Nutritional Requirements During Pregnancy

NUTRITIONAL REQUIREMENTS DURING PREGNANCY

The RDA for an expectant mother is given in list :

ICMR Recommended dietary allowances for an expectant mother

Nutrient in Energy (k.cal)

Normal Adult Woman Vs Pregnant Woman

Sedentary   1875  2175

Moderate    2225  2525

Heavy         2925  3225

Protein (g)   50      65

Fat (g)         20      30

Calcium (mg)        400    1000

Iron (mg)    30      38

Vitamin A           

Retinol (mg)         600    600

(or)            

b carotene (mg)    2400  2400

Thiamine (mg)              

Sedentary   0.9     1.1

Moderate    1.1     1.3

Heavy         1.2     1.4

Riboflavin (mg)             

Sedentary   1.1     1.3

Moderate    1.3     1.5

Heavy         1.5     1.7

Niacin (mg)         

Sedentary   12      14

Moderate    14      16

Heavy         16      18

Pyridoxine (mg)   2.0     2.5

Ascorbic acid (mg)         40      40

Folic acid (mg)     100    400

Vitamin B12 (mg)          1        1

1. Energy:

1.     Energy requirement during pregnancy is increased because of the additional energy required for

2.     growth and activity of foetus

3.     growth of placenta and maternal tissues

4.     increase in maternal body size

5.     steady rise in BMR

For a reference Indian woman (ICMR 1990) weighing 50kg, the total energy cost of pregnancy has been estimated to be 73000 k.cal. This includes the energy required for deposition of 4 kg of body fat (36000 k.cal) to be utilized later during lactation. Considering the increased energy demand during lactation and beneficial effect of increased energy intake on birth weight of infants and also protein sparing action, an additional intake of 300k.cal.per day during pregnancy is recommended.

2. Protein

An additional protein intake of 15g/day i.e. a total of 65g is recommended. The additional protein is essential for

growth of the foetus

development of placenta

enlargement of uterus,mammary gland

increased maternal blood volume

formation of amniotic fluid

preparation for labour, delivery, post partum period and lactation by maternal tissues.

3. Fat

ICMR expert committee has suggested an intake of 30g of visible fat/day during pregnancy. This is based on studies indicating that linoliec acid requirements during this stage is 4.5 percentage of total energy. Of this, some of the essential fatty acid needs are met with by the invisible fat. Therefore an intake of 30g of visible fat has been suggested to meet the essential fatty acid needs.

4. Calcium:

The calcium requirement for an adult woman is 400mg/day. During pregnancy the need increases to 1000mg/day.

The additional calcium is needed for the growth and development of bones as well as teeth of the foetus and also for the protection of calcium resources of the mother to meet the high demand of calcium during lactation.

The amount of calcium deposited in the full grown foetus is around 30g. Therefore an intake of 1g calcium per day which meets the needs of the mother and the additional needs of pregnancy has been recommended by the ICMR. Inadequate intake of calcium results in the mobilization of calcium from mother bones resulting in demineralization of maternal bones and osteoporosis.

5. Iron:

The requirement of iron increases from 30mg/day to 38mg/day during pregnancy.

The increased requirement of 8mg/day is due to

expansion of maternal tissues including red cell mass, iron content of placenta and blood loss during parturition.

to build the iron store in foetal liver to last for atleast 4-6 months after birth. This is because the baby's first food milk is deficient in iron. Generally infants are born with a high level of iron, 18-22g/ 100ml.

6. Iodine

Due to increase in BMR, iodine needs are also enhanced during pregnancy.

7. Zinc

Deficiency of zinc adversely affects the outcome of pregnancy. Apart from being a component of insulin and enzyme systems, it also participates in the synthesis of DNA and RNA, playing a significant role in reproduction. Hence zinc deficiency leads to foetal mortality, foetal, malformations and reduced intra uterine growth rate. The risk of LBW babies doubles and preterm delivery increases three times due to low zinc intake during pregnancy.

8. Sodium

The increase in extra cellular fluid increases sodium requirement. Hence restriction in diet may cause biochemical and hormonal changes.

When sodium level in blood drops (hyponatraemia), the kidney produces hormone renin which causes increased retention of sodium making it unavailable for normal body processes. When the system is overtaxed it results in sodium deficiency causing increased risk of eclempsia, prematurity and low birth weight infants. Normal sodium intake without restriction is advised during pregnancy.

Sodium is restricted when there is oedema or hypertension.

9. Vitamins

Vitamin A

Vitamin A requirements during pregnancy have been computed based on the vitamin A content of liver of the newborn. The additional intake works out to 25mg/day throughout pregnancy. Since this constitutes a very small fraction of the RDA for normal women, no additional allowance during pregnancy is suggested.

Vitamin D:

Vitamin D is essential as it enhances maternal calcium absorption. Its active form calcidiol and calcitriol can pass through placenta with ease and help in calcium metabolism of foetus. Since Vitamin D can be synthesised in adequate amounts by simple exposure to UV rays no recommendation for vitamin D has been made.

Other fat soluble vitamins

Vitamin K is required for synthesis of prothrombin which is essential for normal coagulation of blood. A liberal vitamin K level in the mother's blood proves helpful in preventing neonatal haemorrhage. Hence it has become a routine to administer natural form of this vitamin by injection either to the mother before delivery or to the neonate soon after birth.

Thiamine, Riboflavin, Niacin

The RDA for thiamine, riboflavin and niacin is estimated on the same basis as for a normal adult woman ie., 0.5mg/1000 kcal, 0.6mg/ 1000k.cal and 6.6mg/1000k.cal respectively. As the energy requirement increases during pregnancy, the requirement of these vitamins also increases correspondingly.