The Second Trimester: What Is Happening in Your Body and What Does It Need?

The second trimester is often described as the “easier” part of pregnancy. You may feel nausea starting to settle, appetite coming back and energy improving. Your bump becomes more noticeable, you may feel your baby moving for the first time (the most bizarre yet beautiful feeling!)

But feeling better doesn’t mean your body is doing less. Between approximately weeks 13 and 27, your baby goes through an extraordinary period of growth. The brain and nervous system are developing rapidly, bones are becoming stronger, muscles are developing and organs continue to mature.

At the same time, your own body is changing to support all of this. Your blood volume is expanding, your heart is bumping harder, your uterus is growing, your metabolism is adapting and your nutritional requirements are changing.

This is why I think of the second trimester as a period of growth and nourishment, and once you understand what is happening inside your body, it becomes much easier to understand what it needs.

1. Your baby is growing (fast!)

Your baby's skeleton continues to develop and mineralise. Muscles become stronger and movements become more coordinated. The lungs continue developing and the brain and nervous system become increasingly sophisticated.

All of this growth requires building material: Protein!! Healthy fats and many other nutrients!

Protein provides the amino acids needed to build new tissues. Healthy fats provide important components for developing cells and the nervous system. Nutrients such as iron, iodine, choline, calcium and zinc all have important roles during this period.

This doesn't mean you suddenly need to eat huge amounts of food, it means that the nutritional quality of what you eat becomes increasingly important.

Try to build most of your meals around:

• a good source of protein - pasture-raised meet and eggs, wild sourced fish, as well as slightly increasing the quantity eaten

• plenty of vegetables of all the different 5 colours - different colours mean different nutrients

• healthy fats like olive oil, coconut oil or avocado

• quality carbohydrate sources (prefer the whole grains and potatoes or sweet potatoes)

• fruit (variety is key) as something sweet (because I know we need it!)

• drinking enough water

2. Your baby's brain is developing rapidly

Neurons continue to develop and organise, connections within the nervous system become increasingly complex and your baby's sensory systems continue to mature. During this trimester, your baby also begins to hear sounds.

Several nutrients are particularly important here:

• DHA is an important structural component of the brain and retina.

• Choline contributes to brain and nervous system development and is involved in cell membranes and methylation.

• Iodine is necessary for thyroid hormone production, which plays an essential role in fetal brain development.

• Iron supports oxygen delivery and neurological development.

How can you support this?

• Include low-mercury oily fish such as salmon, sardines or trout regularly for DHA.

• Eggs are one of the most practical dietary sources of choline, alongside fish, meat, dairy and soy.

• Fish, dairy products, eggs and iodised salt can contribute iodine, although intake varies considerably depending on your diet and where you live.

• For iron, include foods such as meat, poultry, fish, lentils, beans, tofu and leafy greens. Pairing plant sources with vitamin-C-rich foods can improve iron absorption.

• Your prenatal supplement can help fill nutritional gaps, but it shouldn't replace a nutrient-dense diet.

3. Your blood volume is increasing

Your body needs to supply your growing uterus and placenta while continuing to meet your own needs. Plasma volume increases substantially and your body also needs to produce more red blood cells. This makes iron particularly important during the second half of pregnancy.

If iron intake and maternal stores cannot keep up with increasing demand, iron deficiency can develop. This is worth paying attention to because symptoms such as tiredness, weakness or breathlessness can easily be dismissed as simply being part of pregnancy.

How can you support this?

Include every day on your diet at least 3 of these:

• red meat

• poultry

• sardines and other fish

• lentils, beans and chickpeas

• tofu

• pumpkin seeds

• leafy green vegetables

When eating plant sources of iron, combine them with vitamin C: lentils with peppers, or beans with tomatoes or leafy greens with lemon.

Your iron status should also be monitored during pregnancy. If your stores become low, food alone may not always be enough and supplementation may be needed under the guidance of your healthcare professional.

4. Your baby's skeleton is becoming stronger

Your baby's skeleton begins as relatively soft tissue and progressively mineralises throughout pregnancy. Calcium is an important part of this process, but it doesn't work alone. Vitamin D supports calcium absorption and bone mineralisation, while magnesium participates in many processes involved in normal bone and muscle function.

Your body is remarkably good at prioritising calcium delivery to your baby, which makes meeting your own needs important too.

How can you support this?

Eat at least 1 of these per day:

• yoghurt and other dairy products

• sardines with bones

• tahini

• almonds

• calcium-fortified foods where appropriate

Vitamin D is more difficult to obtain from food alone. Oily fish and egg yolks provide some, but your needs can vary according to your baseline vitamin D status, diet and sun exposure.

5. Your digestive system may feel different

Progesterone relaxes smooth muscle and can slow gastrointestinal motility. At the same time, your uterus is becoming larger and gradually changing the physical space available to your digestive organs. That is why you may start noticing:

• constipation

• bloating

• heartburn or reflux

• feeling very full after meals

These symptoms are common, but there are things you can do to make digestion more comfortable.

How can you support this?

Before taking any supplement to alleviate the discomfort, try to manage it through diet:

• Focus on fibre-rich foods such as vegetables, fruit, legumes, oats, chia seeds, ground flaxseed, kiwi and prunes.

• Drink water regularly throughout the day and keep moving. Even a short walk after a meal can support digestion.

• If large meals are becoming uncomfortable, try slightly smaller meals distributed throughout the day.

