Pregnancy Weight Gain: What Is Healthy?
Weight gain is a normal and necessary part of pregnancy. The baby, placenta, amniotic fluid, increased blood volume, breast tissue, and maternal fat stores all contribute. But how much weight should you gain?
Weight Gain by Pre-Pregnancy BMI
The Institute of Medicine (IOM) and ACOG recommend the following weight gain ranges based on pre-pregnancy body mass index (BMI):
| Pre-Pregnancy BMI | Recommended Weight Gain | Second/Third Trimester Rate |
|---|---|---|
| Underweight (< 18.5) | 28-40 pounds | 1-1.3 pounds/week |
| Normal (18.5-24.9) | 25-35 pounds | 0.8-1 pound/week |
| Overweight (25-29.9) | 15-25 pounds | 0.5-0.7 pounds/week |
| Obese (30+) | 11-20 pounds | 0.4-0.6 pounds/week |
Source: Institute of Medicine, Weight Gain During Pregnancy: Reexamining the Guidelines; ACOG Committee Opinion 548.
Where Does the Weight Go?
In a typical pregnancy, weight gain is distributed roughly as follows:
- Baby: 7-8 pounds
- Placenta: 1-2 pounds
- Amniotic fluid: 2 pounds
- Breast tissue: 1-3 pounds
- Increased blood volume: 3-4 pounds
- Increased fluid volume: 2-3 pounds
- Uterus: 2 pounds
- Maternal fat stores: 6-8 pounds
Weight Gain by Trimester
First Trimester (Weeks 1-13)
Most women gain 1-5 pounds total in the first trimester. If you have significant nausea or vomiting, you may lose weight initially. This is usually not a concern if you are able to stay hydrated and eat some calories.
Second Trimester (Weeks 14-27)
Weight gain typically accelerates in the second trimester as nausea fades and appetite returns. Most women gain about 1 pound per week.
Third Trimester (Weeks 28-40)
Weight gain continues at about 1 pound per week, though some women gain more in the final weeks. Growth may slow or plateau in the last 2-3 weeks.
Healthy Weight Gain Tips
- Eat nutrient-dense foods: Choose foods rich in vitamins, minerals, and protein over empty calories.
- Stay hydrated: Drink plenty of water. Thirst is sometimes mistaken for hunger.
- Exercise regularly: Moderate exercise during pregnancy is safe for most women and can help manage weight gain.
- Listen to your body: Eat when you are hungry and stop when you are full.
- Avoid "eating for two": You only need about 300 extra calories per day in the second trimester and 450 in the third.
When to Call Your Clinician
Contact your healthcare provider if:
- You are losing weight in the first trimester (beyond normal nausea)
- You are gaining weight too quickly or too slowly
- You have concerns about your weight or nutrition
- You have a history of an eating disorder