Hormonal influences are also responsible for changes in the skin. Pigmentation of the nipples, vulva (the external genital organs), the center of the lower part of the abdomen, and the umbilicus increases. Darkening across the face may appear; this is known as chloasma or melasma, or the mask of pregnancy. Hormones can also cause reddening of the palms and the appearance of small red spots on the skin; these are nests of blood vessels, which are known as spider nevi or telangiectasias. Sweat and oil glands also become more productive during pregnancy.
One of the most important changes during pregnancy is the increase in metabolism, which is necessary to provide nourishment to the fetus. You must eat more to supply adequate protein, carbohydrates, and fat to the fetus and to your own enlarging body. Most women gain about 25 pounds: 3 pounds in the first trimester and 10 to 12 pounds in each of the second and third trimesters. The placenta, fetus, and amniotic fluid and the increased volume of blood and breast and uterine tissue account for 20 pounds of that weight gain. The rest of the weight is fat and extra fluid.
You must also take in more vitamins and minerals for the growing fetus. In general, you need to ingest greater amounts of calcium -- needed for developing bones -- and iron -- used to make new blood cells -- from the fourth month of pregnancy on.
The physical changes during pregnancy are miraculous. And the discomfort during pregnancy that you'll read about next is not to be taken lightly. Amazingly, the physical alterations you undergo reverse after birth: Your body returns to its normal state. For the baby, however, the process of change started nine months before has -- relatively speaking -- just begun.