Protein is one of the most important, and often most overlooked, nutrients for fertility, pregnancy, and postpartum recovery. Far beyond building muscle, high-quality protein supports hormone health, egg and sperm health, blood sugar stability, placental development, and fetal growth. And during pregnancy and breastfeeding, your protein needs rise even higher to fuel your energy, expand blood volume, and support tissue repair.
In this guide, we break down the research on protein for fertility and pregnancy, the benefits of whey protein vs. plant-based protein, and what to know about heavy metals in protein powders so you can choose the cleanest, safest option. Whether you're trying to conceive or already expecting, understanding your protein needs can help optimize your health, and your baby’s development, from day one.
Why protein matters for fertility and pregnancy
Protein does far more than build muscle, it’s one of the most important nutrients for your hormones, fertility, and your baby’s healthy development. Every cell in your body relies on dietary protein not only for tissue growth, but also to regulate the complex hormonal and metabolic processes, nourish eggs and sperm, build the placenta, and even support breast milk production.
From preparing your body for conception to supporting your energy and recovery after birth, getting enough high-quality protein is essential. Adequate protein intake remains essential postpartum as well, aiding in tissue and muscle repair, sustaining energy, and supporting breastmilk production. And it’s not just a “her” nutrient, men need adequate protein, too, to promote optimal sperm quality and hormone health.
1. Protein and hormone production
Your hormones rely on protein as it plays a key role in hormone production and signaling throughout the body. Every time you eat a protein-rich meal, your body uses amino acids to create and regulate gut hormones involved in appetite, satiety, and metabolism, many of which also influence reproductive health.
Certain amino acids and bioactive peptides from protein digestion stimulate the release of hormones like glucagon-like peptide-1 (GLP-1) and cholecystokinin (CCK), which help support nutrient absorption, energy balance, and hormonal communication between organs. In other words, dietary protein acts as a powerful signal that keeps your endocrine system running smoothly.
2. Protein’s role in fertility and egg/sperm quality
When it comes to fertility, protein provides the raw materials (amino acids) your body needs to make hormones like estrogen and progesterone, which regulate ovulation and support a healthy menstrual cycle.
Protein also fuels the enzymes and cellular processes that allow an egg to mature, a sperm to fertilize it, and an embryo to successfully implant in the uterus. Amino acids like cysteine and arginine play key roles in protecting developing eggs from oxidative stress and preparing the uterine lining for implantation.
3. Protein and fetal development
Once you become pregnant, your protein needs increase significantly. Research shows that balanced protein intake supports healthy birth weight, reduces the risk of growth restriction, and promotes optimal placental development.
Balance is key as too little protein can impair fetal growth while excessive amounts may disrupt amino acid metabolism.
Certain amino acids are especially vital during pregnancy:
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Glycine and proline (found abundantly in collagen and bone broth) support fetal tissue development, placental formation, and maternal tissue repair. These become conditionally essential because the body’s production often does not meet the increased demands with fetal tissue growth, placental formation, and maternal tissue repair.
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Arginine helps improve blood flow and placental function through nitric oxide production.
How do protein needs increase during preconception and pregnancy
Research shows that women need more protein during preconception and pregnancy than previously thought. As your body prepares for and supports a growing baby, protein becomes the foundation for nearly every major physiological change.
As pregnancy progresses, protein needs rise steadily to support the expansion of maternal tissues (like blood volume, uterus, and breast tissue), the growth of the placenta, and the baby’s rapidly developing organs.
Older guidelines once recommended around 60 grams of protein per day, however, newer studies show that most women benefit from significantly more.
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Early pregnancy: about 1.2 g/kg/day
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Third trimester: up to 1.5 g/kg/day
That often translates to roughly 70–100 grams of protein per day, depending on your body weight and activity level.
RELATED: Why Protein Matters for Fertility, Pregnancy, and Postpartum Recovery
What is whey protein powder and why does it matter for fertility and pregnancy?
When milk is curdled and strained, the liquid left behind, called whey, is filtered and dried into a concentrated protein. The result is whey protein powder, one of the most complete and bioavailable protein sources available.
