Pound for Pound

How much weight gain is OK in Pregnancy?

That is the magical, mystical question. I can assure you that there is no perfect number I can give you. I can also assure you that whatever preconceived notions you have about what you will and will not gain can go right out of the window.

I have seen morbidly obese women LOSE weight throughout the pregnancy and give birth to perfect, healthy babies and walk away from the experience thinner than they have been in years. I have also seen model thin, skinny minnies balloon up 50+ pounds, have perfect deliveries, and fit back into their True Religions within six months of giving birth.

To truly understand weight gain in pregnancy - let's look at where it goes.  In a weight gain of 29 pounds, the average breakdown is as follows:

• Blood Volume Expansion - 3 pounds
• Breasts - 2 pounds
• Uterus - 2 pounds
• Baby - 7.5 pounds
• Placenta - 1.5 pounds
• Amniotic Fluid - 2 pounds
• Fat, Protein, and other Nutrients - 7 pounds
• Retained Water - 4 pounds

Of course, these are just AVERAGES, and these individual totals may vary. What I generally tell my patients who are of average weight/BMI is, "the first 20 pounds are free, the rest you have to work at."  It seems to be a good rule of thumb for most. 

Of course, there are guidelines - and they should be followed as much as possible. 


If you began pregnancy at a normal weight, you should gain 25–35 pounds over the nine months. Assuming you gain between 1 and about 4 ½ pounds in the first trimester, you should put on about one pound every week in the second and third trimesters

If you began pregnancy underweight, you should probably gain a little more. That's because underweight women are more likely to have small babies. A 28- to 40-pound gain is usually recommended. Assuming you gain between 1 and about 4 ½ pounds in the first trimester, try to gain slightly over a pound a week in the second and third trimesters.

If you began pregnancy overweight, you should gain only 15–25 pounds over the nine months. Assuming you gain between 1 and about 4 ½ pounds in the first trimester, you should put on slightly over ½ pound every week in the second and third trimesters. While you don't want to gain too much weight, you should never try to lose weight during pregnancy because that could harm your baby.

If you were obese at the start of your pregnancy, you should gain only 11–20 pounds over the nine months. Assuming you gain between 1 and about 4 ½ pounds in the first trimester, aim for gaining slightly under ½ pound every week in the second and third trimesters.

If you're expecting twins and began pregnancy at a normal weight, you should probably gain between 37-54 pounds over the nine months. If you began pregnancy overweight, aim for gaining a total of 31-50 pounds. If you were obese at the start of your pregnancy, you should gain between 25-42 pounds over the nine months. That translates into about 1 ½ pounds a week in the last two trimesters.

To find out if you were underweight or overweight before pregnancy, learn your Body Mass Index (BMI). BMI is a measure of body fat based on height and weight.

Putting on weight slowly and steadily is best. But don't worry if you gain less than four pounds in the first trimester, and make up for it later, or vice versa. Also, many women have one or two "growth spurts" during which they gain several pounds in a short time period, and then level off. Again, this is not worrisome unless it becomes a pattern. The important thing is to keep an eye on your overall gain. You can use the weight-gain tracking chart to follow your progress.