At the end of pregnancy, what accounts for the majority of weight gained for the expecting mother?

Is how much weight you gain during pregnancy important?

Yes! A healthy weight gain during pregnancy will help you avoid pregnancy complications such as gestational diabetes, preeclampsia, and cesarean delivery.

Determining how much weight to safely gain during pregnancy depends on your pre-pregnancy Body Mass Index (BMI). BMI is a numerical value of your weight in relation to your height. It’s used to determine if an adult is at a healthy weight.

The Centers for Disease Control offers a BMI calculator. Check yours so you know you’re starting point.

Pre-pregnancy weightRecommended weight gain
Source: Institute of Medicine and National Research Council
Underweight (BMI under 18.5) 28 to 40 lbs. (about 13 to 18 kg)
Normal weight (BMI 18.5 to 24.9) 25 to 35 lbs. (about 11 to 16 kg)
Overweight (BMI 25 to 29.9) 15 to 25 lbs. (about 7 to 11 kg)
Obesity (BMI 30 or more) 11 to 20 lbs. (about 5 to 9 kg)

Your health and your baby’s health also play a role. Talk with your health care provider about what weight gain is right for your pregnancy

Where does pregnancy weight go?

Your baby might weigh in at 7 or 8 pounds (about 3 to 3.6 kilograms). That accounts for some of your pregnancy weight gain. What about the rest? Here’s a sample breakdown:

  • Larger breasts: 1 to 3 pounds (about 0.5 to 1.4 kilogram)
  • Larger uterus: 2 pounds (about 0.9 kilogram)
  • Placenta: 1 1/2 pounds (about 0.7 kilogram)
  • Amniotic fluid: 2 pounds (about 0.9 kilogram)
  • Increased blood volume: 3 to 4 pounds (about 1.4 to 1.8 kilograms)
  • Increased fluid volume: 2 to 3 pounds (about 0.9 to 1.4 kilograms)
  • Fat stores: 6 to 8 pounds (about 2.7 to 3.6 kilograms)

Putting on pounds during pregnancy

A pregnant woman of normal weight, who gets less than 30 minutes of exercise a week should strive for a caloric intake of:

  • 1,800 during the first trimester
  • 2,200 during the second trimester
  • 2,400 during the third trimester

These calories should be attained by eating a diet of grains, dairy, protein, fruits/vegetables, and healthy fats and oils.
Limiting processed foods, sugars and extra fats can help you attain your goals.

Average Pregnancy Weight Gain Chart

  • 7 1/2 pounds is about how much the baby will weigh by the end of pregnancy.
  • 1 1/2 pounds is how much the placenta weighs.
  • 4 pounds is attributed to increased fluid volume.
  • 2 pounds is the weight of the uterus.
  • 2 pounds is the weight of breast tissue.
  • 4 pounds is because of increased blood volume.
  • 7 pounds is attributed to maternal stores of fat, protein, and other nutrients.
  • 2 pounds for the amniotic fluid.
  • Total: 30 pounds

On a trimester basis in a woman with normal pre-pregnancy weight:

  • First trimester: 1-4.5 pounds
  • Second trimester: 1-2 pounds per week
  • Third trimester: 1-2 pounds per week

Remember this is just an average; you and your health care provider need to decide what is best for you.

Want to Know More?

  • Eating for Two When Over or Under Weight
  • Pregnancy and Eating Disorders
  • Pregnancy Nutrition

Compiled using information from the following sources:
American Congress of Obstetricians and Gynecologists
Institute Of Medicine, Report Brief May 2009, Weight Gain during Pregnancy: Reexamining the Guideline

Mayo Clinic: Pregnancy Weight Gain

Institute of Medicine and National Research Council

What accounts for weight gain in pregnancy?

The placenta, the fetus and amniotic fluid account for about 35% of total weight gain during pregnancy. This weight is lost during childbirth. The rest of the weight gain is due to increased blood volume, water retention, breast tissue and uterine tissue.

What is the largest contributor to weight gain during pregnancy?

Of the total weight gain, the fetus accounts for ~ 27%, amniotic fluid 6%, and the placenta 5%. Maternal tissue accretion contributes mainly with fat deposition (average 27%, although highly variable between women).

What makes up the largest portion of weight gain during pregnancy in the third trimester?

A fetus usually gains the most weight during the third trimester. They will gain an average of 5 lb and grow around 4–6 inches during the third trimester, according to the OWH . In addition to the weight from the growing fetus, the body also gains weight from: the placenta.

Do you gain more weight at the end of pregnancy?

You Stop Gaining Weight At the end of your pregnancy, you might begin losing weight. This is completely normal and won't affect the baby's weight. This weight loss may be due to lower levels of amniotic fluid, more bathroom breaks, and increased physical activity.