Of the many body changes you experience during pregnancy, weight gain is one of the most important. Extra pounds help support your baby’s growth and development from an itty bitty embryo to a newborn ready for life outside the womb.
In addition to the weight of your baby, the placenta, amniotic fluid, breast tissue and increased blood volume also add crucial pounds to your pregnancy weight.[1]
If you’re not sure how much you can expect to gain each week and trimester, this pregnancy weight gain calculator tool can help. But keep in mind that there’s a wide range of what’s considered “normal” when it comes to weight gain during pregnancy.
The total weight you end up gaining will depend on a variety of factors, including your metabolism, activity level, genetics and whether you’re carrying twins or multiples, to name a few.
Remember, this is an educational tool meant to give you a rough idea of how much weight you might gain during your pregnancy, not a substitute for your health care provider’s guidance.
More important than the number on the scale is keeping up with your prenatal appointments. If you’re worried that you’re gaining too slowly or quickly, bring up your concerns with your doctor or midwife. They can help determine whether you’re on track.
How much weight should you gain during pregnancy and what is "normal"?
Pregnancy weight gain isn’t one-size-fits-all. The recommended weight range a mom-to-be should aim for varies depending on her pre-pregnancy weight, body mass index (BMI) and whether she’s expecting multiples.
The tool above can help you calculate your BMI to determine your suggested pregnancy weight gain. But in general, the American College of Obstetricians and Gynecologists (ACOG) recommends[2] the following:
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- Pre-pregnancy BMI is less than 18.5: 28 to 40 pounds
- Pre-pregnancy BMI is 18.5 to 24.9: 25 to 35 pounds
- Pre-pregnancy BMI is 25 to 29.9: 15 to 25 pounds
- Pre-pregnancy BMI is 30 or higher: 11 to 20 pounds
If you're carrying multiples, the recommended weight gain for twins is as follows:
- Pre-pregnancy BMI is less than 18.5: 50 to 62 pounds
- Pre-pregnancy BMI is 18.5 to 24.9: 37 to 54 pounds
- Pre-pregnancy BMI is 25 to 29.9: 31 to 50 pounds
- Pre-pregnancy BMI is 30 or higher: 25 to 42 pounds
See the breakdown in this pregnancy weight gain chart:
Using BMI as a gauge for weight gain of any kind has become controversial in recent years, and some experts believe it’s a flawed way of tracking a person’s health.
However, because ACOG, the Centers for Disease Control and Prevention (CDC), and various other medical and health experts still quantify pregnancy weight gain using pre-pregnancy BMI, our pregnancy weight gain calculator incorporates your BMI before pregnancy as a jumping-off point to determine the range for how much weight you may gain while you’re expecting.
Just remember that this tool isn’t meant to replace the advice of your health care provider, and there are a host of factors aside from your pre-pregnancy BMI that contribute to how much weight you may gain during pregnancy, as well as your overall health. Always talk to your health care provider if you have any questions or concerns.
Pregnancy weight gain by week
Your week-by-week pregnancy weight gain will vary depending on your metabolism, activity level and genetics. However, ACOG recommends the following weight gain per week for trimesters two and three:
- Pre-pregnancy BMI is less than 18.5: 1 (1 to 1.3) pounds per week
- Pre-pregnancy BMI is 18.5 to 24.9: 1 (0.8 to 1) pounds per week
- Pre-pregnancy BMI is 25 to 29.9: 0.6 (0.5 to 0.7) pounds per week
- Pre-pregnancy BMI is 30 or higher: 0.5 (0.4 to 0.6) pounds per week
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