Macros During Pregnancy — What Changes by Trimester

Pregnancy does not rearrange the percentages. It raises two fixed gram figures and, from the second trimester on, the calorie total they sit inside. Enter your calories — with the trimester increase already included — to see the split in grams.

The extra calories depend on where you started

The first trimester adds nothing. The current US reference — the 2023 Dietary Reference Intakes for Energy — is explicit that first-trimester weight gain is “minor and therefore not considered here,” so the addition begins in the second trimester and is scaled to pre-pregnancy BMI:

Pre-pregnancy BMI category	Added energy, 2nd and 3rd trimesters
Underweight	about +300 kcal/day
Healthy weight	about +200 kcal/day
Overweight	about +150 kcal/day
Obesity	about −50 kcal/day

Each figure is derived from the recommended rate of weight gain for that category — 73, 60, 40 and 31 grams a day respectively — and the last one is negative on purpose, because the framework expects existing stores to be mobilized rather than new tissue deposited.

If you have seen +340 and +452, those are the older numbers. They come from the 2005 edition, which applied one flat addition to everyone, and they are still repeated widely — MedlinePlus currently publishes about 340 extra calories in the second trimester and around 450 in the last. Expect to meet them; they are not what the current reference says. The healthy-weight figure is now roughly 200, which is a glass of milk and a piece of fruit rather than an extra meal.

This calculator does not add any of that for you. Work out your total daily requirement first — BMR during pregnancy covers the baseline and the deposition on top of it, and the pregnancy BMI calculator tells you which row above applies — then enter the finished total here.

Two numbers that genuinely move

Reference	Non-pregnant adult woman	Pregnancy	Lactation
Carbohydrate RDA	130 g/day	175 g/day	210 g/day
Protein RDA	46 g/day	71 g/day	71 g/day

Both are allowances in grams, not shares of calories, and both are set by the Food and Nutrition Board. The carbohydrate figure rises because the fetal brain draws on maternal glucose; the protein figure rises to build fetal tissue, placenta and maternal stores.

Note how the 71 g figure travels: it is also the protein Daily Value that US labeling rules assign to pregnant and lactating women, which is why a prenatal product’s “percent daily value” is calculated against a different denominator than the 50 g used for everyone else.

The percentages stay where they were

Carbohydrate 45 to 65 percent, fat 20 to 35, protein 10 to 35. A 2,200-calorie day at 50 percent carbohydrate is 275 g — well past the 175 g allowance, which tells you the allowance is a floor and not a target. The same is true of protein: 20 percent of 2,200 calories is 110 g, comfortably above 71.

In other words, an ordinary balanced split already clears both raised minimums. The failure mode in pregnancy is rarely an unfavorable ratio; it is nausea, aversions and an eating pattern that collapses to crackers for several weeks.

What is different, and what to avoid

The 2025–2030 Dietary Guidelines put “iron, folate, and iodine as top priorities” during pregnancy and point to iron-rich meats, folate-rich greens and legumes, choline-rich eggs, calcium-rich dairy and low-mercury omega-3 seafood such as salmon, sardines and trout, alongside a conversation with your clinician about a daily prenatal vitamin. Not one of those items is a macro, and the split will never flag any of them.

On the other side, ketogenic diets are explicitly not recommended in pregnancy: severe carbohydrate restriction has not been shown safe for fetal growth and raises the risk of nutrient gaps. If gestational diabetes puts carbohydrate under management, the numbers come from the prenatal team — not from a calculator, and not from a low-carb plan you ran before conceiving.

For the general split and the ranges behind it, see the macro calculator, and for the two-step method of setting protein in grams first, the macro calculator for women. The carbohydrate line on its own is covered in the daily carb calculator.

This content is informational and does not replace the care of the clinician managing your pregnancy.