pregnant woman on scale

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Second and third trimester weight gain

It’s very important for women to gain weight at a healthy rate during pregnancy so that they can support growing babies. Don’t be scared when you see the number on the scale creep up - the majority of the change is due to increased blood volume, larger breasts, and water retention, in addition to Baby and Baby-related materials (placenta).

The amount of weight you should gain depends on your starting weight, and the change will be most apparent in the second and third trimesters, so here are some guidelines to follow:

Second trimester

Weight gain in the second trimester is a strong indicator of total weight gain at the end of your pregnancy. These values are based on your pre-pregnancy BMI.

  • BMI less than 18.5: 20 lbs. (9 kg) by the end of second trimester
  • BMI between 18.5 - 24.9: 15 - 20 lbs. (6.8 - 9 kg) by the end of second trimester
  • BMI between 25 - 29.9: 10 lbs. (4.5 kg) by the end of second trimester

Third trimester

Weight gain is greatest during the third trimester as this is the time that Baby also needs to gain more weight, so it's important that you’re gaining enough.

  • BMI less than 18.5: 28-40 lbs (12.7 - 18 kg) total at the end of pregnancy
  • BMI between 18.5 - 24.9: 25-35 lbs (11.3 - 15.9 kg) total at the end of pregnancy
  • BMI between 25 - 29.9: 15-25 lbs (6.8 - 11.3 kg) total at the end of pregnancy
  • BMI 30 or greater: 11-20 lbs (5 - 9 kg) total at the end of the pregnancy

The bottom line

Moms-to-be will definitely gain weight during the second and third trimesters - there’s simply no doubt about it. Baby depends on your healthy weight gain for the baby fat she needs to pack on during the last few months, so make sure to get all of the calories you’ll need to facilitate a healthy weight gain. If you have concerns about your weight at any point throughout your pregnancy, your healthcare provider can advise you on a healthy goal for you.


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Sources
  • "Weight Gain During Pregnancy: Number 548." ACOG. American College of Obstetricians and Gynecologists, 1/13/2015. Web.
  • "Weight gain during pregnancy." March of Dimes. March of Dimes, Sept. 2009. Web.
  • "Weight Gain During Pregnancy: Number 548." ACOG. American College of Obstetricians and Gynecologists, 1/13/2015. Web.
  • Mayo Clinic Staff. "Pregnancy weight gain: What's healthy?" Mayo Clinic. Mayo Clinic, 3/4/2014. Web.
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