What a mother-to-be eats preconception, pre-implantation, during pregnancy, and throughout breastfeeding have each been linked to health outcomes in the development of the embryo, fetus, and the growing child. It’s been recently reported that dietary choices, including protein intake, may actually impact a child’s genes or DNA in the womb. Malnutrition before and during gestation can have many consequences for babies after birth, including metabolic disorders, organ dysfunction, and hormone imbalances.

That’s why a woman’s protein supply at each stage is important. Protein contains vital amino acids (the building blocks of proteins) and these are essential for making neurotransmitters, hormones, enzymes for metabolic reactions, and other cell-signalling molecules. We know that protein is important for moms-to-be before and during pregnancy, however, there has been controversy regarding how much protein is actually required and safe.

Preconception: protein for hormonal regulation

One main factor in hormonal regulation is weight management. We know that dietary choices and protein intake are key to achieving a healthy weight for pregnancy (this applies to both women and men who are underweight or overweight). Women who are underweight often stop ovulating and menstruating. On the other end of the BMI (body mass index) spectrum, it’s well understood that obesity can negatively and significantly impact egg quality due to resulting DNA damage. Similarly, obesity is linked to sperm DNA damage and decreased ejaculate volume in men. When we look at the numbers in obesity, losing even just 5% or more of total body weight can help improve reproductive function.

Combining exercise and nutritional changes can positively influence body composition. Women who are underweight and/or malnourished may wish to employ an exercise regime to improve strength and relieve stress, such as yoga. Combining this with increased caloric intake including a minimum of 65g of protein can assist in healthy weight gain.

Women who are overweight and looking to conceive should find an optimal and individualized exercise regime which may consist of more resistance-type exercise. In both situations, protein intake post-exercise is crucial for muscle recovery and growth. Studies have shown that dietary “protein-pacing” (ie. consuming 0.3g/kg body weight per meal or 1.4-2.0 g/kg body weight daily) when combined with lower carbohydrate diets (175g of carbohydrates daily or less) can lead to improvements in cholesterol levels, decreased body fat mass, increased lean body mass, improved insulin and blood sugar levels, and metabolic rates in both men and women.

Embryo development

Recent research has shown that multiple maternal factors, including nutritional status, affect conception and embryo development. Low protein intake surrounding conception can have negative impacts on embryo development, leading to the potential for slowed or halted embryo growth.

At its early stages of development, the embryo requires a great deal of cellular energy supplied by mitochondria (the “powerhouse” of the cell). In the time after the egg has been fertilized, but before it implants in the uterine wall, the embryo is extremely vulnerable to nutritional supply. When mitochondrial function is limited, we see poorer outcomes in embryo survival.

A low-protein diet has been linked to significantly less mitochondria around the cell nucleus (the “command centre” that contains the DNA). As well, both low and excessively high-protein diets have been associated with a decreased number of cells inside the embryo at its blastocyst stage (the same stage when embryos are retrieved and frozen for IVF procedures). There are even some studies that suggest protein deficiency before implantation (conception) also impact the future health of children after birth.  

The amino acid arginine plays a particularly key role in embryo and fetal development. Arginine supports the production of nitric oxide, an important factor in the growth of the embryo, but also in the formation of new blood vessels. Arginine also produces compounds called polyamines, without which the embryo cannot develop6.

Protein in pregnancy

Dietary protein is important in pregnancy as the placenta requires certain levels of amino acids for proper growth and development. Inadequate dietary protein can increase the risk of placental insufficiency and low infant birth weight, which can lead to other health issues such as cardiovascular disease, kidney disease, obstructive airway disease, and obesity later in life. Other negative outcomes of low maternal protein intake include increased risk of pre-eclampsia and pre-term labour.

Of course, too much of a good thing (protein) can cause problems as well. Although much less likely, it’s best not to consume an excessively high-protein diet either. So how much do you need?

The Takeaway

Our current estimated recommendations for daily protein intake during pregnancy is between 1.22-1.52g/kg body weight (pre-pregnancy) per day, with a higher intake required in the third trimester, or in women with high physical activity levels. On average this equates to about 80 – 110g of protein per day. This is supported by other studies showing that women who consumed 100g of high-quality protein per day had the best pregnancy outcomes (babies born at a healthy weight).

Whether you are planning on becoming pregnant sometime in the future, are actively trying now, or are currently expecting, it’s a good idea to make sure you’re getting enough protein in your diet every day.

To learn more about how you can support your fertility, or to book an appointment with Dr. Zadek ND, email us at info@conceivehealth.com or call (416) 364-2236.

Dr. Sarah Zadek ND is a licensed naturopathic doctor in Ontario with a clinical focus on women’s health, endocrinology and fertility. With her own health issues unsolved by medical doctors and specialists, Sarah turned to naturopathic medicine to help solve many of the ailments she had carried for years, including endometriosis and other autoimmune conditions. Her working background includes 14 years in pharmacy and experience as birth doula in the Greater Toronto Area. Dr. Sarah Zadek is a naturopathic doctor with Conceive Health, practicing at Lakeridge Fertility in Whitby.


  1. Chango A and Pogribny IP. Considering maternal dietary modulators for epigenetic regulation and programming of the fetal epigenome. Nutrients. 2015 Apr; 7(4): 2748-70
  2. Herring CM, et al. Impacts of maternal dietary protein intake on fetal survival, growth, and development. Exp Biol Med (Maywood). 2018 Mar; 243(6): 525-33
  3. Arciero PJ, et al. Protein-pacing caloric-restriction enhances body composition similarly in obese men and women during weight loss and sustains efficacy during long-term weight maintenance. Nutrients. 2016 Jul 30; 8(8): pii: E476
  4. Mitchell M, et al. Metabolic and mitochondrial dysfunction in early mouse embryos following maternal dietary protein intervention. Biol Reprod. 2009 Apr; 80(4): 622-30
  5. Fleming TP, Eckert JJ, Denisenko O. The role of maternal nutrition during the periconceptional period and its effect on offspring phenotype. Adv Exp Med Biol. 2017; 1014: 87-105
  6. Wu G, et al. Maternal nutrition and fetal development. J Nutr. 2004 Sep; 134(9): 2169-72
  7. Stephens TV, et al. Protein requirements of healthy pregnant women during early and late gestation are higher than current recommendations. J Nutr. 2015; 145(1): 73-8
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