Pregnancy Nutrition: What to Eat by Trimester for a Healthy Baby

Claire's confusion is universal. Pregnancy nutrition advice is everywhere—and it's often contradictory, outdated, or downright wrong. After 15 years working with over 200 pregnant women across Essex, I've learned that pregnancy nutrition tips need to be clear, evidence-based, and actually achievable.

This guide provides practical, science-backed advice on what to eat during pregnancy, following NHS pregnancy diet guidelines and NICE recommendations for antenatal nutrition.

Why Pregnancy Nutrition Matters: More Than "Eating for Two"

Let's start with the truth: You're NOT eating for two adults. You're eating for one adult and one rapidly developing baby whose nutritional needs are TINY in calorie terms but HUGE in nutrient terms.

The Reality of Pregnancy Calorie Needs:

• First Trimester (Weeks 1-12): NO extra calories needed. Maintain your pre-pregnancy intake (~2,000 calories/day for most women).
• Second Trimester (Weeks 13-27): Add ~300-350 extra calories daily (equivalent to 1 sandwich or 1 smoothie).
• Third Trimester (Weeks 28-40): Add ~450 extra calories daily (equivalent to 1 meal snack with protein + carbs).

But calories are only PART of the story. Nutrient density is what matters. Your baby needs specific vitamins, minerals, and macronutrients to develop properly—and deficiencies can have serious consequences.

Essential Nutrients During Pregnancy: What Your Baby Actually Needs

Here are the critical nutrients for pregnancy nutrition and why they matter:

1. Folic Acid (Folate) - THE Most Critical Nutrient

• Why: Prevents neural tube defects (spina bifida, anencephaly). Critical for spinal cord and brain development in first 12 weeks.
• How Much: 400 micrograms (mcg) daily from pre-conception through week 12. Some women need 5mg daily (if you have diabetes, obesity, or family history of neural tube defects—check with GP).
• Food Sources: Leafy greens (spinach, kale), fortified cereals, beans, lentils, oranges, asparagus.
• Supplement: YES—take a folic acid supplement. You CANNOT get enough from food alone during pregnancy.

2. Iron - Prevents Anemia & Supports Baby's Growth

• Why: Your blood volume increases 50% during pregnancy. Iron makes hemoglobin, which carries oxygen to you and baby. Deficiency causes fatigue, breathlessness, and increases preterm birth risk.
• How Much: 27mg daily (nearly double your pre-pregnancy needs).
• Food Sources: Red meat, chicken, fish, beans, lentils, fortified cereals, dark leafy greens. Pair with vitamin C (orange juice, tomatoes) to increase absorption.
• Supplement: Take iron if your midwife recommends it (many pregnant women become anemic by third trimester).

3. Calcium - Builds Baby's Bones & Teeth

• Why: Baby needs calcium for skeletal development. If you don't eat enough, baby will take it from YOUR bones.
• How Much: 1,000mg daily (same as pre-pregnancy, but critical during pregnancy).
• Food Sources: Dairy (milk, yogurt, cheese), fortified plant milk, tinned fish with bones (salmon, sardines), tofu, almonds.

4. Protein - Essential for Baby's Growth

• Why: Builds baby's tissues, organs, and muscles. Also supports placenta development.
• How Much: 70-100g daily (increases throughout pregnancy).
• Food Sources: Lean meat, poultry, fish, eggs, beans, lentils, tofu, Greek yogurt, nuts.

5. Omega-3 Fatty Acids (DHA) - Brain & Eye Development

• Why: Critical for baby's brain and eye development, especially in third trimester.
• How Much: 200-300mg DHA daily.
• Food Sources: Oily fish (salmon, mackerel, sardines—2 portions weekly max), walnuts, chia seeds, flaxseeds. Consider algae-based DHA supplement if vegetarian/vegan.

6. Vitamin D - Bone Health & Immune Function

• Why: Helps absorb calcium. Supports immune system. UK sunlight is insufficient for adequate vitamin D year-round.
• How Much: 10 micrograms (400 IU) daily.
• Food Sources: Oily fish, egg yolks, fortified foods.
• Supplement: YES—NHS recommends ALL pregnant women take vitamin D supplement (10mcg daily).

What to Eat During Pregnancy: Trimester-by-Trimester Guide

Here's your practical guide for what to eat during pregnancy across each trimester:

First Trimester (Weeks 1-12): Surviving Nausea & Building Foundations

Common Challenges: Nausea, food aversions, fatigue, vomiting.

