This pregnancy weight gain calculator is a handy tool for estimating how much weight you should gain during pregnancy. You can use it to determine the pregnancy weight gain week by week. Remember that these values are only approximate, though - don't worry if your weight gain is a bit faster or slower. In the further part of this article, we will pinpoint what kind of weight fluctuations you should be concerned about.
Expecting a baby? Make sure to check what blood type it will have!
Pregnancy weight gain by week and by trimester
Pregnancy gain depends on two main factors: your prepregnancy BMI and the type of pregnancy (singleton or twin).
- If you were underweight (BMI below 18.5), you should gain between 28 and 40 pounds during your pregnancy.
- If your BMI was normal (18.5–24.9), you should gain between 25 and 35 pounds (and 37 to 54 pounds is you're carrying twins).
- If you were overweight (BMI between 25 and 29.9), you should gain between 15 and 25 pounds (and 31 to 50 pounds for twin pregnancy).
- Finally, if you were obese before the pregnancy (BMI over 30), you should gain between 11 and 20 pounds (25 to 42 pounds during a twin pregnancy).
This weight gain is your target for the 40th week. During your pregnancy, however, you can monitor the changes in your weight as well. The Institute of Medicine of the National Academies suggests a distribution of pregnancy weight gain by week; we built this calculator according to their guidelines so you can check whether your weight is in the recommended range.
During the first trimester, you will probably gain 3-4 pounds in total only - your baby is still tiny, and morning sickness may prevent you from gaining any weight at all. Most of your weight gain will occur during the second trimester. In the third, even though you will still keep gaining weight, the gain will slow down, especially during the ninth month.
How to use the pregnancy weight calculator
- Enter your height and prepregnancy weight into proper boxes.
- The pregnancy weight gain calculator will automatically determine your prepregnancy BMI.
- Mark whether you are expecting twins or not - this will heavily influence your weight gain.
- Choose the week of pregnancy.
- The pregnancy weight gain calculator will determine the minimum and maximum recommended weight gain since the beginning of pregnancy - these values are recommended by The Institute of Medicine of the National Academies. It will also add these values to your initial weight.
How to weigh yourself
First of all, don't stress too much - you don't have to weigh yourself every day. The day-to-day fluctuations, often caused by a bigger dinner the day before, can really drive you crazy! It's enough to weigh yourself once a week. Remember to always do it at the same time of the day, wearing the same amount of clothes, and using the same scale.
What if I gain too much or too little weight?
Don't fret if your weight differs from the recommended one just slightly. Your pregnancy will not follow the "ideal" weight gain distribution. As soon as you approach your target weight, you should be fine. Watch out for the following, though, as these might be some worrying signals:
- Gaining more than three pounds in one week of the second trimester;
- Gaining more than two pounds in one week of the third semester;
- Gaining no weight at all for more than two weeks in a row during months 4-8.
If you are in any of the aforementioned situations, don't forget to consult you doctor.
Take a look at the BSA calculator to get a better understanding of your metabolism, too.