Whey naturally contains all nine essential amino acids, including branched-chain amino acids (BCAAs) like leucine, which play a key role in muscle repair, hormone production, and tissue growth, all crucial processes during fertility preparation, pregnancy, and postpartum recovery.
Because whey is rapidly digested and highly bioavailable, it efficiently delivers amino acids to your body where they’re needed most, whether that’s repairing cells, balancing blood sugar, or supporting your baby’s growth.
Whey protein comes in three forms: concentrate, isolate, and hydrolysate. Each form differs in processing, protein content, lactose levels, absorption rate, and optimal use.
Types of whey protein: Which one is right for you?
The research: Benefits of whey protein for fertility and pregnancy
For fertility:
Balanced blood sugar and hormone health are at the heart of fertility and this is where whey protein shines.
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Supports blood sugar balance and ovulation: Whey protein helps support optimal blood sugar by slowing the absorption of glucose into the bloodstream and stimulating insulin release in a controlled way. This helps prevent sharp spikes and crashes in blood sugar, keeping energy steady and supporting proper hormone signaling for ovulation.
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Improves insulin sensitivity: the amino acids in whey, particularly leucine, can improve insulin sensitivity, making the body more efficient at using glucose which is key for women with PCOS or hormonal imbalances
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Promotes hormone regulation: Whey provides essential amino acids like leucine and cysteine for reproductive hormone regulation needed for regular menstrual cycles and successful conception.
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Maintains a healthy metabolism and body composition: Adequate protein also helps maintain a healthy weight and metabolism, support lean muscle mass and efficient energy use which are all factors linked to better fertility outcomes.
For pregnancy:
Once you’re pregnant, your protein needs rise dramatically and high-quality whey protein can help you meet those increased demands.
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Supports healthy weight gain and fetal growth: Protein provides the amino acids your body needs to expand blood volume, build new tissue, and form your baby’s muscles, organs, and placenta.
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Preserves lean muscle mass: Maintaining muscle supports energy, metabolism, and physical strength to prepare the body for labor and postpartum recovery.
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Boosts antioxidant protection: Whey is rich in cysteine, a precursor to glutathione, the body’s most powerful antioxidant. Glutathione protects cells from oxidative stress, including egg and sperm. Research shows that glutathione levels are often lower in women with pregnancy complications such as preeclampsia. Including high-quality whey in the diet may help support optimal antioxidant status during pregnancy and in turn, could play an important role in reducing oxidative stress and lowering the risk of hypertensive disorders and poor maternal-fetal outcomes.
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Promotes healthy placental function: Research shows that meeting increased protein needs during pregnancy is vital for supporting fetal survival, growth, and healthy development and better birth outcomes.
Including a clean, third-party-tested whey protein powder can be an easy and safe way to fill nutrient gaps, especially when appetite changes, nausea, or food aversions make it hard to meet protein goals through food alone.
RELATED: Pregnancy cravings, aversions & the role of protein
Whey protein vs. plant-based protein powders: Which is better?
Both whey and plant-based proteins can be beneficial—what matters most is quality, digestibility, and ingredient transparency.
Hidden risks: Heavy metals in protein powders
When choosing a protein powder, quality matters. Independent testing from organizations like the Clean Label Project and Consumer Reports has revealed that many commercial protein powders, especially some plant-based varieties, contain measurable levels of heavy metals such as lead, cadmium, arsenic, and mercury.
These contaminants can come from soil, water, or manufacturing processes and may accumulate in the body over time. Even trace amounts can pose concerns, especially during the delicate stages of conception and pregnancy.
Heavy metals pose particular concern for fertility and pregnancy because of their neurotoxic, oxidative stress, and endocrine-disrupting effects, interfering with the body’s natural hormone balance.
Even low-level exposure may impact egg and sperm quality, interfere with menstrual regularity, thyroid health, can mimic hormone function, and negatively impact fetal brain development. Reducing overall toxic burden is important for both partners in supporting optimal fertility and pregnancy outcomes.
