Protein and pregnancy: why protein is important

Your body uses protein to build and repair cells, so it makes sense that when you’re pregnant and building a human, you need a sufficient amount of protein. It’s especially important in the second and third trimesters, when your baby is growing quickly.


What is protein?

Proteins are complex molecules that provide structure to bones, muscles, organs, and skin. Red meat, fish, and dairy provide protein, and  there are plenty of vegetarian and vegan sources too, such as lentils, beans, nuts, and nut butters, seeds, quinoa, and eggs. If you eat red meat, choose grass-fed beef that’s free of hormones and antibiotics. Grass-fed meat has higher levels of omega-3 fatty acids — anywhere from two to six times — and less saturated fat than grain-fed beef. It also has more antioxidants, vitamins, and conjugated linoleic acid (CLA), which supports heart health (1,2).


How does protein during pregnancy affect your baby’s development?

Protein provides building blocks for cells and is critical to your baby’s growth and development. It’s especially important for ensuring the proper growth of tissues and organs, including the brain. Protein increases blood supply, allowing more blood to be sent to your baby during pregnancy. It also helps with breast and uterine tissue growth, helping your body supply what baby needs (3).

Protein-rich foods are high in several nutrients your body requires more of during pregnancy (like vitamin B12, choline, zinc, and iron). When you meet your protein needs you’re also more likely to meet some of your increased vitamin and mineral needs as well.


Protein and vitamin B6

Protein works in combination with important vitamins like vitamin B6. B6 plays a role in the metabolism of protein, carbohydrates, and fats, as well as the production of neurotransmitters, and the formation of nicotinic acid. Vitamin B6 is essential for maintaining a healthy nervous system, and for skin, muscles, and blood. 

In relation to protein, vitamin B6 is vital for protein metabolism where it helps regulate the balance of amino acids in the body. The demands of pregnancy and lactation mean you need more vitamin B6. Look for a prenatal vitamin that includes B6. When you get the B6 your body needs, you also help maximize protein’s ability to work (4). 


Does protein help with blood flow?

Protein is vital for healthy blood supply. Your body requires additional blood volume during pregnancy, dramatically increasing blood supply to support your growing baby. In fact, by the time you give birth, your red blood cell mass will have increased by 20-30%. Protein is essential in facilitating the transport of blood throughout your body and in supplying blood to your baby (5).


Protein and healthy birth weight

Multiple research trials have found that protein intake is directly related to birth weight. Babies born to mothers who eat enough protein during pregnancy have a higher birth weight compared to babies born to mothers who don’t get enough. This is important since low birth weight can lead to problems such as increased risk for jaundice and respiratory distress syndrome (6).


How does protein affect your pregnancy?

Protein helps balance fluids in the body which can aid in maintaining normal blood pressure and prevent pregnancy swelling (7). Protein can also help support a healthy glycemic response, which is key for managing blood sugar and promoting a healthy weight gain during pregnancy. Protein is the most satiating macronutrient. It fills you up and helps manage cravings. Because protein builds the cells needed to carry oxygen and iron through the bloodstream it can also help prevent anemia, dizziness, and fatigue (8). Another important role for protein is collagen production. Collagen holds your connective tissue together, and is important for your growing uterus (9).


How much protein do you need during pregnancy?

The RDA for protein during pregnancy is 60 grams a day. However, that doesn’t take into account the fact that your body needs more protein as you progress through your pregnancy. Two Canadian researchers calculated that protein requirements are, on average, 1.2 grams per kilogram (g/kg) of body weight during early pregnancy (82 grams for a 150-pound woman) and 1.52 g/kg during late pregnancy (103 grams for the same sized woman) (10).


What happens when you don’t eat enough protein during pregnancy?

Protein has many essential roles to play in supporting a healthy pregnancy. It can also be detrimental to not get enough. Lack of proper protein in your diet can make you feel more tired, have trouble sleeping, or you may get sick more frequently. Inadequate protein during pregnancy may also increase your child’s risk for developing heart disease, obesity, or high blood pressure later in life (11).


