Nutrition During Pregnancy - Eating Right for Two

by Dr Tan Thiam Chye
Obstetrician and Gynaecologist
KK Women’s and Children’s Hospital, Singapore

Eating healthy before conception and throughout pregnancy is one of the best things you can do for yourself and your baby. Good nutrition optimizes the growth and development of your baby and at the same time safeguards your own health.

During pregnancy, your energy requirement increases by about 300 kcal a day, which is not much compared to the average non-pregnant Singapore woman’s requirement of 1700 kcal a day. On the other hand, requirements for other nutrients (e.g. protein, folate, calcium, vitamin D and B vitamins) may be significantly higher than in the non-pregnancy stage. As such, you should make smart choices by choosing a variety of nutrient-dense foods, rather than just eating more food! This is especially so if you now experienced a smaller appetite.

Essential nutrients for pregnancy
More than 40 different types of nutrients are needed to sustain good health and promote your unborn child’s growth and development. Yet, certain nutrients are especially important to ensure optimal pregnancy outcomes.

Folate (also known as folic acid)
Folate is vitamin B, which is essential for cell division and organ formation. This nutrient helps prevent neural tube defects (malformations of the brain and spinal cord) in your developing baby and anaemia in pregnant woman. Due to the severe nature of neural tube defects, we strongly advise adequate folate intake of at least 800 microgram daily before conception and throughout the first 3 months of pregnancy.

Dark green vegetables, for examples, spinach, broccoli and asparagus; citrus fruits and juices, yeast extract, liver, dried beans and fortified breakfast cereals foods are rich in folate. Care should be taken however to avoid overcooking the vegetables as folate is easily destroyed by heat.

Iron is needed for the formation of red blood cells, and inadequate iron intake may lead to anaemia. This is because, during pregnancy, your blood volume expands to accommodate the changes in your body. Moreover, your unborn baby also needs to store adequate iron for the first 6 months of life before he starts solid foods.

There are 2 forms of iron in foods, heme and non-heme. Heme iron is better absorbed by the body than non-heme iron. Sources of heme iron include red meat, liver, chicken and fish. Sources of non-heme iron include egg yolk, green leafy vegetables, iron-fortified breakfast cereals, dried fruits and nuts.

To enhance the absorption of non-heme iron, consume vitamin C-rich foods (namely, fruits and vegetables) at the same meal or take vitamin C supplement.

Vitamin B12
This vitamin is required for blood formation. It is only found in foods of animal origin, namely, meat, poultry, fish, milk and eggs. Vegans (vegetarians who do not any animal products including eggs and milk) must take vitamin B12 supplement in order to meet the daily requirements.

Omega-3 Fatty Acids
DHA (Docosahexaenoic acid), one of the omega-3 fatty acids, found in coldwater deep-sea fish, is important for brain and eye development. Studies have shown that pregnant women who eat coldwater fish have babies with higher IQ and better vision than pregnant women who don’t.

Unfortunately, large deep-sea fishes may contain methylmercury, a heavy metal that is toxic to the developing foetus’s neurological system. Hence, the US Food and Drug Administration recommends that pregnant women eat a maximum of 12 ounces (3 servings) of a variety of cooked fish or shellfish per week, and avoid shark, swordfish, king mackerel (known as ‘batang fish’ locally) and tilefish (also called white snapper). Although tuna is a good source of DHA, albacore tuna (found mainly as canned white tuna) is higher in methylmercury than other types of tuna (e.g. Skipjack, Bigeye and Yellowfin, commonly used for canned light tuna), hence pregnant women are also advised to limit albacore tuna to 1 serving a week. Safe DHA-rich sources include salmon, sardines, herring, halibut, canned light tuna and omega-3 fortified eggs. Alternatively, you can ask your doctor to recommend a suitable DHA supplement. For example, NeuroGain PB or NeuroGain S which provides a balanced intake of omega 3 Docosahexaenoic Acid (DHA), omega 6 Arachidonic Acid (AA) and omega 9 Oleic Acid (OA) fatty acids.

Vitamin A
The function of vitamin A is to promote growth of cells and tissues, and prevent night blindness. However, excessive intake of vitamin A above 10,000 IU daily in the first trimester can cause birth defects. Hence, in the first trimester, pregnant women should obtain their vitamin A from food rather than from supplements, and limit liver intake to 2 tablespoons (50g) per week. Good sources include eggs, milk, deep-red and yellow fruits and vegetables (for example, papaya, mango, pumpkin, carrots) and dark-green leafy vegetables (for example, spinach and broccoli).

Both you and your baby need calcium for strong bones and teeth. Excellent sources of calcium are milk, cheese and yoghurt. Other foods that contain calcium are beancurd (‘tauhu’ and ‘tawkwa’), green leafy vegetables, ladies fingers, small fish with edible bones such as ‘ikan bilis’ and sardines, and calcium-fortified soymilk and fruit juice.

If you have lactose intolerance (i.e. bloatedness, wind, diarrhoea after drinking milk), you can consume low-lactose or lactose-free milk, calcium-fortified soymilk, cheese or yoghurt as alternatives to milk. Your doctor can also prescribe a calcium supplement.

Table 1: Recommended daily dietary intake of calcium

Groups ---Recommended daily intake (mg / day)
Pregnant women ---1000 mg/day
Breastfeeding mothers---1000 mg/day

Source : National Academy of Science 2000

Vitamin C
Vitamin C is required for collagen formation in bones, muscles and blood vessels. The Singapore RDA for vitamin C intake in pregnancy is 50 mg a day, whilst the US recommendation is 85 mg a day. It is recommended that pregnant women obtain their vitamin C from food rather than from supplements, as there have been reports of rare cases of ‘rebound scurvy’ occurring in infants born to mothers taking 400 mg or more of vitamin C throughout their pregnancy. “Rebound scurvy’ occurs when the infant becomes tolerant to the high dose of vitamin C from the mother during pregnancy, hence it develops symptoms of scurvy or vitamin C deficiency after birth.

Both our Healthy Diet Pyramid for Pregnancy and the Health Promotion Board’s Healthy Diet Pyramid for Adults recommend 2 servings each of fruits and vegetables, which can meet the requirement for pregnancy.

Table 2 : Vitamin C content per serving of some local fruits and vegetables

Fruit/Vegetable --Vitamin C (mg)
Papaya, 1 wedge-- 93mg
Orange, 1 small-- 88mg
Watermelon, 1 slice-- 11mg
Banana, 1 medium --8mg
Yellow Pear, 1 small-- 6mg
Apple, 1 small --6mg
Broccoli, cooked, ¾ mug-- 65mg
Cauliflower, cooked, ¾ mug --44mg
Cabbage, cooked, ¾ mug --20mg
Lady’s finger, cooked, 100g -- 16mg
Spinach, cooked, ¾ mug --10mg

Vitamin D
Vitamin D helps with calcium absorption. Food sources include fortified milk, margarine and cold water deep-sea fishes e.g. salmon and sardine. Apart from foods, our bodies can also synthesize vitamin D when exposed to sunlight. Spending 10 to 15 minutes twice a week outdoors is sufficient for our bodies to synthesize enough vitamin D to meet our requirements.

Extracted from best-selling “The New Art and Science of Pregnancy and Childbirth” published in January 2008.