Nutrition in pregnancy - A complete guide for beginners, suitable for vegan mothers
Eating healthily in pregnancy does not mean going on a special diet, and unlike what many people think, there is no need to eat for two. Eating a variety of foods from all food groups in 3 meals and 2-3 snacks per day will provide the nutrients the woman and baby need.
Energy requirements in pregnancy
During pregnancy total daily energy requirements are increased because additional energy is required to support the increase in metabolically active tissues of the mother and the foetus, and because of the increased energy cost of moving a heavier body. However, until now, the estimated average requirement (EAR) for energy intake during pregnancy in the UK is the same with that of a non-pregnant woman, with the exception of the third trimester of pregnancy, when there is an increment of 190kcal/day. It should be recognized however that this number may be greater for those women who are underweight at the start of pregnancy and those who do not reduce their activity levels (athletes etc.).
Nutritional Requirements in pregnancy
The diet of a pregnant woman should be based on general healthy eating principles, so as to provide sufficient energy, protein and micro-nutrients. Based on the UK Department of Health, there are modest increments in the dietary requirements for certain vitamins including Thiamine (0.9mg/day), Riboflavin (1.4mg/day), Folate (300μg/day), vitamin C (50mg/day), vitamin A (700μg/day) and vitamin D (10μg/day). There are no recommended increments in mineral and trace element intakes and as such recommendations for non-pregnant women apply.
Supplementation of folic acid (400μg/day) should be given from the time contraception is stopped until the 12th week of pregnancy to reduce the risk of neural tube defects. A good dietary intake is also needed throughout pregnancy from folic-acid rich foods such as broccoli, spinach, beans, orange juice, whole-meal bread and fortified breakfast cereals. Vitamin D (10μg/day) supplementation should also be given throughout the whole pregnancy. Particular caution should be given to women who are more susceptible to vitamin D insufficiency including those who cover themselves for religious/cultural reasons or have limited time in the sun.
Based on the National Institute of Health and Care Excellence iron supplementation should be given to pregnant women only where there is clinical need. Fish oil supplements should be avoided during pregnancy due to their high vitamin A content, and a pregnancy specific DHA supplement may be taken if it does not contain retinol. Multivitamin supplementation specifically manufactured for pregnancy should be considered in all those who are suspected of having inadequate intake of micronutrients. Pregnant teenagers are particularly at risk of inadequate intake and therefore additional intakes of specific nutrients may be required to support the growth of the mother and the foetus.
Pre-pregnancy body weight and maternal obesity
Women who are underweight at the start of pregnancy are at greater risk of anemia, preterm birth and low birth weight of the newborn. On the other hand, obesity during pregnancy has been associated with many adverse outcomes for the mother, including gestational diabetes, thromboembolism, pre-eclampsia, caesarean sections, hemorrhage, and wound infections. It has also been associated with miscarriage, congenital abnormality, stillbirth, preterm birth and neonatal death. The USA guidelines for weight gain during pregnancy provided by the Institute of Medicine/National Research Council in 2009 are based on pre-pregnancy body weight and BMI and are the following:
BMI <18.5kg/m2 (underweight): 13-18kg total pregnancy weight gain
BMI 18.5-24.9kg/m2 (Normal Weight): 11-16kg total pregnancy weight gain
BMI 25-29.9kg/m2 (overweight): 7-11kg total pregnancy weight gain
BMI ≥30kg/m2 (Underweight): 5-9kg total pregnancy weight gain
During pregnancy the mother is relatively immunocompromised and can be more susceptible to foodborne infections. More care should be taken with food safety and hygiene to avoid toxicities and infections including salmonella, listeriosis, and toxoplasmosis. This can be achieved by ensuring the following:
Thorough cooking of eggs, meat, poultry and ready meals.
Avoid raw, undercooked eggs and products containing (mayonnaise, mousse, cold soufflés etc.)
Ensure proper storage of chilled foods.
Good kitchen hygiene practices to prevent cross contamination of cooked food from raw meat and poultry.
Careful washing of produce including fruits and vegetables, cleaning kitchen surfaces and thorough hand washing to prevent transmission of the bacteria Toxoplasma Gondii that causes severe foetal abnormalities.
Wearing protective gloves when handling cat litter trays and for gardening.
