Pregnant women need about 60 grams of protein per day, up from 46 grams for non-pregnant women. That works out to roughly 1.1 grams per kilogram of body weight, compared to 0.8 grams per kilogram before pregnancy. But the increase isn’t uniform across all nine months. Your protein needs stay nearly the same in early pregnancy and rise significantly in the second and third trimesters.
How Needs Change by Trimester
During the first trimester, additional protein needs are minimal, around 1 extra gram per day. Your body is building the placenta and early embryonic structures, but the fetus is still tiny, so the demand on your protein stores is low. The estimated requirement stays close to the non-pregnant value of 0.66 grams per kilogram of body weight per day.
That changes once you hit the second trimester. From week 14 onward, protein needs jump by an average of 21 grams per day, bringing the requirement to about 0.88 grams per kilogram of body weight. This increase holds through the third trimester, when fetal growth accelerates most rapidly. For a woman weighing 150 pounds (68 kg), that translates to roughly 60 grams of protein daily in the later months of pregnancy.
A Simple Way to Calculate Your Target
Rather than relying on a single number, you can personalize the recommendation using your pre-pregnancy weight. Divide your weight in pounds by 2.2 to get kilograms, then multiply by the appropriate factor for your stage of pregnancy:
- First trimester: body weight in kg × 0.8 g (same as before pregnancy)
- Second and third trimesters: body weight in kg × 1.1 g
A 140-pound woman (about 64 kg) would aim for roughly 51 grams in the first trimester and around 70 grams from the second trimester on. These are baseline targets. If you’re very active or carrying multiples, you’ll likely need more.
Protein Needs for Twins or Multiples
Women carrying twins have substantially higher protein requirements. After the 20th week of pregnancy, the Canadian Higgins Nutrition Intervention Program recommends an additional 50 grams of protein per day compared to non-pregnant intake, roughly 25 grams per baby. Some guidelines suggest that 20% of total daily calories should come from protein for twin pregnancies, with higher calorie targets overall (an extra 1,000 calories per day after week 20). If you’re expecting multiples, working with a dietitian to hit these targets can make a real difference in outcomes.
Why Protein Matters for Fetal Development
Protein is the primary structural material for every cell in your baby’s body. Amino acids, the building blocks of protein, are used to construct tissues, synthesize hormones, and produce neurotransmitters that allow the developing brain to form connections. Brain growth in particular depends on a high rate of protein synthesis because protein essentially serves as the structural scaffolding of the brain. The regions most vulnerable to inadequate protein are the cortex, hippocampus, and cerebellum, areas responsible for thinking, memory, and coordination.
Animal research shows that protein deprivation during pregnancy reduces brain size, slows cell maturation, and impairs brain connectivity in offspring. Specific amino acids like leucine and arginine help regulate a signaling pathway that controls how neurons grow in complexity. When those amino acids are missing, the result is fewer connections between brain cells and reduced myelination, the insulating coating that allows nerve signals to travel efficiently.
What Happens When Intake Falls Short
Low maternal protein intake is linked to intrauterine growth restriction (IUGR), a condition where the baby doesn’t grow to a healthy size in the womb. Research on the Dutch famine of 1944-1945 provided stark evidence: women who were malnourished during their second and third trimesters gave birth to babies with reduced weight, shorter length, and smaller head circumference. Beyond birth, IUGR babies face higher neonatal mortality and a greater lifelong risk of metabolic disorders, hormonal imbalances, and cardiovascular disease.
Most women in developed countries get enough protein overall, but intake can dip if nausea limits food variety in the first trimester or if dietary patterns are restrictive. Paying attention to protein becomes especially important from the second trimester onward, when the gap between what you need and what you might casually eat widens.
Best Protein Sources During Pregnancy
Animal proteins like poultry, fish, eggs, and dairy are considered complete proteins because they contain all nine essential amino acids in the proportions your body needs. A 3-ounce serving of chicken breast provides about 26 grams of protein. Two eggs deliver around 12 grams. A cup of Greek yogurt adds roughly 15 to 20 grams.
Plant-based proteins, including lentils, beans, nuts, and whole grains, can meet pregnancy needs but tend to be low in one or more essential amino acids, particularly lysine and threonine. The fix is simple: eat a variety of plant proteins throughout the day. Combining beans with rice, or pairing hummus with whole wheat bread, covers the amino acid gaps without requiring careful meal-by-meal planning.
Globally, plant-based foods supply about 57% of daily protein intake, with meat contributing 18% and dairy 10%. Whether your diet leans plant-based or includes animal products, the key is consistency. Spreading protein across meals rather than loading it into one sitting helps your body absorb and use it more efficiently.
Can You Get Too Much Protein?
There is a ceiling. The World Health Organization has noted that high-protein supplementation during pregnancy does not appear beneficial and may actually be harmful to the fetus. “High-protein” in this context means supplements where protein makes up more than 25% of total energy content. Balanced protein supplementation, where protein accounts for less than 25% of calories, has been shown to promote healthy gestational weight gain and improve outcomes for undernourished women.
For most women eating a normal diet, exceeding protein needs through whole foods is unlikely to cause problems. The risk comes from concentrated protein supplements or extreme high-protein diets that crowd out carbohydrates and fats your body also needs. Keeping protein in the range of 15 to 20% of total calories (or up to 20% for twin pregnancies) is a practical guideline that avoids both deficiency and excess.