Nutrition during pregnancy

It is now recognised that pregnant women do not actually have to ‘eat for two’; however, a healthy and varied diet, which is rich in nutrients, is important for both the mother and the baby. The developing fetus obtains all of its nutrients through the placenta, so dietary intake has to meet the needs of the mother as well as the products of conception, and enable the mother to lay down stores of nutrients required for the development of the fetus and lactation after the birth. 1: Energy:- The maternal diet during pregnancy must provide sufficient energy to ensure the delivery of a full-term, healthy infant of adequate size and appropriate body composition. Ideally, a woman should enter pregnancy with a healthy weight and good nutritional status. The additional energy requirements of pregnancy therefore result from the following: • The need to deposit energy in the form of new tissue; this includes the fetus, placenta and amniotic fluid; • The growth of existing maternal tissues, including breast and uterus, extra maternal fat deposition; • increased energy requirements for tissue synthesis; • increased oxygen consumption by maternal organs; • The energy needs of the products of conception (fetus and placenta), particularly in the later stages of pregnancy. 2: Protein:- The total protein requirement during pregnancy has been estimated to be approximately 925 g for a woman gaining 12.5 kg and delivering an infant of 3.3 kg. Protein is not gained at a constant rate, the rate at which protein is deposited increases as pregnancy progresses. 3: Fats:- However, pregnant women and those planning a pregnancy need an adequate dietary intake of essential fatty acids and their longer-chain derivatives, DHA and AA, which are necessary for the development of the brain and nervous system of the fetus, particularly in late pregnancy. The best dietary source of long chain n-3 fatty acids (EPA and DHA) is oil-rich fish. There is also some evidence that an increased intake of long-chain n-3 fatty acids during pregnancy may have beneficial effects on birth weight or the duration of pregnancy. 4:Carbohydrates:- Requirements for starch, sugar and non-starch polysaccharides (dietary fiber) during pregnancy are not increased. However, constipation, which may be party attributed to reduced motility of the gastrointestinal tract, is common at all stages of pregnancy. Women with low intakes of non-starch polysaccharides may benefit from increased intakes, to within a range of 12–24 g per day, along with increased fluid intakes to encourage regular bowel movement. 5: Vitamins:- Vitamin A: Extra vitamin A is required during pregnancy for growth and maintenance of the fetus, for fetal stores of vitamin A and for maternal tissue growth. Requirements are highest during the third trimester, when fetal growth is most rapid. Intakes should be increased throughout pregnancy by 100 µg per day (to 700 µg per day). However, if taken in excessive amounts, retinol is teratogenic, and therefore pregnant women are advised to avoid liver and liver products and supplements containing retinol [unless advised otherwise by a general practitioner]. Other dietary sources of vitamin A and beta-carotene (e.g. dairy products, eggs, carrots and leafy vegetables) can be included as part of a healthy, balanced diet during pregnancy. Thiamin, riboflavin and folate: Thiamin (B1) and riboflavin (B2) are needed for the release of energy in the body’s cells. Requirements for thiamin parallel the requirements for energy and are subsequently higher for the last trimester of pregnancy (an increase of 0.1 mg to a total of 0.9 mg per day during the last trimester). The increment for average riboflavin intake is 0.3 mg per day (to a total of 1.4 mg per day) throughout pregnancy. Note that an adaptive response to pregnancy is reduced urinary excretion of some nutrients, including riboflavin, helping to meet the increased demand.