Avoid mould ripened soft cheeses (brie, camembert), soft blue vein cheeses (Danish blue), unpasteurized cow’s, goat’s, or ship’s milk or soft cheese made from them, and all types of pâté including vegetable pâté.
Avoid liver, liver products (liver pate and liver sausage) as well as supplements containing retinol (fish liver oils) to prevent vitamin A toxicity.
Avoid shark, marlin, swordfish and limit oily fish including tuna to a maximum of two portions per week (140gr cooked) to prevent mercury toxicity.
The UK Department of Health suggests that pregnant women should restrict caffeine intake to less than 200mg/day, since high caffeine intakes increase the risk of foetal growth restriction. Foods and drinks containing 200mg caffeine include:
- Two mugs of instant coffee (100mg each)
- 1 ½ mug filter coffee (140mg each)
- 2-3 mugs of tea (75mg each)
- 5 cans of cola (up to 40mg each)
- 2 ½ cans of energy drinks (up to 80mg each)
- 4 bars of plain dark chocolate (up to 50mg each)
Pregnant women should not drink alcohol throughout pregnancy especially during the first 3 months because of the increased risk of miscarriage. Alcohol at any stage of pregnancy can cause foetal alcohol syndrome, which may in turn lead to restricted growth, facial abnormalities, as well as learning and behavioral disorders that may only become obvious later on in childhood.
Current advice suggests that there is no need for the mother to avoid peanuts during pregnancy, unless she herself is allergic to them.
Nausea and vomiting in pregnancy
These symptoms are mostly present during the first trimester of pregnancy. Women should manage to stay hydrated and avoid foods and smells that precipitate these symptoms. Although not evidence based the following steps may be helpful:
- Having small frequent meals and snacks
- Choosing starchy foods e.g. toast and crackers
- Drinking liquids in between meals rather than with meals
- Cold, bland, non-greasy foods are often better tolerated
- Avoiding cooking smells
- Keeping rooms well ventilated
- Avoiding high fat and very spicy foods
- Fizzy drinks and ginger flavored drinks could be helpful
This is a common symptom that occurs due to changes to the gut transit time mediated by hormonal changes. Dietary treatment includes eating high fiber foods including fruits and vegetables and breakfast cereals and drinking plenty of fluids. Faecal bulking agents could also be used and changing the type of iron supplementation may be useful.
Heartburn and gastrointestinal refluxes during pregnancy result from increases in abdominal pressure and changes in gut transit time. To alleviate symptoms women should have small frequent meals instead of large meals and avoid foods that may exacerbate symptoms including spicy, fatty, fried or acidic foods and drinks. Antacids may be prescribed to help relieve these symptoms.
Additional Notes for vegan pregnant mothers
Plant-based diets are becoming very popular and if they are well-planned, they can support healthy living at every age and life-stage, including pregnancy. The following will ensure the pregnant mother covers her requirements of nutrients including calcium, omega-3 fatty acids, vitamin D, iron and vitamin B12. Find more details about the nutrients you may be lacking if your plant-based diet is not well planned here.
- Obtain calcium from sources like fortified plant-based dairy alternatives, dried fruits, nuts, red kidney beans, sesame seeds, tahini, tofu and low-oxalate greens like bok choy, broccoli, Chinese cabbage, collards, and kale.
- Plant sources of omega 3 include walnuts, flax (linseed), hemp seeds, chia seeds and soya beans. EPA and DHA supplements from seaweed oil could also be considered.
- Vitamin D is made in our bodies when our skin is exposed to appropriate sunlight. Plant-based sources of vitamin D include sun-exposed mushrooms and fortified foods including vegetable spreads, breakfast cereals and plant-based dairy alternatives. Some vitamin D supplements are not suitable for vegans. Vitamin D2 and lichen-derived vitamin D3 supplements are both suitable.
- Reliable sources of vitamin B12 are supplements and fortified foods including some breakfast cereals, yeast extracts soya yoghurts and plant-based dairy alternatives.
- Plant sources of iron include dried fruits, whole grains, nuts, green leafy vegetables, seeds and pulses. Eat plenty of fruits and vegetables rich in vitamin C to help absorb the iron found in plant foods (e.g. citrus fruits, strawberries, green leafy vegetables and peppers). Consider supplementation if there is a documented iron deficiency.
- Gandy, J. (2014). Manual of dietetic practice. (5th ed.). London: Wiley-Blackwell.