Nutrition Goals: Take folic acid, maintain hydration, eat what you can tolerate.

What to Prioritize:

• Folic Acid Supplement: 400mcg daily (non-negotiable).
• Small, Frequent Meals: Eating every 2-3 hours prevents blood sugar crashes (which worsen nausea).
• Bland, Easy Foods: Toast, crackers, bananas, rice, pasta, potatoes. No judgment—survival mode is valid.
• Protein with Every Meal: Helps stabilize blood sugar. Try eggs, chicken, beans, or Greek yogurt.
• Ginger: Ginger tea, ginger biscuits, or ginger chews can reduce nausea.
• Hydration: Sip water throughout the day. Dehydration worsens nausea.

Foods to AVOID (First Trimester & Beyond):

• Soft cheeses (brie, camembert, feta) - risk of listeria
• Unpasteurized dairy products
• Raw or undercooked eggs (check for British Lion stamp for safe eggs)
• Raw or undercooked meat/fish
• Pâté (all types) - listeria risk
• Liver and liver products - high vitamin A can harm baby
• High-mercury fish (shark, swordfish, marlin)
• Alcohol

Second Trimester (Weeks 13-27): Building Baby & Feeling Better

Common Changes: Energy returns! Appetite increases. Nausea usually subsides. Baby is growing rapidly.

Nutrition Goals: Increase calories by 300-350/day. Focus on nutrient-dense foods. Build iron stores.

What to Prioritize:

• Protein at Every Meal: 25-30g protein per meal. Baby is growing rapidly and needs amino acids.
• Iron-Rich Foods: Red meat 2-3x weekly, beans, lentils, fortified cereals. Pair with vitamin C.
• Colorful Vegetables: Aim for 5+ portions daily. Different colors = different nutrients.
• Healthy Fats: Avocado, nuts, seeds, olive oil. Supports baby's brain development.
• Whole Grains: Brown rice, quinoa, oats, whole wheat bread. Provides sustained energy and fiber (prevents constipation).
• Dairy or Fortified Alternatives: 3 portions daily for calcium. Milk, yogurt, cheese, or fortified plant milk.

Sample Second Trimester Day:

• Breakfast: Porridge with berries, nuts, and Greek yogurt (350 cal, 18g protein)
• Snack: Apple with peanut butter (200 cal, 8g protein)
• Lunch: Chicken and avocado sandwich on whole wheat bread + side salad (450 cal, 30g protein)
• Snack: Carrot sticks with hummus (150 cal, 6g protein)
• Dinner: Salmon fillet with sweet potato and broccoli (500 cal, 35g protein)
• Evening Snack: Glass of milk + 2 oat biscuits (200 cal, 8g protein)

Total: ~1,850 calories, 105g protein (perfect for second trimester).

Third Trimester (Weeks 28-40): Fueling the Final Stretch

Common Challenges: Heartburn, feeling full quickly (baby pressing on stomach), swelling, fatigue.

Nutrition Goals: Increase calories by 450/day. Focus on iron, calcium, protein. Eat smaller, frequent meals.

What to Prioritize:

• Frequent Small Meals: Eat every 2-3 hours. Prevents heartburn and manages blood sugar.
• Iron-Rich Foods: Critical in third trimester. Many women become anemic—prioritize red meat, beans, fortified cereals.
• Omega-3s: Baby's brain development accelerates. Aim for 2 portions of oily fish weekly (salmon, mackerel).
• Dates: Research shows eating 6 dates daily from 36 weeks may shorten labor. Worth trying!
• Fiber: Constipation worsens in third trimester. Eat oats, whole grains, fruits, vegetables, prunes.
• Hydration: 2.5-3 liters daily. Reduces swelling and prevents dehydration.

Managing Third Trimester Challenges:

• Heartburn: Avoid spicy/acidic foods, eat smaller meals, don't lie down immediately after eating.
• Feeling Full: Prioritize nutrient-dense foods (nuts, avocado, smoothies) over high-volume, low-calorie foods.
• Swelling: Reduce salt intake, elevate feet, stay hydrated (counterintuitively, water reduces swelling).

Pregnancy Nutrition Tips: Common Mistakes to Avoid

Here are the most common pregnancy nutrition mistakes I see clients make:

Mistake 1: Skipping Breakfast

Why it matters: Blood sugar crashes quickly during pregnancy. Skipping breakfast causes fatigue, nausea, and cravings later. Eat within 1 hour of waking—even just toast with peanut butter.

