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About this tool
Trimester-adjusted protein target from the IOM reference intakes, with extra energy for the stage and the published weight-gain range.
This calculator gives a daily protein target for pregnancy or breastfeeding from the Institute of Medicine Dietary Reference Intakes: 0.8 g per kg in the first trimester, 1.1 g/kg from the second trimester onward, and 1.3 g/kg while breastfeeding — all based on pre-pregnancy weight. The same DRI also states the increase as an extra 25 g a day, and because those two forms do not agree for every body size the tool computes both and reports the higher, naming which basis it used. Alongside the protein figure it shows the IOM's additional energy allowance for the stage and the 2009 gestational weight-gain range for your pre-pregnancy BMI.
Open Pregnancy Protein Intake Calculator on AltFTool — it loads instantly in your browser.
Enter the values you already know.
Fine-tune the options to match your scenario.
Read the result and use it in your planning or reporting.
Shows the 1.1 g/kg calculation and the +25 g/day calculation, and tells you which one set your target.
First trimester correctly gets no protein increase, while energy rises from +340 to +452 kcal across the second and third.
Pairs the protein target with the IOM 2009 gestational weight-gain band for your pre-pregnancy BMI.
The IOM RDA is 1.1 g per kg of pre-pregnancy body weight per day from the second trimester, equivalently about 25 g a day more than before pregnancy. For a 60 kg pre-pregnancy weight that is 66-73 g a day depending on which form of the RDA is used, against 48 g when not pregnant.
No. The IOM added no extra protein for the first trimester because very little new tissue is being deposited at that stage, and it added no extra calories either. Protein and energy needs rise from the second trimester, when fetal growth accelerates.
About 340 kcal a day in the second trimester and 452 kcal a day in the third, with no increase in the first, according to the IOM 2005 energy requirements. While breastfeeding it is around 330 kcal a day in the first six months and 400 kcal after that. These are averages — your midwife or dietitian will adjust for your own weight-gain pattern.
There is no official Dietary Reference Intake for twin pregnancies, so no calculator can give you a defensible number. What the IOM did publish for twins is provisional weight-gain guidance: 17-25 kg for normal pre-pregnancy BMI, 14-23 kg for overweight and 11-19 kg for obese, with no range issued for underweight women. Protein needs are certainly higher than for a singleton — ask your obstetrician or a dietitian to set the target.
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