"You are eating for two" is one of the most repeated, least precise pieces of pregnancy advice out there. The real answer to how much weight should you gain during pregnancy depends heavily on where you started.
Why One Number Does Not Fit Everyone
The Institute of Medicine, whose guidelines are widely referenced by ACOG and the CDC and used by many prenatal care providers, sets different recommended total weight gain ranges based on pre-pregnancy BMI. The reasoning is straightforward: someone starting at a higher or lower body weight carries different health considerations around gaining too much or too little.
The Recommended Ranges
- Underweight (BMI under 18.5): 28 to 40 pounds total
- Normal weight (BMI 18.5-24.9): 25 to 35 pounds total
- Overweight (BMI 25-29.9): 15 to 25 pounds total
- Obese (BMI 30 and above): 11 to 20 pounds total
These figures apply to singleton pregnancies. Twin and multiple pregnancies call for higher targets, set individually by your doctor.
How Gain Typically Breaks Down by Trimester
Most of the total gain happens in the second and third trimesters rather than the first. A common pattern is a modest 1 to 5 pounds in the first trimester, followed by a steadier weekly rate, roughly 1 pound a week for those starting at a normal BMI, and somewhat less for those starting at a higher BMI.
What If You Are Off Track?
A single week of faster or slower gain is normal and not something to worry over. Weight gain during pregnancy naturally fluctuates. What matters more is the overall trend over several weeks, which is exactly the kind of thing your prenatal appointments are designed to catch.
The Bottom Line
Healthy weight gain during pregnancy is a range, not a single target, and it depends on where you started. Use the guidelines as a general compass, and let your doctor's guidance take priority for your specific situation.
This article is for general informational purposes and is not a substitute for advice from a qualified healthcare provider.
Frequently Asked Questions
What happens if I gain more than the recommended range?
It is worth discussing with your doctor, since gain patterns outside the typical range can sometimes be associated with additional considerations for delivery and recovery, but it does not automatically mean something is wrong.
Do these ranges change for twin pregnancies?
Yes, twin and multiple pregnancies generally have higher recommended total gain, and your doctor will typically provide a specific target for your case.
Is it normal to lose weight in early pregnancy due to nausea?
It happens fairly often and is usually not a major concern if it resolves as the first trimester progresses, but persistent weight loss is worth flagging to your doctor.
Find your recommended range
Get a healthy total weight gain target based on your starting BMI.