Close this search box.

Week 1 to 12 – First Trimester

Your first trimester pregnancy is often spent getting used to the idea that you’re expecting a baby and reading up on all the changes that your body is going through and are yet to come.

Although it’s still early, adopting good eating habits now will give your baby the best chance of healthy development.

Your baby’s development during the
first trimester

During the first 5 weeks, the only sign of pregnancy may be the lack of your usual premenstrual symptoms. However, your baby’s vital organs are developing fast, including their heart. At the end of the first trimester, your baby has grown a lot: his arms and hands are developing as well as muscles and bones. At 12 weeks, your baby’s brain is continuing its development too. Long chain polyunsaturated fats (LCPs), especially docosahexaenoic acid (DHA), are an essential ingredient for healthy grey matter.

What should I eat and avoid during
the first trimester?

To support your baby’s healthy development, a healthy & complete diet is essential:

  • During early pregnancy, you’re advised to take supplements of folic acid to help reduce the risk of neural tube defects such as spina bifida. If you find out you’re pregnant and haven’t been taking folic acid supplements, don’t worry; simply start taking them straight away and carry on until you reach 12 weeks. It is recommended that you take 400mcg per day.
  • During pregnancy your immune system adapts to accept and protect your baby, as well as yourself. Now’s the time to give your immune system as much support as possible by eating healthily and being extra careful when preparing food. Don’t take any chances if something’s not as fresh as you’d like, avoid foods which could pose a risk, wash all food thoroughly and wash your hands regularly.
  • Iron is one of the key nutrients in a healthy pregnancy diet. It’s important for carrying extra oxygen around in your red blood cells and it’s needed for your baby’s developing brain. Low iron levels can cause anemia, which will leave you feeling tired, washed-out and generally unwell.
  • Try to include iron-rich foods in your diet by eating red meat, fish, eggs, dried fruit, fortified breakfast cereals, wholegrain breads and green leafy vegetables. These foods all contain a wide range of important nutrients in addition to iron. Iron is best absorbed by your body if you eat a vitamin C-rich food at the same time. Try a glass of orange juice with your breakfast cereal or fresh fruit as a starter to your main course. If your iron levels become low, your midwife may recommend an iron supplement. Supplements should only be taken if advised by your doctor or midwife, as not all supplements are safe for pregnancy.
  • Vitamins are important for health and development. Pregnant women are advised to take 10mcg of vitamin D per day. It’s important for bone and teeth formation yet it is only found at low levels in few foods and sunlight. However, some vitamins, such as vitamin A, can be harmful to your baby so always check with your doctor before taking any supplements during pregnancy. Even if you were taking a multi-vitamin supplement before you became pregnant, make sure you check its suitability with your doctor if you wish to continue taking it.
  • To support your baby’s brain development, try to include an extra 200mg of DHA each day. Oily fish are an excellent source and eating 1-2 portions of oily fish per week will provide sufficient DHA for you and your baby. However, it’s recommended that you eat no more than two portions per week due to the toxins they may contain. For a healthy intake of other Omega 3 fats on the days you don’t eat oily fish, snack on a handful of nuts or start your day with a bowl of wholegrain cereal.

During pregnancy, there are some foods to avoid for your health as well as for your baby’s health.

  • The following foods could make you ill as they may carry risks of food poisoning:
    • Raw or undercooked eggs; that includes any food that are made from them too (such as mayonnaise, certain ice cream and some home-made mousses)
    • Rare and undercooked meat, fish and chicken
    • Salmon tartare, smoked salmon and sushi or foods which contain raw meat and fish
  • Foods which contain elements that could harm your baby:
    • Unpasteurized milk, cheese or yogurt
    • Liver or products containing liver both carry a risk of listeria and may contain high levels of vitamin A which can harm your baby.
      Swordfish, marlin and shark can contain mercury which can harm your baby’s developing nervous system and should be avoided. Oily fish such as mackerel, tuna, sardines and trout may also contain small amounts of toxins but these fish also provide a healthy range of nutrients so should be included in your diet in moderate amounts – that’s why you’re advised to limit the consumption of the above to two portions a week.

Your health during the first trimester

During the first trimester, you might feel nauseous or experience morning sickness especially during the 6th and 8th week of pregnancy. Pregnancy hormones are building up which can lead to nausea. Eating little and often helps; many mums say a dry cracker in the morning before you get out of bed can help. Most importantly, try to stick to a healthy diet.

It’s usually worst around this period and for another few weeks, but by 12 to 14 weeks most mums feel no further symptoms. It’s worth remembering that nausea and morning sickness are completely normal during a healthy pregnancy.  

Further Reading

You’ve reached your second trimester. For most mums it’s a real milestone because it’s around now that you’ll want to start announcing the news to your friends and family.

As you approach the third trimester of pregnancy, your baby’s development is rapid and it’s common to experience aches and pains as the weight you’re carrying increases.

Important notice

By clicking on the "Continue" button, you can learn more about infant nutrition. If you choose to continue, you agree that Danone is supplying this information at your individual request for information purposes.

Breastmilk is the ideal food for infants: it is best adapted to their specific needs. A healthy and balanced diet of the mother is important for the preparation and continuation of breastfeeding. Mixed breastfeeding can interfere with breastfeeding and reduce milk production. It’s hard to reverse the choice of not breastfeeding. If an infant formula is used for a non-breastfed baby, it is important to carefully observe the instructions for preparation and use and to follow the advice of the medical profession. Incorrect use could pose a risk to the child’s health. Socio-economic implications must be considered in the use of infant formula. After 6 months, in addition to breastmilk, water is the only essential drink. Do not hesitate to consult your health care professional if you need advice on feeding your baby.