Nutrition during pregnancy and its impact on maternal and child health

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The first one thousand days of life (from conception to a child’s second birthday), has been identified as having more influence on an individual’s future health and development than any other time in their life. Fortunately, many women are motivated to focus on their health during pregnancy and demonstrate an increased interest in nutrition.

If a mother’s nutrition is poor during pregnancy this can lead to:

  • Low birth weight (which in turn can lead to increased disease risk later in life)
  • Pre-term birth
  • Infant micronutrient deficiencies
  • Short-term health risks such as hearing/visual impairment or delays in neurological development

It is suggested that gene expression (and hence predisposition for later disease) may be permanently altered by the nutrient environment in utero and early life.

Healthy eating for pregnancy

There is a lot of information out there about foods to avoid during pregnancy (e.g., certain cheeses, pâté, uncooked meat) and it is well-known pregnant women should avoid alcohol and limit caffeine intake (see Tommy’s information page for a full breakdown of foods and drinks to avoid or limit during pregnancy).

Whilst information about what not to eat is important, it is equally important to talk with pregnant women about what they can do to ensure they are gaining the nutrition they need for healthy fetal development.

A healthy balanced diet

A healthy balanced diet includes food from each of the four food groups, in the proportions shown in the Eatwell Guide. In general, pregnant women need:

  • At least 5 portions of fruit and vegetables per day – this provides vitamins A and C, plus dietary fibre.
  • Starchy carbohydrates - provides energy and B vitamins; choosing wholemeal varieties of bread, cereals, rice and pasta will provide good amounts of dietary fibre.
  • High protein foods (e.g., meat, fish, eggs, beans and pulses). Important for protein, zinc and iron – pregnant women need 2-3 portions per day.
  • Milk, dairy or fortified plant-based alternatives - provides protein, calcium and iodine. Pregnant women need 2-3 portions per day. Choosing lower fat versions will provide fewer calories.

If one or more food groups is missing, women can be at risk of nutritional deficiencies. For example avoiding the milk and dairy group may lead to a deficiency of calcium and/or iodine.

See the nutrition module for information regarding the functions and sources of key nutrients in the diet.

Essential Micro Nutrients for fetal development

Click on each tab below to learn why each nutrient is essential during pregnancy, and how pregnant women can ensure they are meeting their nutritional needs.

Calcium

Why is it important? It is important pregnant women get enough calcium (and vitamin D) to ensure healthy fetal bone development.

Maternal calcium (and vitamin D) deficiency is associated with poor fetal bone development, pre-eclampsia, pre-term birth and small for gestational age babies.

How to get it? Pregnant women should be encouraged to consume reliable sources of calcium 2-3 times per day, such as:

  • Milk or fortified milk alternatives (e.g. soya/oat/almond)
  • Cheese, yogurt (or fortified non-dairy alternatives)
  • Tinned fish (eaten with bones, e.g. sardines)
  • Green leafy vegetables
  • Bread

Vitamin D

Why is it important? Maternal vitamin D (and calcium) deficiency is associated with poor fetal bone development and increased risk of rickets in children.

How to get it? As the main source of vitamin D is sunlight on the skin, it can be difficult for pregnant women in the UK to get all their requirement without a supplement, especially during the winter months.

There are also (limited) dietary sources of vitamin D, including oily fish, eggs and fortified foods (e.g., margarine or breakfast cereals).

The National Institute for Health and Care Excellence therefore recommends a supplement of 10 µg/day of Vitamin D during pregnancy and lactation (for all women, regardless of dietary intake).

For women at increased risk of vitamin D deficiency during pregnancy (e.g., women with a higher Body Mass Index (>30kg/m2), darker skin or spend a lot of time indoors), the Royal College of Obstetricians and Gynaecologists recommend a higher dose of 25µg/day may be required.

Find out further information about supplements

Folate

Why is it important? Folate is known to have a key role in fetal development, and is important in preventing fetal defects of the brain and spine.

How to get it? Folate is the natural form of vitamin B9 found in foods. Folic acid is the synthetic version found in supplements and fortified foods. Both forms can prevent folate deficiency.

Pregnant women are encouraged to increase their intake of folate rich foods, such as:

  • Green leafy vegetables
  • Wholemeal or fortified white bread
  • Peas and beans
  • Oranges, berries
  • Fortified breakfast cereal

Taking folic acid supplements of 400µg per day (5 mg for high risk groups) during preconception and the first 12 weeks of pregnancy may provide additional protection against fetal defects.

Folic acid supplements are intended to complement not to replace dietary intake of folate, therefore all women should be encouraged to continue eating folate rich foods within their diets.

Find out further information about supplements

Iodine

Why is it important? Iodine is vital for thyroid hormone production (important hormones for growth and metabolism for both mother and child), fetal brain development, plus fetal growth and metabolism. Extreme iodine deficiency before or during pregnancy can result in severe physical and intellectual disability in babies. Even a mild iodine deficiency during pregnancy is associated with reduced IQ in children (see Bath, 2019).

How to get it? Pregnant women should be encouraged to consume reliable sources of iodine 2-3 times per day.

There are limited reliable sources of iodine in the UK diet, but these include:

  • Milk, yogurt, cheese (or fortified non-dairy alternatives)
  • Sea fish and eggs

Some fortified dairy alternatives may also include iodine, but not all. Therefore it is important to check the labels when buying plant-based milks and yogurts.

Iron

Why is it important? In 2008, the World Health Organisation reported iron deficiency anaemia to be the most prevalent nutrient deficiency globally, affecting 1.62 billion people and including 56 million (41.8%) pregnant women. In the UK, the National Diet and Nutrition Survey from 2014-2016 found that 27% of women aged 19-49 years had insufficient intakes of iron.

Iron deficiency during preconception and/or early pregnancy is associated with poor fetal development, low birth weight and pre-term birth. It can also cause tiredness and breathlessness in the mother and can increase risks of bleeding during delivery.

How to get it? Pregnant women should be encouraged to include reliable sources of iron 2-3 times per day, including:

  • Meat, fish, poultry
  • Beans, peas, pulses
  • Nuts, quinoa
  • Wholemeal bread, dried fruit
  • Fortified breakfast cereal

Omega-3 fatty acids

Why are they important? Omega-3 fatty acids, particularly docosahexaenoic fatty acid (DHA), are important for promoting fetal brain and neurological development.

If pregnant women are deficient in Omega-3 they are at increased risk of gestational diabetes and pre-eclampsia. Recent research suggests these conditions could limit the amount of Omega-3 transferred to the foetus, which could have short and long-term impacts on the child’s brain health.

How to get it? Good dietary sources include:

  • Oily fish*
  • Rapeseed oil, walnuts
  • Soya and soya products

*Pregnant women need to consume sources of Omega-3 fatty acids regularly, but should limit fish intake to no more than two portions per week. Tuna should be limited to less than two tuna steaks per week (or less than 4 cans per week – although canned tuna is not a good source of omega 3). Pregnant women are also recommended to avoid shark, swordfish and marlin (as it can contain mercury, which is harmful to the fetal nervous system).

Key messages:
  • A healthy balanced diet during pregnancy is important for successful pregnancy outcomes
  • Pregnant women need to include food from all food groups shown on the Eat Well Guide
  • Certain micronutrients are vital for fetal development, including calcium, vitamin D, Folic acid, iron, iodine and omega 3 fatty acids
  • Pregnant women need to ensure a good intake of reliable sources of these micro nutrients daily