Pregnancy Nutrition Guide: Trimester by Trimester
Pregnancy is one of the most transformative things your body will ever go through. From the moment you conceive, your body becomes the lifeline for a growing human. And what you eat really does matter. But alongside the excitement comes confusion. Questions like, “Should I be eating for two?”, “Can I still have soft cheese?”, or “Do I need supplements?” are incredibly common.
I’m Julia Scott, a New Zealand registered dietitian and mum, and I’m here to take the guesswork out of pregnancy nutrition. This guide is designed to walk you through what your body and baby need during each trimester—from key nutrients and practical food ideas, to how to stay safe with food and what supplements are actually necessary. Have a listen to the Podcast above for more detail.
First Trimester (Weeks 1–12): Survive, Then Thrive
The first trimester can be a whirlwind. Between the excitement and the exhaustion, food might be the last thing on your mind—especially if you're dealing with nausea, food aversions or fatigue. The good news is that your energy needs don’t increase much just yet. But the quality of what you eat does matter.
Nutrients to Prioritise
Folate/Folic Acid – This is absolutely critical in the first trimester to support early brain and spinal cord development. In fact, it’s best to take folic acid when you’re trying to conceive.
The NZ Ministry of Health recommends 800mcg/day until 12 weeks.
Food sources include leafy greens, legumes, oranges, and fortified breads.
Iron – Iron supports your expanding blood volume and helps form baby’s cells.
Found in red meat, lentils, tofu, and dark leafy greens.
Pair with vitamin C-rich foods like oranges or capsicum to enhance absorption.
Iodine – This mineral helps support baby’s brain development and thyroid health.
Use iodised salt and include eggs, seafood, and dairy.
Supplement with 150mcg daily throughout all of pregnancy and breastfeeding.
Vitamin B6 and Ginger – Both can help reduce nausea. You’ll find B6 in bananas, potatoes and wholegrains, and ginger in tea, capsules, and crystallised snacks.
Top tips: Small, frequent meals that include some protein can help keep nausea at bay. Try a dry cracker before getting out of bed and keep a snack stash handy.
Second Trimester (Weeks 13–26): Growing Stronger
This is often the trimester where you start to feel more like yourself. Nausea subsides, energy improves, and your appetite often comes back. Your baby is now growing rapidly, so your body needs more fuel—about 300 extra calories per day.
What to Focus On
Iron and Protein – Baby’s muscles, organs and tissues are forming fast. Keep up your intake of lean meat, chicken, tofu, legumes, and eggs.
Calcium – Your baby’s bones are forming and calcium needs are high. Aim for three servings of calcium-rich foods each day.
Think milk, cheese, yoghurt, calcium-fortified plant milks, tofu, and leafy greens.
Vitamin D – Crucial for calcium absorption and overall immunity.
Get some sun each day and include oily fish, eggs, and fortified foods.
Ask your midwife if you might need a supplement.
Omega-3s (especially DHA) – Essential for baby’s brain and eye development.
Oily fish like salmon and sardines are top sources.
Vegetarian? Opt for an algae-based DHA supplement. Chia seeds, flaxseeds and walnuts are also good sources.
Did you know? Around 20 weeks, your baby’s taste buds are developed and they're starting to taste the foods you eat via the amniotic fluid. A varied, colourful diet now could encourage adventurous eating later on.
Third Trimester (Weeks 27–40): Finishing Touches
The final stretch! Your baby is packing on weight and getting ready for birth. Energy needs now increase by around 450 calories a day to support rapid growth.
Nutrients That Really Matter Now
Iron – Most women need supplementation by this point. Iron deficiency can lead to fatigue, preterm delivery, or low birth weight.
Check your iron levels and include iron-rich meals with vitamin C boosters.
Protein – Still essential for growth and repair. Include protein in every meal and snack if you can.
Calcium – Baby draws about 250mg from you daily. Keep up those three servings per day.
Omega-3s – Baby’s brain is still developing rapidly, so keep up your fish intake or supplement.
Choline – Critical for brain development, placenta function and much more.
Eggs are a key source, along with legumes and soy products.
Zinc – Important for immune function and cell growth.
Include meat, seafood, legumes, seeds and wholegrains.
Heartburn or indigestion? Try smaller, more frequent meals, stay upright after eating, and avoid lying down right after dinner.
Hydration and Fibre: The Unsung Heroes
Your fluid needs increase during pregnancy to support blood circulation, digestion, and amniotic fluid. Aim for about 9 to 10 cups of fluids daily.
Water is best, but herbal teas, milk, smoothies, and juicy fruits and vegetables all count. If you're dealing with nausea, sipping through a straw or trying sparkling water can help.
Fibre is your ally too. Constipation is common in pregnancy due to hormonal changes and iron supplements.
Include wholegrains, legumes, fruit with skin, vegetables, nuts, and seeds daily.
Increase fluid intake alongside fibre to avoid making constipation worse.
Food Safety in Pregnancy
Pregnancy reduces your immune defences, which makes you more vulnerable to foodborne illnesses. Listeria and toxoplasmosis are some of the key ones to watch out for.
Avoid raw fish, rare or undercooked meat, deli meats (unless reheated), soft cheeses, and unpasteurised dairy.
Avoid pre-packed salads and ensure leftovers are reheated until piping hot.
Limit high-mercury fish like marlin or swordfish. Stick with salmon, tarakihi, hoki, or canned light tuna.
It’s not about being afraid of food—but being smart with your choices.
Recommended Supplements (NZ Guidelines)
The Ministry of Health New Zealand recommends:
Folic Acid – 800mcg daily until 12 weeks gestation.
Iodine – 150mcg daily throughout pregnancy and breastfeeding.
Iron – If your blood levels are low.
Vitamin D – Based on sun exposure and blood levels.
DHA – If not eating oily fish 2–3 times per week.
Popular pregnancy multivitamin options in New Zealand include Elevit, Blackmores, Clinicians PregaVit and Thompson’s. Always check the label and consult with your healthcare provider.
Final Thoughts: You’ve Got This
Pregnancy nutrition doesn’t have to be perfect. It’s about building balance, eating nutrient-rich whole foods, and being kind to yourself along the way. Some days will be better than others—and that’s okay. Every positive step you take helps support your baby’s development and your own wellbeing.
Stay hydrated, move your body gently, get as much rest as you can, and nourish yourself like you deserve.
Want more?
Listen to the Little Bites Podcast for baby and family nutrition support.