The Nine Months of Pregnancy
By the end of the first week, the cell cluster comes to rest in the upper part of the uterus, where it clings and takes root. The nesting cluster finds nourishment in the lining of the uterus, prepared during the menstrual cycle. Toward the end of the second week, the cluster begins to form an embryo. Production by the woman’s body of pituitary hormones is inhibited, so that ovulation is now suppressed, the lining of the uterus is maintained, and menstruation is postponed for the duration of the pregnancy.
During the first two months of pregnancy, the mother’s breasts will enlarge and begin to be tender as a result of the change in the hormone level in her body. Morning sickness may occur temporarily. After about the twenty-seventh day, the placenta, the so-called afterbirth, which is attached to the lining of the uterus and is linked to the embryo by the umbilical cord, starts a variety of functions necessary to maintain the pregnancy. One of these functions is the production of the hormone chorionic gonadotropin. Since chorionic gonadotropin rises to a high level for a short period of time, its detection in urine serves as a test for pregnancy. This test can be performed in a few minutes with a high degree of accuracy. (This is the simple test that you can now do yourself with a kit purchased at your pharmacy.) Another function of the placenta is the production of progesterone. It takes over this important job as the ovary stops secreting progesterone. This hormone from the placenta is vitally important in maintaining the pregnant uterus and equally important in preventing the ovaries from developing another mature egg.
Quietly a tremendous change is taking place. The whole embryo is being formed from head to toe. Every feature and every vital organ starts to form in the first two months. The heart begins to beat on about the twenty-second day but it is still so small that it cannot be heard easily for another four to five months. At the end of the first month, the embryo is only about the size of a small pea. By the end of the second month, it is about one inch long and nearly weightless. At this time the embryo is called the fetus. It can move the arms and legs, turn the head, open and close the mouth, and swallow.
In the last three months of pregnancy, the reproductive system becomes stretched to its limits in size and in capacity for supplying nourishment. The baby gains about five to six additional pounds, some of it as a padding of fat. From the maternal bloodstream the baby also accumulates essential immunities to diseases. Its lungs mature, and its strength and coordination improve.
The uterus has now increased its capacity about five hundred times. In the ninth month a little understood chemical reaction occurs, which causes profound changes in the great muscles of the uterus. This is called labor. In the first stage of labor, the muscles of the uterus exert a force of about fifty pounds per square inch to push the baby out through the cervix. The narrow opening of the cervix gradually expands to let the baby’s head and body pass through. Next, the baby’s body stretches the walls of the vagina and reaches the light of day.
Posted in Understanding the Basics
To Ed Wheat Sr. and Gladys Gibson Wheat, whose commitment, devotion, warmth, generosity, and integrity stood for fifty years as a beautiful picture of genuine agape love.