Calorie intake is of great importance during pregnancy because of its relationship to maternal weight gain. Failure to gain weight in the first trimester or in the second increases the chances of premature birth. Although obesity is a problem in pregnancy, weight reduction during pregnancy is not desirable. A pregnant woman should not restrict her calorie intake. Inadequate energy intakes are found to decrease the nitrogen retention of women during pregnancy. Approximately about 300 calories daily in addition to the normal requirement is usually sufficient for a normal weight gain of 7 to 10 kg.
There is an increased demand for protein during pregnancy particularly in the second half of pregnancy. The major portion of the protein is acquired by the foetus in the three months prior to birth. During the last six months of pregnancy about 950 gm of protein are deposited. An allowance of 15 gm of protein added to the normal allowance for the non-pregnant woman is satisfactory.
There is an improvement in the efficiency of absorption of minerals such as calcium and iron during pregnancy, but the demands of the foetus and other developing tissues necessitates increases in the diet during the second and third trimester. Mothers should also anticipate demands for calcium during lactation and hence the need for more calcium and iron in the diet. A healthy baby of three months receives a large amount of calcium from mother’s milk. An infant is liable to suffer on account of the poor nutritional status of the mother. A generous amount of milk and green leafy vegetables are thus recommended during pregnancy and lactation.
Phosphorus allowances should be about equal to that for calcium and this will easily be supplied through calcium-rich and protein-rich foods.
Iron requirement during pregnancy is increased for the foetus and to replace iron loss during parturition (child-birth). In terms of dietary iron, the daily allowance for pregnant women will be 38 mg. pregnant women often suffer from anaemia. This condition can be corrected by taking medicinal iron in addition to the consumption of iron rich foods. Fortification of common salt with iron can prevent iron deficiency-specially among the vulnerable groups. Pregnancy also increases the need for dietary iodine. The iodine can be obtained from iodized salt.
Some studies have shown that an additional daily intake of retinol is necessary. It is not certain, however, whether extra Vitamin A is needed for functions other than meeting the foetal needs. An increased conversion of tryptophan to niacin occurs in pregnancy. The niacin, thiamine and riboflavin allowances are also increased in proportion to the calorie increase. The pregnant woman should get about 400 I.U. Vitamin D daily. There are no data to indicate that Vitamin C requirement during pregnancy is increased. The increase due to foetal requirement may be small. Therefore, extra allowance may not be necessary during pregnancy since normal adult allowance includes a sufficient safety margin. Two servings of citrus fruits will take care of the recommended allowances.
The pregnant woman is not able to eat much at a time and, therefore, must space her meals and must include drinks such as buttermilk, milk or lemon juice and simple snacks between meals. Taking lemon or orange juice in the morning and before meals helps to relieve the nausea of early pregnancy. Very rich sweets and fried foods should be avoided.
Under-nutrition in pregnancy is also found in the high-income groups. The common saying that “A pregnant woman must eat for two” is not correct as the requirements of the growing foetus are quite small as compared to those of the mother. Many women of high-income groups include in their diet rich foods such as ghee and almonds during pregnancy and put on a lot of weight. Many of them do not breast-feed their babies, with the result that they do not utilise the extra weight acquired during pregnancy.