  
  

6. Your glucose metabolism is changing too

As pregnancy progresses, your body naturally becomes somewhat less sensitive to insulin. This is part of the metabolic adaptation of pregnancy and helps maintain glucose availability to support the growing baby.

Most of us compensate by producing more insulin. However, if your body cannot compensate sufficiently, you may develop gestational diabetes. This is one reason gestational diabetes screening is commonly performed around weeks 24 to 28.

You don't need to eliminate carbohydrates to support healthy glucose regulation. Instead, pay attention to how you build  and eat your meals: always combine carbohydrates with protein, healthy fats and fibre AND eat first fibre and protein and only carbohydrates later. For example:

• Greek yoghurt + berries + chia seeds rather than fruit alone.

• Oats + yoghurt + nuts and seeds rather than a sweet breakfast cereal.

• vegetables + salmon + potatoes+ olive oil

Walking after meals can also support glucose regulation, so don't forget to walk your steps after eating.

7. What about supplements?

By the second trimester, I would pay particular attention to folate, iron, iodine, choline, vitamin D, calcium and omega-3s, particularly DHA.

When choosing a prenatal, actually read the amounts rather than relying on the word “prenatal” on the front. As a practical starting point, look for one providing 400 to 800 mcg of methylfolate/5-MTHF, around 150 mcg of iodine from the supplement, vitamin D, and iron appropriate to your individual needs; total iron requirements during pregnancy are around 27 mg/day, but additional iron should take your blood results and diet into account.

Then check if those are there:

• choline: pregnancy needs are around 450 mg/day, yet many prenatals contain little or none

• DHA is frequently sold separately.

• Calcium is also difficult to fit adequately into a prenatal, thta's why you should eat calcium-rich foods in parallel.

Don't assume higher doses make a prenatal better: more is not always safer in pregnancy, particularly with nutrients such as preformed vitamin A, iodine and iron. Your prenatal should complement what you eat and your individual needs, not try to provide everything in one capsule.

8. Movement helps your body adapt

If your energy has returned, the second trimester can be a good time to continue or establish a regular movement routine, provided there is no medical reason for you to restrict exercise.

Walking, pregnancy-appropriate strength training, swimming, mobility work and prenatal exercise can all be useful depending on your fitness level and pregnancy.

9. Feeling better doesn't mean you need less rest

One thing I think we underestimate during the second trimester is the need for recovery.

When the exhaustion and nausea of early pregnancy finally improve, it can be tempting to go straight back to doing everything you were doing before. However, your body hasn't suddenly stopped working hard.

Rest doesn't necessarily mean sleeping. Sometimes it means sitting down for 20 minutes. Having lunch away from your computer. Not filling every evening with plans. Taking a slower day after a busy one.

10. Sleep deserves attention too

Sleep can change throughout pregnancy. Some women sleep better during the second trimester than they did during the first. Others begin experiencing more frequent urination, reflux, leg cramps, vivid dreams or difficulty finding a comfortable sleeping position as their bump grows.

Rather than waiting until sleep becomes a major problem, start protecting it now.

• Try to maintain relatively consistent sleep and wake times.

• Get daylight and movement during the day.

• Start slowing things down before bedtime.

• Avoid very large meals close to bed if reflux is becoming a problem.

• Use pillows to make your sleeping position more comfortable as your body changes.

• And perhaps most importantly, don't repeatedly sacrifice sleep because you feel more energetic again.

Bringing it all together: What should you focus on during the second trimester?

Come back to the fundamentals:

• Protein: Include a good source with each main meal.

• Omega-3 fats: Include low-mercury oily fish regularly and consider DHA supplementation when appropriate.

• Iron: Eat iron-rich foods regularly and monitor your iron status during pregnancy.

• Choline: Include foods such as eggs, fish, meat, dairy and soy.

• Calcium + vitamin D: Support your baby's developing skeleton while meeting your own needs.

• Colourful plants: Eat a variety of vegetables and fruit rather than searching for one perfect “superfood.”

• Fibre + hydration: Support digestion and bowel regularity.

• Movement: Stay active in a way that is appropriate for your pregnancy and your body.

• Sleep + rest: Don't wait until you're exhausted to prioritise recovery.

• Stress recovery: You don't need to eliminate stress. Give your nervous system opportunities to come down from it.

• Supplements: Use them intentionally to complement your diet and individual needs rather than taking more simply because you're pregnant.

How I support women during pregnancy

There is an enormous amount of pregnancy information available. The difficult part is often knowing what actually applies to you.

You may know that iron is important, but are your iron stores actually low?

You may already take a prenatal, but does it provide enough of the nutrients that are difficult to obtain from your particular diet?

You may be struggling with constipation, reflux, exhaustion or poor sleep and wondering what is a normal part of pregnancy, what you can improve and what deserves further investigation.

This is where personalised pregnancy care can make a difference.

When I work with a woman during pregnancy, we look at the whole picture: her diet, symptoms, lifestyle, medical and pregnancy history, blood results when available, current supplements, digestion, sleep, movement and stress. Then we decide what actually needs attention.

That may mean improving meal composition, increasing specific foods, correcting nutritional gaps, reviewing supplements, supporting digestion, adapting movement, working on sleep or simply helping her understand which things are worth prioritising and which ones she doesn't need to worry about.

The plan evolves with pregnancy. What your body needs at 14 weeks may not be what it needs at 34 weeks. And what you need during pregnancy isn't necessarily what you'll need once your baby is here.