What should be my weight gain during pregnancy?

    Health and weight    Expected weight gain

Gaining weight when you are pregnant is perfectly natural, it is even recommended for the health of your baby.

Use the Rosso curves to calculate your ideal weight and your expected weight gain

A widely used indicator in nutrition research is the Ideal Weight. It is calculated according to the formula of Lorentz (the scientist who established it). You can use our instant calculator to calculate your Ideal Weight:

in (e.g.: 64 if you measure 64 inches or 5ft4)
cm (e.g.: 165 if you measure 1m65)
Your ideal weight before pregnancy is: kg

Your expected weight gain

Based on the ideal weight and the actual weight before pregnancy, we can then use the Rosso curves to determine your theoretical weight gain during pregnancy. The Rosso curves have the advantage of giving a much more precise indication of how the weight gain should be spread during the pregnancy (which is not the case of the BMI that only gives you the end target):

  • In summary, it is worth noting that the weight at the end of the pregnancy should reach around 120% of the ideal weight before pregnancy for women whose initial weight is comprised between 70 and 105% of their ideal weight.
  • If the mother-to-be was overweight before the pregnancy, she should in principle gain less weight than a mother-to-be who was normal or underweight.
(in cm, e.g.: 165 if you measure 1m65)
(in kg, e.g : 61.4 if you weigh 61kg400)
(in kg, e.g : 61.4 if you weigh 61kg400)
Weeks of pregnancy  40
Ideal weight   kg   lb
% W/IW   %
Weight in a given week of pregnancy   kg   lb
Expected end weight   kg   lb
Weight gain in a given week of pregnancy  0 kg  0 lb
Expected end weight gain   kg   lb

Your personalised weight gain curve


Do not hesitate to register to keep track of your results and monitor the progression of your weight during your pregnancy.

How should the weight gain be spread during the 9 months of pregnancy?

Disclaimer/Source: Adapted from several serious sources and more specifically from an article from The American Journal of Clinical Nutrition: “A new chart to monitor weight gain during pregnancy” (P. Rosso, MD)