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Nutrition During Pregnancy

A healthy pregnancy can depend as much on the pre pregnancy diet and subsequent body composition as it does the nutrients consumed during pregnancy.

It is important to ensure that there is no dramatic weight loss during pregnancy.

This article outlines key nutritional considerations that need to be taken into account for pregnant women.

It is vital that you seek approval from your medical specialist before making any changes to your diet. Always consult with you GP before supplementing with any additional nutrients.

How much should I eat?

It is important that during pregnancy you do not under or overeat. Despite the common ‘eating for two’ myth that is still heard today, it is recommended that an increase of approximately 200 calories per day is needed during the 3rd trimester only. If you are exclusively breastfeeding after your baby is born, an increase of approximately 330 calories per day may be needed for the first 6 months.

There are consequences of both undereating and overeating during pregnancy that need to be considered. If energy requirements are not met the baby risks having a low birth weight which can lead to a range of problems later in life, such as increased risk of suffering from coronary heart disease, hypertension and insulin resistance.

On the other hand, if energy requirements are exceeded then the mother is at risk of suffering from pre-eclampsia, gestational diabetes, labour difficulties, post-natal weight retention and stress incontinence. The baby would also be at risk of having malformations, preterm birth, being large for gestational age, perinatal death and being overweight at age 1.

Weight gain during pregnancy

Every woman should gain weight during their pregnancy but how much weight each pregnant woman gain can vary quite a lot. Only a small amount of this weight gain will be fat, the rest will be the developing baby, the placenta, amniotic fluid (protective fluid that protects the baby and provides nutrients) and the extra fluid in your blood. Most of this weight gain will occur in the second and third trimester, with only a small amount of weight gain in the first trimester.

Although in the UK there are no guidelines as to how much weight each woman should gain during pregnancy it has been estimated that the average weight gain in pregnancy is around 10-12.5kg. If you are worried about your weight during pregnancy, always speak to your GP.

It is important to not gain too much weight during pregnancy as this can increases your risk of complications during pregnancy, such as gestational diabetes and high blood pressure. Gaining too much weight during pregnancy can also cause problems during childbirth and may cause you to hold onto this weight after birth.

It is also extremely important that you do not try to diet or lose any weight whilst you are pregnant, even if you are starting your pregnancy at an overweight or an obese BMI. Trying to lose weight means restricting your dietary intake which could lead to your baby not getting all the nutrients it requires for development.

What should you be eating during your pregnancy?

During pregnancy you should try to have a healthy, balanced diet. It is important to start thinking about your dietary choices as your diet plays an important role in not only your health but also your baby’s. We know that preferences for foods may start to develop in the womb during pregnancy at around 30 weeks gestation when your baby is able to start swallowing. Tastes from the food consumed by the mother are thought to influence the taste of the amniotic fluid, which has been shown to lead to increased preference for these flavours after birth (Mennella, 2006). Therefore, pregnant women should try to eat a healthy, balanced diet in order to promote the baby’s interest in all types of foods and favouring healthier food choices.

5 or more portions of fruits and vegetables a day – Fruits and vegetables are full of important vitamins and minerals needed for growth and life sustaining chemical reactions in yourself and your baby. If you don’t get your 5 a day in already, now is the time to start!

Starchy foods & carbohydrates – Try to eat wholemeal and more fibrous options over refined carbohydrates. These foods provide our main source of energy, which can help alleviate fatigue symptoms during pregnancy, and increase our fibre and B vitamins intake. Fibre is important for digestive health and can help to prevent and ease constipation, which pregnant women often suffer from.

Protein - Protein rich foods are important for growth and repair of tissues for mum and provide iron and omega-3 fatty acids (oily fish) which plays an important role in heart, nerve and brain development in baby. No more than 2 portions of oily fish should be consumed during pregnancy per week, as these can contain toxins. Protein requirements do increase during pregnancy and increase further in breastfeeding however if a source of protein is consumed with each meal then you should easily meet this additional requirement. Protein sources include poultry, fish, meat, eggs, dairy, tofu, tempeh, beans and pulses.

Dairy – Needed to provide calcium for healthy bone development in baby and to promote bone health in mum. There are certain dairy products that should be avoided during pregnancy and they will be covered in the ‘what to avoid’ section further down in this article. If you do not eat dairy but do eat dairy substitutes always check the product is fortified! Sources of dairy include milk, yoghurt, quark and cheese.

Other nutrient considerations

During pregnancy a woman’s requirements for certain nutrients increase. Most nutrients can be obtained through a healthy and balanced diet but there are a couple that you should be supplementing your diet with which will be highlighted.

Please note: Always talk to your GP and midwife prior to taking any supplements.

