For many years women were told to limit weight gain during pregnancy to between 15 and 18 pounds. This kept babies relatively small, decreasing the risk of complications in delivery. It was also thought to lower the chance for toxemia, a potentially fatal disorder characterized by extremely high blood pressure.
Gradually, however, it has become clear that pregnancy is not the time to unduly restrict food intake. A good prenatal diet not only helps ensure proper fetal development, but protects the mother from depleting her nutrient stores. While smaller babies may make for a less-stressful delivery, their larger counterparts, whose entrance into the world has grown easier through advanced obstetrical techniques, tend to suffer fewer complications after birth. In addition, great weight gain is no longer considered an important factor in raising the risk of toxemia.
It is now recommended that weight gain range somewhere between 22 and 27 pounds, depending on pre-pregnancy weight. Very thin women are encouraged to gain more because they lacked adequate fat reserves. Conversely, those who start out overweight are generally advised to gain less.
Besides increasing calorie consumption (about 300 extra per day), and protein intake (a daily increase of 30 grams, roughly the amount in two ounces of meat and two cups of milk), more vitamins and minerals are needed. Assuming that a woman was eating well before she became pregnant, these new goals will be met just by the overall increase in food consumption. But a few nutrients may require special effort to ensure adequate intake.
The most common nutritional problem associated with pregnancy is iron-deficiency anemia. Many women have a borderline iron status prior to conception. Since the mineral is needed for fetal and placental blood supplies and to cover blood loss during delivery, pregnancy puts considerable demand on maternal iron stores, particularly in the last trimester. In addition, the mother`s iron status can affect the infant`s stores at birth.
Although the efficiency of iron absorption appears to improve during pregnancy, some women may not be able to meet their iron needs through diet alone. Many physicians recommend daily supplements containing 30 to 60 milligrams of the mineral. An effort should be made to incorporate iron-rich foods in the diet as well. These include red meat, liver, dried fruits
(especially prunes), dried beans, nuts, whole grains and enriched cereals. Eating non-meat iron sources with citrus fruits or other fruits and vegetables high in vitamin C enhances the absorption of the less available form of iron in these foods. So, too, do animal foods such as meat, fish and poultry.
Folic-acid deficiency also can become a problem during pregnancy. In fact, its need as a vitamin was first recognized in pregnant women. Since it is part of the enzyme systems responsible for synthesizing DNA, an adequate intake is critical during fetal development--a time of rapid cell growth and division.
Some evidence links folic-acid deficiency to premature delivery. It also has been suggested that folic-acid supplements can prevent the birth defect, spina bifida. Controversy surrounds this issue, which is under study.
Folic-acid supplementation can mask a vitamin B-12 deficiency. It cures the B-12 related anemia, while the less readily diagnosed neurological disturbances also associated with a B-12 deficiency go untreated. For this reason the Food and Drug Administration restricts the levels of folic acid in over-the-counter preparations. Prenatal supplements available by prescription contain larger amounts and may be recommended by the physician. Good dietary sources of folic acid include organ meats such as liver, dried peas and beans, and dark green leafy vegetables. Because excessive amounts may impair zinc absorption, there is no advantage to exceeding the Recommended Dietary Allowance for pregnant women of 0.8 milligrams a day.
As with iron, maternal stores of calcium may be strained during pregnancy if intake is insufficient. The mother`s bones will give up the mineral to provide for the growing fetal skeleton. And data exist tying calcium deficiency to a heightened risk of toxemia.
Many women stop drinking milk after adolescence--an unfortunate trend, since milk represents one of the best calcium sources. Each eight-ounce glass provides 280 milligrams, or about 25 percent of the Recommended Dietary Allowance during pregnancy. Yogurt and hard cheeses make a contribution as well. Average-size servings of sardines and salmon (if eaten with the bones)
and oysters, broccoli, collard, kale and mustard greens also contain significant amounts of calcium.
For proper nutrition throughout the nine months of pregnancy, all that is needed is some extra emphasis on these few critical nutrients, coupled with the same good eating habits that should always be in place.