Mistake 2: Not Eating Enough Protein

Why it matters: Baby is built from protein. Insufficient protein = muscle loss for YOU, suboptimal growth for baby. Aim for 20-30g per meal.

Mistake 3: Avoiding All "Unsafe" Foods Out of Fear

Why it matters: The "avoid" list is shorter than you think. Don't eliminate entire food groups unnecessarily. Pasteurized dairy, British Lion eggs, and cooked meat are all SAFE.

Mistake 4: Drinking Coffee/Caffeine in Excess

Why it matters: Limit to 200mg caffeine daily (2 cups of instant coffee or 1.5 cups of filter coffee). Excessive caffeine increases miscarriage risk.

Mistake 5: Taking Herbal Supplements Without Checking Safety

Why it matters: Many herbal teas and supplements are UNSAFE during pregnancy (e.g., St. John's Wort, high-dose vitamin A). Always check with your midwife before taking ANYTHING beyond standard pregnancy vitamins.

Supplements During Pregnancy: What You Actually Need

You CANNOT get all necessary nutrients from food alone during pregnancy. Here's what to take:

Essential Supplements (Take Daily):

• Folic Acid: 400mcg daily (or 5mg if high-risk). Start pre-conception if possible, continue through week 12.
• Vitamin D: 10mcg (400 IU) daily throughout pregnancy and breastfeeding.

Optional But Recommended:

• Pregnancy Multivitamin: Easier than taking multiple individual supplements. Look for one containing folic acid, vitamin D, iron, and omega-3.
• Iron: If your midwife diagnoses anemia or low iron stores.
• Omega-3/DHA: If you don't eat oily fish twice weekly.

Avoid These Supplements:

• Vitamin A supplements (retinol form—toxic to baby)
• Fish liver oil (contains vitamin A)
• High-dose multivitamins not designed for pregnancy

Frequently Asked Questions: Pregnancy Nutrition

Can I drink coffee during pregnancy?

Yes, but limit to 200mg caffeine daily (approximately 2 mugs of instant coffee or 1.5 mugs of filter coffee). Excessive caffeine is linked to miscarriage and low birth weight. Remember caffeine is also in tea, cola, energy drinks, and chocolate. Switch to decaf or limit to 1-2 cups daily. Herbal teas (e.g., peppermint, ginger) are generally safe but check specific types—some herbs are unsafe during pregnancy.

Is it safe to eat fish during pregnancy?

Yes! Fish is excellent for baby's brain development. Eat 2 portions of fish weekly (1 portion = 140g), including 1 portion of oily fish (salmon, mackerel, sardines). AVOID high-mercury fish: shark, swordfish, marlin. Limit tuna to 2 steaks or 4 cans weekly (fresh/frozen). All other fish and seafood are safe if fully cooked. Omega-3s in fish are critical for baby's cognitive development.

What if I'm vegetarian or vegan during pregnancy?

You can have a healthy pregnancy on a plant-based diet—but you need to plan carefully. Focus on protein (beans, lentils, tofu, tempeh, nuts), iron (fortified cereals, beans, leafy greens—pair with vitamin C), calcium (fortified plant milk, tofu, tahini), B12 (fortified foods or supplement), and omega-3s (chia seeds, flaxseeds, walnuts, algae-based DHA supplement). Consider working with a registered dietitian to ensure you're meeting all nutrient needs.

How much weight should I gain during pregnancy?

It depends on your pre-pregnancy BMI. NHS guidelines: Underweight (BMI <18.5): 12.5-18kg; Normal weight (BMI 18.5-24.9): 11.5-16kg; Overweight (BMI 25-29.9): 7-11.5kg; Obese (BMI 30+): 5-9kg. Weight gain should be gradual—most occurs in second and third trimesters. Don't "diet" during pregnancy, but also don't use pregnancy as an excuse to eat excessively. Focus on nutrient-dense foods and listen to your hunger cues.

What should I do about food cravings and aversions?

Cravings are normal (80-90% of pregnant women experience them). It's fine to indulge occasionally—but if you're craving non-food items (pica—e.g., ice, dirt, chalk), tell your midwife immediately (it's often a sign of iron deficiency). Food aversions are also normal, especially in the first trimester. If you can't stomach vegetables, try hiding them in smoothies or soups. If you can't eat meat, get protein from eggs, beans, dairy, or nuts. Do your best, but don't stress—baby is resilient.

Last updated: November 26, 2025 | Serving Epping Forest District: Epping, Loughton, Chigwell, Buckhurst Hill, Waltham Abbey, Theydon Bois, Debden, and surrounding Essex communities.