Second trimester nutrition

Second trimester nutrition

5 nutrients to focus on in the second trimester

Kelly Benton – Pregnancy & Baby Nutritionist

The second trimester is between weeks 13 and 27. For many women it is seen as a sunny period, where nausea subsides and energy returns, so you can start to be a bit more adventurous again when it comes to food.

Read on for 5 key nutrients to focus on in the second trimester:

  1. IRON

Blood volume increases progressively through pregnancy with an average increase of around 45% (Sanghavi, M. 2014). To cater for this, it recommended women consume 27mg of iron daily throughout pregnancy, up from 18mg/day in non-pregnant women (National Health and Medical Research Council [NHMRC], 2006). Iron is available through food in 2 main forms: Heme iron, which is found in meat, seafood, and chicken; and non-heme iron, which is found in plants, such as lentils, quinoa, beans, tomato puree, asparagus, and spinach. Heme iron has higher bioavailability, meaning your body will be able to absorb more, so it is a good idea to include in your diet regularly. You can still obtain iron if you are following a plant-based diet, however you will need to set your overall intake 1.8x higher to meet pregnancy needs. Lastly, it is a good idea to have your pregnancy care team check in on your iron levels throughout pregnancy, as supplementation may be required in some instances.


Whilst the NHMRC guidelines don’t recommend an increase in calcium during pregnancy (they are set at 1,000mg daily), it is important to be mindful of calcium-rich foods since 73% of women do not get enough calcium (Australian Institute of Health and Welfare, 2017). Focus on a range of calcium-rich foods daily, especially from 20 weeks onwards, to support the development of baby's skeletal system, muscles, and heart. Food sources include cheese, yoghurt, kefir, salmon, chia seeds and leafy greens. Calcium can impact iron absorption, so aim to separate iron-rich and calcium-rich meals to maximise your intakes of each mineral through food.


Proteins are the building blocks for muscle, bone, cartilage, skin, hair, and nails so it should be a huge focus from the second trimester. Protein supports foetal growth but is also necessary to support growth of the placenta and maternal skin, uterus, and breast tissue. Aim to include 1 palm sized portion of protein with main meals, such as fish, chicken, beef, or lamb. I also like to ensure snacks are balanced with protein to avoid blood sugar spikes, for example snacking on nuts & seeds, adding a good quality collagen or chia seeds into smoothies, and sprinkling hemp seeds on rice cakes with avocado and lemon.


In an ideal world, our vitamin D should be checked every trimester, especially after a change in season (such as winter). Vitamin D supports development and maintenance of bone health, which begins in utero (Luo et al., 2022). The best way to get vitamin D is through the sun. Aim for 15-20mins of sun exposure daily (safely of course), plus a variety of vitamin D-rich foods, including fatty fish, milk, and eggs. Vitamin D deficiency during pregnancy is prevalent globally, impacting 54% of pregnant women and 75% of newborns (Saraf et al., 2016), so although not routinely tested, I like to recommend women ask to be screened in pregnancy, especially if they are pregnant during winter.

  1. OMEGA 3 / DHA:

Researchers have found that over 95% of women don't meet their daily intakes of EPA and DHA (Zhang et al. 2018). These fatty acids are essential for infant brain development (which accelerates rapidly in the 3rd trimester), so increasing intake during the 2nd trimester will ensure you have a good level of stores to nourish baby. In addition, adequate intake of Omega 3’s can reduce risk of preterm birth and low birth weight babies (Middleton et al. 2018). Aim for 2-3 high quality portions of fatty fish weekly, such as wild caught salmon, sardines, cod, trout, tuna, and mackerel. If you are plant-based or don't consume fish, then good quality supplementation in the form of marine algae should be considered with the guidance of a health practitioner.


Lastly, aim to consume a whole foods diet rich in a variety of fresh vegetables, fruit, nuts, and seeds daily and vary your protein sources across the week, including fish, chicken, red meat, legumes, and eggs to maximise intake of all key nutrients required for a healthy pregnancy. If you are struggling with what to eat, reach out to your healthcare provider or a qualified nutritionist / dietitian for support.


Kelly Benton is a Nutritionist specialising in maternal and baby nutrition. She is a mother of two little ones, right there in the thick of it with you. After experiencing maternal nutrient depletion through her first pregnancy and postpartum period, Kelly saw a need to educate and empower other women to proactively take health into their hands so they can have a more positive experience. Kelly is available for 1:1 consults, to book please visit her website or Instagram page.



Australian Institute of Health and Welfare (2017). Risk factors for health. accessed 16th May 2023.

Luo T, Lin Y, Lu J, Lian X, Guo Y, Han L, Guo Y (2022). Effects of vitamin D supplementation during pregnancy on bone health and offspring growth: A systematic review and meta-analysis of randomized controlled trials. PLoS One. Oct 13;17(10):e0276016. DOI:

Middleton P, Gomersall JC, Gould JF, Shepherd E, Olsen SF, Makrides M. (2018). Omega-3 fatty acid addition during pregnancy. Cochrane Database Systematic Reviews. Nov 15;11(11):CD003402. DOI:

National Health and Medical Research Council (2006). Nutrient Reference Values for Australia and New Zealand. Version 1.2.

Sanghavi, M. and Rutherford, J.D. (2014) Cardiovascular Physiology of Pregnancy. Circulation, 130, 1003-1008. 

Saraf R, Morton SM, Camargo CA Jr, Grant CC. (2016). Global summary of maternal and newborn vitamin D status - a systematic review. Maternal and Child Nutrition. 2016 Oct;12(4):647-68. DOI:

Zhang Z, Fulgoni VL, Kris-Etherton PM, Mitmesser SH. (2018). Dietary Intakes of EPA and DHA Omega-3 Fatty Acids among US Childbearing-Age and Pregnant Women: An Analysis of NHANES 2001-2014. Nutrients. 2018 Mar 28;10(4):416. DOI:

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