelous and takes place in a very specific set of stages over the course of the nine months. Although the entire normal pregnancy cycle is a period of 40 weeks, the actual development of the fetus does not take place from the first week itself. Instead, the first week is the one in which the egg is released and travels via the fallopian tubes to meet the partner’s sperm and start the fertilization process. Once the egg has been fertilized it is known as a zygote and continues traveling down the fallopian tubes to reach the uterus almost 3 or 4 days after the fertilization. In the fourth week of the pregnancy, the zygote will plant itself in the uterine lining and form an embryo which divides itself into two: of which one part will merge into and develop within the placenta while the other half will evolve into the actual baby.  It is only up until the sixth week of the pregnancy that the baby’s heart will have developed and start to beat – thereby allowing the blood to circulate through its small body. This is also the period where the umbilical cord starts to develop, along with other parts of the baby such as the head, eyes, intestines and liver. Coming up into the tenth week of the pregnancy, the baby is considered to be out of the embryonic stage of its development and is medically called a fetus. During this phase, the external genetalia will start to form and the facial features and limbs become more prominent and stronger. Usually, by the end of the tenth week of pregnancy, not only will the baby’s organs have formed, but they are also likely to be completely functional as well. The second trimester starts around the fourteenth week and new formations on the baby’s body include eyelids, hair, finger and toenails. This is also a stage that sees a drastic increase in the risk of miscarriage. Some mothers may even experience the baby kicking at this point.

Between the 18th and 22nd week, the baby’s fingers and toes will have been formed, while the development of the baby’s inner ear will make it possible for it to respond to significantly loud external noises. During the 26th week, the baby is likely to be able to open its eyes and blink leading up to the third trimester that starts in the 27th week. The third trimester will see the baby attempt to breathe and put on some body weight that is essential to keep him or her warm after birth.

Submitted by P T on June 1, 2010 at 03:05

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