Folic acid – Also known as folate (the naturally occurring form of folic acid) is an important vitamin for spinal development and in the prevention of neural tube defects. It is quite difficult to get the recommended amount of folic acid purely from food and the recommended amount does increase during pregnancy. Therefore, a supplement of folic acid a day is recommended (NICE, 2014) from when you decide to start trying to become pregnant and until you’re 12 weeks pregnant. In some cases, a higher dose may be necessary; some examples include but are not limited to, if you have a high BMI, diabetes, if you or the father have a history of neural tube defects or if you are taking anti-epileptic medication. Always talk to your GP if you are trying to conceive so they can advise based on your personal situation.

It is also recommended that you try to eat plenty of foods that are rich in folate. These foods include dark leafy vegetables including spinach, broccoli, cabbage, cavolo nero, brussel sprouts, peas, chickpeas and some breakfast cereals which have been fortified with folic acid.

Vitamin D – Is important for bone and muscle health due to the role it plays in calcium and phosphate regulation. Our bodies produce vitamin D from direct sunlight on the skin when outdoors, however due to the lack of sunlight we get in the UK we are at risk of not obtaining the amount of vitamin D we need. Aim to get outside in the sunshine for 15-30 minutes each day, exposing your lower arms and legs but remember to look after your skin and use UV protection. Vitamin D is also found in a select few foods such as salmon, mackerel, sardines, eggs and red meat. It is therefore advised regardless of the time of year, pregnant and breastfeeding women take a vitamin D supplement of 10mg a day (SACN, 2007). This is equal to 1000 iU so keep an eye out for this unit on labels. Always talk to your GP prior to taking any supplements.

Vitamin B12 – Is required for the formation of blood cells and nerves and is essential for growth. Foods that are good sources of vitamin B12 include dairy products, red meat, fish and eggs. If you don’t include animal products in your diet you may want to consider taking a vitamin B12 supplement but please consult your GP before doing so.

Vitamin C – Is an important antioxidant, plays a key role in immune function, collagen production and aids with iron absorption. Although pregnant women require more vitamin C during pregnancy than they do when they are not pregnant, this requirement is obtainable through the diet. Foods that are rich in vitamin C include peppers, broccoli, citrus fruits, tomatoes, brussels sprouts, kiwis and strawberries.

Iron – Is required to support the growth of the baby, increase blood volume as well as to supplement the iron lost during childbirth. However, during pregnancy, the body becomes more efficient at absorbing iron from food sources and iron losses are reduced so there is not an increased requirement for iron during pregnancy. It is possible to obtain all of your iron requirements through food and good sources include: red meat, eggs, nuts, beans, pulses, wholegrains and some fortified breakfast cereals. Iron from plant-based foods aren’t absorbed as well as the iron found in animal products so if you don’t eat animal products, make sure that you include lots of plant-based iron rich foods such as lentils, chickpeas, tofu, kale and apricots. It is also a good idea to consume iron rich foods with vitamin C rich foods as vitamin C helps with iron absorption.

Iodine – Plays an important role brain and neurological development and is an essential component of thyroid hormones. Iodine requirements do increase during pregnancy, but it is possible to obtain the recommended amount through food. Good sources of iodine include dairy products, eggs and fish. Consuming excessive iodine can cause thyroid issues therefore it is important to be aware your iodine intake.

If you do not include these foods in your diet due to veganism for example, you may be at higher risk of being iodine deficient and may require an iodine supplement. If you have a history of iodine deficiency or thyroid deficiency, it is recommended that you speak to your GP about supplementing with iodine. Always talk to your GP before taking a supplement during pregnancy as it is possible to have too much iodine in your diet.

Calcium – Plays a crucial role in the development of bones and teeth, regulates muscle contractions including contractions of the heart muscle and ensures blood can clot normally. The recommended intake of calcium does not change during pregnancy as the body adapts to increase the efficiency of calcium absorption from foods. Vitamin D helps your body to absorb calcium, so it is important that you are achieving the recommended intake of vitamin D in order to absorb calcium effectively. Good sources of calcium include dairy products, broccoli, cabbage, okra, soya beans, tofu, and nuts. If you do not consume dairy but instead opt for dairy alternatives, ensure that you are choosing a brand that fortifies their products with calcium.

During breastfeeding calcium requirements are increased considerably (1250mg/day vs 700mg/day in pregnancy) so it’s important to include calcium rich foods in your diet if you are breastfeeding.

Omega-3 Fatty Acids – Are essential for neural, brain, retina, blood and heart development. There are recommendations specifically for EPA and DHA intake in the UK – the two types of omega-3 fatty acids, but there is a general recommendation that 1-2 portions of oily fish should be consumed per week. Mackerel, sardines, trout and salmon are all great sources of omega-3 fatty acids. If you don’t eat oily fish, good sources are walnuts, flaxseeds, pumpkin seeds, soya products, rapeseed and linseed oil.

