Nutrition for the first trimester

Finding out that you are pregnant brings much excitement and hope to you and your family.  With the miracle of a new life comes the responsibility of giving your baby the gift of a lifetime – good health. Your lifestyle and environment during pregnancy can influence baby health during infancy and into early childhood, so it is important to take extra care of yourself during this critical period.

Eating a balanced, nutritious diet is essential to maintain good physical condition for a healthy pregnancy. During the first trimester you do not need to consume any extra calories, however you do need to ensure you are getting good nutrition from your diet.

Key nutrients for first trimester


Folate is involved in the development of your baby’s neural tube which happens very early on in pregnancy. Commencing a prenatal multivitamin before you conceive helps to reduce the risk of neural tube defects. It is recommended to take a multivitamin containing 400mcg of folic acid at least 1 month prior to conceiving and throughout pregnancy and breastfeeding [1].

Dietary sources of folate:

Green vegetables: spinach, kale, silverbeet, asparagus
Legumes: lentils, beans, peas and chickpeas


Iodine supplementation is recommended during pregnancy to reduce the risk of deficiency which can cause abnormalities to the foetus. These risks are preventable by supplementing with iodine, and although you can get iodine from food, many diets do not include enough to support a healthy pregnancy [2].

Dietary sources of iodine:

Seaweed, dairy, iodized salt, seafood, eggs, prunes and lima beans


 Iron is needed for haemoglobin production (oxygen transport) & neural development. Requirements during pregnancy increase from 17mg to 27mg, however your prenatal multivitamin should cover this increase if you eat a well-balanced diet adequate in iron. Taking additional iron is not always necessary and can cause toxic effects in high doses. For this reason, it is important never to supplement with extra iron without having a blood test to confirm iron deficiency [3].

Dietary sources of iron:

Red meat, beans and lentils, dark green leafy greens

Omega-3 DHA 

DHA found in omega-3 is essential throughout your entire pregnancy and postpartum for the development of your baby’s brain, eyes and nervous system. Studies show that taking an omega-3 supplement during pregnancy may reduce the risk for pregnancy complications such as preeclampsia, preterm labour and low birth weight [4].

Dietary sources of DHA:

Fish: salmon, tuna, sardines, mackerel, herring


Drinking enough water is important during pregnancy as your body needs extra hydration to form the placenta and amniotic fluid which feed nutrients to your baby. You also need water for the extra blood volume and new tissues that you are building. Pregnant women should aim to drink at least 8-12 glasses of water a day [5].

Lifestyle choices in the first trimester

You should consider avoiding as many of the following as possible throughout your pregnancy, for some of the reasons listed below.

What to avoid Why?
Alcohol Alcohol is toxic and can retard fetal brain development, body growth and cause circulatory problems.
Smoking Restricts oxygen and fetal blood delivery, increases blood pressure, restricts growth of organs and damages immune system. Exposure to second hand smoke increase chemical toxins in your bloodstream, which cross the placenta.
Drugs Many recreational drugs and medications can cause irreversible birth defects.
Caffeine Low amounts are suitable (less than 200mg per day) which is around 1-2 cups of coffee or tea. Higher amounts can affect development and increase risk of maternal complications. Restrict caffeine intake to 1 cup of tea or coffee a day.
Fish with high mercury content (shark, flake, swordfish, marlin, orange roughy, barramundi, ling) Mercury from regularly consuming some types of fish can significantly impair development, especially brain formation. Reduce intake to once a fortnight during pregnancy. Salmon, canned tuna or prawns are a good substitute.
Raw seafood/fish & Undercooked (rare) meat May contain bacteria that can cross the placental barrier and harm your unborn baby, even though you may not be affected.  Avoid eating raw seafood and fish and ensure that chicken, beef, pork are cooked properly.
Processed meats, hams and unpasteurized products (soft cheeses) May contain bacteria that are harmful to your baby. Always check the expiration dates on product packaging.
Food handing (raw meat, chicken, unwashed salads, vegetables); exposure to soil, cat litter Can increase risk of harmful bacterial infections.  Take extra care when preparing food or gardening.  Always wash hands with soap straight after or use gloves.

Remember that all nutrients are important and eating a balanced diet is the best way to support a healthy pregnancy.

For additional information, here is a list of important vitamins and minerals that play a role in early pregnancy.

Nutrient Dietary Sources Function
Folic acid (folate) Green leafy vegetables Early brain and heart development, DNA synthesis, rapid cell division in all fetal organs
Zinc Seafood

Lean meat

Implantation, general cell development, differentiation and growth, tissue healing
Vitamin D Sunlight exposure



Placenta formation, metabolic processes, gene transcription and regulation of important developmental stages
Iron Red meat



Haemoglobin production (oxygen transport) & neural development.
B vitamins Lean meat



Neural tube development, general cell development. Important for red blood cell production (fetal circulation)
Iodine Seafood



Brain, neural development, general growth, metabolism
Omega-3 fatty acids (DHA & EPA) Seafood


Brain & neural development, early behaviour, general growth
Vitamin C Citrus fruits

Tropical fruits

Cell and protein metabolism, increase iron absorption, antioxidant support
Vitamin E Nuts


Antioxidant support, cell growth and development
Magnesium Vegetables,

Nuts & seeds

Meat & seafood

Cell & tissue development (skeletal formation)
Calcium Dairy

Green vegetables

Sesame seeds

Skeletal formation, regulate circulatory system
Beta-carotene Carrots

Sweet potato


Antioxidant protection, eye development, general growth and development
  4. Middleton P, et al. Cochrane Database Syst Rev. 2018 Nov 15;11(11):CD003402
Author: adminsg