What to eat when you are pregnant: A simple nutrition guide for every trimester

A nutritious diet is important for everyone but when you are pregnant it needs to be prioritised for obvious reasons. It can, however, be complicated by the fact you might be feeling nauseous, your body might start craving foods you wouldn’t normally eat and at the same time you are being advised to avoid others for safety reasons. So, what should you be feeding yourself – trimester by trimester - to support your body’s changing needs and that of your growing baby? In this article, Nutritionist Helen Roach shares insights on why pregnancy nutrition matters, and how you can support your wellbeing during each trimester.

The general principles of healthy eating when you are pregnant are much the same as for anyone else – a good balance of nutrient-dense foods including vegetables, fruits, wholegrains, lean proteins and healthy fats with limited amounts of drinks and food high in sugar and fat¹. That said, there can be fresh challenges involved in achieving a balanced diet when you are expecting, not least because your nutritional needs, desires and requirements can change and evolve across the trimesters. In the early stages, for instance, you might feel nauseous at the very thought (or smell) of certain foods. Conversely, you might crave foods you wouldn’t normally give house room to, and which are not particularly nutritious or gut-friendly. Then there are foods you are advised to avoid for safety reasons and key nutrients that you need for your growing baby but which you may not be able to get enough of from food alone - all of which can make balanced eating slightly more complex. It can be helpful then to understand what you should ideally be eating trimester by trimester and why.

Why pregnancy nutrition matters

It might seem blindingly obvious but good nutrition becomes vital when you are pregnant because it needs to support the general health of both the mum-to-be and the baby’s growth and development.

The advice below is based on the latest research and recommended guidelines and should act as a general template for healthy eating during your pregnancy. However, being pregnant should be an exciting and enjoyable experience and whilst nutrition is key to it hopefully being a healthy and happy one you shouldn’t get too hung up on creating the ‘perfect’ pregnancy diet and/or feel guilty or that you have ‘failed’ in some way if, at times, you choose cake and crisps over oily fish and leafy greens. Making small, achievable changes can be important than overhauling your entire way of eating. It is important too if, at any point, you are particularly overwhelmed, worried or confused about what you are eating or drinking and how it may affect you and your baby that you seek professional guidance from a nutritionist or your GP or midwife.

General nutritional guidelines

The British Nutrition Foundation (BNF) has recently published a comprehensive guide outlining the latest academic research and recommendations for healthy nutrition during pregnancy, described as ‘a roadmap’ for parents-to-be². Its general advice is to get a good balance of vegetables and fruits, wholegrains, lean proteins and healthy fats and ensure you are getting an adequate intake of nutrients that contribute to maternal and foetal health including foods rich in folate (green leafy vegetables such as broccoli, spinach and kale), iodine (seafood and dairy products like yogurt, milk and cheese), iron (red meat, fish, eggs, lentils, nuts, seeds, tofu, leafy greens) vitamin D and omega 3 fatty acids (oily fish, walnuts, flaxseeds, soybeans). More specific advice includes:

Limit caffeine. Found in coffee, tea, green tea, energy drinks and cola high levels of caffeine have been linked to increased risk of miscarriage and low birth weight⁴.
Aim to eat two portions of oily fish (such as salmon, mackerel or sardines) weekly to get enough DHA, an omega 3 fatty acid which plays a vital role in the development of babies’ brains and eyes (this is especially important in the second and third trimesters).
Prioritise foods that are rich in iodine such as white fish and dairy products.
Get enough calcium (found in dairy products or fortified alternatives like plant milks and leafy green vegetables) which plays a crucial role in building babies’ teeth and bones.
Keep well hydrated to help reduce common pregnancy complaints like tiredness and constipation.
Don’t drink alcohol.
Avoid certain types of fish such as smoked salmon or cured fish which can carry listeria, a bacterium that can be harmful during pregnancy. Canned fish and thoroughly cooked fresh fish are safe to enjoy but it is suggested pregnant women eat no more than 4 cans of tuna a week due to high levels of mercury. Mercury can negatively impact foetal neurodevelopment⁵. Swordfish and marlin are also potentially high in mercury.

Being mindful of the fact your calorie needs may also change across the trimesters. This is not the time to be going on a weight loss diet – even if you are overweight - as your body needs additional energy and nutrients when you are pregnant.

What to eat: trimester by trimester

First trimester (Weeks 1-12): Foundation and foetal development

Don’t be tempted to ‘eat for two’ from the outset – pregnant women need surprisingly few extra calories particularly in the early stages of pregnancy. Focus not on eating more but on getting more nutrient-dense foods from all the main food groups – protein, carbohydrates, vegetables and fruits and healthy fats. Good ones to serve up include folate-rich vegetables like broccoli, spinach or kale; sources of lean protein, such as white or oily fish, lean chicken or steak, eggs, pulses or tofu; fruits like berries and citrus fruits and fortified breakfast cereals which have added vitamins and minerals like iron, folic acid and vitamin D.
Focus on small, easy to digest meals (nothing too greasy, rich, too spicy or large portions) as you are likely to go through digestive changes in early pregnancy. If you are experiencing nausea (and around 8 out of 10 women do feel sick or are sick when pregnant) help to alleviate it by eating frequent small meals of bland foods like toast, bananas and/or ginger-based snacks. This is also the time to be taking a daily prenatal vitamin supplement which should include folic acid, iron, iodine and vitamin D. Drink plenty of water throughout the day to stay well-hydrated and continue to do this throughout all trimesters.

