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Energy: Energy requirements are only marginally increased. An excess of 350k.cal/day are required only during second and third trimesters for the following reasons -
- Growth and physical activity of the fetus
- Growth of plasma
- Normal increase in maternal body size
- Additional work involved in carrying the weight of fetus and extra maternal tissues
- Slow and steady rise in BMR during pregnancy
ICMR (2010) recommended energy requirement of pregnant woman is as follows:
Sedentary worker ------- 1900+350 = 2250 kcal/ day
Moderate worker ------- 2230+ 350 = 2580 kcal/ day
Heavy worker -------- 2850+ 350 = 3200 kcal/ day
Protein:
The expansion of maternal blood volume and growth of fetus, placenta and maternal tissues requires additional protein. The RDA of protein during pregnancy is an additional 27.2 g/day. Use of high protein supplements is not necessary as a good diet can meet the protein requirements.
Sufficient carbohydrates must be included to spare the protein needed for growth.
Normal protein requirement of an adult woman is 55 g/ day. ICMR recommended an additional 15g for pregnant woman. Additional protein is essential for:
- Rapid growth of fetus
- Enlargement of uterus, mammary glands and placenta
- Increase in maternal circulating blood volume and subsequent demand of increased plasma and maintenance of colloidal osmotic pressure and circulation of tissue fluids
- Formation of amniotic fluid
- Transfer of amino acids from mother to fetus up to 20 weeks ( all amino acids must be provided to the fetus as it cannot oxidize amino acids as a source of energy).
If protein requirements are not met during pregnancy:
- There is increased risk to the pregnancy
- Fetus may grow at the expense of mother
- Maximum growth of baby cannot be obtained
- Number of cells in tissues particularly in brain may not be optimum Milk, meat, egg and cheese are complete proteins with high biological value. Additional protein may be obtained from legumes and whole grains, nuts and oil seeds.
Fat : Fat is a concentrated source of energy and about 30g of fat should be included in the diet of a pregnant woman. Care should be exercised to avoid excess of fat as this could lead to excessive increase in weight.
B complex vitamins: The need for B vitamins increases in proportion to the energy and protein intake.
Requirements for B6 especially increase for pregnant adolescents and for women carrying more than one fetus. Such women need to be given supplements.
Folate has a fundamental role in DNA synthesis and cell replication. A deficiency in early pregnancy could impair cell growth and replication resulting in placental and fetal abnormalities. The requirement for folate is 500 micrograms/day during pregnancy. Folate can easily be obtained from the diet but if it is inadequate supplementation may be carried out.
B12 is also necessary for normal cell division and protein synthesis. It also activates the folate enzyme. The slight increase in need for B12 can be met through diet. Strict vegetarians may need a supplement of 1.2 micro grams /day to prevent deficiency.
Minerals
Calcium:
ICMR recommended calcium requirement of adult woman is 600 mg/ day. Requirement increases during pregnancy to 1200 mg/day.
Increased intake of calcium is highly essential for:
- Calcification of foetal bones and teeth
- For protection of calcium depletion from mother to meet high demands during lactation
| A full term foetal body is made of 30 g of Calcium
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Mother’s diet should contain less of phytic acid, adequate amount of Vitamin D and sufficient amount of calcium to prevent ‘Osteomalacia’ and muscular cramps. Mother should avoid repeated pregnancies.
Adequate milk and other dairy products and greenleefy vegetables should be consumed (supplements if necessary).
Iron:
Normal iron requirement of an adult woman is 21 mg/day. ICMR recommendation for iron during pregnancy is 35 mg/ day.
Increase of 8 mg iron / day can be attributed to the following:
- Infants are generally born with haemoglobin levels of 18- 22g/100ml of blood. Iron stores in the liver of the infant lasts from 3 to 6 months. Iron is also required for the growth of fetus and placenta (provide for placental and fetal needs) . To achieve these levels mother must transfer 240 mg of iron to the fetus during gestation.
- Iron is also required for the formation of haemoglobin as there is 40 -50 per cent increase in maternal blood volume (support the enlarged blood volume). For this 400mg of iron is required.
- Loss of maternal iron through skin and sweat is about 170mg of iron.
- The total iron requirement for the entire period of pregnancy is 810mg. including blood loss at the time of delivery (Provide for inevitable blood loss at delivary)
Liver, dried beans, dried fruits, green leafy vegetables, eggs, enriched cereals and iron fortified salt provide additional sources of iron.
Thus the need for iron during pregnancy is increased to Iron deficiency anemia raises the risk of low birth weight, preterm birth and perinatal mortality.
Iron is available in both heme and non heme sources. A judicious combination of these sources with iron absorption enhancers like vitamin C will help in meeting iron requirements during pregnancy. A daily supplement of 60mg. of iron is recommended to make up for inadequate sources.
Zinc:
Zinc is required for cell development and low levels of zinc during pregnancy lead to low birth weight. Therefore slightly higher levels of zinc are recommended specially for pregnant woman 12 mg/day is the RDA for zinc during pregnancy. Zinc is generally not supplemented unless iron supplementation is also given- iron in large doses can interfere with the absorption of zinc.
Sodium
During pregnancy, there is increase in extra cellular fluid which calls for 80% increase in body sodium. When blood sodium level drops, kidney produces the hormone rennin, as a result of which sodium is retained in body. In case of edema and hypertension sodium is restricted.
Iodine
Maternal iodine deficiency impairs fetal development causing extreme and irreversible mental and physical retardation in the fetus. To prevent this damage, iodine deficiency needs to be corrected before conception. RDA for iodine is 175 µg/day. ICMR recommends additional requirement of 25 µg of iodine/day during pregnancy to normal requirement of 100- 200 µg of Iodine / day. Iodine deficiency in mother can lead to abortion, still birth, congenital anomalies, increased prenatal mortality, Cretinism and psychomotor defects.
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