Understanding Pregnancy and the three Trimesters Essay

Understanding Pregnancy and the three Trimesters - Essay Example The 1st Trimester encompasses the time from the moment of conception to 13 weeks and many experts feel that the 1st Trimester is the most crucial, because it is at this stage that body structure and organ systems are designed (The Regents of the University of California, 2014). During the first two weeks the woman is not technically pregnant, not yet. Conception actually occurs about two weeks after the end of your last menstrual cycle. By the 3rd week fertilization is achieved. At this point the offspring is called a zygote and is made up of the base 46 chromosomes that will account for many of the baby’s future traits, including gender. Week four begins the process called implantation. From here the zygote is now referred to as a blastocyst, which is a ball of multiplying cells. This is also when the placenta begins to prepare itself (Vishton, 2013). Week five begins the embryonic stage of development. The brain, spinal cord, and heart begin to form; inner and exterior skin layers develop, as well as, certain amounts of connective tissue. Week six marks the closing of the neural tube and the embryo’s heart begins to beat independently and buds protrude from the embryos body, which will become arms and legs. The seventh week sees vast change s in the embryo; head develops, including eye sockets, ears, and facial features begin to be defined. However, with all of this change the embryo is no bigger than the end of a pencil’s eraser. During the 8th, 9th, and 10th week the eyelids, fingers, toes, lips, straightening of the torso, and rounding of the head can be seen. By the 11th week the embryo is now a fetus. Red blood cells are forming and genitalia will begin to form. In the 12th week fingernails are forming and the fetus’s profile is clearly human. At this stage the fetus is only, approximately, 2  ½ inches long and weighing a  ½ of an ounce (Mayo Clinic, 2014). Through the definitive 1st Trimester it is not just the baby-to-be that is going