The good news: with the right product, you can enjoy all the benefits of protein without the hidden risks. Here’s what to look for:
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Third-party testing: Choose brands that test for heavy metals, contaminants, and label accuracy, and make their results publicly available.
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Transparent sourcing: Look for grass-fed whey or plant proteins grown in clean, low-contamination soils.
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Clean ingredients: Avoid artificial sweeteners, gums, or synthetic flavorings that can add unnecessary chemical load.
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Simple formulas: Fewer ingredients often mean fewer potential contaminants.
RELATED: WeNatal Protein +: A 3-in-1 fertility and pregnancy support formula
A note from WeNatal on the importance of protein for pregnancy and fertility
From the earliest stages of preconception through postpartum recovery, your body relies on high-quality protein support every part of the reproductive journey. It fuels hormone production, promotes egg and sperm health, builds the placenta, and aids in tissue repair after birth.
During pregnancy and breastfeeding, your body’s protein demands climb even higher to sustain energy, expand blood volume, and support breastmilk production. Meeting those needs with clean, bioavailable sources can make all the difference in how you feel and how your body functions.
WeNatal Protein + was designed with these critical needs in mind to make it simple, safe, and effective to meet protein needs. Each serving combines 20 g of complete protein from grass-fed whey and collagen peptides with key vitamins and minerals found in our WeNatal prenatal supplement, without unnecessary fillers, sweeteners, or artificial additives.
Every batch is third-party tested for purity and safety, ensuring you get highly bioavailable amino acids to support reproductive health and your fertility journey. The result is a science-backed, delicious, and convenient protein blend that supports:
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Reproductive health for both partners
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Optimal fetal development
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Maternal energy, tissue repair, and recovery
Because at WeNatal, we believe the journey to parenthood isn’t just about her or him, it’s about both of you. WeNatal Protein + helps you nourish that journey from the very beginning.
References
Elango R, Ball RO. Protein and Amino Acid Requirements during Pregnancy. Adv Nutr. 2016;7(4):839S-44S. Published 2016 Jul 15. doi:10.3945/an.115.011817
Herring CM, Bazer FW, Johnson GA, Wu G. Impacts of maternal dietary protein intake on fetal survival, growth, and development. Exp Biol Med (Maywood). 2018;243(6):525-533. doi:10.1177/1535370218758275
Iftikhar A, Azam H, Ahmed M, et al. Effect of balanced protein-energy supplementation given to pregnant women on birth outcomes: A systematic review and meta-analysis. Womens Health (Lond). 2025;21:17455057251335366. doi:10.1177/17455057251335366
Lee S, Min JY, Min KB. Female Infertility Associated with Blood Lead and Cadmium Levels. Int J Environ Res Public Health. 2020;17(5):1794. Published 2020 Mar 10. doi:10.3390/ijerph17051794
López-Botella A, Velasco I, Acién M, et al. Impact of Heavy Metals on Human Male Fertility-An Overview. Antioxidants (Basel). 2021;10(9):1473. Published 2021 Sep 15. doi:10.3390/antiox10091473
Mignone LE, Wu T, Horowitz M, Rayner CK. Whey protein: The "whey" forward for treatment of type 2 diabetes?. World J Diabetes. 2015;6(14):1274-1284. doi:10.4239/wjd.v6.i14.1274
Minich DM, Brown BI. A Review of Dietary (Phyto)Nutrients for Glutathione Support. Nutrients. 2019;11(9):2073. Published 2019 Sep 3. doi:10.3390/nu11092073
Moon J, Koh G. Clinical Evidence and Mechanisms of High-Protein Diet-Induced Weight Loss. J Obes Metab Syndr. 2020;29(3):166-173. doi:10.7570/jomes20028
Sepandi M, Samadi M, Shirvani H, et al. Effect of whey protein supplementation on weight and body composition indicators: A meta-analysis of randomized clinical trials. Clin Nutr ESPEN. 2022;50:74-83. doi:10.1016/j.clnesp.2022.05.020
Yanagisawa Y. How dietary amino acids and high protein diets influence insulin secretion. Physiol Rep. 2023;11(2):e15577. doi:10.14814/phy2.15577