What is the best form to get protein during pregnancy?

As with many nutrients, all forms of protein are not equal. The Digestible Indispensable Amino Acid Score (DIAAS) ranks proteins by quality. Scores over 100 indicate that if a person were to fulfill their entire day’s protein needs with that food, 100 percent of their amino acid requirements would be met. Because vegan proteins tend to have lower DIAAS values than animal proteins, vegans may need to eat more protein than other folks.

DIAAS Scores

Good sources of high-protein foods for pregnancy:

  • Superfoods such as low-mercury species of fish (small fish), eggs, beans, nuts, seeds, & quinoa
  • Grass-fed beef and free-range pork
  • Pastured chicken
  • Wild-caught salmon
  • Lamb
  • Nut butters
  • Dairy (if tolerated well)
  • Greek yogurt


    Vegan diets & protein for pregnancy

    Many of the nutrients commonly lacking in prenatal diets (such as choline, vitamin B12, iron, and DHA) are found in the highest amounts in animal products. Meeting vitamin and mineral needs through plant-based foods alone is difficult without supplementation during pregnancy (13).  


    Is protein powder during pregnancy safe?

    With protein being so important, you may wonder if it’s safe to drink protein shakes during pregnancy. It depends. While some protein powders and shakes may be safe, others contain ingredients such as herbs, caffeine, and high sugar that may be harmful. They may have excessive amounts of protein, they may contain additives, or they may be packed with vitamins and minerals already in your prenatal vitamin so you could end up getting more than you need (15).

    The best way to meet your protein needs is by eating a variety of protein-rich foods. Another great and easy way is to drink a protein shake made of certified organic ingredients. Mama Bird Plant Protein is an excellent source.


    (1) Grass-fed beef: is it good for you? Nourish by WebMD. Reviewed 2020 Sept 30. 

    (2) A review of fatty acid profiles and antioxidant content in grass-fed and grain-fed beef. Nutr J. 2010 Mar 10;9:10. doi: 10.1186/1475-2891-9-10.

    (3) Protein and Amino Acid Requirements during Pregnancy. Adv Nutr. 2016;7(4):839S-44S. Published 2016 Jul 15.

    (4) Vitamin B6, Science Direct.

    (5) Blood volume changes in normal pregnancy. Clin Haematol. 1985 Oct;14(3):601-12. PMID: 4075604.

    (6) Effects of nutrition interventions during pregnancy on low birth weight: an overview of systematic reviews. BMJ Global Health 2017;2:e000389.

    (7) Fluid balance concepts in medicine: Principles and practice. World J Nephrol. 2018;7(1):1-28.

    (8) Protein in Diet, MedlinePlus, U.S. National Library of Medicine.

    (9) Biochemistry, Collagen Synthesis. [Updated 2020 Sep 11]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan.

    (10) Protein and amino acid requirements during pregnancy. Adv Nutr. 2016 Jul;&(4):839S-844S. doi: 0.3945/ an.115.011817.

    (11) The effect of maternal protein deficiency during pregnancy and lactation on glucose tolerance and pancreatic islet function in adult rat offspring. J Endocrinol. 1997 Jul;154(1):177-85.

    (12) Food-first approach to enhance the regulation of post-exercise skeletal muscle protein synthesis and remodeling. Sports Med. 2019 Feb;49(Suppl 1):59-68. doi: 10.1007/s40279-018-1009-y. https://pubmed.ncbi.nlm.nihgov/30671904/

    (13) Adequacy and Sources of Protein Intake among Pregnant Women in the United States, NHANES 2003-2012. Nutrients. 2021;13(3):795. Published 2021 Feb 28.

    (14) Can you promote a healthy pregnancy before getting pregnant? National Institutes of Health. Reviewed 2019 March 28.

    (15) Harvard Health Publishing. 2020. The scoop on protein powder. Harvard Medical School. [Accessed September 2021]