The Official Guidelines for Healthy Pregnancy Weight Gain

Watching the number on the scale climb higher and higher can be a difficult psychological hurdle for many pregnant women. Society places intense pressure on women to "only gain a cute bump" and to bounce back immediately postpartum.

However, gaining a significant amount of weight during pregnancy is not just normal—it is biologically mandatory for the health of your baby.

Where Does the Weight Go?

If a woman gains the recommended 30 pounds during a singleton pregnancy, almost none of that weight is "unnecessary fat." Here is the literal breakdown of what you are carrying by the third trimester:

The Baby: ~7.5 lbs
Increased Blood Volume: ~4 lbs
Increased Tissue Fluid: ~4 lbs
Uterus Growth: ~2 lbs
Placenta: ~1.5 lbs
Amniotic Fluid: ~2 lbs
Breast Tissue: ~2 lbs
Maternal Fat Stores (for breastfeeding energy): ~7 lbs

As you can see, over 20 pounds of the weight is purely the baby and its life-support system!

How Much Should You Gain?

There is no single number that applies to every woman. The Institute of Medicine (IOM) guidelines are based entirely on your Pre-Pregnancy Body Mass Index (BMI).

Underweight (BMI < 18.5): Should gain 28 - 40 lbs.
Normal Weight (BMI 18.5 - 24.9): Should gain 25 - 35 lbs.
Overweight (BMI 25.0 - 29.9): Should gain 15 - 25 lbs.
Obese (BMI ≥ 30.0): Should gain 11 - 20 lbs.

To find out exactly what your BMI is and what your target range should be, use our Pregnancy Weight Gain Calculator.

The Trimester Pacing

You are not supposed to gain this weight evenly. During the first trimester, the baby is only the size of a peach. You only need to gain 1 to 5 pounds total during these first 13 weeks.

It is during the second and third trimesters that the weight gain ramps up. Depending on your BMI category, you should aim to steadily gain about 0.5 to 1 pound per week until delivery.

Track your health accurately: Try our free Pregnancy Weight Gain Calculator to get instant, personalized medical math for your pregnancy journey.