nutrients for the third trimester

The third trimester is officially Weeks 28-40 in pregnancy, and this is when a few more changes start happening. Baby’s nutritional needs reach their peak during this time of rapid growth, so it’s important to take a final check on diet and supplements for these last few weeks leading into delivery AND postpartum.

Protein and iron needs increase during the second trimester, and these are still two crucial nutrients in the third trimester. Protein actually increases a little more now and both protein and iron are needed to maintain the increase in blood volume, the rapid growth and cellular development of baby, along with ensuring healthy placental growth.

Don’t forget that the first trimester nutrients are still crucial throughout the rest of pregnancy too!

Vivienne-Stallwood-Third-Trimester-Nutrients-Nutritionist-Prenatal

Calcium continues to play a key role, and the two other nutrients that are very important in relation to this are the fat soluble vitamins – D3 and K2.

Vitamin D3 is always on my radar throughout pregnancy, and this is a nutrient that’s often depleted. It’s particularly important in pregnancy for both you and baby. Requirements are often higher than the dose found in a prenatal supplement, and it’s worth considering checking your blood levels to determining the correct D3 supplement dose for you. The importance of this vitamin has become widely recognised, but K2 – this is actually becoming more and more recognised for its role during pregnancy.

The role of K2 during pregnancy is especially fascinating, and is known to cross the placenta efficiently, particularly during the third trimester. Vitamin K2 has a different role to K1, and is required for depositing calcium into bones. Babies rely on their mothers stores as the GI tract of a fetus isn’t mature enough to make its own K2, therefore supplementation is often recommended.

Diet should always be first choice and you’ll find this nutrient in foods including – 

  • Egg yolks from pasture raised chicken

  • Grass-fed butter

  • Fermented foods like sauerkraut & kefir

  • Pork chops (boneless)

  • Ribs on the bone

  • Ghee

You may already be aware that Vitamin K1 is known for its blood clotting abilities, and is found mostly in green leafy vegetables. Deficiency is rare in adults, but newborns are commonly deficient in this nutrient because it doesn’t cross the placenta well (for reasons we still don’t fully understand). Because of this deficiency in newborns, they’re routinely given an injection of synthetic vitamin K at birth, and you’ll be given all of the information pertaining to this from your healthcare provider.

One final point to mention about vitamin K2 is that it has a very high transfer rate to breast milk, and colostrum contains much higher amounts of K2 than mature milk. Breastfeeding (ideally from a well nourished momma) within the first hour after birth is beneficial and will be encouraged by your midwife. There are many other reasons for breastfeeding early – this is just one of them!


Omega-3’s, especially DHA, along with choline and probiotics are other nutrients that I recommend in the third trimester (if you’re not already taking them). These are required to support your gut health, along with the the significant brain growth and development in baby that happens during the third trimester.

We’ll be talking more in-depth about these nutrients soon!

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