Second trimester (Weeks 13-27): Supporting growth and wellbeing

This is the time to increase the amount of protein and calcium you are consuming as your baby’s bones and organs are rapidly developing during this phase. Include daily amounts of calcium-rich foods such as dairy products (milk, cheese, yogurt); fortified nut milks, tofu and green leafy veg. If calcium intake is low your body can draw it from your bones to provide for the baby which can potentially lead to low maternal bone mineral density and increase the risk of osteoporosis later in life⁷. Aim to eat two portions of oily fish (such as salmon, mackerel or sardines) a week to increase your omega 3 intake but limit other fish that may be high in mercury. If you don’t eat fish, you might want to consider taking an omega 3 supplement which includes DHA and EPA. Omega 3s are essential for the development of your baby’s brain and eyes. Constipation can also be an issue during the first and second trimesters so try to increase your intake of high-fibre foods like vegetables, fruit (research shows kiwi fruits are helpful constipation relievers⁸), wholemeal bread, quinoa, brown rice and whole-wheat pasta. Drinking plenty of water can similarly help to alleviate constipation.

Third trimester (Weeks 28-birth): Preparing for the birth

Keep your energy levels up by continuing with your healthy eating habits from the first two trimesters. Be aware that you need to be eating a bit more at this stage. Extra calories (approximately 200 kcal a day more) consumed daily in this final trimester will help to support your baby’s growth and this is the period in which they gain the most weight. Adding more healthy fats to your diet in the form of avocados, salmon and nuts and seeds is a good way to increase calories and nutrients, including omega 3s. The bulk of foetal skeletal development also takes place during this trimester⁹ so ensure you are still eating enough calcium-rich foods on a daily basis. Constipation may still be a factor (see above in Second Trimester). Other late pregnancy symptoms such as heartburn can also be alleviated by avoiding large meals, fatty or spicy foods and instead opting for smaller, more frequent and nutritious meals. This should also have the effect of giving you more sustained energy levels.

Nutritious and easy meal suggestions during pregnancy

Breakfast options: overnight oats with berries and natural live yogurt sprinkled with chopped nuts and seeds; a mushroom and/or spinach omelette; eggs on wholemeal toast.
Lunch options: hummus and raw vegetables; a three bean salad; lean chicken with smashed avocado; broccoli and cheese soup.
Dinner options: salmon, baked sweet potato and a selection of greens such as broccoli, cabbage and/or kale; tofu stir-fry with brown rice; lean steak with a selection of mashed root vegetables and steamed or boiled greens such as broccoli and kale; traditional or vegetarian bolognaise.

At a glance: foods to avoid during pregnancy

It is more helpful to think about all the delicious food you can eat rather than those you can’t when you are pregnant, but these are what you need to be careful with or avoid including¹⁰ :

- Undercooked or raw eggs – which may contain salmonella bacteria.
- Undercooked or raw meats and deli meats like salami, Parma ham and chorizo.
- Unpasteurised cheeses and/or some soft cheeses – the pasteurisation process removes potentially harmful bacteria like E. coli and listeria.
- High mercury fish such as swordfish or marlin.
- Smoked fish such as smoked salmon and smoked salmon pate – due to the risk of listeria bacteria.

Liver and/or liver pâté – liver and liver products can contain large amounts of vitamin A which may be harmful to your baby¹¹. All types of pates may contain listeria bacteria.

FAQs

Q. Can I eat sushi when pregnant?

A. You can only eat sushi if it is made with fish or vegetables that have been cooked such as cooked salmon, prawns and crab, or vegetables like avocado, cucumber and carrot. It is unsafe for pregnant women is sushi (or any dish) which contains raw fish and can potentially harbour parasites and bacteria - or fish that may be high in mercury.

Q. I am pregnant and vegan, how do I ensure I get enough calcium in my diet?

A. Calcium is a key nutrient needed during pregnancy for building baby’s teeth and bones so if you are excluding dairy products from your diet make sure you are getting it from alternative sources such as fortified plant milks, leafy green vegetables (including kale, spinach, broccoli), nuts (particularly almonds) and tofu.

Q. Is it safe drink small amounts of alcohol when pregnant?

A. No, there is no proven safe amount a woman can drink during her pregnancy and if you do, some of that alcohol will cross the placenta to the baby¹². The more you drink, at any stage in your pregnancy, the greater the risk of harm to your baby, which is why it is best avoided completely.

Q. I don’t eat fish; can I get enough omega 3 for my baby from other foods?

A. Omega 3 fatty acids fall into two main categories – DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid) which is found in fish and seafood and ALA (alpha-linolenic acid) which is a type of omega 3 found in a range of plant sources such as chia seeds, walnuts, hazelnuts, soybeans and plant oils such as flaxseed. The body can convert some ALA into EPA and DHA from these plant sources but only in small amounts. Omega 3 enriched eggs are good alternative sources. You might also consider taking an omega 3 supplement which contains EPA and DHA.