What should be avoided during pregnancy?

There are a few different foods that should be avoided and limited during pregnancy. This list can seem overwhelming so please take careful notice of what should be avoided completely and what you must be cautious to not over consume.

Certain cheeses – Including mould-ripened soft cheeses such as brie, Camembert and chevre. Soft blue cheeses such as Danish blue, stilton, Gorgonzola and Roquefort. These cheeses may contain bacteria called listeria which can be harmful to your baby so only eat them if they have been thoroughly cooked to steaming hot.

Unpasteurised dairy products – Including unpasteurised cow, goat or sheep milk or any foods made from unpasteurised milks. Unpasteurised dairy products can also contain listeria which can harm your baby.

Raw or undercooked meat – Make sure all food is cooked thoroughly and warmed all the way through. Eating raw or undercooked meat can potentially cause toxoplasmosis which can cause miscarriage. Be cautious of cured meats such as salami, pepperoni, chorizo and prosciutto unless thoroughly cooked through.

Undercooked eggs – Avoid raw or partially cooked eggs and always opt for British Lion eggs, you can identify these as they have a lion stamp on them. British Lion eggs are less likely to have salmonella in them which is unlikely to harm your baby but would give you food poisoning.

Liver and liver products – Such as pate or liver sausage which contain very high doses of vitamin A. Excessive vitamin A intakes can cause abnormalities as your baby is developing.

Game meats – Such as goose, partridge or pheasant as these meats may contain lead shots.

Certain fish – You should avoid shark, swordfish, marlin and any undercooked or raw fish. Additionally, you should limit your tuna intake to no more than 4 medium sized cans or 2 fresh tuna steaks per week. This is due to the mercury content of these foods which can be harmful to your baby’s nervous system.

Alcohol – Alcohol should be completely avoided during pregnancy and if you are planning to get pregnant. Drinking alcohol during pregnancy can lead to fetal alcohol syndrome and permanent nerve damage.

What to limit your intake of

Caffeine – No more than 200mg of caffeine should be consumed per day. This is equivalent to around 2 cups of coffee or 4 cups of tea. Consuming too much caffeine can increase the risk of a miscarriage.

Fish – Other than the fish that you should avoid which are covered in the ‘What should be avoided during pregnancy?’ section of this article, oily fish consumption should be limited to 2 portions a week. Oily fish can contain pollutants which can cause harm to your baby if excessive amounts are consumed.

Vitamin A – Whilst vitamin A is essential for you and your baby during pregnancy high levels of it should be avoided. If you are taking any supplements during your pregnancy make sure that they do not contain any vitamin A. Vitamin A toxicity can lead to birth defects and abnormalities.

High fat and sugar foods – Try to limit the consumption of saturated fat and sugar such as cakes, crisps, biscuits and other sweets. These foods do not provide any beneficial nutrients for you or your baby and are very energy dense, so if consumed in excess can lead to excessive weight gain during pregnancy.

What to be cautious of

Food hygiene – Ensuring that you practise good food and hand hygiene whilst you are preparing and eating foods. This is key to ensuring that you do not transfer any bacteria from raw foods or any bacteria from soil traces to your baby.

Hydration - During pregnancy water is required to make amniotic fluid, help with nutrient transport and aid digestion and waste excretion. Morning sickness is common during pregnancy and will increase fluid loss so do try to make up for this loss if you have morning sickness. Aim to drink around 8 glasses of water a day, this amount varies from person to person so try to keep an eye on your levels of hydration. An easy way to do this is to check the colour of your urine, which should be a pale straw colour, if it is darker than this you probably need to drink more.

Top tips

  • If you are trying to get pregnant always consider your health first to make sure you are in the best possible position to support the growth of a baby.
  • During pregnancy consume a healthy, balanced diet consisting of a variety of fruits and vegetables, starchy carbohydrates, proteins and healthy fats to support yours and you baby’s health.
  • All pregnant women should supplement with 400mcg folic acid and 10mg vitamin D per day.
  • Do not go on a diet or attempt to lose weight whilst you are pregnant. This can lead to nutritional deficiencies in yourself and your baby and can also impair the development of your baby.
  • Always consult your GP with any concerns during pregnancy, these are general guidelines but every pregnancy is unique.

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National Institute for Health and Clinical Excellence (NICE). (2014). Public Health Guideline 11 Maternal and child nutrition.

National Institute for Health and Clinical Excellence (NICE). (2014). Weight management before, during and after pregnancy. 

National Institute for Health and Clinical Excellence (NICE). (2010). Public Health Guideline 27. Weight management before, during and after pregnancy. 2010.

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