Weight Gain

Ah, pregnancy. That time in your life when not only is it okay to pack on a few extra pounds, it’s actually encouraged! For some of us, it’s hard to know how much weight gain is “normal” during pregnancy, and how much (or how little) might be considered unhealthy for mom and baby.

How much weight should I expect to gain?

For a healthy mother who maintained a normal weight before pregnancy, the average weight gain is between 25 and 35 pounds throughout the pregnancy. About two to four pounds are typically gained during the first trimester, and then an average of about one to two pounds per week during the second and third trimesters. A woman who was very thin when she became pregnant might need to gain an extra five pounds or so to ensure a healthy pregnancy, while a woman who was overweight should aim to gain a total of 15-25 pounds (or about half a pound per week after the first trimester).

What is all that weight, anyway?

That’s an excellent question. With the average newborn tipping the scales at just 7.5 pounds, why does the mother need to gain as much as four times that amount? Here’s the breakdown of where you’ll be carrying that extra poundage:

  • Placenta: 1.5 pounds
  • Extra fluid in mom’s body: 4 pounds
  • Uterus: 2 pounds
  • Extra breast tissue: 2 pounds
  • Extra blood volume: 4 pounds
  • Amniotic fluid: 2 pounds
  • Extra storage of protein, fat and other nutrients: 7 pounds
  • Baby: 7.5 pounds

Why does the amount of weight gain matter so much?

You want to try to aim for a number close to the recommended range for weight gain during pregnancy. Gaining too little weight increases the risk of preterm birth and low birth weight. Gaining more weight than recommended increases the risk of:

  • A very large baby
  • Delivery complications
  • Unplanned C-section
  • Childhood obesity
  • Mother’s obesity later in life

For more information on the motherhood wellness journey, visit BayCare's Motherhood Wellness Program.