Pregnancy
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There are a number of things that must fall into place in order to have a baby. The creation of a human being requires the right environment, the right factors, the right timing, and a great deal of luck. The first step occurs when an egg cell from a woman unites with a sperm cell from a man to form an embryo the beginnings of a human being. This process is called conception. After conception comes the process of fertilization, which is the process in which sperm cells must be present in the womans reproductive tract at the time the egg enters the fallopian tube. This can happen in several ways. If the woman has intercourse with a man during the week preceding ovulation, then he may deposit semen (a fluid containing sperm cells) into the womans vagina. Some of the sperm can make their way through the cervix (the opening of the uterus, located at the end of the vagina), into the uterus, and on up into the fallopian tubes. There, one of them may meet with the egg as it travels down one of the tubes toward the uterus. Intercourse is not the only way to get sperm in position. Another way is for a doctor to place sperm cells directly into the womans uterus at the right time in her cycle, a technique called intrauterine insemination. These sperm can also swim up the fallopian tubes, seeking the egg. Furthermore, when the sperm meets the egg, they attempt to penetrate the eggs outer layer. When one succeeds, the eggs outer surface forms a barrier to prevent other sperm from penetrating. The union of the sperm and egg is called fertilization. The fertilized egg is the first cell of a new human being. It contains a complete set of the genetic information necessary for the development of a baby. Half of that genetic material comes from the mother, carried in the egg; the other half comes from the father, carried in the sperm cell. That means the baby will have a combination of characteristics from both parents.
The next step after fertilization consists of the fertilized cell floating down the fallopian tube toward the uterus, where the cell divides into two. Those two cells then divide to make four, and the division continues. In a week or so after fertilization, the growing cluster contains about 100 cells. We can now say that the woman carrying this embryo is pregnant and the embryo is ready to go through the three trimesters of pregnancy. During the first trimester, the embryo goes through a variety of changes. The embryo reorganizes and forms three distinct types of cells, the ectoderm, mesoderm, and endoderm. The ectoderm develops the nervous system, and epidermis of the skin. The mesoderm develops the muscle tissue, connective tissue, and organs. The endoderm develops the digestive, and respiratory systems. The embryo will then develop into a fetus, which will be 2 inches long when the trimester ends. Following the first trimester comes the second trimester. During the second trimester the fetus will develops many of its vital organs and processes. Also during this stage, the mother’s abdomen and fetus enlarges, and the fetus’s heartbeat can be heard. The fetus will sleep, kick, curl, hiccup, and all these movements can be felt by the mother. The fetus is 13 inches long by the end of the second trimester. Finally the fetus goes into the third trimester which tells us that the fetus will grow very rapidly at this point. The fetus will undergo changes that will enable it to survive outside of the mother. The fetus can now see light, hear music and feel movements.
During any parts of the trimesters, the mother can do tests to see how the baby is doing. Some of these tests include an ultrasound, testing of the chemical Alpha-Fetoprotein in the mothers’ blood, fetal motion counts and an Amniocentesis. An Ultrasound uses high frequency sound waves to form an image of the uterus, placenta, and fetus. This view into the uterus allows doctors to measure many details about the fetus, including: Growth of the fetus, Abnormalities of the fetal structures such as heart, brain, limbs, kidneys, and stomach, Birth defects, Location and development of the placenta. The testing of the chemical Alpha-Fetoprotein is a process in which the doctor analyzes the pregnant mothers blood. If the test shows that the level of Alpha-Fetoprotein is higher or lower than normal, further tests will be done to confirm or rule out fetal problems. In fetal motion counts, the doctor may keep track of the number of fetal movements in a specified period of time. Finally, in an Amniocentesis the doctor will draw out a sample of amniotic fluid that surrounds the baby for examination. The doctor does this because the amniotic fluid that surrounds the growing fetus can carry important information, and an amniocentesis allows a small sample of this fluid to be collected for analysis. An Amniocentesis may be done for many reasons including, the identification of genetic defects, and identify any birth